pipdeptree/README.rst

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pipdeptree
==========
``pipdeptree`` is a command line utility for displaying the python
packages installed in an virtualenv in form of a dependency
tree. Since ``pip freeze`` shows all dependencies as a flat list,
finding out which are the top level packages and which packages do
they depend on requires some effort. It can also be tedious to resolve
conflicting dependencies because ``pip`` doesn't yet have true
dependency resolution (more on this later). This utility tries to
solve these problem.
To some extent, this tool is inspired by ``lein deps :tree`` command
of `Leiningen <http://leiningen.org/>`_.
Installation
------------
.. code-block:: bash
$ pip install pipdeptree
Usage and examples
------------------
To give you a brief idea, here is the output of ``pipdeptree``
compared with ``pip freeze``:
.. code-block:: bash
$ pip freeze
Flask==0.10.1
Flask-Script==0.6.6
Jinja2==2.7.2
-e git+git@github.com:naiquevin/lookupy.git@cdbe30c160e1c29802df75e145ea4ad903c05386#egg=Lookupy-master
Mako==0.9.1
MarkupSafe==0.18
SQLAlchemy==0.9.1
Werkzeug==0.9.4
alembic==0.6.2
argparse==1.2.1
ipython==2.0.0
itsdangerous==0.23
psycopg2==2.5.2
redis==2.9.1
slugify==0.0.1
wsgiref==0.1.2
And now see what ``pipdeptree`` outputs,
.. code-block:: bash
$ pipdeptree
Warning!!! Possible confusing dependencies found:
* Mako==0.9.1 -> MarkupSafe [required: >=0.9.2, installed: 0.18]
Jinja2==2.7.2 -> MarkupSafe [installed: 0.18]
------------------------------------------------------------------------
Lookupy==0.1
wsgiref==0.1.2
argparse==1.2.1
psycopg2==2.5.2
Flask-Script==0.6.6
- Flask [installed: 0.10.1]
- Werkzeug [required: >=0.7, installed: 0.9.4]
- Jinja2 [required: >=2.4, installed: 2.7.2]
- MarkupSafe [installed: 0.18]
- itsdangerous [required: >=0.21, installed: 0.23]
alembic==0.6.2
- SQLAlchemy [required: >=0.7.3, installed: 0.9.1]
- Mako [installed: 0.9.1]
- MarkupSafe [required: >=0.9.2, installed: 0.18]
ipython==2.0.0
slugify==0.0.1
redis==2.9.1
What's with the warning about confusing dependencies?
-----------------------------------------------------
As seen in the above output, ``pipdeptree`` by default warns about
possible confusing dependencies. Any package that's specified as a
dependency of multiple packages with a different version is considered
as a possible confusing dependency. This is helpful because ``pip``
`doesn't have true dependency resolution
<https://github.com/pypa/pip/issues/988>`_ yet. The warning is printed
to stderr instead of stdout and it can be completely disabled by using
the ``--nowarn`` flag.
Warnings about circular dependencies
------------------------------------
In case any of the packages have circular dependencies (eg. package A
depending upon package B and package B depending upon package A), then
``pipdeptree`` will print warnings about that as well.
.. code-block:: bash
$ pipdeptree
Warning!!! Cyclic dependencies found:
- CircularDependencyA => CircularDependencyB => CircularDependencyA
- CircularDependencyB => CircularDependencyA => CircularDependencyB
------------------------------------------------------------------------
wsgiref==0.1.2
argparse==1.2.1
As with the confusing dependencies warnings, these are printed to
stderr and can be disabled using the ``--nowarn`` flag.
Using pipdeptree to write requirements.txt file
-----------------------------------------------
If you wish to track only the top level packages in your
``requirements.txt`` file, it's possible to do so using ``pipdeptree``
by grep-ing only the top-level lines from the output,
.. code-block:: bash
$ pipdeptree | grep -P '^\w+'
Lookupy==0.1
wsgiref==0.1.2
argparse==1.2.1
psycopg2==2.5.2
Flask-Script==0.6.6
alembic==0.6.2
ipython==2.0.0
slugify==0.0.1
redis==2.9.1
There is a problem here though. The output doesn't mention anything
about ``Lookupy`` being installed as an editable package (refer to the
output of ``pip freeze`` above) and information about it's source is
lost. To fix this, ``pipdeptree`` must be run with a ``-f`` or
``--freeze`` flag.
.. code-block:: bash
$ pipdeptree -f --nowarn | grep -P '^[\w0-9\-=.]+'
-e git+git@github.com:naiquevin/lookupy.git@cdbe30c160e1c29802df75e145ea4ad903c05386#egg=Lookupy-master
wsgiref==0.1.2
argparse==1.2.1
psycopg2==2.5.2
Flask-Script==0.6.6
alembic==0.6.2
ipython==2.0.0
slugify==0.0.1
redis==2.9.1
$ pipdeptree -f --nowarn | grep -P '^[\w0-9\-=.]+' > requirements.txt
The freeze flag will also not output the hyphens for child
dependencies, so you could dump the complete output of ``pipdeptree
-f`` to the requirements.txt file making the file human-friendly (due
to indentations) as well as pip-friendly. (Take care of duplicate
dependencies though)
Usage
-----
.. code-block:: bash
usage: pipdeptree.py [-h] [-f] [-a] [-l] [-w]
Dependency tree of the installed python packages
optional arguments:
-h, --help show this help message and exit
-f, --freeze Print names so as to write freeze files
-a, --all list all deps at top level
-l, --local-only If in a virtualenv that has global access donot show
globally installed packages
-w, --nowarn Inhibit warnings about possibly confusing packages
Known Issues
------------
* To work with packages installed inside a virtualenv, pipdeptree also
needs to be installed in the same virtualenv even if it's already
installed globally.
* One thing you might have noticed already is that ``flask`` is shown
as a dependency of ``flask-script``, which although correct, sounds
a bit odd. ``flask-script`` is being used here *because* we are
using ``flask`` and not the other way around. Same with
``sqlalchemy`` and ``alembic``. I haven't yet thought about a
possible solution to this! (May be if libs that are "extensions"
could be distinguished from the ones that are
"dependencies". Suggestions are welcome.)
Runnings Tests (for contributors)
---------------------------------
Tests require some dummy virtualenvs to be created. If you run them
using `tox <http://tox.readthedocs.org/en/latest/>`_, then that will
take care of creating the virtualenvs, so it's recommended that you
run the tests using ``tox`` for the first time.
.. code-block:: bash
$ pip install tox
$ tox
Thereafter, you may use either `pytest <http://pytest.org/latest/>`_
or `nose <https://nose.readthedocs.org/en/latest/>`_ to run them.
However, before pushing the code or sending pull requests it's
recommended to run ``tox`` once so that tests are run on all
environments.
License
-------
MIT (See LICENSE)