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Add CurrentRepository() to Python runfiles library
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`runfiles.CurrentRepository()` can be used to get the canonical name of
the Bazel repository containing the caller at runtime. This information
is required to look up runfiles while taking repository mappings into
account.
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fmeum committed Oct 13, 2022
1 parent 3d5c5d7 commit 1a2dbf7
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Showing 6 changed files with 215 additions and 2 deletions.
102 changes: 102 additions & 0 deletions src/test/py/bazel/py_test.py
Original file line number Diff line number Diff line change
Expand Up @@ -207,6 +207,108 @@ def testPyTestWithStdlibCollisionRunsRemotely(self):
self.AssertExitCode(exit_code, 0, stderr, stdout)
self.assertIn('Test ran', stdout)

class PyRunfilesLibraryTest(test_base.TestBase):
def testPyRunfilesLibraryCurrentRepository(self):
self.CreateWorkspaceWithDefaultRepos('WORKSPACE', [
'local_repository(',
' name = "other_repo",',
' path = "other_repo_path",',
')'
])

self.ScratchFile('pkg/BUILD.bazel', [
'py_library(',
' name = "library",',
' srcs = ["library.py"],',
' visibility = ["//visibility:public"],',
' deps = ["@bazel_tools//tools/python/runfiles"],',
')',
'',
'py_binary(',
' name = "binary",',
' srcs = ["binary.py"],',
' deps = [',
' ":library",',
' "@bazel_tools//tools/python/runfiles",'
' ],',
')',
'',
'py_test(',
' name = "test",',
' srcs = ["test.py"],',
' deps = [',
' ":library",',
' "@bazel_tools//tools/python/runfiles",',
' ],',
')',
])
self.ScratchFile('pkg/library.py', [
'from bazel_tools.tools.python.runfiles import runfiles',
'def print_repo_name():',
' print("in pkg/library.py: \'%s\'" % runfiles.Create().CurrentRepository())',
])
self.ScratchFile('pkg/binary.py', [
'from bazel_tools.tools.python.runfiles import runfiles',
'from pkg import library',
'library.print_repo_name()',
'print("in pkg/binary.py: \'%s\'" % runfiles.Create().CurrentRepository())',
])
self.ScratchFile('pkg/test.py', [
'from bazel_tools.tools.python.runfiles import runfiles',
'from pkg import library',
'library.print_repo_name()',
'print("in pkg/test.py: \'%s\'" % runfiles.Create().CurrentRepository())',
])

self.ScratchFile('other_repo_path/WORKSPACE')
self.ScratchFile('other_repo_path/pkg/BUILD.bazel', [
'py_binary(',
' name = "binary",',
' srcs = ["binary.py"],',
' deps = [',
' "@//pkg:library",',
' "@bazel_tools//tools/python/runfiles",'
' ],',
')',
'',
'py_test(',
' name = "test",',
' srcs = ["test.py"],',
' deps = [',
' "@//pkg:library",',
' "@bazel_tools//tools/python/runfiles",',
' ],',
')',
])
self.ScratchFile('other_repo_path/pkg/binary.py', [
'from bazel_tools.tools.python.runfiles import runfiles',
'from pkg import library',
'library.print_repo_name()',
'print("in external/other_repo/pkg/binary.py: \'%s\'" % runfiles.Create().CurrentRepository())',
])
self.ScratchFile('other_repo_path/pkg/test.py', [
'from bazel_tools.tools.python.runfiles import runfiles',
'from pkg import library',
'library.print_repo_name()',
'print("in external/other_repo/pkg/test.py: \'%s\'" % runfiles.Create().CurrentRepository())',
])

_, stdout, _ = self.RunBazel(['run', '//pkg:binary'])
self.assertIn('in pkg/binary.py: \'\'', stdout)
self.assertIn('in pkg/library.py: \'\'', stdout)

_, stdout, _ = self.RunBazel(['test', '//pkg:test', '--test_output=streamed'])
self.assertIn('in pkg/test.py: \'\'', stdout)
self.assertIn('in pkg/library.py: \'\'', stdout)

_, stdout, _ = self.RunBazel(['run', '@other_repo//pkg:binary'])
self.assertIn('in external/other_repo/pkg/binary.py: \'other_repo\'', stdout)
self.assertIn('in pkg/library.py: \'\'', stdout)

_, stdout, _ = self.RunBazel(['test', '@other_repo//pkg:test', '--test_output=streamed'])
self.assertIn('in external/other_repo/pkg/test.py: \'other_repo\'', stdout)
self.assertIn('in pkg/library.py: \'\'', stdout)


if __name__ == '__main__':
unittest.main()
32 changes: 32 additions & 0 deletions tools/python/gen_runfiles_constants.bzl
Original file line number Diff line number Diff line change
@@ -0,0 +1,32 @@
# Copyright 2022 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

