SSL backend error when using OpenSSL

SSL backend error when using OpenSSL - python

I was trying to install pycurl in a virtualenv using pip and I got this error
ImportError: pycurl: libcurl link-time ssl backend (openssl) is different from compile-time ssl backend (none/other)
I read some documentation saying that "To fix this, you need to tell setup.py what SSL backend is used" (source) although I am not sure how to do this since I installed pycurl using pip.
How can I specify the SSL backend when installing pycurl with pip?
Thanks

for most people
After reading their INSTALLATION file, I was able to solve my problem by setting an environment variable and did a reinstall
# remove existing `pycurl` installation
pip uninstall pycurl
# export variable with your link-time ssl backend (which is openssl above)
export PYCURL_SSL_LIBRARY=openssl
# then, re-install `pycurl` with **no cache**
pip install pycurl --no-cache-dir
There could be other solution out there but this works perfectly for me on a virtualenv and pip installation.
Some people have a different error message complaining about nss instead of openssl
ImportError: pycurl: libcurl link-time ssl backend (nss)
(the key part is nss) so you have to do something different for this error message:
pip uninstall pycurl
pip install --no-cache-dir --compile --compile-options="--with-nss" pycurl

helloworld2013's answer is correct, but the key is matching the SSL library that pycurl is expecting. The error will be something like:
pycurl: libcurl link-time ssl backend (<library>) is different from compile-time ssl backend (<library> or "none/other")
To fix it, you have to use the library pycurl is expecting. In my case, my error was "pycurl: libcurl link-time ssl backend (nss) is different from compile-time ssl backend (openssl)", so my fix was:
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=nss
pip install pycurl

With macOS 10.13, a brew-installed openSSL, and virtualenv, I was successful with:
# cd to your virtualenv, then…
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=openssl
export LDFLAGS=-L/usr/local/opt/openssl/lib
export CPPFLAGS=-I/usr/local/opt/openssl/include
pip install pycurl --compile --no-cache-dir

With pip 7.1 you can put the following in your requirements file:
pycurl==7.19.5.1 --global-option="--with-nss"
Simply replace nss with the relevant ssl backend library.

The method to fix the pycurl after Mac OS High Sierra update:
Reinstall the curl libraries to use OpenSSL instead of SecureTransport
brew install curl --with-openssl
Install pycurl with correct build-time environment and paths
export PYCURL_SSL_LIBRARY=openssl
pip uninstall pycurl
pip install --no-cache-dir --global-option=build_ext --global-option="-L/usr/local/opt/openssl/lib" --global-option="-I/usr/local/opt/openssl/include" --user pycurl

This worked for me:
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=nss
easy_install pycurl
None of this worked for me (note the difference is simply easy_install vs pip):
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=[nss|openssl|ssl|gnutls]
pip install pycurl
#xor
curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.19.3.1.tar.gz
#...
python setup.py --with-[nss|openssl|ssl|gnutls] install

I had this problem for days. Finally with the help of other answers here (mainly Alexander Tyapkov's) I got it working for AWS Elastic Beanstalk.
Manual install (connecting with SSH):
sudo pip uninstall pycurl
curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
sudo pip install pycurl-7.43.0.tar.gz --global-option="--with-nss"
IMPORTANT: Please note that you have to make sure you are using the currect version of Python and PIP, otherwise you might be compiling it for Python 2.x and using v3.x.
Auto-install in Elastic Beanstalk:
files:
"/usr/local/share/pycurl-7.43.0.tar.gz" :
mode: "000644"
owner: root
group: root
source: https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
commands:
01_download_pip3:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
command: 'curl -O https://bootstrap.pypa.io/get-pip.py'
02_install_pip3:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
command: 'python3 get-pip.py'
03_pycurl_uninstall:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
command: '/usr/bin/yes | sudo pip uninstall pycurl'
04_pycurl_download:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
command: 'curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz'
05_pycurl_reinstall:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
command: 'sudo pip install pycurl-7.43.0.tar.gz --global-option="--with-nss"'
container_commands:
09_pycurl_reinstall:
# run this before PIP installs requirements as it needs to be compiled with OpenSSL
# the upgrade option is because it will run after PIP installs the requirements.txt file.
# and it needs to be done with the virtual-env activated
command: 'source /opt/python/run/venv/bin/activate && pip3 install /usr/local/share/pycurl-7.43.0.tar.gz --global-option="--with-nss" --upgrade'
I had this problem because I was trying to configure Celery 4 with Django 1.10 in Elastic Beanstalk. If that's your case, I wrote a full blog post about it.

I'm on CentOS 7. I tried all of the above and couldn't get anything to work. It turns out I needed to run these as a root user. So if you're having trouble, try any of the above solutions as a root user. As an example, here is what worked for me:
su -
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=[nss|openssl|ssl|gnutls]
pip install pycurl
Of course, all the usual disclaimers about running as a root user apply.
Note: [nss|openssl|ssl|gnutls] in the code above means to pick one, and don't include the square brackets or pipes. The person who asked the original question would have chosen openssl. In my particular case, I chose nss. Your error message should tell you which choice to make.
2019 Edit: Doing a sudo pip install might cause a problem with the machine's system install of Python. Perhaps try working in a Python virtual environment and install the packages there. If that doesn't work, the sudo trick in my answer is probably one of the last options to consider.

You can download the tar.gz file from here. Then extract it into a folder. You'll find a setup.py file there. Run the command over there that the site mentioned. For example:
python setup.py --with-[ssl|gnutls|nss] install
FYI: I tried to install pycurl at my windows, but I couldn't. But did it on my linux.

I am running this on OS X and some of the above solutions weren't working. Similar to Edward Newell's comment the PYCURL_SSL_LIBRARY variable seemed to have been completely ignored.
Further reading of the PycURL installation doc revealed the following:
pip may reinstall the package it has previously compiled instead of recompiling pycurl with newly specified options
Therefore, I had to force it to compile with:
pip install --compile pycurl
That works on a number of cases. However, I did run into a few systems that continued to ignore the variable so, similar to maharg101's answer, I resorted to the install options which through pip can be set like this:
pip install pycurl --global-option="--with-[ssl|gnutls|nss]"
where you select one of the three options inside the square brackets. Notice that the available option is ssl and not openssl. If you specify --with-openssl you'll get an error. Also note that if you were messing around with the PYCURL_SSL_LIBRARY variable and switching it to funky values to see what would happen this last command will definitely catch it and throw an error if the value is set but not valid.

For anyone having problem inside PyCharm CE on macOS
Mojave this is how i got it working in venv:
specify version: 7.43.0.1
Options: --install-option=--with-openssl --install-option=--openssl-dir=/usr/local/opt/openssl

Reinstallation of curl
I tried every suggestion from this discussion but no one worked for me. As solution I have reinstalled curl and curlib. After that I was able to install pycurl with ssl support inside environment.
At start:
'PycURL/7.43.0 libcurl/7.47.0 GnuTLS/3.4.10 zlib/1.2.8 libidn/1.32
librtmp/2.3'
Part 1.Re/Installation with pip
Firstly I have removed pycurl from virtualenv using pip as was suggested previous answers:
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=openssl
pip install pycurl --global-option="--with-openssl"
The idea here is that package was cached and we just reintstall it with openssl option.
I also tried to recompile pycurl with pip using:
pip install pycurl --compile pycurl --no-cache
..but had the same error after running:
python
import pycurl
pycurl.version
ImportError: pycurl: libcurl link-time ssl backend (gnutls) is
different from compile-time ssl backend (openssl)
Part 2. Installation from tar
After previous method didn't work I have decidede to install pycurl from tar with:
curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
sudo tar -xzvf pycurl-7.43.0.tar.gz
cd pycurl-7.43.0/
sudo python setup.py --with-ssl install
It has installed pycurl globally but not within virtualenv. I also didn't check if it was installed with SSL support or not but think that still without ssl.
Part 3. Reinstallation of curl and curllib
Finally I understood that pycurl doesn't installs normally into environment because global curl and libcurl are compiled with gnutls.
Before starting check it with:
curl-config --configure
One of the output lines will be
'--without-ssl' '--with-gnutls'
To recompile it:
Firstly remove curl:
sudo apt-get purge curl
Install any build dependencies needed for curl
sudo apt-get build-dep curl
Get latest (as of Dec 20, 2016) libcurl
mkdir ~/curl
wget http://curl.haxx.se/download/curl-7.51.0.tar.bz2
tar -xvjf curl-7.51.0.tar.bz2
cd curl-7.51.0
The usual steps for building an app from source
./configure
./make
sudo make install
If openssl installed correctly then configure will find it automatically. The output will be:
curl version: 7.51.0
Host setup: x86_64-pc-linux-gnu
Install prefix: /usr/local
Compiler: gcc
SSL support: enabled (OpenSSL) ...
Resolve any issues of C-level lib location caches ("shared library cache")
sudo ldconfig
Now try to reinstall pycurl within environment:
curl -O https://pypi.python.org/packages/source/p/pycurl/pycurl-7.43.0.tar.gz
pip install pycurl-7.43.0.tar.gz --global-option="--with-openssl"
The result should be:
python
import pycurl
pycurl.version
'PycURL/7.43.0 libcurl/7.51.0 OpenSSL/1.0.2g zlib/1.2.8 librtmp/2.3'

