tools/build_defs/repo/utils.bzl - bazel - Git at Google

 # Copyright 2018 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.
 """Utils for manipulating external repositories, once fetched.

 ### Setup

 These utility are intended to be used by other repository rules. They
 can be loaded as follows.

 ```python
 load(
     "@bazel_tools//tools/build_defs/repo:utils.bzl",
     "workspace_and_buildfile",
     "patch",
     "update_attrs",
 )
 ```
 """

 def workspace_and_buildfile(ctx):
     """Utility function for writing WORKSPACE and, if requested, a BUILD file.

     This rule is inteded to be used in the implementation function of a
     repository rule.
     It assumes the parameters `name`, `build_file`, `build_file_contents`,
     `workspace_file`, and `workspace_file_content` to be
     present in `ctx.attr`, the latter four possibly with value None.

     Args:
       ctx: The repository context of the repository rule calling this utility
         function.
     """
     if ctx.attr.build_file and ctx.attr.build_file_content:
         ctx.fail("Only one of build_file and build_file_content can be provided.")

     if ctx.attr.workspace_file and ctx.attr.workspace_file_content:
         ctx.fail("Only one of workspace_file and workspace_file_content can be provided.")

     if ctx.attr.workspace_file:
         ctx.delete("WORKSPACE")
         ctx.symlink(ctx.attr.workspace_file, "WORKSPACE")
     elif ctx.attr.workspace_file_content:
         ctx.delete("WORKSPACE")
         ctx.file("WORKSPACE", ctx.attr.workspace_file_content)
     else:
         ctx.file("WORKSPACE", "workspace(name = \"{name}\")\n".format(name = ctx.name))

     if ctx.attr.build_file:
         ctx.delete("BUILD.bazel")
         ctx.symlink(ctx.attr.build_file, "BUILD.bazel")
     elif ctx.attr.build_file_content:
         ctx.delete("BUILD.bazel")
         ctx.file("BUILD.bazel", ctx.attr.build_file_content)

 def _is_windows(ctx):
     return ctx.os.name.lower().find("windows") != -1

 def _use_native_patch(ctx):
     """If patch_tool is empty and patch_args only contains -p<NUM> options, we use the native patch implementation."""
     if ctx.attr.patch_tool:
         return False
     for arg in ctx.attr.patch_args:
         if not arg.startswith("-p"):
             return False
     return True

 def patch(ctx):
     """Implementation of patching an already extracted repository.

     This rule is inteded to be used in the implementation function of a
     repository rule. It assuumes that the parameters `patches`, `patch_tool`,
     `patch_args`, `patch_cmds` and `patch_cmds_win` are present in `ctx.attr`.

     Args:
       ctx: The repository context of the repository rule calling this utility
         function.
     """
     bash_exe = ctx.os.environ["BAZEL_SH"] if "BAZEL_SH" in ctx.os.environ else "bash"
     powershell_exe = ctx.os.environ["BAZEL_POWERSHELL"] if "BAZEL_POWERSHELL" in ctx.os.environ else "powershell.exe"
     if len(ctx.attr.patches) > 0 or len(ctx.attr.patch_cmds) > 0:
         ctx.report_progress("Patching repository")

     if _use_native_patch(ctx):
         if ctx.attr.patch_args:
             strip = int(ctx.attr.patch_args[-1][2:])
         else:
             strip = 0
         for patchfile in ctx.attr.patches:
             ctx.patch(patchfile, strip)
     else:
         for patchfile in ctx.attr.patches:
             patch_tool = ctx.attr.patch_tool
             if not patch_tool:
                 patch_tool = "patch"
             command = "{patchtool} {patch_args} < {patchfile}".format(
                 patchtool = patch_tool,
                 patchfile = ctx.path(patchfile),
                 patch_args = " ".join([
                     "'%s'" % arg
                     for arg in ctx.attr.patch_args
                 ]),
             )
             st = ctx.execute([bash_exe, "-c", command])
             if st.return_code:
                 fail("Error applying patch %s:\n%s%s" %
                      (str(patchfile), st.stderr, st.stdout))

     if _is_windows(ctx) and hasattr(ctx.attr, "patch_cmds_win") and ctx.attr.patch_cmds_win:
         for cmd in ctx.attr.patch_cmds_win:
             st = ctx.execute([powershell_exe, "/c", cmd])
             if st.return_code:
                 fail("Error applying patch command %s:\n%s%s" %
                      (cmd, st.stdout, st.stderr))
     else:
         for cmd in ctx.attr.patch_cmds:
             st = ctx.execute([bash_exe, "-c", cmd])
             if st.return_code:
                 fail("Error applying patch command %s:\n%s%s" %
                      (cmd, st.stdout, st.stderr))

 def update_attrs(orig, keys, override):
     """Utility function for altering and adding the specified attributes to a particular repository rule invocation.

