I'm trying to deploy my Django site on Heroku, and thus, I need a requirements.txt file with the necessary packages that Heroku needs to install for me. I understand Django is a necessary package to be installed. Unfortunately, Django isn't included in the file when I run pip freeze > requirements.txt. Why is this? I'm not sure what to show you so you can tell me what's going wrong. Let me know and I'll add it. FYI the site hosts just fine on my local computer, so Django is definitely installed.
Sounds like you are working in a virtual environment, yet your Django dependency is installed globally. Check which Python packages are installed globally and uninstall Django (you probably don't need it globally). Then install it into your virtual environment. Now the freeze command should output Django as well.
General note: Most packages should be installed into your project virtual environment. There are only few packages where it makes sense to install them globally (eg aws management tools).
Related
I'm an experienced developer, but not very familiar with Python and Pyramid.
I'm trying to follow some (a bit old and unclear) instructions on deploying a Pyramid web application. My OS is Ubuntu 16.04.
The instructions say to install virtualenv and Pyramid - I do so with apt install virtualenv and apt install python-pyramid. Then they say I should run the app in a virtual environment, so I build that with virtualenv . -ppython3, and activate it with source bin/activate. I install the application from a ready-to-run buildout from GitHub. The buildout includes a "production.ini" file with parameters to pserve.
But Pyramid is not included in the virtual environment built with virtualenv. (There is no "pserve" in the bin directory, e.g.) So I can't run the applications with bin/pserve etc/production.ini, as the instructions say. And if I try with only "pserve", I get errors when trying to access files like "var/waitress-%(process_num)s.sock". Files that the app excepts to find in the virtual environment.
I've looked for flags to tell virtualenv to include Pyramid, but couldn't find any. Am I overlooking something? I'd be most grateful for some help! :-)
/Anders from Sweden
Perhaps you might want to try installing Pyramid in your virtual environment using pip, since apt-installed libraries are installed into /opt, rather than being visible to Python. In the guide, it seems like you're wanting to install Pyramid through the virtual environment so that it can be used by your program, so I think you'd be best using pip rather than apt-get. I did a quick Google search, and it seems like this is the library you need. Here, all you'd have to do is run the installation command once you've already entered the virtual environment with pip install pyramid. This way, you should only have access to it within the virtual environment, as well!
You mentioned it's using buildout - I assume this is zc.buildout. buildout usually manages its own virtualenv and handles installing all of the necessary dependencies. It really depends on how that buildout is configured as there's no standard there for what to do or how to run your app. I would normally expect pserve to be exposed in the bin folder, but maybe another app-specific script is exposed instead.
(.env) C:\Users\shara\Desktop\testfolder\_djhole>pip install Django (executed)
(.env) C:\Users\shara\Desktop\testfolder\_djhole>django-admin start project my site (No Module Found Error)
I have repeated this process for a long time. Cannot start working on Django so far due to this:
ModuleNotFoundError: No module named 'django.core'; 'Django' is not a package
I have uninstalled it and reinstalled it several times. when I use pip freeze then
asgiref==3.2.7
Django==3.0.7
pytz==2020.1
sqlparse==0.3.1
But still cannot start working on Django because the module is not found an error.
By the way, there is only one python version 3.8.3 and added to the path. I hope that there would be some genius out there who could give me some answer because I have searched all over the internet for resolving this diabolical problem and got no company.
If you do not have such an environment for your current project, then you need to do this
mkvirtualenv .env
You either already have an environment or just created it. Then you need to use the virtual environment. You can do that with this:
workon .env
Check if there is a requirements.txt file in the root of your project. If there is, then it means someone (perhaps you), has created a file which lists all of the packages that have to be installed to get it up and running. If that’s the case, then you only need to run this:
pip install -R requirements.txt
If you don’t have a requirements.txt files, then just run this:
pip install django
This will install the latest version of Django. If you need a specific version, then you can do that as well with:
pip install django==2.2.4
Lets say a developer is working on a project when he realizes he needs to use some package.
He uses pip to install it. Now, after installing it, would a the developer write it down as a dependency in the requirements file / setup.py?
