.. _basic:

Basic Usage of Pipenv
=====================

.. image:: https://farm4.staticflickr.com/3931/33173826122_b7ee8f1a26_k_d.jpg

This document covers some of Pipenv's more basic features.

☤ Example Pipfile & Pipfile.lock
--------------------------------

.. _example_files:

Here is a simple example of a ``Pipfile`` and the resulting ``Pipfile.lock``.

Example Pipfile
///////////////

::

    [[source]]
    url = "https://pypi.python.org/simple"
    verify_ssl = true
    name = "pypi"

    [packages]
    requests = "*"


    [dev-packages]
    pytest = "*"


Example Pipfile.lock
////////////////////

::

    {
        "_meta": {
            "hash": {
                "sha256": "8d14434df45e0ef884d6c3f6e8048ba72335637a8631cc44792f52fd20b6f97a"
            },
            "host-environment-markers": {
                "implementation_name": "cpython",
                "implementation_version": "3.6.1",
                "os_name": "posix",
                "platform_machine": "x86_64",
                "platform_python_implementation": "CPython",
                "platform_release": "16.7.0",
                "platform_system": "Darwin",
                "platform_version": "Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64",
                "python_full_version": "3.6.1",
                "python_version": "3.6",
                "sys_platform": "darwin"
            },
            "pipfile-spec": 5,
            "requires": {},
            "sources": [
                {
                    "name": "pypi",
                    "url": "https://pypi.python.org/simple",
                    "verify_ssl": true
                }
            ]
        },
        "default": {
            "certifi": {
                "hashes": [
                    "sha256:54a07c09c586b0e4c619f02a5e94e36619da8e2b053e20f594348c0611803704",
                    "sha256:40523d2efb60523e113b44602298f0960e900388cf3bb6043f645cf57ea9e3f5"
                ],
                "version": "==2017.7.27.1"
            },
            "chardet": {
                "hashes": [
                    "sha256:fc323ffcaeaed0e0a02bf4d117757b98aed530d9ed4531e3e15460124c106691",
                    "sha256:84ab92ed1c4d4f16916e05906b6b75a6c0fb5db821cc65e70cbd64a3e2a5eaae"
                ],
                "version": "==3.0.4"
            },
            "idna": {
                "hashes": [
                    "sha256:8c7309c718f94b3a625cb648ace320157ad16ff131ae0af362c9f21b80ef6ec4",
                    "sha256:2c6a5de3089009e3da7c5dde64a141dbc8551d5b7f6cf4ed7c2568d0cc520a8f"
                ],
                "version": "==2.6"
            },
            "requests": {
                "hashes": [
                    "sha256:6a1b267aa90cac58ac3a765d067950e7dbbf75b1da07e895d1f594193a40a38b",
                    "sha256:9c443e7324ba5b85070c4a818ade28bfabedf16ea10206da1132edaa6dda237e"
                ],
                "version": "==2.18.4"
            },
            "urllib3": {
                "hashes": [
                    "sha256:06330f386d6e4b195fbfc736b297f58c5a892e4440e54d294d7004e3a9bbea1b",
                    "sha256:cc44da8e1145637334317feebd728bd869a35285b93cbb4cca2577da7e62db4f"
                ],
                "version": "==1.22"
            }
        },
        "develop": {
            "py": {
                "hashes": [
                    "sha256:2ccb79b01769d99115aa600d7eed99f524bf752bba8f041dc1c184853514655a",
                    "sha256:0f2d585d22050e90c7d293b6451c83db097df77871974d90efd5a30dc12fcde3"
                ],
                "version": "==1.4.34"
            },
            "pytest": {
                "hashes": [
                    "sha256:b84f554f8ddc23add65c411bf112b2d88e2489fd45f753b1cae5936358bdf314",
                    "sha256:f46e49e0340a532764991c498244a60e3a37d7424a532b3ff1a6a7653f1a403a"
                ],
                "version": "==3.2.2"
            }
        }
    }


.. _initialization:

☤ Importing from requirements.txt
---------------------------------

If you only have a ``requirements.txt`` file available when running ``pipenv install``,
pipenv will automatically import the contents of this file and create a ``Pipfile`` for you.