      This is used to make a rule reproducible.

     Args:
         orig: dict of actually set attributes (either explicitly or implicitly)
             by a particular rule invocation
         keys: complete set of attributes defined on this rule
         override: dict of attributes to override or add to orig

     Returns:
         dict of attributes with the keys from override inserted/updated
     """
     result = {}
     for key in keys:
         if getattr(orig, key) != None:
             result[key] = getattr(orig, key)
     result["name"] = orig.name
     result.update(override)
     return result

 def maybe(repo_rule, name, **kwargs):
     """Utility function for only adding a repository if it's not already present.

     This is to implement safe repositories.bzl macro documented in
     https://docs.bazel.build/versions/master/skylark/deploying.html#dependencies.

     Args:
         repo_rule: repository rule function.
         name: name of the repository to create.
         **kwargs: remaining arguments that are passed to the repo_rule function.

     Returns:
         Nothing, defines the repository when needed as a side-effect.
     """
     if name not in native.existing_rules():
         repo_rule(name = name, **kwargs)

 def read_netrc(ctx, filename):
     """Utility function to parse at least a basic .netrc file.

     Args:
       ctx: The repository context of the repository rule calling this utility
         function.
       filename: the name of the .netrc file to read

     Returns:
       dict mapping a machine names to a dict with the information provided
       about them
     """
     contents = ctx.read(filename)

     # Parse the file. This is mainly a token-based update of a simple state
     # machine, but we need to keep the line structure to correctly determine
     # the end of a `macdef` command.
     netrc = {}
     currentmachinename = None
     currentmachine = {}
     macdef = None
     currentmacro = ""
     cmd = None
     for line in contents.splitlines():
         if macdef:
             # as we're in a macro, just determine if we reached the end.
             if line:
                 currentmacro += line + "\n"
             else:
                 # reached end of macro, add it
                 currentmachine[macdef] = currentmacro
                 macdef = None
                 currentmacro = ""
         else:
             # Essentially line.split(None) which starlark does not support.
             tokens = [
                 w.strip()
                 for w in line.split(" ")
                 if len(w.strip()) > 0
             ]
             for token in tokens:
                 if cmd:
                     # we have a command that expects another argument
                     if cmd == "machine":
                         # a new machine definition was provided, so save the
                         # old one, if present
                         if not currentmachinename == None:
                             netrc[currentmachinename] = currentmachine
                         currentmachine = {}
                         currentmachinename = token
                     elif cmd == "macdef":
                         macdef = "macdef %s" % (token,)
                         # a new macro definition; the documentation says
                         # "its contents begin with the next .netrc line [...]",
                         # so should there really be tokens left in the current
                         # line, they're not part of the macro.

                     else:
                         currentmachine[cmd] = token
                     cmd = None
                 elif token in [
                     "machine",
                     "login",
                     "password",
                     "account",
                     "macdef",
                 ]:
                     # command takes one argument
                     cmd = token
                 elif token == "default":
                     # defines the default machine; again, store old machine
                     if not currentmachinename == None:
                         netrc[currentmachinename] = currentmachine

                     # We use the empty string for the default machine, as that
                     # can never be a valid hostname ("default" could be, in the
                     # default search domain).
                     currentmachinename = ""
                     currentmachine = {}
                 else:
                     fail("Unexpected token '%s' while reading %s" %
                          (token, filename))
     if not currentmachinename == None:
         netrc[currentmachinename] = currentmachine
     return netrc

 def use_netrc(netrc, urls):
     """compute an auth dict from a parsed netrc file and a list of URLs

     Args:
       netrc: a netrc file already parsed to a dict, e.g., as obtained from
         read_netrc
       urls: a list of URLs.

     Returns:
       dict suitable as auth argument for ctx.download; more precisely, the dict
       will map all URLs where the netrc file provides login and password to a
       dict containing the corresponding login and passwored, as well as the
       mapping of "type" to "basic"
     """
     auth = {}
     for url in urls:
         schemerest = url.split("://", 1)
         if len(schemerest) < 2:
             continue
         if not (schemerest[0] in ["http", "https"]):
             # For other protocols, bazel currently does not support
             # authentication. So ignore them.
             continue
         host = schemerest[1].split("/")[0].split(":")[0]
         if not host in netrc:
             continue
         authforhost = netrc[host]
         if "login" in authforhost and "password" in authforhost:
             auth[url] = {
                 "type": "basic",
                 "login": authforhost["login"],
                 "password": authforhost["password"],
             }
     return auth
	# Copyright 2018 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.
	"""Utils for manipulating external repositories, once fetched.