I tried everything here on macOS 10.13 with no success. Then I found https://gist.github.com/webinista/b4b6a4cf8f158431b2c5134630c2cbfe which worked:
brew install curl --with-openssl
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=openssl
export LDFLAGS=-L/usr/local/opt/openssl/lib;export CPPFLAGS=-I/usr/local/opt/openssl/include; pip install pycurl --compile --no-cache-dir
This worked for me both when not using a virtualenv and within a virtualenv.

This worked for me:
pip install --compile --install-option="--with-openssl" pycurl

Not sure if this is because of running in a virtualenv, but on CentOS 7 these solutions weren't working for me; the compiled objects were still being grabbed from the cache dir when I was reinstalling. If you're running into the same problem after trying other solutions here, try the following:
pip uninstall pycurl
export PYCURL_SSL_LIBRARY=[nss|openssl|ssl|gnutls]
pip install pycurl --no-cache-dir

Error:
ImportError: pycurl: libcurl link-time ssl backend (openssl) is different from compile-time ssl backend (none/other)
This worked for me, Mac 10.13, python 3.5, pycurl import worked after installing like this
pip3 uninstall pycurl;
pip3 install --compile --install-option="--with-openssl" pycurl

After being stuck on this for a long time, I found out that apple stopped including OpenSSL headers since OS X 10.11 El Capitan.
how to fix?
1) brew install openssl
2) echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile (or .zshrc for zsh, etc)
3) pip uninstall pycurl
4) pip install --install-option="--with-openssl" --install-option="--openssl-dir=/usr/local/opt/openssl" pycurl

Same problem on amazonlinux - solved
I had this problem while creating a docker image based on amazonlinux, installing python3.7 and adding the pycurl module.
All other python modules were installed correctly except pycurl.
After trying many of the solutions proposed in the threads linked to this problem I finally solved my problem by using following commands for installation of all the pieces.
yum -y install python3 python3-devel gcc libcurl-devel aws-cli openssl-static.x86_64
then installed other modules like psycopg2-binary, requests, certifi using:
pip3 install --user --no-cache-dir -r requirements.txt
and finally installed pycurl module using:
pip3 install --user --global-option="--with-openssl" --no-cache-dir pycurl
and passing here the openssl global option.
The installation of the static library openssl-static.x86_64 solved the problem in my case as using global option used by the second pip3 command.

For python 2.7
sudo apt-get install build-essential libssl-dev libffi-dev python-dev
For python 3.5 also install the next:
sudo apt-get install python3.5-dev
Download the latest pycurl-7.43.0.tar.gz (md5) Source from pypi https://pypi.python.org/pypi/pycurl/7.43.0#downloads
and run the next command:
python setup.py --with-openssl install
Also you can do it into python environment:
(test_env)user#pc:~/Downloads/pycurl-7.43.0$ python setup.py --with-openssl install

pip install -U pip
if [ "$(curl --version | grep NSS 2>/dev/null)" ]; then
pip install --compile --install-option="--with-nss" pycurl
else
pip install --compile --install-option="--with-openssl" pycurl
fi

I encountered this problem and Sanket Jagtap's answer worked for me. I tried the answer with the most votes answer but it did not work.
My openssl old version is 1.0.1t, I think reinstalling openssl may solve this problem.
--- pycurl's openssl backend time....
I rebuilt the latest openssl and tried this answer. Check this out.
pip install --compile --install-option="--with-openssl" pycurl
This worked for me.
i recommend we should reinstall our openssl for try..

Following worked for me with Python3.6
MacOS High-Sierra
sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-openssl" pycurl
CentOS 7
sudo pip3 uninstall pycurl
sudo pip3 install --compile --install-option="--with-nss" pycurl

This link sums up the reason why the errors occur and gives a clear instruction to fix the problem.
https://cscheng.info/2018/01/26/installing-pycurl-on-macos-high-sierra.html
For me, the problem occurred when I upgraded to High-Sierra from El
Captain.

FWIW, I ran into a lot of issues getting this working via AWS Elastic Beanstalk and finally was able to get it working with:
packages:
yum:
openssl-devel: []
libcurl-devel: []
container_commands:
# Reinstall PyCurl with correct ssl backend
05_reinstall_pycurl:
command: |
pip install --upgrade pip
pip uninstall -y pycurl
pip install --global-option='--with-openssl' pycurl

Recently while upgrading a Django project I had the similar error. But this time setting the environment variable did not work. So I had to set both environment variable export PYCURL_SSL_LIBRARY=openssl and pass the flag --global-option="with-openssl".
The original answer was posted on this page

export CPPFLAGS=-I/usr/local/opt/openssl/include
export LDFLAGS=-L/usr/local/opt/openssl/lib
pip install pycurl --global-option="--with-openssl"

Related

Python get-pip.py fails due to site-package not writtable and SSL not available while they seem OK [duplicate]

I've install Python 3.4 and Python 3.6 on my local machine successfully, but am unable to install packages with pip3.
When I execute pip3 install <package>, I get the following SSL related error:
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Collecting <package>
Could not fetch URL https://pypi.python.org/simple/<package>/: There was a problem confirming the ssl certificate: Can't connect to HTTPS URL because the SSL module is not available. - skipping
Could not find a version that satisfies the requirement <package> (from versions: )
No matching distribution found for <package>
How can I fix my Python3.x install so that I can install packages with pip install <package>?

Step by step guide to install Python 3.6 and pip3 in Ubuntu
Install the necessary packages for Python and ssl: $ sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev
Download and unzip "Python-3.6.8.tar.xz" from https://www.python.org/ftp/python/ into your home directory.
Open terminal in that directory and run: $ ./configure
Build and install: $ make && sudo make install
Install packages with: $ pip3 install package_name
Disclaimer: The above commands are not tested in Ubuntu 20.04 LTS.

If you are on Windows and use anaconda this worked for me:
I tried a lot of other solutions which did not work (Environment PATH Variable changes ...)
The problem can be caused by DLLs in the Windows\System32 folder (e.g. libcrypto-1_1-x64.dll or libssl-1_1-x64.dll or others) placed there by other software.
The fix was installing openSSL from https://slproweb.com/products/Win32OpenSSL.html which replaces the dlls by more recent versions.

If you are on Red Hat/CentOS:
# To allow for building python ssl libs
yum install openssl-devel
# Download the source of *any* python version
cd /usr/src
wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
tar xf Python-3.6.2.tar.xz
cd Python-3.6.2
# Configure the build w/ your installed libraries
./configure
# Install into /usr/local/bin/python3.6, don't overwrite global python bin
make altinstall

I had a similar problem on OSX 10.11 due to installing memcached which installed python 3.7 on top of 3.6.
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Spent hours on unlinking openssl, reinstalling, changing paths.. and nothing helped. Changing openssl version back from to older version did the trick:
brew switch openssl 1.0.2e
I did not see this suggestion anywhere in internet. Hope it serves someone.

