Recode extract_image_id.sh in python (as well as the compare_ids_test rule)

contrib/BUILD

@@ -19,11 +19,22 @@ exports_files(["push-all.sh.tpl"])
 
 exports_files(["structure-test.sh.tpl"])
 
-exports_files(["compare_ids_test.sh.tpl"])
+exports_files(["compare_ids_test.py"])
 
 exports_files(["compare_ids_test.bzl"])
 
-exports_files(["extract_image_id.sh"])
+exports_files(["extract_image_id.py"])
+
+py_binary(
+    name = "extract_image_id",
+    srcs = [":extract_image_id.py"],
+)
+
+py_binary(
+    name = "compare_ids_test",
+    srcs = [":compare_ids_test.py"],
+    deps = ["extract_image_id"],
+)
 
 alias(
     name = "structure_test_executable",

contrib/compare_ids_test.bzl

@@ -24,20 +24,17 @@ def _compare_ids_test_impl(ctx):
     if (len(tar_files) == 1 and not ctx.attr.id):
         fail("One tar provided. Need either second tar or an id to compare it to.")
 
-    tars_string = ""
-    for tar in tar_files:
-        tars_string += tar.short_path + " "
+    runfiles = ctx.runfiles(files = tar_files + ctx.files._compare_ids_test_script)
 
-    runfiles = ctx.runfiles(files = tar_files + [ctx.file._id_extract_script])
+    id_args = []
+    if ctx.attr.id:
+        id_args = ["--id", ctx.attr.id]
 
-    ctx.actions.expand_template(
-        template = ctx.file._executable_template,
+    args = " ".join([f.short_path for f in tar_files] + id_args)
+
+    ctx.actions.write(
         output = ctx.outputs.executable,
-        substitutions = {
-            "{id}": ctx.attr.id,
-            "{tars}": tars_string,
-            "{id_script_path}": ctx.file._id_extract_script.short_path,
-        },
+        content = "python {} {}".format(ctx.executable._compare_ids_test_script.short_path, args),
         is_executable = True,
     )
 
@@ -80,15 +77,11 @@ compare_ids_test = rule(
             mandatory = False,
             default = "",
         ),
-        "_executable_template": attr.label(
-            allow_files = True,
-            single_file = True,
-            default = "compare_ids_test.sh.tpl",
-        ),
-        "_id_extract_script": attr.label(
+        "_compare_ids_test_script": attr.label(
             allow_files = True,
-            single_file = True,
-            default = "extract_image_id.sh",
+            default = ":compare_ids_test",
+            executable = True,
+            cfg = "host",
         ),
     },
     test = True,

contrib/compare_ids_test.py

@@ -0,0 +1,63 @@
+# Copyright 2015 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.
+"""Compares the ids of the given valid image tarballs.
+
+usage: compare_ids_test.py [-h] [--id ID] tars [tars ...]
+
+positional arguments:
+  tars
+
+optional arguments:
+  -h, --help  show this help message and exit
+  --id ID
+
+Used in compare_ids_test.bzl
+  More info can be found there
+
+"""
+import argparse
+
+from extract_image_id import get_id
+
+
+def compare_ids(tars, id_=None):
+  """Compares the ids of the given valid image tarballs.
+
+  Args:
+    tars: list of str paths to the image tarballs
+    id_: (optional) the id we want the images to have
+          if None, just makes sure they are all the same
+
+  """
+
+  for image in tars:
+    current_id = get_id(image)
+    if id_ is None:
+      id_ = current_id
+    elif current_id != id_:
+      exit(1)
+
+  exit(0)
+
+
+if __name__ == "__main__":
+  parser = argparse.ArgumentParser()
+
+  parser.add_argument("tars", nargs="+", type=str, default=[])
+
+  parser.add_argument("--id", type=str, default=None)
+
+  args = parser.parse_args()
+
+  compare_ids(args.tars, args.id)

contrib/extract_image_id.py

@@ -0,0 +1,64 @@
+# Copyright 2015 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.
+"""Extracts the id of a docker image from its tarball.
+
+Takes one argument, the path to the tarball.
+"""
+
+
+from __future__ import print_function
+from json import JSONDecoder
+import sys
+import tarfile
+
+
+def get_id(tar_path):
+  """Extracts the id of a docker image from its tarball.
+
+  Args:
+    tar_path: str path to the tarball
+
+
+  Returns:
+    str id of the image
+
+  """
+  tar = tarfile.open(tar_path, mode="r")
+
+  decoder = JSONDecoder()
+  try:
+    # Extracts it as a file object (not to the disk)
+    manifest = tar.extractfile("manifest.json").read().decode("utf-8")
+  except Exception as e:
+    print((
+        "Unable to extract manifest.json, make sure {} "
+        "is a valid docker image.\n").format(tar_path),
+          e,
+          file=sys.stderr)
+    exit(1)
+
+  # Get the manifest dictionary from JSON
+  manifest = decoder.decode(manifest)[0]
+
+  # The name of the config file is of the form <image_id>.json
+  config_file = manifest["Config"]
+
+  # Get the id
+  id_ = config_file.split(".")[0]
+
+  return id_
+
+
+if __name__ == "__main__":
+  print(get_id(sys.argv[1]))

