Python Venv Cheats

Repo consists of personal notes of using different python version management systems.

Initialise

Tool	Command
pdm	mkdir my-project && cd my-project && pdm init
hatch	hatch new my-project
poetry	poetry new my-project

Dependencies

Pdm

pdm add requests   # add requests
pdm add requests==2.25.1   # add requests with version constraint
pdm add requests[socks]   # add requests with extra dependency
pdm add "flask>=1.0" flask-sqlalchemy   # add multiple dependencies with different specifiers

# Local dependencies
pdm add ./sub-package
pdm add ./first-1.0.0-py2.py3-none-any.whl

Add development only dependencies

pdm add -dG test pytest

• This will create the following

[tool.pdm.dev-dependencies]
test = ["pytest"]

• You can specify more

[tool.pdm.dev-dependencies]
lint = [
    "flake8",
    "black"
]
test = ["pytest", "pytest-cov"]
doc = ["mkdocs"]

Update dependencies

pdm update

# specific
pdm update requests

# comma-separated list
pdm update -G "security,http"

# Update all default + dev-dependencies
pdm update -d
# Update a package in the specified group of dev-dependencies
pdm update -dG test pytest

Remove dependencies

# Remove requests from the default dependencies
pdm remove requests
# Remove h11 from the 'web' group of optional-dependencies
pdm remove -G web h11
# Remove pytest-cov from the `test` group of dev-dependencies
pdm remove -dG test pytest-cov

• More info here

Hatch

Installing dependencies in `hatch` is a bit different. You have to specify the dependencies in `pyproject.toml` or in `hatch.toml` file and when you `hatch shell` or `hatch run` the dependencies will automatically install.

Examples

You can select which environment to enter or run commands in by using the -e/--env root option or by setting the HATCH_ENVenvironment variable.

The run command allows for more explicit selection by prepending <ENV_NAME>: to commands. For example, if you had the following configuration:

# pyproject.toml
[tool.hatch.envs.docs]
dependencies = [
  "mkdocs"
]
[tool.hatch.envs.docs.scripts]
build = "mkdocs build --clean --strict"
serve = "mkdocs serve --dev-addr localhost:8000"

# hatch.toml
[envs.docs]
dependencies = [
  "mkdocs"
]
[envs.docs.scripts]
build = "mkdocs build --clean --strict"
serve = "mkdocs serve --dev-addr localhost:8000"

you could then serve your documentation by running:

hatch run docs:serve

• More info here

Poetry

You can simply do

poetry add requests # to install requrests

Examples

• If you specify new dependecies in pyproject.toml file you can do poetry install to install them.

[tool.poetry.dependencies]  # main dependency group
httpx = "*"
pendulum = "*"
[tool.poetry.group.test.dependencies]
pytest = "^6.0.0"
pytest-mock = "*"

• Optional groups can be installed in addition to the default dependencies by using the --with option of the install command.

[tool.poetry.group.docs]
optional = true

[tool.poetry.group.docs.dependencies]
mkdocs = "*"

poetry install --with docs

• More info here

Shell

Tool	Command
pdm	pdm shell
hatch	hatch shell
poetry	poetry shell

Active venv in Pdm

=== "bash/csh/zsh"

``` sh
eval $(pdm venv activate for-test)
```

=== "fish"

```sh
eval (pdm venv activate for-test)
```

=== "powershell"

```ps1
PS1> Invoke-Expression (pdm venv activate for-test)
```

N.B. In order to do pdm shell you have to set the following in your shell.

• Add a shell function to activate the virtualenv, here is an example of BASH function that also works on ZSH & BASH:

pdm() {
  local command=$1

  if [[ "$command" == "shell" ]]; then
      eval $(pdm venv activate)
  else
      command pdm $@
  fi
}

Copy and paste this function to your ~/.bashrc or ~/.zshrc file and restart your shell.

• For fish shell you can put the following into your ~/fish/config.fish or in ~/.config/fish/config.fish

  function pdm
      set cmd $argv[1]

      if test "$cmd" = "shell"
          eval (pdm venv activate)
      else
          command pdm $argv
      end
  end

Example pyproject.toml

N.B They are not the ideal projects and I don't recommend anyone to strictly follow them. They just get the job done :)

Tool	Link
pdm	swarm-bee-py
hatch	bmt-py
poetry	Delegation