In Ubuntu, this can help:
cd Python-3.6.2
./configure --with-ssl
make
sudo make install

Agree with the answer by mastaBlasta. Worked for me. I encountered the same problem as the topic description.
Environment: MacOS Sierra. And I use Homebrew.
My solution:
Reinstall openssl by brew uninstall openssl; brew install openssl
According to the hints given by Homebrew, do the following:
echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile
export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"

I had the same issue with python3.8.5 installation on Debian9. I have done a build, but when I have tried to download some modules, pip3.8 issued following error:
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
I have searched for the root of my problem and found out that there is a system dependent portion of the python build which is called by system independent one. In case of missing ssl you just needed to open python terminal and check whether is _ssl present:
>>> help('modules')
.
.
_sre enum pwd wave
_ssl errno py_compile weakref
_stat faulthandler pyclbr webbrowser
.
.
If not your system dependent ssl module part is missing. You can check it also by listing content of <python_installation_root>/lib/python3.8/lib-dynload:
>ls ./lib/python3.8/lib-dynload | grep ssl
_ssl.cpython-38-x86_64-linux-gnu.so
The problem was caused as written by PengShaw by missing libssl-dev during the build. Therefore you have to follow the recommended python installation flow. First install prerequisites and then build and install the python. Installation without devel versions of libs resulted in my case in the missing system dependent part. In this case _ssl.
Note that the devel lib name differs for Debian and CentOS, therefore check whether the installation hints posted on net are suitable for your specific Linux system type:
For Debian:
sudo apt install -y libbz2-dev libffi-dev libssl-dev
./configure --enable-optimizations
make
make altinstall
For CentOS:
sudo yum -y install bzip2-devel libffi-devel openssl-devel
./configure --enable-optimizations
make
make altinstall
It is for sure a good idea to list configuration options prior the configuration and evtl. use some additional options:
./configure --help
Last but not least in case you use --prefix for a non-default installation location, remember to add your <python_installation_root>/lib to your LD_LIBRARY_PATH .

If you are on Windows and use Anaconda you can try running "pip install ..." command in Anaconda Prompt instead of cmd.exe, as user willliu1995 suggests here. This was the fastest solution for me, that does not require installation of additional components.

The problem probably caused by library missing.
Before you install python 3.6, make sure you install all the libraries required for python.
$ sudo apt-get install build-essential checkinstall
$ sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev
More information in How to Install Python 3.6.0 on Ubuntu & LinuxMint

If you are on OSX and have compiled python from source:
Install openssl using brew brew install openssl
Make sure to follow the instructions brew gives you about setting your CPPFLAGS and LDFLAGS. In my case I am using the openssl#1.1 brew formula and I need these 3 settings for the python build process to correctly link to my SSL library:
export LDFLAGS="-L/usr/local/opt/openssl#1.1/lib"
export CPPFLAGS="-I/usr/local/opt/openssl#1.1/include"
export PKG_CONFIG_PATH="/usr/local/opt/openssl#1.1/lib/pkgconfig"
Assuming the library is installed at that location.

Downgrading openssl worked for me,
brew switch openssl 1.0.2s

I encountered the same problem on windows 10. My very specific issue is due to my installation of Anaconda. I installed Anaconda and under the path Path/to/Anaconda3/, there comes the python.exe. Thus, I didn't install python at all because Anaconda includes python. When using pip to install packages, I found the same error report, pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available..
The solution was the following:
1) you can download python again on the official website;
2) Navigate to the directory where "Python 3.7 (64-bit).lnk"is located
3) import ssl and exit()
4) type in cmd, "Python 3.7 (64-bit).lnk" -m pip install tensorflow for instance.
Here, you're all set.

I tried A LOT of ways to solve this problem and none solved. I'm currently on Windows 10.
The only thing that worked was:
Uninstall Anaconda
Uninstall Python (i was using version 3.7.3)
Install Python again (remember to check the option to automatically add to PATH)
Then I've downloaded all the libs I needed using PIP... and worked!
Don't know why, or if the problem was somehow related to Anaconda.

for osx brew users
my issue appeared related to my python installation and was quickly resolved by re-installing python3 and pip. i think it started misbehaving after an OS update but who knows (at this time I am on Mac OS 10.14.6)
brew reinstall python3 --force
# setup pip
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
python3 get-pip.py
# installa pkg successfully
pip install pandas

You can do either of these two:
While installing Anaconda, select the option to add Anaconda to the path.
or
Find these (complete) paths from your installation folder of Anaconda and add them to the environment variable :
\Anaconda
\Anaconda\Library\mingw-w64\bin
\Anaconda\Library\usr\bin
\Anaconda\Library\bin
\Anaconda\Scripts
\anaconda\Library
\anaconda\condabin
Add the above paths to the "Path" system variable and it should show the error no more :)

The ssl module is a TLS/SSL wrapper for accessing Operation Sytem (OS) socket (Lib/ssl.py). So when ssl module is not available, chances are that you either don't have OS OpenSSL libraries installed, or those libraries were not found when you install Python. Let assume it is a later case (aka: you already have OpenSSL installed, but they are not correctly linked when installing Python).
I will also assume you are installing from source. If you are installing from binary (ie: Window .exe file), or package (Mac .dmg, or Ubuntu apt), there is not much you can do with the installing process.
During the step of configuring your python installation, you need to specify where the OS OpenSSL will be used for linking:
# python 3.8 beta
./configure --with-openssl="your_OpenSSL root"
So where will you find your installed OpenSSL directory?
# ubuntu
locate ssl.h | grep '/openssl/ssl.h'
/home/user/.linuxbrew/Cellar/openssl/1.0.2r/include/openssl/ssl.h
/home/user/envs/py37/include/openssl/ssl.h
/home/user/miniconda3/envs/py38b3/include/openssl/ssl.h
/home/user/miniconda3/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.0.2s-h7b6447c_0/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.1.1b-h7b6447c_1/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.1.1c-h7b6447c_1/include/openssl/ssl.h
/usr/include/openssl/ssl.h
Your system may be different than mine, but as you see here I have many different installed openssl libraries. As the time of this writing, python 3.8 expects openssl 1.0.2 or 1.1:
Python requires an OpenSSL 1.0.2 or 1.1 compatible libssl with X509_VERIFY_PARAM_set1_host().
So you would need to verify which of those installed libraries that you can use for linking, for example
/usr/bin/openssl version
OpenSSL 1.0.2g 1 Mar 2016
./configure --with-openssl="/usr"
make && make install
You may need to try a few, or install a new, to find the library that would work for your Python and your OS.

I was having the same issue and was able to resolve with the following steps:
sudo yum install -y libffi-devel
sudo yum install openssl-devel
cd /usr/src
sudo wget https://www.python.org/ftp/python/3.7.1/Python-3.7.1.tar.xz
sudo tar xf Python-3.7.1.tar.xz
cd Python-3.7.1
sudo ./configure --enable-optimizations
# Install into /usr/local/bin/python3.7, don't overwrite global python bin
sudo make altinstall
depending on perms, you may not need sudo.
Results:
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-10.0.1 setuptools-39.0.1
should now be able to run
python3.7 -V
and
pip3.7 -V
When installing packages:
pip3.7 install pandas
or depending on perms, you can also add the --user flag like so:
pip3.7 install pandas --user

In my case with using Mac, I deleted
/Applications/Python 3.7.
because I already had Python3.7 by brew install python3 .
But it was a trigger of the message
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
What I did in my situation
I downloaded macOS 64-bit installer again, and installed.
Double click /Applications/Python3.6/Install Certificates.command and /Applications/Python3.6/Update Shell Profile.command.
Reboot mac
And I am not sure but possibly contributed to succeed is pip.conf. See pip install fails.

I finally solve this issue. These are the detail of my env:
Version of Python to install: 3.6.8
OS: Ubuntu 16.04.6 LTS
Root access: No
Some people suggest to install libssl-dev, but it did not work for me. I follow this link and I fixed it!
In short, I download, extract, build, and install OpenSSL (openssl-1.1.1b.tar.gz). Then, I modify .bashrc file follow this link.
Next, I download and extract Python-3.6.8.tgz. I edit Modules/Setup.dist to modify SSL path (lines around #211). I did ./configure --prefix=$HOME/opt/python-3.6.8, make and make install. Last, I modify my .bashrc. Notice that I do not include --enable-optimizations in ./configure.

