Add stamp attribute to pkg_tar (in the style of cc_binary(stamp=-1,0,1)

examples/time_stamping/BUILD

@@ -0,0 +1,41 @@
+# Copyright 2021 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.
+# -*- coding: utf-8 -*-
+
+licenses(["notice"])
+
+load("@rules_pkg//:pkg.bzl", "pkg_tar")
+
+pkg_tar(
+    name = "never_stamped",
+    srcs = [
+        ":BUILD",
+    ],
+)
+
+pkg_tar(
+    name = "always_stamped",
+    srcs = [
+        ":BUILD",
+    ],
+    stamp = 1,
+)
+
+pkg_tar(
+    name = "controlled_by_stamp_option",
+    srcs = [
+        ":BUILD",
+    ],
+    stamp = -1,
+)

examples/time_stamping/WORKSPACE

@@ -0,0 +1,26 @@
+# Copyright 2021 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.
+
+workspace(name = "rules_pkg_examples")
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+local_repository(
+    name = "rules_pkg",
+    path = "../../pkg",
+)
+
+load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")
+
+rules_pkg_dependencies()

examples/time_stamping/readme.md

@@ -0,0 +1,52 @@
+# Examples of how time stamping works.
+
+## How it works
+
+Target declarations may use the `stamp` attribute to control
+the time stamping of files in an archive. The behavior follows
+the pattern of the cc_binary rule:
+
+https://docs.bazel.build/versions/main/be/c-cpp.html#cc_binary
+
+Read the BUILD file for more details.
+
+## Try this
+
+```
+bazel build :* 
+for tarball in bazel-bin/*.tar ; do
+  echo ==== $tarball
+  tar tvf $tarball
+done
+
+bazel build :*  --stamp=1
+for tarball in bazel-bin/*.tar ; do
+  echo ==== $tarball
+  tar tvf $tarball
+done
+```
+
+You should see something like:
+```
+INFO: Build completed successfully, 3 total actions
+==== bazel-bin/always_stamped.tar
+drwxr-xr-x  0 0      0           0 May  3 17:34 ./
+-r-xr-xr-x  0 0      0         968 May  3 17:34 ./BUILD
+==== bazel-bin/controlled_by_stamp_option.tar
+drwxr-xr-x  0 0      0           0 Dec 31  1999 ./
+-r-xr-xr-x  0 0      0         968 Dec 31  1999 ./BUILD
+==== bazel-bin/never_stamped.tar
+drwxr-xr-x  0 0      0           0 Dec 31  1999 ./
+-r-xr-xr-x  0 0      0         968 Dec 31  1999 ./BUILD
+INFO: Build option --stamp has changed, discarding analysis cache.
+INFO: Build completed successfully, 3 total actions
+==== bazel-bin/always_stamped.tar
+drwxr-xr-x  0 0      0           0 May  3 17:34 ./
+-r-xr-xr-x  0 0      0         968 May  3 17:34 ./BUILD
+==== bazel-bin/controlled_by_stamp_option.tar
+drwxr-xr-x  0 0      0           0 May  6 17:42 ./
+-r-xr-xr-x  0 0      0         968 May  6 17:42 ./BUILD
+==== bazel-bin/never_stamped.tar
+drwxr-xr-x  0 0      0           0 Dec 31  1999 ./
+-r-xr-xr-x  0 0      0         968 Dec 31  1999 ./BUILD
+```

pkg/BUILD

@@ -20,7 +20,6 @@ licenses(["notice"])
 exports_files(
     glob([
         "*.bzl",
-        "private/**",
     ]),
     visibility = ["//visibility:public"],
 )
@@ -88,6 +87,7 @@ py_binary(
     deps = [
         ":archive",
         ":helpers",
+        "//private:build_info",
     ],
 )
 