_RUNFILES_CONSTANTS_TEMPLATE = """# Generated by gen_runfiles_constants.bzl
# Internal-only; do no use.
# The name of the runfiles directory corresponding to the main repository.
MAIN_REPOSITORY_RUNFILES_DIRECTORY = '%s'
"""

def _gen_runfiles_constants_impl(ctx):
out = ctx.actions.declare_file(ctx.attr.name + ".py")
ctx.actions.write(out, _RUNFILES_CONSTANTS_TEMPLATE % ctx.workspace_name)

return DefaultInfo(
files = depset([out]),
runfiles = ctx.runfiles([out]),
)

gen_runfiles_constants = rule(
implementation = _gen_runfiles_constants_impl,
)
10 changes: 9 additions & 1 deletion tools/python/runfiles/BUILD
Original file line number Diff line number Diff line change
@@ -1,3 +1,4 @@
load("//tools/python:gen_runfiles_constants.bzl", "gen_runfiles_constants")
load("//tools/python:private/defs.bzl", "py_library", "py_test")

package(default_visibility = ["//visibility:private"])
Expand All @@ -20,7 +21,14 @@ filegroup(
py_library(
name = "runfiles",
testonly = 1,
srcs = ["runfiles.py"],
srcs = [
"runfiles.py",
":_runfiles_constants",
],
)

gen_runfiles_constants(
name = "_runfiles_constants",
)

py_test(
Expand Down
10 changes: 9 additions & 1 deletion tools/python/runfiles/BUILD.tools
Original file line number Diff line number Diff line change
@@ -1,7 +1,15 @@
load("//tools/python:gen_runfiles_constants.bzl", "gen_runfiles_constants")
load("//tools/python:private/defs.bzl", "py_library")

py_library(
name = "runfiles",
srcs = ["runfiles.py"],
srcs = [
"runfiles.py",
":_runfiles_constants",
],
visibility = ["//visibility:public"],
)

gen_runfiles_constants(
name = "_runfiles_constants",
)
60 changes: 60 additions & 0 deletions tools/python/runfiles/runfiles.py
Original file line number Diff line number Diff line change
Expand Up @@ -58,9 +58,12 @@
p = subprocess.Popen([r.Rlocation("path/to/binary")], env, ...)
"""

import inspect
import os
import posixpath
import sys

from ._runfiles_constants import MAIN_REPOSITORY_RUNFILES_DIRECTORY

def CreateManifestBased(manifest_path):
return _Runfiles(_ManifestBased(manifest_path))
Expand Down Expand Up @@ -114,6 +117,7 @@ class _Runfiles(object):

def __init__(self, strategy):
self._strategy = strategy
self._python_runfiles_root = _FindPythonRunfilesRoot()

def Rlocation(self, path):
"""Returns the runtime path of a runfile.
Expand Down Expand Up @@ -161,6 +165,62 @@ def EnvVars(self):
"""
return self._strategy.EnvVars()

def CurrentRepository(self, frame = 1):
"""Returns the canonical name of the caller's Bazel repository.
For example, this function returns '' (the empty string) when called from
the main repository and a string of the form 'rules_python~0.13.0` when
called from code in the repository corresponding to the rules_python Bazel
module.
More information about the difference between canonical repository names and
the `@repo` part of labels is available at:
https://bazel.build/build/bzlmod#repository-names
NOTE: This function inspects the callstack to determine where in the
runfiles the caller is located to determine which repository it came from.
This may fail or produce incorrect results depending on who the caller is.
Use the `frame` argument to control the stack lookup, or pre-resolve the
repository via other means, for example by passing it in from Starlark, to
avoid this.
Args:
frame: int; the stack frame to return the repository name for. Defaults to
1, the caller of the CurrentRepository function.
Returns:
The canonical name of the Bazel repository containing the file containing
the frame-th caller of this function
Raises:
ValueError: if the caller cannot be determined or the caller's file path
is not contained in the Python runfiles tree
"""
try:
caller_path = inspect.getfile(sys._getframe(frame))
except ValueError:
raise ValueError("failed to determine caller's file path")
caller_runfiles_path = os.path.relpath(caller_path, self._python_runfiles_root)
if caller_runfiles_path.startswith(".." + os.path.sep):
raise ValueError('{} does not lie under the runfiles root {}'.format(caller_path, self._python_runfiles_root))

caller_runfiles_directory = caller_runfiles_path[:caller_runfiles_path.find(os.path.sep)]
if caller_runfiles_directory == MAIN_REPOSITORY_RUNFILES_DIRECTORY:
# The canonical name of the main repository (also known as the workspace)
# is the empty string.
return ''
# For all other repositories, the name of the runfiles directory is the
# canonical name.
return caller_runfiles_directory

def _FindPythonRunfilesRoot():
root = __file__
# Walk up our own runfiles path to the root of the runfiles tree from which
# the current file is being run. This path coincides with what the Bazel
# Python stub sets up as sys.path[0]. Since that entry can be changed at
# runtime, we rederive it here.
for _ in range("bazel_tools/tools/python/runfiles/runfiles.py".count("/") + 1):
root = os.path.dirname(root)
return root


class _ManifestBased(object):
"""`Runfiles` strategy that parses a runfiles-manifest to look up runfiles."""
Expand Down
3 changes: 3 additions & 0 deletions tools/python/runfiles/runfiles_test.py
Original file line number Diff line number Diff line change
Expand Up @@ -262,6 +262,9 @@ def testPathsFromEnvvars(self):
self.assertEqual(mf, "")
self.assertEqual(dr, "")

def testCurrentRepository(self):
self.assertEqual(runfiles.Create().CurrentRepository(), "")

@staticmethod
def IsWindows():
return os.name == "nt"
Expand Down

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