I was able to fix this by updating the python version in this file.
pyenv: version `3.6.5' is not installed (set by /Users/taruntarun/.python-version)
Though i had the latest version installed, my command was still using old version 3.6.5
Moving to version 3.7.3

Termux
This worked because i didnt have an existing openssl version installed.
pkg install openssl-tool

If you are on OSX and in case the other solutions didn't work for you (just like me).
You can try uninstalling python3 and upgrade pip3
brew uninstall --ignore-dependencies python3
pip3 install --upgrade pip
This worked for me ;)

(NOT on Windows!)
This made me tear my hair out for a week, so I hope this will help someone
I tried everything short of re-installing Anaconda and/or Jupyter.
Setup
AWS Linux
Manually installed Anaconda 3-5.3.0
Python3 (3.7) was running inside anaconda (ie, ./anaconda3/bin/python)
there was also /usr/bin/python and /usr/bin/python3 (but these were not being used as most of the work was done in Jupyter's terminal)
Fix
In Jupyter's terminal:
cp /usr/lib64/libssl.so.10 ./anaconda3/lib/libssl.so.1.0.0
cp /usr/lib64/libcrypto.so.10 ./anaconda3/lib/libcrypto.so.1.0.0
What triggered this?
So, this was all working until I tried to do a conda install conda-forge
I'm not sure what happened, but conda must have updated openssl on the box (I'm guessing) so after this, everything broke.
Basically, unknown to me, conda had updated openssl, but somehow deleted the old libraries and replaced it with libssl.so.1.1 and libcrypto.so.1.1.
Python3, I guess, was compiled to look for libssl.so.1.0.0
In the end, the key to diagnosis was this:
python -c "import ssl; print (ssl.OPENSSL_VERSION)"
gave the clue library "libssl.so.1.0.0" not found
The huge assumption I made is that the yum version of ssl is the same as the conda version, so just renaming the shared object might work, and it did.
My other solution was to re-compile python, re-install anaconda, etc, but in the end I'm glad I didn't need to.
Hope this helps you guys out.

In the case of using pyenv to manage python installations on Mac OS Catalina, I had to install openssl with brew first and then after that run pyenv install 3.7.8 which seemed to build the python installation using the openssl from homebrew (it even said as such in the installation output). Then pyenv global 3.7.8 and I was away.

On macos, configure python 3.8.1 with the command below will solve the problem, i think it would also work on Linux.
./configure --enable-optimizations --with-openssl=/usr/local/opt/openssl#1.1/
change the dir parameter based on your system.

I've made some PATH changes to mimic part of the Anaconda Powershell Prompt $env:PATH
C:\Users\merheb\Miniconda3;C:\Users\merheb\Miniconda3\Library\mingw-w64\bin;C:\Users\merheb\Miniconda3\Library\usr\bin;C:\Users\merheb\Miniconda3\Library\bin;C:\Users\merheb\Miniconda3\Scripts;C:\Users\merheb\Miniconda3\bin;C:\Users\merheb\Miniconda3\condabin;
And It worked for me.

Building from source was what worked for me on Ubuntu 22.10:
Install OpenSSL manually, tested here with OpenSSL 1.1.1s, extracted then ran:
./config --prefix='/opt/openssl' --openssldir='/opt/ssl'
make
make install
Then with your older Python 3 version (here Python-3.8.16) run:
export LD_RUN_PATH='/opt/openssl/lib'
export CC='gcc-12' # sudo apt install gcc-12
./configure --enable-optimizations \
--with-openssl='/opt/openssl' \
--prefix='/opt/python/3.8' -C
make
make install
Test with:
/opt/python/3.8/bin/python3 -c 'import ssl; print(ssl.OPENSSL_VERSION)'
OpenSSL 1.1.1s 1 Nov 2022

The python documentation is actually very clear, and following the instructions did the job whereas other answers I found here were not fixing this issue.
first, install python 3.x.x from source using, for example with version 3.6.2 https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
make sure you have openssl installed by running brew install openssl
unzip it and move to the python directory: tar xvzf Python-3.6.2.tar.xz && cd Python-3.6.2
then if the python version is < 3.7, run
CPPFLAGS="-I$(brew --prefix openssl)/include" \
LDFLAGS="-L$(brew --prefix openssl)/lib" \
./configure --with-pydebug
5. finallly, run make -s -j2 (-s is the silent flag, -j2 tells your machine to use 2 jobs)

I had the same issue trying to install python3.7 on an ubuntu14.04 machine.
The issue was that I had some custom folders in my PKG_CONFIG_PATH and in my LD_LIBRARY_PATH, which prevented the python build process to find the system openssl libraries.
so try to clear them and see what happens:
export PKG_CONFIG_PATH=""
export LD_LIBRARY_PATH=""

Ok the latest answer to this, as of now don't use Python 3.8, use only 3.7 or less , because of most of the libraries fail to install with the above error

Problems with Python installing anything [duplicate]

I've install Python 3.4 and Python 3.6 on my local machine successfully, but am unable to install packages with pip3.
When I execute pip3 install <package>, I get the following SSL related error:
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Collecting <package>
Could not fetch URL https://pypi.python.org/simple/<package>/: There was a problem confirming the ssl certificate: Can't connect to HTTPS URL because the SSL module is not available. - skipping
Could not find a version that satisfies the requirement <package> (from versions: )
No matching distribution found for <package>
How can I fix my Python3.x install so that I can install packages with pip install <package>?

Step by step guide to install Python 3.6 and pip3 in Ubuntu
Install the necessary packages for Python and ssl: $ sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev
Download and unzip "Python-3.6.8.tar.xz" from https://www.python.org/ftp/python/ into your home directory.
Open terminal in that directory and run: $ ./configure
Build and install: $ make && sudo make install
Install packages with: $ pip3 install package_name
Disclaimer: The above commands are not tested in Ubuntu 20.04 LTS.

If you are on Windows and use anaconda this worked for me:
I tried a lot of other solutions which did not work (Environment PATH Variable changes ...)
The problem can be caused by DLLs in the Windows\System32 folder (e.g. libcrypto-1_1-x64.dll or libssl-1_1-x64.dll or others) placed there by other software.
The fix was installing openSSL from https://slproweb.com/products/Win32OpenSSL.html which replaces the dlls by more recent versions.

If you are on Red Hat/CentOS:
# To allow for building python ssl libs
yum install openssl-devel
# Download the source of *any* python version
cd /usr/src
wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
tar xf Python-3.6.2.tar.xz
cd Python-3.6.2
# Configure the build w/ your installed libraries
./configure
# Install into /usr/local/bin/python3.6, don't overwrite global python bin
make altinstall

I had a similar problem on OSX 10.11 due to installing memcached which installed python 3.7 on top of 3.6.
WARNING: pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
Spent hours on unlinking openssl, reinstalling, changing paths.. and nothing helped. Changing openssl version back from to older version did the trick:
brew switch openssl 1.0.2e
I did not see this suggestion anywhere in internet. Hope it serves someone.

In Ubuntu, this can help:
cd Python-3.6.2
./configure --with-ssl
make
sudo make install

Agree with the answer by mastaBlasta. Worked for me. I encountered the same problem as the topic description.
Environment: MacOS Sierra. And I use Homebrew.
My solution:
Reinstall openssl by brew uninstall openssl; brew install openssl
According to the hints given by Homebrew, do the following:
echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile
export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"

If you are on Windows and use Anaconda you can try running "pip install ..." command in Anaconda Prompt instead of cmd.exe, as user willliu1995 suggests here. This was the fastest solution for me, that does not require installation of additional components.

The problem probably caused by library missing.
Before you install python 3.6, make sure you install all the libraries required for python.
$ sudo apt-get install build-essential checkinstall
$ sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-dev
More information in How to Install Python 3.6.0 on Ubuntu & LinuxMint

If you are on OSX and have compiled python from source:
Install openssl using brew brew install openssl
Make sure to follow the instructions brew gives you about setting your CPPFLAGS and LDFLAGS. In my case I am using the openssl#1.1 brew formula and I need these 3 settings for the python build process to correctly link to my SSL library:
export LDFLAGS="-L/usr/local/opt/openssl#1.1/lib"
export CPPFLAGS="-I/usr/local/opt/openssl#1.1/include"
export PKG_CONFIG_PATH="/usr/local/opt/openssl#1.1/lib/pkgconfig"
Assuming the library is installed at that location.

Downgrading openssl worked for me,
brew switch openssl 1.0.2s

I encountered the same problem on windows 10. My very specific issue is due to my installation of Anaconda. I installed Anaconda and under the path Path/to/Anaconda3/, there comes the python.exe. Thus, I didn't install python at all because Anaconda includes python. When using pip to install packages, I found the same error report, pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available..
The solution was the following:
1) you can download python again on the official website;
2) Navigate to the directory where "Python 3.7 (64-bit).lnk"is located
3) import ssl and exit()
4) type in cmd, "Python 3.7 (64-bit).lnk" -m pip install tensorflow for instance.
Here, you're all set.