@@ -148,6 +148,6 @@ py_library(
 py_binary(
     name = "filter_directory",
     srcs = ["filter_directory.py"],
-    visibility = ["//visibility:public"],
     python_version = "PY3",
+    visibility = ["//visibility:public"],
 )

pkg/build_tar.py

@@ -21,6 +21,7 @@
 
 import archive
 import helpers
+from private import build_info
 
 
 class TarFile(object):
@@ -264,6 +265,8 @@ def main():
            'path/to/file=root.root.')
   parser.add_argument('--root_directory', default='./',
                       help='Default root directory is named "."')
+  parser.add_argument('--stamp_from', default='',
+                      help='File to find BUILD_STAMP in')
   options = parser.parse_args()
 
   # Parse modes arguments
@@ -303,11 +306,15 @@ def main():
         f = f[1:]
       ids_map[f] = (int(user), int(group))
 
+  default_mtime = options.mtime
+  if options.stamp_from:
+    default_mtime = build_info.get_timestamp(options.stamp_from)
+
   # Add objects to the tar file
   with TarFile(
       options.output, helpers.GetFlagValue(options.directory),
       options.compression, options.compressor, options.root_directory,
-      options.mtime) as output:
+      default_mtime=default_mtime) as output:
 
     def file_attributes(filename):
       if filename.startswith('/'):

pkg/distro/BUILD

@@ -36,6 +36,7 @@ pkg_tar(
     srcs = [
         ":small_workspace",
         "//:standard_package",
+        "//private:standard_package",
         "//releasing:standard_package",
         "//toolchains:standard_package",
     ],
@@ -97,7 +98,7 @@ genrule(
 bzl_library(
     name = "rules_pkg_lib",
     srcs = [
-        "//:private/util.bzl",
+        "//private:util.bzl",
         "//:package_variables.bzl",
         "//:path.bzl",
         "//:pkg.bzl",

pkg/pkg.bzl

@@ -15,7 +15,7 @@
 
 load(":path.bzl", "compute_data_path", "dest_path")
 load(":providers.bzl", "PackageArtifactInfo", "PackageVariablesInfo")
-load("private/util.bzl", "setup_output_files", "substitute_package_variables")
+load("//private:util.bzl", "setup_output_files", "substitute_package_variables")
 
 # TODO(aiuto): Figure  out how to get this from the python toolchain.
 # See check for lzma in archive.py for a hint at a method.
@@ -30,6 +30,7 @@ SUPPORTED_TAR_COMPRESSIONS = (
 )
 deb_filetype = [".deb", ".udeb"]
 _DEFAULT_MTIME = -1
+_stamp_condition = str(Label("//private:private_stamp_detect"))
 
 def _remap(remap_paths, path):
     """If path starts with a key in remap_paths, rewrite it."""
@@ -151,6 +152,10 @@ def _pkg_tar_impl(ctx):
         "--link=%s:%s" % (_quote(k, protect = ":"), ctx.attr.symlinks[k])
         for k in ctx.attr.symlinks
     ]
+    if ctx.attr.stamp == 1 or (ctx.attr.stamp == -1 and
+                               ctx.attr.private_stamp_detect):
+        args.append("--stamp_from=%s" % ctx.version_file.path)
+        files.append(ctx.version_file)
     arg_file = ctx.actions.declare_file(ctx.label.name + ".args")
     files.append(arg_file)
     ctx.actions.write(arg_file, "\n".join(args))
@@ -337,6 +342,7 @@ def _pkg_deb_impl(ctx):
         ),
     ]
 
+
 # A rule for creating a tar file, see README.md
 pkg_tar_impl = rule(
     implementation = _pkg_tar_impl,
@@ -372,6 +378,10 @@ pkg_tar_impl = rule(
             doc = "See Common Attributes",
             providers = [PackageVariablesInfo],
         ),
+        "stamp": attr.int(default = 0),
+        # Is --stamp set on the command line?
+        # TODO(https://github.com/bazelbuild/rules_pkg/issues/340): Remove this.
+        "private_stamp_detect": attr.bool(default = False),
 
