Develop Reference

Unable to install MySQL driver for Python [duplicate]

First off, yeah, I've already seen this:
pip install mysql-python fails with EnvironmentError: mysql_config not found
The problem
I am trying to use Django on a Google App Engine project. However, I haven't been able to get started as the server fails to start properly due to:
ImproperlyConfigured("Error loading MySQLdb module: %s" % e)
ImproperlyConfigured: Error loading MySQLdb module: No module named MySQLdb
I did some research and it all pointed to having to install Mysql-python, as apparently it isn't on my system. I actually tried uninstalling it and got this:
Cannot uninstall requirement mysql-python, not installed
Whenever I actually do try to install via:
sudo pip install MySQL-python
I get an error stating:
raise EnvironmentError("%s not found" % (mysql_config.path,))
EnvironmentError: mysql_config not found
I've already tried running:
export PATH=$PATH:/usr/local/mysql/bin
but that didn't seem to help, as I ran the installation command again and it still failed.
Any ideas?
Please note I'm not in a virtualenv.

Ok, well, first of all, let me check if I am on the same page as you:
You installed python
You did brew install mysql
You did export PATH=$PATH:/usr/local/mysql/bin
And finally, you did pip install MySQL-Python (or pip3 install mysqlclient if using python 3)
If you did all those steps in the same order, and you still got an error, read on to the end, if, however, you did not follow these exact steps try, following them from the very beginning.
So, you followed the steps, and you're still geting an error, well, there are a few things you could try:
Try running which mysql_config from bash. It probably won't be found. That's why the build isn't finding it either. Try running locate mysql_config and see if anything comes back. The path to this binary needs to be either in your shell's $PATH environment variable, or it needs to be explicitly in the setup.py file for the module assuming it's looking in some specific place for that file.
Instead of using MySQL-Python, try using 'mysql-connector-python', it can be installed using pip install mysql-connector-python. More information on this can be found here and here.
Manually find the location of 'mysql/bin', 'mysql_config', and 'MySQL-Python', and add all these to the $PATH environment variable.
If all above steps fail, then you could try installing 'mysql' using MacPorts, in which case the file 'mysql_config' would actually be called 'mysql_config5', and in this case, you would have to do this after installing: export PATH=$PATH:/opt/local/lib/mysql5/bin. You can find more details here.
Note1: I've seen some people saying that installing python-dev and libmysqlclient-dev also helped, however I do not know if these packages are available on Mac OS.
Note2: Also, make sure to try running the commands as root.
I got my answers from (besides my brain) these places (maybe you could have a look at them, to see if it would help): 1, 2, 3, 4.
I hoped I helped, and would be happy to know if any of this worked, or not. Good luck.

I had been debugging this problem forever - 3 hours 17 mins. What particularly annoyed me was that I already had sql installed on my system through prior uni work but pip/pip3 wasn't recognising it. These threads above and many other I scoured the internet for were helpful in eluminating the problem but didn't actually solve things.
ANSWER
Pip is looking for mysql binaries in the Homebrew Directory which is located relative to Macintosh HD #
/usr/local/Cellar/
so I found that this requires you making a few changes
step 1: Download MySql if not already done so https://dev.mysql.com/downloads/
Step 2: Locate it relative to Macintosh HD and cd
/usr/local/mysql/bin
Step 3: Once there open terminal and use a text editor of choice - I'm a neovim guy myself so I typed (doesn't automatically come with Mac... another story for another day)
nvim mysql_config
Step 4: You will see at approx line 112
# Create options
libs="-L$pkglibdir"
libs="$libs -l "
Change to
# Create options
libs="-L$pkglibdir"
libs="$libs -lmysqlclient -lssl -lcrypto"
*you'll notice that this file has read-only access so if your using vim or neovim
:w !sudo tee %
Step 5: Head to the home directory and edit the .bash_profile file
cd ~
Then
nvim .bash_profile
and add
export PATH="/usr/local/mysql/bin:$PATH"
to the file then save
Step 6: relative to Macintosh HD locate paths and add to it
cd /private/etc/
then
nvim paths
and add
/usr/local/mysql/bin
*you'll again notice that this file has read-only access so if your using vim or neovim
:w !sudo tee %
then
cd ~
then refresh the terminal with your changes by running
source .bash_profile
Finally
pip3 install mysqlclient
And Viola. Remember it's a vibe.