I tried A LOT of ways to solve this problem and none solved. I'm currently on Windows 10.
The only thing that worked was:
Uninstall Anaconda
Uninstall Python (i was using version 3.7.3)
Install Python again (remember to check the option to automatically add to PATH)
Then I've downloaded all the libs I needed using PIP... and worked!
Don't know why, or if the problem was somehow related to Anaconda.

for osx brew users
my issue appeared related to my python installation and was quickly resolved by re-installing python3 and pip. i think it started misbehaving after an OS update but who knows (at this time I am on Mac OS 10.14.6)
brew reinstall python3 --force
# setup pip
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
python3 get-pip.py
# installa pkg successfully
pip install pandas

You can do either of these two:
While installing Anaconda, select the option to add Anaconda to the path.
or
Find these (complete) paths from your installation folder of Anaconda and add them to the environment variable :
\Anaconda
\Anaconda\Library\mingw-w64\bin
\Anaconda\Library\usr\bin
\Anaconda\Library\bin
\Anaconda\Scripts
\anaconda\Library
\anaconda\condabin
Add the above paths to the "Path" system variable and it should show the error no more :)

The ssl module is a TLS/SSL wrapper for accessing Operation Sytem (OS) socket (Lib/ssl.py). So when ssl module is not available, chances are that you either don't have OS OpenSSL libraries installed, or those libraries were not found when you install Python. Let assume it is a later case (aka: you already have OpenSSL installed, but they are not correctly linked when installing Python).
I will also assume you are installing from source. If you are installing from binary (ie: Window .exe file), or package (Mac .dmg, or Ubuntu apt), there is not much you can do with the installing process.
During the step of configuring your python installation, you need to specify where the OS OpenSSL will be used for linking:
# python 3.8 beta
./configure --with-openssl="your_OpenSSL root"
So where will you find your installed OpenSSL directory?
# ubuntu
locate ssl.h | grep '/openssl/ssl.h'
/home/user/.linuxbrew/Cellar/openssl/1.0.2r/include/openssl/ssl.h
/home/user/envs/py37/include/openssl/ssl.h
/home/user/miniconda3/envs/py38b3/include/openssl/ssl.h
/home/user/miniconda3/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.0.2s-h7b6447c_0/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.1.1b-h7b6447c_1/include/openssl/ssl.h
/home/user/miniconda3/pkgs/openssl-1.1.1c-h7b6447c_1/include/openssl/ssl.h
/usr/include/openssl/ssl.h
Your system may be different than mine, but as you see here I have many different installed openssl libraries. As the time of this writing, python 3.8 expects openssl 1.0.2 or 1.1:
Python requires an OpenSSL 1.0.2 or 1.1 compatible libssl with X509_VERIFY_PARAM_set1_host().
So you would need to verify which of those installed libraries that you can use for linking, for example
/usr/bin/openssl version
OpenSSL 1.0.2g 1 Mar 2016
./configure --with-openssl="/usr"
make && make install
You may need to try a few, or install a new, to find the library that would work for your Python and your OS.

I was having the same issue and was able to resolve with the following steps:
sudo yum install -y libffi-devel
sudo yum install openssl-devel
cd /usr/src
sudo wget https://www.python.org/ftp/python/3.7.1/Python-3.7.1.tar.xz
sudo tar xf Python-3.7.1.tar.xz
cd Python-3.7.1
sudo ./configure --enable-optimizations
# Install into /usr/local/bin/python3.7, don't overwrite global python bin
sudo make altinstall
depending on perms, you may not need sudo.
Results:
Collecting setuptools
Collecting pip
Installing collected packages: setuptools, pip
Successfully installed pip-10.0.1 setuptools-39.0.1
should now be able to run
python3.7 -V
and
pip3.7 -V
When installing packages:
pip3.7 install pandas
or depending on perms, you can also add the --user flag like so:
pip3.7 install pandas --user

In my case with using Mac, I deleted
/Applications/Python 3.7.
because I already had Python3.7 by brew install python3 .
But it was a trigger of the message
pip is configured with locations that require TLS/SSL, however the ssl module in Python is not available.
What I did in my situation
I downloaded macOS 64-bit installer again, and installed.
Double click /Applications/Python3.6/Install Certificates.command and /Applications/Python3.6/Update Shell Profile.command.
Reboot mac
And I am not sure but possibly contributed to succeed is pip.conf. See pip install fails.

I finally solve this issue. These are the detail of my env:
Version of Python to install: 3.6.8
OS: Ubuntu 16.04.6 LTS
Root access: No
Some people suggest to install libssl-dev, but it did not work for me. I follow this link and I fixed it!
In short, I download, extract, build, and install OpenSSL (openssl-1.1.1b.tar.gz). Then, I modify .bashrc file follow this link.
Next, I download and extract Python-3.6.8.tgz. I edit Modules/Setup.dist to modify SSL path (lines around #211). I did ./configure --prefix=$HOME/opt/python-3.6.8, make and make install. Last, I modify my .bashrc. Notice that I do not include --enable-optimizations in ./configure.

I was able to fix this by updating the python version in this file.
pyenv: version `3.6.5' is not installed (set by /Users/taruntarun/.python-version)
Though i had the latest version installed, my command was still using old version 3.6.5
Moving to version 3.7.3

Termux
This worked because i didnt have an existing openssl version installed.
pkg install openssl-tool

If you are on OSX and in case the other solutions didn't work for you (just like me).
You can try uninstalling python3 and upgrade pip3
brew uninstall --ignore-dependencies python3
pip3 install --upgrade pip
This worked for me ;)

(NOT on Windows!)
This made me tear my hair out for a week, so I hope this will help someone
I tried everything short of re-installing Anaconda and/or Jupyter.
Setup
AWS Linux
Manually installed Anaconda 3-5.3.0
Python3 (3.7) was running inside anaconda (ie, ./anaconda3/bin/python)
there was also /usr/bin/python and /usr/bin/python3 (but these were not being used as most of the work was done in Jupyter's terminal)
Fix
In Jupyter's terminal:
cp /usr/lib64/libssl.so.10 ./anaconda3/lib/libssl.so.1.0.0
cp /usr/lib64/libcrypto.so.10 ./anaconda3/lib/libcrypto.so.1.0.0
What triggered this?
So, this was all working until I tried to do a conda install conda-forge
I'm not sure what happened, but conda must have updated openssl on the box (I'm guessing) so after this, everything broke.
Basically, unknown to me, conda had updated openssl, but somehow deleted the old libraries and replaced it with libssl.so.1.1 and libcrypto.so.1.1.
Python3, I guess, was compiled to look for libssl.so.1.0.0
In the end, the key to diagnosis was this:
python -c "import ssl; print (ssl.OPENSSL_VERSION)"
gave the clue library "libssl.so.1.0.0" not found
The huge assumption I made is that the yum version of ssl is the same as the conda version, so just renaming the shared object might work, and it did.
My other solution was to re-compile python, re-install anaconda, etc, but in the end I'm glad I didn't need to.
Hope this helps you guys out.

In the case of using pyenv to manage python installations on Mac OS Catalina, I had to install openssl with brew first and then after that run pyenv install 3.7.8 which seemed to build the python installation using the openssl from homebrew (it even said as such in the installation output). Then pyenv global 3.7.8 and I was away.

On macos, configure python 3.8.1 with the command below will solve the problem, i think it would also work on Linux.
./configure --enable-optimizations --with-openssl=/usr/local/opt/openssl#1.1/
change the dir parameter based on your system.

I've made some PATH changes to mimic part of the Anaconda Powershell Prompt $env:PATH
C:\Users\merheb\Miniconda3;C:\Users\merheb\Miniconda3\Library\mingw-w64\bin;C:\Users\merheb\Miniconda3\Library\usr\bin;C:\Users\merheb\Miniconda3\Library\bin;C:\Users\merheb\Miniconda3\Scripts;C:\Users\merheb\Miniconda3\bin;C:\Users\merheb\Miniconda3\condabin;
And It worked for me.