         # Implicit dependencies.
         "build_tar": attr.label(
@@ -413,6 +423,10 @@ def pkg_tar(name, **kwargs):
     pkg_tar_impl(
         name = name,
         out = kwargs.pop("out", None) or (name + "." + extension),
+        private_stamp_detect = select({
+            _stamp_condition: True,
+            "//conditions:default": False,
+        }),
         **kwargs
     )
 

pkg/private/BUILD

@@ -0,0 +1,55 @@
+# Copyright 2021 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.
+"""rules_pkg internal code.
+
+This is subject to change at any time.
+"""
+
+load("@rules_python//python:defs.bzl", "py_library")
+
+licenses(["notice"])
+
+filegroup(
+    name = "standard_package",
+    srcs = glob([
+        "BUILD",
+        "*.bzl",
+        "*.py",
+    ]),
+    visibility = ["//distro:__pkg__"],
+)
+
+exports_files(
+    glob([
+        "*.bzl",
+    ]),
+    visibility = ["//distro:__pkg__"],
+)
+
+config_setting(
+    name = "private_stamp_detect",
+    values = {"stamp": "1"},
+)
+
+py_library(
+    name = "build_info",
+    srcs = [
+        "build_info.py",
+    ],
+    srcs_version = "PY3",
+    visibility = [
+        "//:__pkg__",
+        "//tests:__pkg__",
+    ],
+)

pkg/private/build_info.py

@@ -0,0 +1,37 @@
+# Copyright 2021 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.
+"""Get BUILD_TIMESTAMP."""
+
+
+def get_timestamp(volatile_status_file):
+  """Get BUILD_TIMESTAMP as an integer.
+
+  Reads a file of "name<space>value" pairs and returns the value
+  of the BUILD_TIMESTAMP. The file should be in the workspace status
+  format: https://docs.bazel.build/versions/master/user-manual.html#workspace_status
+
+  Args:
+    volatile_status_file: path to input file. Typically ctx.version_file.path.
+  Returns:
+    int: value of BUILD_TIMESTAMP
+  Exceptions:
+    Exception: Raised if there is no BUILD_TIMESTAMP or if it is not a number.
+  """
+  with open(volatile_status_file, 'r') as status_f:
+    for line in status_f:
+      parts = line.strip().split(' ')
+      if len(parts) > 1 and parts[0] == 'BUILD_TIMESTAMP':
+        return int(parts[1])
+  raise Exception(
+      "Invalid status file <%s>. Expected to find BUILD_TIMESTAMP" % volatile_status_file)

pkg/private/util.bzl

@@ -13,7 +13,7 @@
 # limitations under the License.
 """Internal utilities for rules_pkg."""
 
-load(":providers.bzl", "PackageVariablesInfo")
+load("//:providers.bzl", "PackageVariablesInfo")
 
 def setup_output_files(ctx, package_file_name = None, default_output_file = None):
     """Provide output file metadata for common packaging rules

pkg/rpm_pfg.bzl

@@ -25,7 +25,7 @@ find_system_rpmbuild(name="rules_pkg_rpmbuild")
 ```
 """
 
-load("//:private/util.bzl", "setup_output_files")
+load("//private:util.bzl", "setup_output_files")
 load("//:providers.bzl", "PackageArtifactInfo", "PackageFilegroupInfo", "PackageVariablesInfo")
 
 rpm_filetype = [".rpm"]

pkg/tests/BUILD

@@ -575,3 +575,22 @@ py_test(
         "@bazel_tools//tools/python/runfiles",
     ],
 )
+
+pkg_tar(
+    name = "stamped_tar",
+    srcs = ["BUILD"],
+    stamp = 1,
+)
+
+py_test(
+    name = "stamp_test",
+    srcs = [
+        "stamp_test.py",
+    ],
+    data = [
+        "stamped_tar.tar",
+    ],
+    deps = [
+        "@bazel_tools//tools/python/runfiles",
+    ],
+)