If you don't want to install full mysql, we can fix this by just installing mysql-client
brew install mysql-client
Once cmd is completed it will ask to add below line to ~/.bash_profile:
echo 'export PATH="/usr/local/opt/mysql-client/bin:$PATH"' >> ~/.bash_profile
Close terminal and start new terminal and proceed with pip install mysqlclient.

I am running Python 3.6 on MacOS Catalina. My issue was that I tried to install mysqlclient==1.4.2.post1 and it keeps throwing mysql_config not found error.
This is the steps I took to solve the issue.
Install mysql-connector-c using brew (if you have mysql already install unlink first brew unlink mysql) - brew install mysql-connector-c
Open mysql_config and edit the file around line 112
# Create options
libs="-L$pkglibdir"
libs="$libs -lmysqlclient -lssl -lcrypto"
brew info openssl - this will give you more information on what needs to be done about putting openssl in PATH
in relation to step 3, you need to do this to put openssl in PATH - echo 'export PATH="/usr/local/opt/openssl/bin:$PATH"' >> ~/.bash_profile
for compilers to find openssl - export LDFLAGS="-L/usr/local/opt/openssl/lib"
for compilers to find openssl - export CPPFLAGS="-I/usr/local/opt/openssl/include"

Also this happens when I was installing mysqlclient,
$ pip install mysqlclient
As user3429036 said,
$ brew install mysql

If you have installed mysql using Homebrew by specifying a version then mysql_config would be present here. - /usr/local/Cellar/mysql#5.6/5.6.47/bin
you can find the path of the sql bin by using ls command in /usr/local/ directory
/usr/local/Cellar/mysql#5.6/5.6.47/bin
Add the path to bash profile like this.
nano ~/.bash_profile
export PATH="/usr/local/Cellar/mysql#5.6/5.6.47/bin:$PATH"

This answer is for MacOS users who did not install from brew but rather from the official .dmg/.pkg. That installer fails to edit your PATH, causing things to break out of the box:
All MySQL commands like mysql, mysqladmin, mysql_config, etc cannot be found, and as a result:
the "MySQL Preference Pane" fails to appear in System Preferences, and
you cannot install any API that communicates with MySQL, including mysqlclient
What you have to do is appending the MySQL bin folder (typically /usr/local/mysql/bin in your PATH by adding this line in your ~/.bash_profile file:
export PATH="/usr/local/mysql/bin/:$PATH"
You should then reload your ~/.bash_profile for the change to take effect in your current Terminal session:
source ~/.bash_profile
Before installing mysqlclient, however, you need to accept the XcodeBuild license:
sudo xcodebuild -license
Follow their directions to sign away your family, after which you should be able to install mysqlclient without issue:
pip install mysqlclient
After installing that, you must do one more thing to fix a runtime bug that ships with MySQL (Dynamic Library libmysqlclient.dylib not found), by adding this line to your system dynamic libraries path:
export DYLD_LIBRARY_PATH=/usr/local/mysql/lib/:$DYLD_LIBRARY_PATH

brew install mysql added mysql to /usr/local/Cellar/..., so I needed to add :/usr/local/Cellar/ to my $PATH and then which mysql_config worked!

The problem in my case was that I was running the command inside a python virtual environment and it didn't had the path to /usr/local/mysql/bin though I have put it in the .bash_profile file. Just exporting the path in the virtual env worked for me.
For your info sql_config resides inside bin directory.

Install brew or apt-get is also not easy for me so I downloaded mysql via: https://dev.mysql.com/downloads/connector/python/, installed it. So I can find mysql_config int this directory: /usr/local/mysql/bin
the next step is:
export PATH=$PATH:/usr/local/mysql/bin
pip install MySQL-python==1.2.5

Python pip: install in specific non-user directory and ignore system wide packages

I want to set up a Python environment for a whole team and I don't have root access to the server.
I have done a similar thing with Perl and expected to be able to do this for Python in a similar way but I keep running into a problem.
Basically, I want to be able to install a package into /SOME/DIR on the system while ignoring any system wide versions of that package.
However, when I run
pip install --install-option="--prefix=/SOME/DIR/" --up --ignore-installed SOME-MODULE
I keep getting a "permission denied" error because pip keeps trying to remove system-wide packages when upgrading.
What does work is this
pip install --user --up --ignore-installed SOME-MODULE
Which does not try to touch the system-wide packages but it installs the module into a directory in $HOME/.lib, which is not what I need.
It seems impossible to combine --user and a "--prefix" option, so it sems that I can either install into an arbitrary path but then get conflicts with already install system-wide packages or install into my home directory. Neither of them are what I need.
For now I have been using the --user option and then moved the installed files across to /SOME/DIR which works but seems odd.
Am I missing something? I have read up on virtualenv but this also doesn't quite sound like what I need. Thanks for your help!