Building from source was what worked for me on Ubuntu 22.10:
Install OpenSSL manually, tested here with OpenSSL 1.1.1s, extracted then ran:
./config --prefix='/opt/openssl' --openssldir='/opt/ssl'
make
make install
Then with your older Python 3 version (here Python-3.8.16) run:
export LD_RUN_PATH='/opt/openssl/lib'
export CC='gcc-12' # sudo apt install gcc-12
./configure --enable-optimizations \
--with-openssl='/opt/openssl' \
--prefix='/opt/python/3.8' -C
make
make install
Test with:
/opt/python/3.8/bin/python3 -c 'import ssl; print(ssl.OPENSSL_VERSION)'
OpenSSL 1.1.1s 1 Nov 2022

The python documentation is actually very clear, and following the instructions did the job whereas other answers I found here were not fixing this issue.
first, install python 3.x.x from source using, for example with version 3.6.2 https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
make sure you have openssl installed by running brew install openssl
unzip it and move to the python directory: tar xvzf Python-3.6.2.tar.xz && cd Python-3.6.2
then if the python version is < 3.7, run
CPPFLAGS="-I$(brew --prefix openssl)/include" \
LDFLAGS="-L$(brew --prefix openssl)/lib" \
./configure --with-pydebug
5. finallly, run make -s -j2 (-s is the silent flag, -j2 tells your machine to use 2 jobs)

I had the same issue trying to install python3.7 on an ubuntu14.04 machine.
The issue was that I had some custom folders in my PKG_CONFIG_PATH and in my LD_LIBRARY_PATH, which prevented the python build process to find the system openssl libraries.
so try to clear them and see what happens:
export PKG_CONFIG_PATH=""
export LD_LIBRARY_PATH=""

Ok the latest answer to this, as of now don't use Python 3.8, use only 3.7 or less , because of most of the libraries fail to install with the above error

error installing psycopg2, library not found for -lssl

I run
sudo pip install psycopg2
and I get a bunch of output that looks like:
cc -DNDEBUG -g -fwrapv -Os .....
.....
cc -DNDEBUG -g -fwrapv -Os .....
.....
And at the end it says:
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: command 'cc' failed with exit status 1
----------------------------------------
Cleaning up...
Command /usr/bin/python -c "import setuptools, tokenize;__file__='/private/var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip_build_root/psycopg2/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip-uE3thn-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /private/var/folders/bz/pvj1g9xj16d10pjjgbrfl3fw0000gn/T/pip_build_root/psycopg2
Storing debug log for failure in /Users/Tyler/Library/Logs/pip.log
Running easy_install or doing it from source both give me the same error at the end (the part about library not found for -lssl).
Running brew install (or upgrade) openssl yields the below
$ brew upgrade openssl
Error: openssl-1.0.1h already installed
Can anyone help me out?

For anyone looking for a solution for this on macOS Sierra 10.12 (or later, most likely): I fixed this by installing the command line tools:
xcode-select --install
After that, pip install psycopg2 should work.
If it doesn't, you could also try to link against brew's openssl:
env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install psycopg2
with openssl installed via brew. Note that the brew link openssl --force does not work anymore:
$ brew link openssl --force 17.5s
Warning: Refusing to link: openssl
Linking keg-only openssl means you may end up linking against the insecure,
deprecated system OpenSSL while using the headers from Homebrew's openssl.
Instead, pass the full include/library paths to your compiler e.g.:
-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib
As #macho points out below if this still does not work, you might need to use the --no-cache option of pip, e.g.
env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip --no-cache install psycopg2
Remember to adjust these paths accordingly should you for instance build on ARM/Apple M1 Macs (as homebrew is installed at /opt/homebrew/); command as follows:
env LDFLAGS="-I/opt/homebrew/opt/openssl/include -L/opt/homebrew/opt/openssl/lib" pip --no-cache install psycopg2

If you have OpenSSL installed from brew (brew install openssl)
The following works:
export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"
pip install psycopg2

Using brew link openssl is dangerous as it might mess up your system by symlinking Homebrew's OpenSSL headers while the actual libraries will remain the system-supplied ones, causing all kinds of issues. Homebrew actually warns you against this if you try (and other answers suggest linking won't solve the problem anymore anyway):
$ brew link openssl
Warning: Refusing to link: openssl
Linking keg-only openssl means you may end up linking against the insecure,
deprecated system OpenSSL while using the headers from Homebrew's openssl.
Instead, pass the full include/library paths to your compiler e.g.:
-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib
Following this advice here's the pip command you need to use:
$ pip install -r requirements.txt --global-option=build_ext --global-option="-I/usr/local/opt/openssl/include" --global-option="-L/usr/local/opt/openssl/lib"
For pipenv, I am not aware of any command-line attributes you can pass to it, however you can export the aforementioned paths as environment variables prior to running pipenv install:
$ export LDFLAGS="-L/usr/local/opt/openssl/lib" export CPPFLAGS="-I/usr/local/opt/openssl/include"
$ pipenv install

With MacOS Catalina 10.15.4, the following was the only command that worked for me:
env LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib" pip install psycopg2

Solution for MacOS 12 Monterey - M1 Chipset:
xcode-select --install
brew install openssl
echo 'export PATH="/opt/homebrew/opt/openssl#3/bin:$PATH"' >> ~/.zshrc
echo 'export LIBRARY_PATH=$LIBRARY_PATH:/opt/homebrew/opt/openssl#3/lib/' >> ~/.zshrc

Solution for MacOS BigSur (May 2021)
I was having a similar issue.
But just befor kicking my pc of the desk I found a solution, that worked for me on MacOS BigSur:
My OpenSSL installation was corrupted.
brew reinstall openssl
After the reinstallation is completed it will spit out 3 commands you need to execute:
The commands will look like this:
DONT JUST COPY
echo 'export PATH="/opt/homebrew/opt/openssl#1.1/bin:$PATH"' >> ~/.zshrc
export LDFLAGS="-L/opt/homebrew/opt/openssl#1.1/lib"
export CPPFLAGS="-I/opt/homebrew/opt/openssl#1.1/include"
This worked for me! There is no guarantee that this will work for you too.
brew reinstall might not be the best solution, but it worked and provided the necessary commands.

What worked for me was the hint provided in the command to link openssl,
$ brew link openssl
Warning: Refusing to link macOS-provided software: openssl
If you need to have openssl first in your PATH run:
echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.zshrc
For compilers to find openssl you may need to set:
export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"
$ export LDFLAGS="-L/usr/local/opt/openssl/lib"
$ export CPPFLAGS="-I/usr/local/opt/openssl/include"
$ pip install psycopg2
Collecting psycopg2
Using cached https://files.pythonhosted.org/packages/23/7e/93c325482c328619870b6cd09370f6dbe1148283daca65115cd63642e60f/psycopg2-2.8.2.tar.gz
Installing collected packages: psycopg2
Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.2

On mojave I added these to the .bash_profile
export PATH="/usr/local/opt/openssl/bin:$PATH"
export LDFLAGS="-L/usr/local/opt/curl/lib -L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/curl/include -I/user/local/opt/openssl/include"
was then able to install psycopg 2.8.3 in a python 3.7.4 virtualenv.
This after reinstalling xcode and the command line tools.
All the answers above helped!

This's the problem of new macOs version, where pip cannot install cryptography. What fixed my problem is to provide the env to the install command:
brew install openssl
env LDFLAGS="-L$(brew --prefix openssl)/lib" CFLAGS="-I$(brew --prefix openssl)/include" <YOUR COMMAND HERE>
You can replace <YOUR COMMAND HERE> with pip install cryptography, or pip install <SOMETHING THAT REQUIRES cryptography> for example.
Credit to this article: Fixing macOS Sierra fatal error: 'openssl/opensslv.h' or 'openssl/aes.h' file not found

export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl/lib/
worked for me

Using Fish, the following two commands solved this issue for me after installing OpenSSL with Homebrew.
set -gx LDFLAGS "-L/usr/local/opt/openssl/lib"
set -gx CPPFLAGS "-I/usr/local/opt/openssl/include"
Use brew info openssl to get up-to-date info.

If the export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl/lib/ command doesn't change anything for you, then you may also need to specify openssl version in this path like
export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl#1.1/lib/
Note the #1.1 after openssl.

If you:
Are trying to install psycopg2 inside of a Python venv AND
Are trying to install psycopg2 on Apple Silicon (new ARM CPUs)
Then, as IamAshay directed in their answer, we need to export some variables to point to our OpenSSL installation.
The install directory on Apple Silicon is apparently different ofrom Apple Intel machines. Regardless, to find where OpenSSL is installed (via homebrew) on your system, you can run
brew --prefix openssl
In my case, we have /opt/homebrew/opt/openssl#1.1. So this means that the variables we need to export would be
export LDFLAGS="-L/opt/homebrew/opt/openssl/lib"
export CPPFLAGS="-I/opt/homebrew/opt/openssl/include"
Then we can run
pip install psycopg2

Instead of installing psycopg2, install psycopg2-binary, from the same authors:
pip install psycopg2-binary
This is what the documentation says about this PyPI package:
You can [...] obtain a stand-alone package, not requiring a compiler or external libraries, by installing the psycopg2-binary package from PyPI:
$ pip install psycopg2-binary
The binary package is a practical choice for development and testing but in production it is advised to use the package built from sources.

