Comment by eigenvalue

3 years ago

Thanks for reminding me to look at PyPy again. I usually start all my new Python projects with this block of commands that I keep handy:

Create venv and activate it and install packages:

  python3 -m venv venv
  source venv/bin/activate
  python3 -m pip install --upgrade pip
  python3 -m pip install wheel
  pip install -r requirements.txt

I wanted a similar one-liner that I could use on a fresh Ubuntu machine so I can try out PyPy easily in the same way. After a bit of fiddling, I came up with this monstrosity which should work with both bash and zsh (though I only tested it on zsh):

Create venv and activate it and install packages using pyenv/pypy/pip:

  if [ -d "$HOME/.pyenv" ]; then rm -Rf $HOME/.pyenv; fi && \
  curl https://pyenv.run | bash && \
  DEFAULT_SHELL=$(basename "$SHELL") && \
  if [ "$DEFAULT_SHELL" = "zsh" ]; then RC_FILE=~/.zshrc; else RC_FILE=~/.bashrc; fi && \
  if ! grep -q 'export PATH="$HOME/.pyenv/bin:$PATH"' $RC_FILE; then echo -e '\nexport PATH="$HOME/.pyenv/bin:$PATH"' >> $RC_FILE; fi && \
  if ! grep -q 'eval "$(pyenv init -)"' $RC_FILE; then echo 'eval "$(pyenv init -)"' >> $RC_FILE; fi && \
  if ! grep -q 'eval "$(pyenv virtualenv-init -)"' $RC_FILE; then echo 'eval "$(pyenv virtualenv-init -)"' >> $RC_FILE; fi && \
  source $RC_FILE && \
  LATEST_PYPY=$(pyenv install --list | grep -P '^  pypy[0-9\.]*-\d+\.\d+' | grep -v -- '-src' | tail -1) && \
  LATEST_PYPY=$(echo $LATEST_PYPY | tr -d '[:space:]') && \
  echo "Installing PyPy version: $LATEST_PYPY" && \
  pyenv install $LATEST_PYPY && \
  pyenv local $LATEST_PYPY && \
  pypy -m venv venv && \
  source venv/bin/activate && \
  pip install --upgrade pip && \
  pip install wheel && \
  pip install -r requirements.txt

Maybe others will find it useful.

8 comments

eigenvalue

nicce 3 years ago

Just a note; these scrips are not comparable in monstrosity as the first is about to initiate the project when as the second one is to initiate whole PyPy installation.

So if you have PyPy already on your machines;

  pypy -m venv venv && \
    source venv/bin/activate && \
    pip install --upgrade pip && \
    pip install wheel && \
    pip install -r requirements.txt

Was not that bad after all, when my initial thought was that do I need all the above to just initiate the project :D

eigenvalue 3 years ago

That's true, but you can run the first block of commands on a brand new Ubuntu installation because regular CPython is installed by default. Whereas you would need to do the whole second block when starting on a fresh machine.

deizel 3 years ago

Given you'll want to activate a virtual environment for most Python projects, and projects live in directories.. I find myself constantly reaching for direnv. https://github.com/direnv/direnv/wiki/Python

    echo "layout python\npip install --upgrade pip pip-tools setuptools wheel\npip-sync" > .envrc

When you CD into a given project, it'll activate the venv, upgrade to non-ancient versions of Pip/etc with support for latest PEPs (ie. `pyproject.toml` support on new Python 3.9 env), verify the latest pinned packages are present.. it's just too useful not to have.

    direnv stdlib

This command (or this link https://direnv.net/man/direnv-stdlib.1.html) will print many useful functions that can be used in the `.envrc` shell script that is loaded when entering directories, ranging from many languages, to `dotenv` support, to `on_git_branch` for e.g. syncing deps when switching feature branches.

Check it out if you haven't.. I've been using it for more years than I can count and being able to CD from a PHP project to a Ruby project to a Python project with ease really helps with context switching.

stefanor 3 years ago

If you have a system-level installed pypy, the pypy equivalent is:

  python3 -m venv -p pypy3 venv
  source venv/bin/activate
  python3 -m pip install --upgrade pip
  python3 -m pip install wheel
  pip install -r requirements.txt

Not very different...

saila 3 years ago

For a more apples to apples comparison, you would install pypy using your package manager, e.g. apt install pypy3 or brew install pypy3. On Linux, you might have to add a package repo first.

eigenvalue 3 years ago
I find that much scarier to do personally since it seems a lot more likely to screw up other stuff on your machine, whereas with pyenv it's all self-contained in the venv. Also using apt packages tends to install a pretty old version.
- smarnach 3 years ago
  
  No, installing a package with apt is not more likely to screw up your machine than installing it manually. Moreover, you seem to be completely fine using the apt-installed CPython, while you think PyPy needs to be installed manually.
- saila 3 years ago
  
  I use pyenv myself, but that is beside the point. The two examples above are using different strategies to install python3 versus pypy. A valid comparison would use a package manager for both or pyenv for both.