Note that --install-options is passed directly to the packages setup.py install command - this requires the installation directory to be in your python path.
add it to your PYTHONPATH i.e.
set -gx PYTHONPATH $PYTHONPATH '/home/user/temp/lib/python3.4/site-packages'
and run pip
pip install django==1.6 --ignore-installed --install-options="--prefix=/home/user/temp"
Mostly this is a pain in the ass if you have to do this for each library (note that you will still have potential conflicts with imports if you want to use certain standard libraries from the default site-packages dir, and others from your custom dir). And the best choice is probably, as the comment says, to install virtualenv and virtualenvwrapper

I had a similar problem (permission denied + no root access), --build option made it work: pip install --install-option="--prefix=/path/to/local/lib" --build=/tmp wget

How to find pg_config path

Complete newbie here, trying to set up Django to work with PostgreSQL.
I'm using mac osx 10.6.8. I have also installed PostgreSQL 9.3
When I run pip install psycopg2 in terminal I get the following error
Downloading/unpacking psycopg2
Downloading psycopg2-2.5.2.tar.gz (685kB): 685kB downloaded
Running setup.py (path:/private/var/folders/A9/A99cs6x0FNusPejCVkYNTE+++TI/-Tmp-/pip_build_bengorman/psycopg2/setup.py) egg_info for package psycopg2
Error: pg_config executable not found.
Please add the directory containing pg_config to the PATH
or specify the full executable path with the option:
python setup.py build_ext --pg-config /path/to/pg_config build ...
or with the pg_config option in 'setup.cfg'.
Complete output from command python setup.py egg_info:
running egg_info
creating pip-egg-info/psycopg2.egg-info
writing pip-egg-info/psycopg2.egg-info/PKG-INFO
writing top-level names to pip-egg-info/psycopg2.egg-info/top_level.txt
writing dependency_links to pip-egg-info/psycopg2.egg-info/dependency_links.txt
writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
warning: manifest_maker: standard file '-c' not found
Error: pg_config executable not found.
Please add the directory containing pg_config to the PATH
or specify the full executable path with the option:
python setup.py build_ext --pg-config /path/to/pg_config build ...
or with the pg_config option in 'setup.cfg'.
I've seen a number of posts on this
how-to-install-psycopg2-with-pip-on-python
pg-config-executable-not-found
but I have no clue how to find the bin folder location containing pg_config. Any tips on finding this path?

I recommend that you try to use Postgres.app. (http://postgresapp.com)
This way you can easily turn Postgres on and off on your Mac.
Once you do, add the path to Postgres to your .profile file by appending the following:
PATH="/Applications/Postgres.app/Contents/Versions/latest/bin:$PATH"
Only after you added Postgres to your path you can try to install psycopg2 either within a virtual environment (using pip) or into your global site packages.

sudo find / -name "pg_config" -print
The answer is /Library/PostgreSQL/9.1/bin/pg_config in my configuration (MAC Maverick)

Installing homebrew
/usr/bin/ruby -e "$(curl -fsSL https://raw.github.com/gist/323731)"
And then installing postgresql
brew install postgresql
gave me this lovely bit of output:
checking for pg_config... yes
ahhh yeahhhhh

Postgres.app was updated recently. Now it stores all the binaries in "Versions" folder
PATH="/Applications/Postgres.app/Contents/Versions/9.4/bin:$PATH"
Where 9.4 – version of PostgreSQL.

Once you install the current PostgreSQL app on the MacOS X 10.11, this is where the pg_config file is /Library/PostgreSQL/9.5/bin/pg_config.
Then on the Terminal:
$ export PG_HOME=/Library/PostgreSQL/9.5
$ export PATH=$PATH:$PG_HOME/bin
This will put the path in the .profile of whatever terminal you are using.
In your environment (assuming you are using virtualenv) you then install psycopg2:
$ pip install psycopg2
You should see if you had downloaded it before:
Collecting psycopg2
Using cached psycopg2-2.6.1.tar.gz
Installing collected packages: psycopg2
Running setup.py install for psycopg2 ... done
Successfully installed psycopg2-2.6.1

To summarize -- PostgreSQL installs its files (including its binary or executable files) in different locations, depending on the version number and the installation method.
Some of the possibilities:
/usr/local/bin/
/Library/PostgreSQL/9.2/bin/
/Applications/Postgres93.app/Contents/MacOS/bin/
/Applications/Postgres.app/Contents/Versions/9.3/bin/
No wonder people get confused!
Also, if your $PATH environment variable includes a path to the directory that includes an executable file (to confirm this, use echo $PATH on the command line) then you can run which pg_config, which psql, etc. to find out where the file is located.