	### Setup

	These utility are intended to be used by other repository rules. They
	can be loaded as follows.

	```python
	load(
	"@bazel_tools//tools/build_defs/repo:utils.bzl",
	"workspace_and_buildfile",
	"patch",
	"update_attrs",
	)
	```
	"""

	def workspace_and_buildfile(ctx):
	"""Utility function for writing WORKSPACE and, if requested, a BUILD file.

	This rule is inteded to be used in the implementation function of a
	repository rule.
	It assumes the parameters `name`, `build_file`, `build_file_contents`,
	`workspace_file`, and `workspace_file_content` to be
	present in `ctx.attr`, the latter four possibly with value None.

	Args:
	ctx: The repository context of the repository rule calling this utility
	function.
	"""
	if ctx.attr.build_file and ctx.attr.build_file_content:
	ctx.fail("Only one of build_file and build_file_content can be provided.")

	if ctx.attr.workspace_file and ctx.attr.workspace_file_content:
	ctx.fail("Only one of workspace_file and workspace_file_content can be provided.")

	if ctx.attr.workspace_file:
	ctx.delete("WORKSPACE")
	ctx.symlink(ctx.attr.workspace_file, "WORKSPACE")
	elif ctx.attr.workspace_file_content:
	ctx.delete("WORKSPACE")
	ctx.file("WORKSPACE", ctx.attr.workspace_file_content)
	else:
	ctx.file("WORKSPACE", "workspace(name = \"{name}\")\n".format(name = ctx.name))

	if ctx.attr.build_file:
	ctx.delete("BUILD.bazel")
	ctx.symlink(ctx.attr.build_file, "BUILD.bazel")
	elif ctx.attr.build_file_content:
	ctx.delete("BUILD.bazel")
	ctx.file("BUILD.bazel", ctx.attr.build_file_content)

	def _is_windows(ctx):
	return ctx.os.name.lower().find("windows") != -1

	def _use_native_patch(ctx):
	"""If patch_tool is empty and patch_args only contains -p<NUM> options, we use the native patch implementation."""
	if ctx.attr.patch_tool:
	return False
	for arg in ctx.attr.patch_args:
	if not arg.startswith("-p"):
	return False
	return True

	def patch(ctx):
	"""Implementation of patching an already extracted repository.

	This rule is inteded to be used in the implementation function of a
	repository rule. It assuumes that the parameters `patches`, `patch_tool`,
	`patch_args`, `patch_cmds` and `patch_cmds_win` are present in `ctx.attr`.

	Args:
	ctx: The repository context of the repository rule calling this utility
	function.
	"""
	bash_exe = ctx.os.environ["BAZEL_SH"] if "BAZEL_SH" in ctx.os.environ else "bash"
	powershell_exe = ctx.os.environ["BAZEL_POWERSHELL"] if "BAZEL_POWERSHELL" in ctx.os.environ else "powershell.exe"
	if len(ctx.attr.patches) > 0 or len(ctx.attr.patch_cmds) > 0:
	ctx.report_progress("Patching repository")

	if _use_native_patch(ctx):
	if ctx.attr.patch_args:
	strip = int(ctx.attr.patch_args[-1][2:])
	else:
	strip = 0
	for patchfile in ctx.attr.patches:
	ctx.patch(patchfile, strip)
	else:
	for patchfile in ctx.attr.patches:
	patch_tool = ctx.attr.patch_tool
	if not patch_tool:
	patch_tool = "patch"
	command = "{patchtool} {patch_args} < {patchfile}".format(
	patchtool = patch_tool,
	patchfile = ctx.path(patchfile),
	patch_args = " ".join([
	"'%s'" % arg
	for arg in ctx.attr.patch_args
	]),
	)
	st = ctx.execute([bash_exe, "-c", command])
	if st.return_code:
	fail("Error applying patch %s:\n%s%s" %
	(str(patchfile), st.stderr, st.stdout))

	if _is_windows(ctx) and hasattr(ctx.attr, "patch_cmds_win") and ctx.attr.patch_cmds_win:
	for cmd in ctx.attr.patch_cmds_win:
	st = ctx.execute([powershell_exe, "/c", cmd])
	if st.return_code:
	fail("Error applying patch command %s:\n%s%s" %
	(cmd, st.stdout, st.stderr))
	else:
	for cmd in ctx.attr.patch_cmds:
	st = ctx.execute([bash_exe, "-c", cmd])
	if st.return_code:
	fail("Error applying patch command %s:\n%s%s" %
	(cmd, st.stdout, st.stderr))

	def update_attrs(orig, keys, override):
	"""Utility function for altering and adding the specified attributes to a particular repository rule invocation.