You can also specify ``$ pipenv install -r path/to/requirements.txt`` to import a requirements file.

Note, that when importing a requirements file, they often have version numbers pinned, which you likely won't want
in your ``Pipfile``, so you'll have to manually update your ``Pipfile`` afterwards to reflect this.


.. _specifying_versions:

☤ Specifying Versions of a Package
----------------------------------

To tell pipenv to install a specific version of a library, the usage is simple::

    $ pipenv install requests==2.13.0

This will update your ``Pipfile`` to reflect this requirement, automatically.


☤ Specifying Versions of Python
-------------------------------

To create a new virtualenv, using a specific version of Python you have installed (and
on your ``PATH``), use the ``--python VERSION`` flag, like so:

Use Python 3::

   $ pipenv --python 3

Use Python3.6::

   $ pipenv --python 3.6

Use Python 2.7.14::

    $ pipenv --python 2.7.14

When given a Python version, like this, Pipenv will automatically scan your system for a Python that matches that given version.

If a ``Pipfile`` hasn't been created yet, one will be created for you, that looks like this::

    [[source]]
    url = "https://pypi.python.org/simple"
    verify_ssl = true

    [dev-packages]

    [packages]

    [requires]
    python_version = "3.6"

Note the inclusion of ``[requires] python_version = "3.6"``. This specifies that your application requires this version
of Python, and will be used automatically when running ``pipenv install`` against this ``Pipfile`` in the future
(e.g. on other machines). If this is not true, feel free to simply remove this section.

If you don't specify a Python version on the command–line, either the ``[requires]`` ``python_full_version`` or ``python_version`` will be selected
automatically, falling back to whatever your system's default ``python`` installation is, at time of execution.


☤ Editable Dependencies (e.g. ``-e .`` )
----------------------------------------

You can tell Pipenv to install a path as editable — often this is useful for
the current working directory when working on packages::

    $ pipenv install '-e .' --dev

    $ cat Pipfile
    [dev-packages]
    "e1839a8" = {path = ".", editable = true}

Note that all sub-dependencies will get added to the ``Pipfile.lock`` as well.

☤ Automatic Python Installation
-------------------------------

If you have `pyenv <https://github.com/pyenv/pyenv#simple-python-version-management-pyenv>`_ installed and configured, Pipenv will automatically ask you if you want to install a required version of Python if you don't already have it available.

This is a very fancy feature, and we're very proud of it::

    $ cat Pipfile
    [[source]]
    url = "https://pypi.python.org/simple"
    verify_ssl = true

    [dev-packages]

    [packages]
    requests = "*"

    [requires]
    python_version = "3.6"

    $ pipenv install
    Warning: Python 3.6 was not found on your system…
    Would you like us to install latest CPython 3.6 with pyenv? [Y/n]: y
    Installing CPython 3.6.2 with pyenv (this may take a few minutes)…
    ...
    Making Python installation global…
    Creating a virtualenv for this project…
    Using /Users/kennethreitz/.pyenv/shims/python3 to create virtualenv…
    ...
    No package provided, installing all dependencies.
    ...
    Installing dependencies from Pipfile.lock…
    🐍   ❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒❒ 5/5 — 00:00:03
    To activate this project's virtualenv, run the following:
     $ pipenv shell

Pipenv automatically honors both the ``python_full_version`` and ``python_version`` `PEP 508 <https://www.python.org/dev/peps/pep-0508/>`_ specifiers.

💫✨🍰✨💫


.. _environment_management:

☤ Environment Management with Pipenv
------------------------------------

The three primary commands you'll use in managing your pipenv environment are
``$ pipenv install``, ``$ pipenv uninstall``, and ``$ pipenv lock``.

.. _pipenv_install:

$ pipenv install
////////////////

``$ pipenv install`` is used for installing packages into the pipenv virtual environment
and updating your Pipfile.