I had exactly the same error, but I installed postgreSQL through brew and re-run the original command and it worked perfectly :
brew install postgresql

This is how to simply get the path of pg_config
$ which pg_config // prints the directory location
/usr/bin/pg_config

Have same issue on mac, you probably need to
brew install postgresql
then you can run
pip install psycopg2
The brew will fix PATH issue for you
this solution works for me at least.

You can find the pg_config directory using its namesake:
$ pg_config --bindir
/usr/lib/postgresql/9.1/bin
$
Tested on Mac and Debian. The only wrinkle is that I can't see how to find the bindir for different versions of postgres installed on the same machine. It's fairly easy to guess though! :-)
Note: I updated my pg_config to 9.5 on Debian with:
sudo apt-get install postgresql-server-dev-9.5

check /Library/PostgreSQL/9.3/bin and you should find pg_config
I.E. /Library/PostgreSQL/<version_num>/
ps: you can do the following if you deem it necessary for your pg needs -
create a .profile in your ~ directory
export PG_HOME=/Library/PostgreSQL/9.3
export PATH=$PATH:$PG_HOME/bin
You can now use psql or postgres commands from the terminal, and install psycopg2 or any other dependency without issues, plus you can always just ls $PG_HOME/bin when you feel like peeking at your pg_dir.

I used :
export PATH=$PATH:/Library/PostgreSQL/9.6/bin
pip install psycopg2

Works for me by installing the first the following pip packages: libpq-dev and postgresql-common

For people looking for the pg_config path for postgresql installed via brew on Apple silicon: /opt/homebrew/Cellar/postgresql/<postgres_version>/bin.
For Intel based Mac system /usr/local/Cellar/postgresql/<postgres_version>/bin (Need to verify this).

For those using macOS Big Sur and have their default shell as the Z shell, you can add the path to the py_config binary in the .zprofile which is equivalent to the .bash_profile as explained in this link https://support.apple.com/en-us/HT208050
I had similar issues when using PyCharm with a virtual environment within which I was unable to change my shell to bash to get things going. Adding the postgres bin path fixed my issue:
MacBook-Pro ~ % cat .zprofile
# Setting PATH for Postgres
PATH="/Applications/Postgres.app/Contents/Versions/latest/bin:$PATH"
export PATH
Then running this worked without any issues:
pip install psycopg2

path of pg_config in my case (MacOS)
/Library/PostgreSQL/13/bin
Execute the following in the terminal:
PATH="/Library/PostgreSQL/13/bin:$PATH"
Then
pip install psycopg2

pip installing in global site-packages instead of virtualenv

Using pip3 to install a package in a virtualenv causes the package to be installed in the global site-packages folder instead of the one in the virtualenv folder. Here's how I set up Python3 and virtualenv on OS X Mavericks (10.9.1):
I installed Python3 using Homebrew:
ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
brew install python3 --with-brewed-openssl
Changed the $PATH variable in .bash_profile; added the following line:
export PATH=/usr/local/bin:$PATH
Running which python3 returns /usr/local/bin/python3 (after restarting the shell).
Note: which python3 still returns /usr/bin/python though.
Installed virtualenv using pip3:
pip3 install virtualenv
Next, create a new virtualenv and activate it:
virtualenv testpy3 -p python3
cd testpy3
source bin/activate
Note: if I don't specify -p python3, pip will be missing from the bin folder in the virtualenv.
Running which pip and which pip3 both return the virtualenv folder:
/Users/kristof/VirtualEnvs/testpy3/bin/pip3
Now, when I try to install e.g. Markdown using pip in the activated virtualenv, pip will install in the global site-packages folder instead of the site-packages folder of the virtualenv.
pip install markdown
Running pip list returns:
Markdown (2.3.1)
pip (1.4.1)
setuptools (2.0.1)
virtualenv (1.11)
Contents of /Users/kristof/VirtualEnvs/testpy3/lib/python3.3/site-packages:
__pycache__/
_markerlib/
easy_install.py
pip/
pip-1.5.dist-info/
pkg_resources.py
setuptools/
setuptools-2.0.2.dist-info/
Contents of /usr/local/lib/python3.3/site-packages:
Markdown-2.3.1-py3.3.egg-info/
__pycache__/
easy-install.pth
markdown/
pip-1.4.1-py3.3.egg/
setuptools-2.0.1-py3.3.egg
setuptools.pth
virtualenv-1.11-py3.3.egg-info/
virtualenv.py
virtualenv_support/
As you can see, the global site-packages folder contains Markdown, the virtualenv folder doesn't.
Note: I had Python2 and Python3 installed before on a different VM (followed these instructions) and had the same issue with Python3; installing packages in a Python2 based virtualenv worked flawlessly though.
Any tips, hints, … would be very much appreciated.

