Somewhat complementary work - this change would make the generated packages
equivalent to the ultimate goal of replacing these top-level BUILD files
directly with setup.py files. Users could begin testing deployment with the
pants-generated sdists and seamlessly drop in setup.py-generated
replacements. Users wishing to deploy via PEX could use the pex tool on the
generated sdists rather than the pants pex plugin.
On Thu, Jul 30, 2015 at 4:13 PM, Bill Farner <wfar...@apache.org> wrote:
> We've talked in the past about switching build tools. Just to keep that in
> context - how would you weigh this effort against a tool change?
>
> -=Bill
>
> On Thu, Jul 30, 2015 at 4:00 PM, Kevin Sweeney <kevi...@apache.org> wrote:
>
> > I propose a simplification of the Python BUILD layout as follows and a
> set
> > of new conventions, as follows:
> >
> > 1) 1 BUILD per 3rd level directory. These are currently
> >
> > ```
> > % find src/main/python -maxdepth 3 -mindepth 3 -type d |while read
> dirname;
> > do echo $dirname | sed 's@src
> /main/python/\(.*\)/\(.*\)/\(.*\).*@\1.\2.\3@
> > ';
> > done
> > apache.aurora.client
> > apache.aurora.common
> > apache.aurora.tools
> > apache.aurora.admin
> > apache.aurora.executor
> > apache.aurora.config
> > apache.thermos.monitoring
> > apache.thermos.common
> > apache.thermos.cli
> > apache.thermos.testing
> > apache.thermos.core
> > apache.thermos.runner
> > apache.thermos.observer
> > apache.thermos.config
> > ```
> >
> > 2) Each BUILD file exports 1 python_library that provides a setup_py
> > containing each python_binary in the BUILD file, named the same as the
> > directory it's in so that it can be referenced without a ':' character.
> The
> > sources field in the python_binary will always be rglobs('*.py').
> >
> > 3) Other BUILD files may only depend on this single public python_library
> > target. Any other target is considered a private implementation detail
> and
> > should be prefixed with an _.
> >
> > 4) python_binary targets are always named the same as the exported
> console
> > script.
> >
> > 5) python_binary targets must have identical dependencies to the
> > python_library exported by the package and must use entry_point.
> >
> > The advantage of this change is that a PEX file generated by pants will
> > contain exactly the same files that will be available on the PYTHONPATH
> in
> > the case of pip-installation of the corresponding library target. This
> will
> > help our migration off pants in the future.
> >
> > Annotated example: apache.thermos.runner (renamed thermos/bin ->
> > thermos/runner)
> >
> > ```
> > % find src/main/python/apache/thermos/runner
> > src/main/python/apache/thermos/runner
> > src/main/python/apache/thermos/runner/__init__.py
> > src/main/python/apache/thermos/runner/thermos_runner.py
> > src/main/python/apache/thermos/runner/BUILD
> > % cat src/main/python/apache/thermos/runner/BUILD
> > # License boilerplate omitted
> > import os
> >
> >
> > # Private target so that a setup_py can exist without a circular
> > dependency. Only targets within this file should depend on
> > # this.
> > python_library(
> > name = '_runner',
> > # The target covers every python file under this directory and
> > subdirectories.
> > sources = rglobs('*.py'),
> > dependencies = [
> > '3rdparty/python:twitter.common.app',
> > '3rdparty/python:twitter.common.log',
> > # Source dependencies are always referenced without a ':'.
> > 'src/main/python/apache/thermos/common',
> > 'src/main/python/apache/thermos/config',
> > 'src/main/python/apache/thermos/core',
> > ],
> > )
> >
> > # Binary target for thermos_runner.pex. Nothing should depend on this -
> > it's only used as an argument to ./pants binary.
> > python_binary(
> > name = 'thermos_runner',
> > # Use entry_point, not source so the files used here are the same ones
> > tests see.
> > entry_point = 'apache.thermos.bin.thermos_runner',
> > dependencies = [
> > # Notice that we depend only on the single private target from this
> > BUILD file here.
> > ':_runner',
> > ],
> > )
> >
> > # The public library that everyone importing the runner symbols uses.
> > # The test targets and any other dependent source code should depend on
> > this.
> > python_library(
> > name = 'runner',
> > dependencies = [
> > # Again, notice that we depend only on the single private target from
> > this BUILD file here.
> > ':_runner',
> > ],
> > # We always provide a setup_py. This will cause any dependee libraries
> to
> > automatically reference this library
> > # in their requirements.txt rather than copy the source files into
> their
> > sdist.
> > provides = setup_py(
> > # Conventionally named and versioned.
> > name = 'apache.thermos.runner',
> > version = open(os.path.join(get_buildroot(),
> > '.auroraversion')).read().strip().upper(),
> > ).with_binaries({
> > # Every binary in this file should also be repeated here.
> > # Always use the dict-form of .with_binaries so that commands with
> > dashes in their names are supported.
> > # The console script name is always the same as the PEX with .pex
> > stripped.
> > 'thermos_runner': ':thermos_runner',
> > }),
> > )
> > ```
> >
> > Let me know what you think, if y'all agree I'll prepare a patch shortly.
> >
>
--
Kevin Sweeney
@kts