Along with the basic install command, which takes the form::

    $ pipenv install [package names]

The user can provide these additional parameters:

    - ``--two`` — Performs the installation in a virtualenv using the system ``python2`` link.
    - ``--three`` — Performs the installation in a virtualenv using the system ``python3`` link.
    - ``--python`` — Performs the installation in a virtualenv using the provided Python interpreter.

    .. warning:: None of the above commands should be used together. They are also
                 **destructive** and will delete your current virtualenv before replacing
                 it with an appropriately versioned one.

    .. note:: The virtualenv created by Pipenv may be different from what you were expecting.
              Dangerous characters (i.e. ``$`!*@"`` as well as space, line feed, carriage return,
              and tab) are converted to underscores. Additionally, the full path to the current
              folder is encoded into a "slug value" and appended to ensure the virtualenv name
              is unique.

    - ``--dev`` — Install both ``develop`` and ``default`` packages from ``Pipfile.lock``.
    - ``--system`` — Use the system ``pip`` command rather than the one from your virtualenv.
    - ``--ignore-pipfile`` — Ignore the ``Pipfile`` and install from the ``Pipfile.lock``.
    - ``--skip-lock`` — Ignore the ``Pipfile.lock`` and install from the ``Pipfile``. In addition, do not write out a ``Pipfile.lock`` reflecting changes to the ``Pipfile``.

.. _pipenv_uninstall:

$ pipenv uninstall
//////////////////

``$ pipenv uninstall`` supports all of the parameters in `pipenv install <#pipenv-install>`_,
as well as one additonal, ``--all``.

    - ``--all`` — This parameter will purge all files from the virtual environment,
      but leave the Pipfile untouched.


.. _pipenv_lock:

$ pipenv lock
/////////////

``$ pipenv lock`` is used to create a ``Pipfile.lock``, which declares **all** dependencies (and sub-dependencies) of your project, their latest available versions, and the current hashes for the downloaded files. This ensures repeatable, and most importantly *deterministic*, builds.

☤ About Shell Configuration
---------------------------

Shells are typically misconfigured for subshell use, so ``$ pipenv shell --fancy`` may produce unexpected results. If this is the case, try ``$ pipenv shell``, which uses "compatibility mode", and will attempt to spawn a subshell despite misconfiguration.

A proper shell configuration only sets environment variables like ``PATH`` during a login session, not during every subshell spawn (as they are typically configured to do). In fish, this looks like this::

    if status --is-login
        set -gx PATH /usr/local/bin $PATH
    end

You should do this for your shell too, in your ``~/.profile`` or ``~/.bashrc`` or wherever appropriate.

.. note:: The shell launched in interactive mode. This means that if your shell reads its configuration from a specific file for interactive mode (e.g. bash by default looks for a ``~/.bashrc`` configuration file for interactive mode), then you'll need to modify (or create) this file.


☤ A Note about VCS Dependencies
-------------------------------

Pipenv will resolve the sub–depencies of VCS dependencies, but only if they are editable, like so::

    [packages]
    requests = {git = "https://github.com/requests/requests.git", editable=true}

If editable is not true, sub–dependencies will not get resolved.


☤ Pipfile.lock Security Features
--------------------------------

``Pipfile.lock`` takes advantage of some great new security improvements in ``pip``.
By default, the ``Pipfile.lock`` will be generated with the sha256 hashes of each downloaded
package. This will allow ``pip`` to guarantee you're installing what you intend to when
on a compromised network, or downloading dependencies from an untrusted PyPI endpoint.

We highly recommend approaching deployments with promoting projects from a development
environment into production. You can use ``pipenv lock`` to compile your dependencies on
your development environment and deploy the compiled ``Pipfile.lock`` to all of your
production environments for reproducible builds.

.. note:

    If you'd like a ``requirements.txt`` output of the lockfile, run ``$ pipenv lock -r``.
    This will include all hashes, however (which is great!). To get a ``requirements.txt``
    without hashes, use ``$ pipenv run pip freeze``.