Funny you brought this up, I just had the exact same problem. I solved it eventually, but I'm still unsure as to what caused it.
Try checking your bin/pip and bin/activate scripts. In bin/pip, look at the shebang. Is it correct? If not, correct it. Then on line ~42 in your bin/activate, check to see if your virtualenv path is right. It'll look something like this
VIRTUAL_ENV="/Users/me/path/to/virtual/environment"
If it's wrong, correct it, deactivate, then . bin/activate, and if our mutual problem had the same cause, it should work. If it still doesn't, you're on the right track, anyway. I went through the same problem solving routine as you did, which piping over and over, following the stack trace, etc.
Make absolutely sure that
/Users/kristof/VirtualEnvs/testpy3/bin/pip3
is what you want, and not referring to another similarly-named test project (I had that problem, and have no idea how it started. My suspicion is running multiple virtualenvs at the same time).
If none of this works, a temporary solution may be to, as Joe Holloway said,
Just run the virtualenv's pip with its full path (i.e. don't rely on searching the executable path) and you don't even need to activate the environment. It will do the right thing.
Perhaps not ideal, but it ought to work in a pinch.
Link to my original question:
VirtualEnv/Pip trying to install packages globally

For me this was not a pip or virtualenv problem. It was a python problem. I had set my $PYTHONPATH manually in ~/.bash_profile (or ~/.bashrc) after following some tutorial online. This manually set $PYTHONPATH was available in the virtualenv as it probably should be allowed.
Additionally add2virtualenv was not adding my project path to my $PYTHONPATH for some reason within the virtualenv.
Just some forking paths for those who might still be stuck! Cheers!

I had the same problem, I solved it by removing venv directory and recreating it!
deactivate (if venv is activated first deactivate it)
rm -rf venv
virtualenv -p python3 venv
. ENV/bin/activate
pip3 install -r requirements.txt
Now everything works like a charm.
Edit: Here's the above code modified for Python3's venv:
deactivate # (if venv is activated first deactivate it)
rm -rf venv # Delete the old venv directory
python3 -m venv venv # Recreate a new, empty venv
. venv/bin/activate # Activate it
pip3 install -r requirements.txt # Install the dependencies

The first thing to check is which location pip is resolving to:
which pip
if you are in a virtualenv you would expect this to give you something like:
/path/to/virtualenv/.name_of_virtualenv/bin/pip
However it may be the case that it's resolving to your system pip for some reason. For example you may see this from within your virtualenv (this is bad):
/usr/local/bin/pip
(or anything that isn't in your virtualenv path).
To solve this check your pipconfig in:
~/.pipconf
~/.conf/pip
/etc/pip.conf
and make sure that there is nothing that is coercing your Python path or your pip path (this fixed it for me).
Then try starting a new terminal and rebuild your virtualenv (delete then create it again)

I had the same issue on macos with python 2 and 3 installed.
Also, I had aliases to point to python3 and pip3 in my .bash_profile.
alias python=/usr/local/bin/python3
alias pip=/usr/local/bin/pip3
Removing aliases and recreating virtual env using python3 -m venv venv fixed the issue.

Go to bin directory in your virtual environment and write like this:
./pip3 install <package-name>

I had this problem too. Calling pip install <package_name> from the /bin directory within my Python 3.3 virtual environment on my Mavericks Mac caused the Python package to be installed in the Python 2.7 global site packages directory. This was despite the fact that my $PATH started with the directory containing pip. Weird. This doesn't happen on CentOS. For me, the solution was calling pip3 instead of pip. When I had installed pip within the virtual environment via ez_setup, three "pip" executables had been installed in the /bin directory - pip, pip3, and pip3.3. Curiously, all three files were exactly the same. Calling pip3 install <package_name> caused the Python package to be installed correctly into the local site-packages directory. Calling pip with the full pathname into the virtual environment also worked correctly. I'd be interested to know why my Mac isn't using $PATH the way I would expect it to.