	This is used to make a rule reproducible.

	Args:
	orig: dict of actually set attributes (either explicitly or implicitly)
	by a particular rule invocation
	keys: complete set of attributes defined on this rule
	override: dict of attributes to override or add to orig

	Returns:
	dict of attributes with the keys from override inserted/updated
	"""
	result = {}
	for key in keys:
	if getattr(orig, key) != None:
	result[key] = getattr(orig, key)
	result["name"] = orig.name
	result.update(override)
	return result

	def maybe(repo_rule, name, **kwargs):
	"""Utility function for only adding a repository if it's not already present.

	This is to implement safe repositories.bzl macro documented in
	https://docs.bazel.build/versions/master/skylark/deploying.html#dependencies.

	Args:
	repo_rule: repository rule function.
	name: name of the repository to create.
	**kwargs: remaining arguments that are passed to the repo_rule function.

	Returns:
	Nothing, defines the repository when needed as a side-effect.
	"""
	if name not in native.existing_rules():
	repo_rule(name = name, **kwargs)

	def read_netrc(ctx, filename):
	"""Utility function to parse at least a basic .netrc file.

	Args:
	ctx: The repository context of the repository rule calling this utility
	function.
	filename: the name of the .netrc file to read

	Returns:
	dict mapping a machine names to a dict with the information provided
	about them
	"""
	contents = ctx.read(filename)

	# Parse the file. This is mainly a token-based update of a simple state
	# machine, but we need to keep the line structure to correctly determine
	# the end of a `macdef` command.
	netrc = {}
	currentmachinename = None
	currentmachine = {}
	macdef = None
	currentmacro = ""
	cmd = None
	for line in contents.splitlines():
	if macdef:
	# as we're in a macro, just determine if we reached the end.
	if line:
	currentmacro += line + "\n"
	else:
	# reached end of macro, add it
	currentmachine[macdef] = currentmacro
	macdef = None
	currentmacro = ""
	else:
	# Essentially line.split(None) which starlark does not support.
	tokens = [
	w.strip()
	for w in line.split(" ")
	if len(w.strip()) > 0
	]
	for token in tokens:
	if cmd:
	# we have a command that expects another argument
	if cmd == "machine":
	# a new machine definition was provided, so save the
	# old one, if present
	if not currentmachinename == None:
	netrc[currentmachinename] = currentmachine
	currentmachine = {}
	currentmachinename = token
	elif cmd == "macdef":
	macdef = "macdef %s" % (token,)
	# a new macro definition; the documentation says
	# "its contents begin with the next .netrc line [...]",
	# so should there really be tokens left in the current
	# line, they're not part of the macro.

	else:
	currentmachine[cmd] = token
	cmd = None
	elif token in [
	"machine",
	"login",
	"password",
	"account",
	"macdef",
	]:
	# command takes one argument
	cmd = token
	elif token == "default":
	# defines the default machine; again, store old machine
	if not currentmachinename == None:
	netrc[currentmachinename] = currentmachine

	# We use the empty string for the default machine, as that
	# can never be a valid hostname ("default" could be, in the
	# default search domain).
	currentmachinename = ""
	currentmachine = {}
	else:
	fail("Unexpected token '%s' while reading %s" %
	(token, filename))
	if not currentmachinename == None:
	netrc[currentmachinename] = currentmachine
	return netrc

	def use_netrc(netrc, urls):
	"""compute an auth dict from a parsed netrc file and a list of URLs

	Args:
	netrc: a netrc file already parsed to a dict, e.g., as obtained from
	read_netrc
	urls: a list of URLs.

	Returns:
	dict suitable as auth argument for ctx.download; more precisely, the dict
	will map all URLs where the netrc file provides login and password to a
	dict containing the corresponding login and passwored, as well as the
	mapping of "type" to "basic"
	"""
	auth = {}
	for url in urls:
	schemerest = url.split("://", 1)
	if len(schemerest) < 2:
	continue
	if not (schemerest[0] in ["http", "https"]):
	# For other protocols, bazel currently does not support
	# authentication. So ignore them.
	continue
	host = schemerest[1].split("/")[0].split(":")[0]
	if not host in netrc:
	continue
	authforhost = netrc[host]
	if "login" in authforhost and "password" in authforhost:
	auth[url] = {
	"type": "basic",
	"login": authforhost["login"],
	"password": authforhost["password"],
	}
	return auth