What does that same dev do if he forgot to write down all the dependencies of the project (or if he didn't know better since he hasn't been doing it long)?
What I'm asking is what's the workflow when working with external packages from the PyPi?
The command:
pip freeze > requirements.txt
will copy all of the dependencies currently in your python environment into requirements.txt. http://pip.readthedocs.org/en/latest/reference/pip_freeze.html
It depends on the project.
If you're working on a library, you'll want to put your dependencies in setup.py so that if you're putting the library on PyPi, people will be able to install it, and its dependencies automatically.
If you're working on an application in Python (possibly web application), a requirements.txt file will be easier for deploying. You can copy all your code to where you need it, set up a virtual environment with virtualenv or pyvenv, and then do pip install -r requirements.txt. (You should be doing this for development as well so that you don't have a mess of libraries globally).
It's certainly easier to write the packages you're installing to your requirements.txt as soon as you've installed them than trying to figure out which ones you need at the end. What I do so that I never forget is I write the packages to the file first and then install with pip install -r.
pip freeze helps if you've forgotten what you've installed, but you should always read the file it created to make sure that you actually need everything that's in there. If you're using virtualenv it'll give better results than if you're installing all packages globally.
I run Vagrant on Mac OS X. I am coding inside a virtual machine with CentOS 6, and I have the same versions of Python and Ruby in my development and production environment. I have these restrictions:
I cannot manually install. Everything must come through RPM.
I cannot use pip install and gem install to install the libraries I want as the system is managed through Puppet, and everything I add will be removed.
yum has old packages. I usually cannot find the latest versions of the libraries.
I would like to put my libraries locally in a lib directory near my scripts, and create an RPM that includes those frozen versions of dependencies. I cannot find an easy way to bundle my libraries for my scripts and push everything into my production server. I would like to know the easiest way to gather my dependencies in Python and Ruby.
I tried:
virtualenv (with --relocatable option)
PYTHONPATH
sys.path.append("lib path")
I don't know which is the right way to go. Also for ruby, is there any way to solve my problems with bundler? I see that bundler is for rails. Does it work for custom small scripts?
I like the approach in Node.JS and NPM; all packages are stored locally in node_modules. I have nodejs rpm installed, and I deploy a folder with my application on the production server. I would like to do it this way in Ruby and Python.
I don't know Node, but what you describe for NPM seems to be exactly what a virtualenv is. Once the virtualenv is activated, pip installs only within that virtualenv - so puppet won't interfere. You can write out your current list of packages to a requirements.txt file with pip freeze, and recreate the whole thing again with pip install -r requirements.txt. Ideally you would then deploy with puppet, and the deploy step would involve creating or updating the virtualenv, activating it, then running that pip command.
Maybe take a look at Docker?
With Docker you could create a image of your specific environment and deploy that.
https://www.docker.com/whatisdocker/
I'm new to virtualenv but I'm writting django app and finally I will have to deploy it somehow.
So lets assume I have my app working on my local virtualenv where I installed all the required libraries. What I want to do now, is to run some kind of script, that will take my virtualenv, check what's installed inside and produce a script that will install all these libraries on fresh virtualenv on other machine. How this can be done? Please help.
You don't copy paste your virtualenv. You export the list of all the packages installed like -
pip freeze > requirements.txt
Then push the requirements.txt file to anywhere you want to deploy the code, and then just do what you did on dev machine -
$ virtualenv <env_name>
$ source <env_name>/bin/activate
(<env_name>)$ pip install -r path/to/requirements.txt
And there you have all your packages installed with the exact version.
You can also look into Fabric to automate this task, with a function like this -
def pip_install():
with cd(env.path):
with prefix('source venv/bin/activate'):
run('pip install -r requirements.txt')
You can install virtualenvwrapper and try cpvirtualenv, but the developers advise caution here:
Warning
Copying virtual environments is not well supported. Each virtualenv
has path information hard-coded into it, and there may be cases where
the copy code does not know it needs to update a particular file. Use
with caution.
If it is going to be on the same path you can tar it and extract it on another machine. If all the same dependencies, libraries etc are available on the target machine it will work.