I hit into the same issue while installing a python package from within a virtualenv.
The root cause in my case was different.
From within the virtualenv, I was (out of habit on Ubuntu), doing:
sudo easy_install -Z <package>
This caused the bin/pip shebang to be ignored and it used the root's non virtualenv python to install it in the global site-packages.
Since we have a virtual environment, we should install the package without "sudo"

I stumbled upon the same problem running Manjaro. I created the virtual environment using python3 -m ven venv and then activated using source venv/bin/actiave. which python and which pip both pointed towards the correct binaries in the virtualenv, however I was not able to install to the virtualenv, even when using the full path of the binaries. Turned out that when I uninstalled the python-pip package with sudo pacman -R python-pip python-reportlab (had to include reportlab to satisfy dependencies) everything started to work as expected. Not sure why, but this is probably due to a double install where the system package is taking precedence.

I had a similar problem after updating to pip==8.0.0. Had to resort to debugging pip to trace out the bad path.
As it turns out my profile directory had a distutils configuration file with some empty path values. This was causing all packages to be installed to the same root directory instead of the appropriate virtual environment (in my case /lib/site-packages).
I'm unsure how the config file got there or how it had empty values but it started after updating pip.
In case anyone else stumbles upon this same problem, simply deleting the file ~/.pydistutils.cfg (or removing the empty config path) fixed the problem in my environment because pip went back to the default distributed configuration.

Here are some practices that could avoid headaches when using Virtual Environments:
Create a folder for your projects.
Create your Virtualenv projects inside of this folder.
After activating the environment of your project, never use "sudo pip install package".
After finishing your work, always "deactivate" your environment.
Avoid renaming your project folder.
For a better representation of this practices, here is a simulation:
creating a folder for your projects/environments
$ mkdir venv
creating environment
$ cd venv/
$ virtualenv google_drive
New python executable in google_drive/bin/python
Installing setuptools, pip...done.
activating environment
$ source google_drive/bin/activate
installing packages
(google_drive) $ pip install PyDrive
Downloading/unpacking PyDrive
Downloading PyDrive-1.3.1-py2-none-any.whl
...
...
...
Successfully installed PyDrive PyYAML google-api-python-client oauth2client six uritemplate httplib2 pyasn1 rsa pyasn1-modules
Cleaning up...
package available inside the environment
(google_drive) $ python
Python 2.7.6 (default, Oct 26 2016, 20:30:19)
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import pydrive.auth
>>>
>>> gdrive = pydrive.auth.GoogleAuth()
>>>
deactivate environment
(google_drive) $ deactivate
$
package NOT AVAILABLE outside the environment
(google_drive) $ python
Python 2.7.6 (default, Oct 26 2016, 20:32:10)
[GCC 4.8.4] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
>>> import pydrive.auth
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named pydrive.auth
>>>
Notes:
Why not sudo?
Virtualenv creates a whole new environment for you, defining $PATH and some other variables and settings. When you use sudo pip install package, you are running Virtualenv as root, escaping the whole environment which was created, and then, installing the package on global site-packages, and not inside the project folder where you have a Virtual Environment, although you have activated the environment.
If you rename the folder of your project (as mentioned in the accepted answer)...
...you'll have to adjust some variables from some files inside the bin directory of your project.
For example:
bin/pip, line 1 (She Bang)
bin/activate, line 42 (VIRTUAL_ENV)

Came across the same issue today. I simply reinstalled pip globally with sudo easy_install pip (OSX/ Max), then created my virtualenv again with sudo virtualenv nameOfVEnv. Then after activating the new virtualenv the pip command worked as expected.
I don't think I used sudo on the first virtualenv creation and that may have been the reason for not having access to pip from within the virtualenv, I was able to get access to pip2 before this fix though which was odd.

I had this problem. It turned out there was a space in one of my folder names that caused the problem. I removed the space, deleted and reinstantiated using venv, and all was well.

This problem occurs when create a virtualenv instance and then change the parent folder name.