Recently had this problem in High Sierra, having just installed Python 3.7 in a virtualenv.
The solution is to use a later version of psycopg2. Version 2.7.7 worked, where 2.7.1 did not.

I installed OpenSSL using MacPorts therefore directories are not like those of Brew.
sudo port install openssl
I found the directories by doing:
port contents openssl | grep lib
port contents openssl | grep include
Then I exported the variables:
export LDFLAGS="-L/opt/local/lib"
export CPPFLAGS="-I/opt/local/include/openssl"
You might also have to:
xcode-select --install

If using homebrew, it may not be the best idea to force link openssl. As some above answers outlined, the following worked for me inside a venv:
export LDFLAGS="-L/opt/homebrew/opt/openssl#1.1/lib"
export CPPFLAGS="-I/opt/homebrew/opt/openssl#1.1/include"
pip install psycopg2

I was having this issue on Mojave. Mojave does not create a /usr/include directory, which psycopg2 needs to install. This was not obvious. I found the solution here:
How to update Xcode from command line, which references:
https://forums.developer.apple.com/thread/104296

I had this same error and got it to resolve after I pip installed cython

Running PyCharm from conda environment, solved my issue using:
--> conda install psycopg2
The following packages will be UPDATED: ...
...
Proceed ([y]/n)?
--> y
--> pip3 install psycopg2
Installing collected packages: psycopg2
Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.8.4
'''

I know you are asking for development environment but if you are deploying on server say, Heroku. Just add below line in the requirements.txt of your project.
django-heroku==0.3.1
As this package itself will install the required packages like psycopg2 on server deployment. So let heroku server handle this.

In my case, openssl is located inside homebrew directory and suggested answers don't work.
Bad:
LDFLAGS="-I/usr/local/opt/openssl/include -L/usr/local/opt/openssl/lib"
Good:
LDFLAGS="-I/opt/homebrew/Cellar/openssl#1.1/1.1.1i/include -L/opt/homebrew/Cellar/openssl#1.1/1.1.1i/lib" pip install psycopg2
Tip:
You can easily find homebrew's openssl directory using brew --prefix openssl. Make sure to include version folder (1.1.1i in my case).

I tried most of the other answers here without success. The only thing that worked for me was updating from psycopg2 from 2.8 to 2.9.2 (running MacOS 12 with Apple M1)

Tried everything listed here, then switched shell from zsh to bash, then it worked.

I've managed to fix it by using:
brew unlink openssl && brew link openssl --force
I am not sure how this differs from the brew uninstall/upgrades that I did on OpenSSL in prior attempts I've made. My assumption is that these operations left some of the "faulty" shared libraries which were preventing this from working. Note that this also fixed issues with installing python cryptography module.

ImportError: No module named requests

I tried importing requests:
import requests
But I get an error:
ImportError: No module named requests

Requests is not a built in module (does not come with the default python installation), so you will have to install it:
OSX/Linux
Python 2: sudo pip install requests
Python 3: sudo pip3 install requests
if you have pip installed (pip is the package installer for python and should come by default with your python installation).
If pip is installed but not in your path you can use python -m pip install requests (or python3 -m pip install requests for python3)
Alternatively you can also use sudo easy_install -U requests if you have easy_install installed.
Linux
Alternatively you can use your systems package manager:
For centos: sudo yum install python-requests
For Debian/Ubuntu Python2: sudo apt-get install python-requests
For Debian/Ubuntu Python3: sudo apt-get install python3-requests
Windows
Use pip install requests (or pip3 install requests for python3) if you have pip installed and Pip.exe added to the Path Environment Variable. If pip is installed but not in your path you can use python -m pip install requests (or python3 -m pip install requests for python3)
Alternatively from a cmd prompt, use > Path\easy_install.exe requests, where Path is your Python*\Scripts folder, if it was installed. (For example: C:\Python32\Scripts)
If you manually want to add a library to a windows machine, you can download the compressed library, uncompress it, and then place it into the Lib\site-packages folder of your python path. (For example: C:\Python27\Lib\site-packages)
From Source (Universal)
For any missing library, the source is usually available at https://pypi.python.org/pypi/. You can download requests here: https://pypi.python.org/pypi/requests
On mac osx and windows, after downloading the source zip, uncompress it and from the termiminal/cmd run python setup.py install from the uncompressed dir.
(source)

It's not obvious to me which version of Python you are using.
If it's Python 3, a solution would be sudo pip3 install requests

To install requests module on Debian/Ubuntu for Python2:
$ sudo apt-get install python-requests
And for Python3 the command is:
$ sudo apt-get install python3-requests

Brew users can use reference below,
command to install requests:
python3 -m pip install requests
Homebrew and Python
pip is the package installer for Python and you need the package requests.

This may be a liittle bit too late but this command can be run even when pip path is not set. I am using Python 3.7 running on Windows 10 and this is the command
py -m pip install requests
and you can also replace 'requests' with any other uninstalled library

If you are using Ubuntu, there is need to install requests
run this command:
pip install requests
if you face permission denied error, use sudo before command:
sudo pip install requests

In my case requests was already installed, but needed an upgrade. The following command did the trick
$ sudo pip install requests --upgrade

On OSX, the command will depend on the flavour of python installation you have.
Python 2.x - Default
sudo pip install requests
Python 3.x
sudo pip3 install requests

On Windows Open Command Line
pip3 install requests

I had the same issue, so I copied the folder named "requests" from https://pypi.python.org/pypi/requests#downloadsrequests download to
"/Library/Python/2.7/site-packages".
Now when you use: import requests, it should work fine.

In the terminal/command-line:
pip install requests
then use it inside your Python script by:
import requests
or else if you want to use pycharm IDE to install a package:
go to setting from File in menu
next go to Python interpreter
click on pip
search for requests package and install it

Adding Third-party Packages to the Application
Follow this link
https://cloud.google.com/appengine/docs/python/tools/libraries27?hl=en#vendoring
step1 : Have a file by named a file named appengine_config.py in the root of your project, then add these lines:
from google.appengine.ext import vendor
Add any libraries installed in the "lib" folder.
vendor.add('lib')
Step 2: create a directory and name it "lib" under root directory of project.
step 3: use pip install -t lib requests
step 4 : deploy to app engine.

Try sudo apt-get install python-requests.
This worked for me.

If you are using anaconda as your python package manager, execute the following:
conda install -c anaconda requests
Installing requests through pip didn't help me.

The only thing that worked for me:
curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py
python get-pip.py
pip install requests

Facing the same issue but unable to fix it with the above solution, so I tried this way and it worked:-
curl https://bootstrap.pypa.io/pip/2.7/get-pip.py --output get-pip.py
sudo python2 get-pip.py
python -m pip install requests

For windows just give path as cd and path to the "Scripts" of python and then execute the command easy_install.exe requests.Then try import requests...

I have had this issue a couple times in the past few months. I haven't seen a good solution for fedora systems posted, so here's yet another solution. I'm using RHEL7, and I discovered the following:
If you have urllib3 installed via pip, and requests installed via yum you will have issues, even if you have the correct packages installed. The same will apply if you have urllib3 installed via yum, and requests installed via pip. Here's what I did to fix the issue:
sudo pip uninstall requests
sudo pip uninstall urllib3
sudo yum remove python-urllib3
sudo yum remove python-requests
(confirm that all those libraries have been removed)
sudo yum install python-urllib3
sudo yum install python-requests
Just be aware that this will only work for systems that are running Fedora, Redhat, or CentOS.
Sources:
This very question (in the comments to this answer).
This github issue.

Python Common installation issues
These commands are also useful if Homebrew screws up your path on macOS.
python -m pip install requests
or
python3 -m pip install requests
Multiple versions of Python installed in parallel?

You must make sure your requests module is not being installed in a more recent version of python.
When using python 3.7, run your python file like:
python3 myfile.py
or enter python interactive mode with:
python3
Yes, this works for me. Run your file like this: python3 file.py

I have installed python2.7 and python3.6
Open Command Line to ~/.bash_profile I find that #Setting PATH for Python 3.6 , So
I change the path to PATH="/usr/local/Cellar/python/2.7.13/bin:${PATH}" ,
(please make sure your python2.7's path) ,then save.
It works for me.

if you want request import on windows:
pip install request
then beautifulsoup4 for:
pip3 install beautifulsoup4

Please try the following. If one doesn't work, skip to the next method.
pip install requests
or...
pip3 install requests
or...
python -m pip install requests
or...
python3 -m pip install requests
or...
python -m pip3 install requests
If all of these don't work, please leave a comment!
How does this work? Depending on the operating system you currently use, the pip command may vary or not work on some. These are the commands you may try in order for a fix.

