pip

Building a new pip package

setup.py updates

Update the REQUIRED_PACKAGES list in the same file to ensure that all of our dependencies are listed and that they match the versions of the packages referenced in the Bazel WORKSPACE file. Also check that the correct version of tensorflow is listed.

Building the package

bazel build //magenta/tools/pip:build_pip_package
bazel-bin/magenta/tools/pip/build_pip_package /tmp/magenta_pkg

Before this next step, make sure your preferred virtualenv or conda environment is activated.

pip install -U /tmp/magenta_pkg/magenta-N.N.N-py2-none-any.whl

Next, test that it worked:

$ python
>>> import magenta
>>> magenta.music.midi_file_to_sequence_proto('test.mid')

You should see the NoteSequence representation of the midi file.

Upload the new version to pypi

twine upload /tmp/magenta_pkg/magenta-N.N.N-py2-none-any.whl

After this step, anyone should be able to pip install magenta and get the latest version.

Adding to the pip package

Libraries

As a convention, libraries that we want to expose externally through the pip package should be listed as dependencies in otherwise empty py_library targets that share the same name as their directory. Those targets should then be referenced as dependencies by the target for the directory above them, all the way up to the root //magenta target. (Targets named the same as their package are implicit; //magenta is short for //magenta:magenta.)

This allows us to list //magenta as the main py_library dependency for building the pip package and distributes maintenance of public API dependencies to each package.

For example, to expose magenta.pipelines.statistics, the magenta/pipelines/BUILD file will have a section that looks like this:

# The Magenta public API.
py_library(
    name = "pipelines",
    deps = [
        ":statistics",
    ],
)

And the magenta/BUILD file will have a section that looks like this:

# The Magenta public API.
py_library(
    name = "magenta",
    visibility = ["//magenta:__subpackages__"],
    deps = [
        "//magenta/pipelines",
    ],
)

Because we want import magenta to make all modules immediately available, we also need to create a custom __init__.py in the magenta directory and reference it in the srcs field for the //magenta:magenta target.

When you add a new module to be exported, you'll also need to add it to this __init__.py file. There are instructions in that file for how to automatically generate the list based on the python library dependencies.

Now the //magenta/tools/pip:build_pip_package target just needs to depend on //magenta.

The //magenta dependency also provides an easy way to verify that the models developed within the magenta repo use the same code that is available to external developers. Rather than depend directly on library targets, models should depend only on the //magenta target.

Libraries should continue to use dependencies like normal: one target for every python file, and every import statement should have a corresponding dependency. This ensures we avoid circular dependencies and also makes builds faster for tests.

Scripts

Our pip package also includes several executable scripts (e.g., convert_dir_to_note_sequences). These are just python files that pip create executable wrappers around and installs to the python binary path. After installation, users will have the script installed in their path. To add a new script to the distribution, follow these steps:

First, add the script as a data dependency to the //magenta/tools/pip:build_pip_package target. You will likely also need to modify the visibility of the script's target so the pip builder can see it by adding this line to the script's target:

visibility = ["//magenta/tools/pip:__subpackages__"],

Next, modify setup.py so the script's python module is listed under CONSOLE_SCRIPTS.

Finally, you will need to modify the script itself so that it can be invoked either directly or by the pip-generated wrapper script. The pip wrapper will look for a method called console_entry_point as defined in setup.py, but running the script directly (e.g., after a bazel build'ing it) will just invoke the if __name__ == '__main__': condition. Both of those need to trigger tf.app.run to run the actual main function because tf.app.run takes care of things like initializing flags. The easiest way to do this is by adding the following snippet to the end of your script:

def console_entry_point():
  tf.app.run(main)


if __name__ == '__main__':
  console_entry_point()