None of the above solutions worked for me.
My venv was active.
pip -V and which pip gave me the correct virtualenv path, but when I pip install-ed packages with activated venv, my pip freeze stayed empty.
All the environment variables were correct too.
Finally, I just changed pip and removed virtualenv:
easy_install pip==7.0.2
pip install pip==10
sudo pip uninstall virtualenv
Reinstall venv:
sudo pip install virtualenv
Create venv:
python -m virtualenv venv_name_here
And all packages installed correctly into my venv again.

After creating virtual environment, try to use pip located in yourVirtualEnvName\Scripts
It should install a package inside Lib\site-packages in your virtual environment

I had a similar problem on Windows. It was caused by renaming folder structures in my project within a virtualenv folder name. The paths in files didn't change but stayed as they were when virtual env was created. As Chase Ries mentioned I've changed the paths to VIRTUAL_ENV and python.exe in files
./venv/Scripts/activate.bat, set "VIRTUAL_ENV=path_to_venv\venv" 11 line in file
./venv/Scripts/Activate.ps1, $env:VIRTUAL_ENV="path_to_venv\venv" 30 line in file
./venv/Scripts/pip.exe, #!d:\path_to_env\venv\scripts\python.exe this line is at the end of a file, in my case moved to the right in 667 line, I am working on disc d so at the begining of the path is the letter of it
./venv/Scripts/pip3.7.exe, #!d:\path_to_env\venv\scripts\python.exe this line is at the end of a file, in my case moved to the right in 667 line
./venv/Scripts/pip3.exe, #!d:\path_to_env\venv\scripts\python.exe this line is at the end of a file, in my case moved to the right in 667 line

I had this problem too. Calling sudo pip install caused Python packages to be installed in the global site-packages diretory and calling pip install just worked fine.
So no use sudo in virtualenv.

The same problem. Python3.5 and pip 8.0.2 installed from Linux rpm's.
I did not find a primary cause and cannot give a proper answer. It looks like there are multiple possible causes.
However, I hope I can help with sharing my observation and a workaround.
pyvenv with --system-site-packages
./bin does not contain pip, pip is available from system site packages
packages are installed globally (BUG?)
pyvenv without --system-site-packages
pip gets installed into ./bin, but it's a different version (from ensurepip)
packages are installed within the virtual environment (OK)
Obvious workaround for pyvenv with --system-site-packages:
create it without the --system-site-packages option
change include-system-site-packages = false to true in pyvenv.cfg file

It's also worth checking that you didn't modify somehow the path to your virtualenv.
In that case the first line in bin/pip (and the rest of the executables) would have an incorrect path.
You can either edit these files and fix the path or remove and install again the virtualenv.

For Python 3ers
Try updating. I had this exact same problem and tried Chases' answer, however no success. The quickest way to refactor this is to update your Python Minor / Patch version if possible. I noticed that I was running 3.5.1 and updated to 3.5.2. Pyvenv once again works.

This happened to me when I created the virtualenv in the wrong location. I then thought I could move the dir to another location without it mattering. It mattered.
mkdir ~/projects
virtualenv myenv
cd myenv
git clone [my repository]
Oh crap, I forgot to cd into projects before creating the virtualenv and cloning the rep. Oh well, I'm too lazy to destroy and recreate. I'll just move the dir with no issues.
cd ~
mv myenv projects
cd projects/myenv/myrepo
pip install -r requirements
Nope, wants more permissions, what the?
I thought it was strange but SUDO AWAY! It then installed the packages into a global location.
The lesson I learned was, just delete the virtualenv dir. Don't move it.

Had this issue after installing Divio: it had changed my PATH or environment in some way, as it launches a terminal.
The solution in this case was just to do source ~/.bash_profile which should already be setup to get you back to your original pyenv/pyenv-virtualenv state.

Somehow a setup.cfg file with a prefix="" in the project folder
running pip install on the virtualenv outside the project folder worked so from the inside it was telling pip to use an empty prefix which defaults to "/"
removing the file fixed it

I had this problem, and after trying all the above solution I just removed everything and started afresh.
In my own case i used sudo in creating one of the folders in which the virtual environment existed, and sudo give the priviledges to root
I was very pissed! But it worked!

I have to use 'sudo' for installing packages through pip on my ubuntu system for some reason. This is causing the packages to be installed in global site-packages. Putting this here for anyone who might face this issue in future.

I had exactly the problem from the title, and I solved it. Pip started to install in the venv site-packages after I cleaned my PATH: it had a path to my local ~/bin directory at the very beginning.
So, my advice: thoroughly check your environment variables for "garbage" or any non-standard things. Unfortunately, virtualenv can be sensitive to those.
Good luck!