In case you hit pip install requests and had an output massage of Requirement already satisfied but yet you still get the error: ImportError: No module named requests.
This is likely to happen when you find yourself in a different interpreter/virtual environment.
You can copy and append the path of the module into your working environment.
Note: This path usually comes with the message Requirement already satisfied
Before import requests, you should import sys and then append the copied path.
Example:
Command Prompt:
pip install requests
Output:
Requirement already satisfied: requests in /usr/local/lib/python3.9/site-packages
import sys
sys.path.append("/usr/local/lib/python3.9/site-packages")
import requests

I solved this problem.You can try this method.
In this file '.bash_profile', Add codes like alias python=/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7

Type this command in Command Prompt (Windows) or Terminal (Linux/macOS):
pip install requests

My answer is basically the same as #pi-k. In my case my program worked locally but failed to build on QA servers. (I suspect devops had older versions of the package blocked and my version must have been too out-of-date) I just decided to upgrade everything
$ pip install pip-review
$ pip-review --local --interactive

You get an import error because requests are not a built-in module instead, it is created by someone else and you need to install the requests.
use the following command on your terminal then it will work correctly.
pip install requests
Install python requests library and this error will be solved.

I found that my issue was VSCode was reading from the wrong Python Interpreter. This youtube tutorial solved it for me.

If you are using anaconda
step 1:
where python
step 2:
open anaconda prompt in administrator mode
step 3:
cd <python path>
step 4:
install the package in this location

ImportError: No module named psycopg2

In installation process of OpenERP 6, I want to generate a config file with these commands:
cd /home/openerp/openerp-server/bin/
./openerp-server.py -s --stop-after-init -c /home/openerp/openerp-server.cfg
But it always showed the message: ImportError: No module named psycopg2
When I checked for psycopg2 package, it's already installed. Package python-psycopg2-2.4.5-1.rhel5.x86_64 is already installed to its latest version. Nothing to do. What's wrong with this? My server is CentOS, I've installed Python 2.6.7.

Step 1: Install the dependencies
sudo apt-get install build-dep python-psycopg2
Step 2: Run this command in your virtualenv
pip install psycopg2-binary
Ref: Fernando Munoz

Use psycopg2-binary instead of psycopg2.
pip install psycopg2-binary
Or you will get the warning below:
UserWarning: The psycopg2 wheel package will be renamed from release 2.8; in order to keep installing from binary please use "pip install psycopg2-binary" instead. For details see: http://initd.org/psycopg/docs/install.html#binary-install-from-pypi.
Reference: Psycopg 2.7.4 released | Psycopg

I faced the same issue and resolved it with following commands:
sudo apt-get install libpq-dev
pip install psycopg2

Try installing
psycopg2-binary
with
pip install psycopg2-binary --user

Please try to run the command import psycopg2 on the python console. If you get the error then check the sys.path where the python look for the install module. If the parent directory of the python-psycopg2-2.4.5-1.rhel5.x86_64 is there in the sys.path or not. If its not in the sys.path then run export PYTHONPATH=<parent directory of python-psycopg2-2.4.5-1.rhel5.x86_64> before running the openerp server.

Import Error on Mac OS
If psycopg2 is getting installed but you are unable to import it in your .py file then the problem is libpq, its linkages, and the library openssl, on which libpq depends upon. The overall steps are reproduced below. You can check it step by step to know which is the source of error for you and then you can troubleshoot from there.
Check for the installation of the openssl and make sure it's working.
Check for installation of libpq in your system it may not have been installed or not linked. If not installed then install it using the command brew install libpq. This installs libpq library. As per the documentation
libpq is the C application programmer's interface to PostgreSQL. libpq is a set of library functions that allow client programs to pass queries to the PostgreSQL backend server and to receive the results of these queries.
Link libpq using brew link libpq, if this doesn't work then use the command: brew link libpq --force.
Also put in your .zshrc file the following export PATH="/usr/local/opt/libpq/bin:$PATH". This creates all the necessary linkages for libpq library .
Now restart the terminal or use the following command source ~/.zshrc.
Now use the command pip install psycopg2. It will work.
This works, even when you are working in conda environment.
N.B. pip install psycopg2-binaryshould be avoided because as per the developers of the psycopg2 library
The use of the -binary packages in production is discouraged because in the past they proved unreliable in multithread environments. This might have been fixed in more recent versions but I have never managed to reproduce the failure.

Try with these:
virtualenv -p /usr/bin/python3 test_env
source test_env/bin/activate
pip install psycopg2
run python and try to import if you insist on installing it on your systems python try:
pip3 install psycopg2

Recently faced this issue on my production server. I had installed pyscopg2 using
sudo pip install psycopg2
It worked beautifully on my local, but had me for a run on my ec2 server.
sudo python -m pip install psycopg2
The above command worked for me there. Posting here just in case it would help someone in future.

sudo pip install psycopg2-binary

You need to install the psycopg2 module.
On CentOS:
Make sure Python 2.7+ is installed. If not, follow these instructions: http://toomuchdata.com/2014/02/16/how-to-install-python-on-centos/
# Python 2.7.6:
$ wget http://python.org/ftp/python/2.7.6/Python-2.7.6.tar.xz
$ tar xf Python-2.7.6.tar.xz
$ cd Python-2.7.6
$ ./configure --prefix=/usr/local --enable-unicode=ucs4 --enable-shared LDFLAGS="-Wl,-rpath /usr/local/lib"
$ make && make altinstall
$ yum install postgresql-libs
# First get the setup script for Setuptools:
$ wget https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py
# Then install it for Python 2.7 and/or Python 3.3:
$ python2.7 ez_setup.py
$ easy_install-2.7 psycopg2
Even though this is a CentOS question, here are the instructions for Ubuntu:
$ sudo apt-get install python3-pip python-distribute python-dev
$ easy_install psycopg2
Cite: http://initd.org/psycopg/install/

For python3 on ubuntu, this worked for me:
$sudo apt-get update
$sudo apt-get install libpq-dev
$sudo pip3 install psycopg2-binary

i have the same problem, but this piece of snippet alone solved my problem.
pip install psycopg2

Run into the same issue when I switch to Ubuntu from Windows 10.. the following worked for me.. this after googling and trying numerous suggestions for 2 hours...
sudo apt-get install libpq-dev
then
pip3 install psycopg2
I hope this helps someone who has encountered the same problem especially when switching for windows OS to Linux(Ubuntu).

I have done 2 things to solve this issue:
use Python 3.6 instead of 3.8.
change Django version to 2.2 (may be working with some higher but I change to 2.2)

For Python3
Step 1: Install Dependencies
sudo apt-get install python3 python-dev python3-dev
Step 2: Install
pip install psycopg2

check correctly if you had ON your virtual env of your peoject, if it's OFF then make it ON. execute following cammands:
workon <your_env_name>
python manage.py runserver
It's working for me

It's very simple, not sure why nobody mentioned this for mac before.
brew install postgresql
pip3 install psycopg2
In simple terms, psycopg2 wants us to install postgres first.
PS: Don't forget to upvote, so that it can help other people as well.

Solved the issue with below solution :
Basically the issue due to _bz2.cpython-36m-x86_64-linux-gnu.so Linux package file. Try to find the the location.
Check the install python location ( which python3)- Example: /usr/local/bin/python3
copy the file under INSTALL_LOCATION/lib/python3.6
cp -rvp /usr/lib64/python3.6/lib-dynload/_bz2.cpython-36m-x86_64-linux-gnu.so /usr/local/lib/python3.6

try:
pip install psycopg2 --force-reinstall --no-cache-dir

Python2 importerror no module named psycopg2
pip install psycopg2-binary
Requirement already satisfied...
Solved by following steps:
sudo curl https://bootstrap.pypa.io/pip/2.7/get-pip.py -o get-pip.py
sudo python get-pip.py
sudo python -m pip install psycopg2-binary

pip install psycopg-binary
The line above helped me

For Python3 use this:
sudo apt-get install -y python3-psycopg2

Develop Reference

Python is a programming language that lets you work quickly and integrate systems more effectively.