Short answer is run Command virtualenv with parameter “—no-site-packages”.
Long answer with explanation :-
So after running here and there, and going through lot of threads i found my self the problem. Above answers have given the idea but I would like to go again over everything though.
The problem is even if you’re activating the environment it’s referring to the system environment because of the way we have crated the virtualenv.
when we run the command virtualenv env -p python3
it will install the virtualenv but it will not create no-global—site-packages.txt.
Because of that when you activate the environment by source activate command there this file called site.py (name can be different, i just forgot ) which runs and checks if this file is not present it will not add your env path to sys.path and use systems python.
to fix this issue just run virtualenv with extra parameter —no-site-packages it will create that file and when you activate the environment it will add your custom environment path in your PATH variable making it accessible.

Lot of good discussion above, but virtualenv examples were used. Since 'conda' is now the recommended tool to manage virtualenv, I have summarized the steps in running pip in conda env as follow.
I'll use py36r as the name of the env, and /opt/conda/envs is the prefix to the envs):
$ source /opt/conda/etc/profile.d/conda.sh # skip if already done
$ conda activate py36r
$ pip install pkg_xyz
$ pip list | grep pkg_xyz
Note that the pip executed should be in /opt/conda/envs/py36r/bin/pip (not /opt/conda/bin/pip).
Alternatively, you can simply run the following without conda activate
$ /opt/conda/envs/py36r/bin/pip
Also, if you install using conda, you can install without activate:
$ conda install -n py36r pkg_abc ...

WINDOWS
For me solution was not to use
mkvirtualenv, but:
python -m venv path/to/your/virtualenv
workon works correctly.
while in virtualenv: pip -V shows virtualenv's path to pip

Pythonpath is still ignored and unable to install locally with pip

I'm finding that my pythonpath environment variable is ignored. I'm using python 2.6 on ubuntu. I have in my .bashrc the following:
export PTYHONPATH=/my/home/mylibs/lib/python2.6/site-packages/:$PYTHONPATH
Then I install a new version of numpy using:
python setup.py install --prefix=/my/home/mylibs/
and it gets correctly installed locally. However, when I try to install other packages (also using setup.py) that depend on the new version of numpy, they cannot find it, because by default the loaded numpy is the one in /usr/llib, and not the one specified in my PYTHONPATH. My PYTHONPATH gets correctly set but the system-wide directory is still overruling it.
How can this be fixed? I just want my local version of numpy to be accessed when I do import numpy. I saw other posts related to this with python 2.4 but as far as I can tell it never got resolved. Also, i'd like to do this without installing pip or virtualenv for now. It seems like it should be possible using --prefix or --home options passed to setup.py and then alteration of PYTHONPATH but this does not work for me... the system wide lib dirs are read first.
edit: I try to follow the suggestions and use pip. I have a system wide install of an old pip that does not recognize --user (ver 0.3). I tried to upgrade pip with pip itself but of course that failed because I cannot install it locally, so pip install pip --upgrade --user is not an option. I downloaded a new version of pip and installed locally in my home directory but the system wide old one is still used when I type pip at the prompt. I looked into the pip package and found runner.py so I tried to use it to install packages using:
runner.py install --user numpy --upgrade
That still fails with permission denied:
OSError: [Errno 13] Permission denied: '/usr/bin/f2py2.6'
It looks like --user is broken. I also am not sure how this would solve the fact that the system wide python uses the system wide packages in /usr/lib... is there a solution to this? It seems like it's virtually impossible to install local packages in python nowadays.

Ok, Python will use the first package it finds. The PYTHONPATH gets appended to sys.path, after the system one. So it will normally find the system one first. But the "official" per-user packages directory seems to be placed before that. So create your personal site-packages directory:
mkdir -p $HOME/.local/lib64/python2.7/site-packages
mkdir $HOME/bin
(You may have to change "lib64" to "lib32" or just "lib")
This directory gets placed before the system one on my system. But you should verify it by printing out sys.path.
Then install your packages into there. However, the --user option in the latest pip version should already place it there.
As a list resort you can manipulate sys.path. You can insert your directory into sys.path before the system site-packages, then import numpy.
You are getting permissions errors from the scripts installation, trying to put that in the system location. You can pass additional options to install scripts in your $HOME/bin directory.
Install like this:
pip install --user --install-option="--install-scripts=$HOME/bin"