tests/contrib/compare_ids_fail_test.bzl

@@ -19,7 +19,7 @@ def _impl(ctx):
 load("//:compare_ids_test.bzl", "compare_ids_test")
 
 compare_ids_test(
-    name = "test",
+    name = "test_for_failure",
     id = {id},
     images = {tars},
 )
@@ -40,8 +40,9 @@ compare_ids_test(
 
     runfiles = ctx.runfiles(files = tar_files + [
         ctx.file._compare_ids_test_bzl,
-        ctx.file._compare_ids_test_sh_tpl,
+        ctx.file._compare_ids_test,
         ctx.file._extract_image_id,
+        ctx.file._BUILD,
     ])
 
     # Produces string of form (Necessary because of spaces): " 'reg exp 1' 'reg exp 2'"
@@ -56,10 +57,11 @@ compare_ids_test(
             "{tars}": tars_string,
             "{test_code}": test_code,
             "{bzl_path}": ctx.file._compare_ids_test_bzl.short_path,
-            "{tpl_path}": ctx.file._compare_ids_test_sh_tpl.short_path,
+            "{test_bin_path}": ctx.file._compare_ids_test.short_path,
             "{extractor_path}": ctx.file._extract_image_id.short_path,
             "{name}": ctx.attr.name,
             "{reg_exps}": reg_exps,
+            "{BUILD_path}": ctx.file._BUILD.short_path,
         },
         is_executable = True,
     )
@@ -110,15 +112,20 @@ compare_ids_fail_test = rule(
             single_file = True,
             default = "//contrib:compare_ids_test.bzl",
         ),
-        "_compare_ids_test_sh_tpl": attr.label(
+        "_compare_ids_test": attr.label(
             allow_files = True,
             single_file = True,
-            default = "//contrib:compare_ids_test.sh.tpl",
+            default = "//contrib:compare_ids_test.py",
         ),
         "_extract_image_id": attr.label(
             allow_files = True,
             single_file = True,
-            default = "//contrib:extract_image_id.sh",
+            default = "//contrib:extract_image_id.py",
+        ),
+        "_BUILD": attr.label(
+            allow_files = True,
+            single_file = True,
+            default = "//contrib:BUILD",
         ),
     },
 )

tests/contrib/compare_ids_fail_test.sh.tpl

@@ -25,8 +25,8 @@ mkdir -p new_temp_workspace_{name}
 cd new_temp_workspace_{name}
 
 touch WORKSPACE
-
-echo > BUILD {test_code}
+mkdir test_folder
+echo > test_folder/BUILD {test_code}
 
 # Link the test files we will be using and make sure the links point to real files
 # No second operand means it just links the file in the current directory,
@@ -36,27 +36,32 @@ echo > BUILD {test_code}
 ln -s ../{bzl_path}
 test -f $(basename {bzl_path})
 
-# Link compare_ids_test.sh.tpl
-ln -s ../{tpl_path}
-test -f $(basename {tpl_path})
+# Link compare_ids_test.py
+ln -s ../{test_bin_path}
+test -f $(basename {test_bin_path})
 
 # Link extract_image_id.sh
 ln -s ../{extractor_path}
 test -f $(basename {extractor_path})
 
+# Link BUILD
+ln -s ../{BUILD_path}
+test -f $(basename {BUILD_path})
 
+cd test_folder
 tar_num=0
 for tar in {tars}
 do
   # Link the supplied tars and rename them to 0.tar, 1.tar, etc.
-  eval mv $(ln -vs ../$tar | cut -d " " -f1) ${tar_num}.tar
+  eval mv $(ln -vs ../../$tar | cut -d " " -f1) ${tar_num}.tar
   test -f ${tar_num}.tar
   tar_num=$(expr $tar_num + 1)
 done
+cd ..
 
 # Save the output from the bazel call (this is in an if because the bazel
 # call is expected to fail, but should not terminate the script)
-if out="$(bazel test --test_output=all //:test 2>&1)"
+if out="$(bazel test --test_output=all //test_folder:test_for_failure 2>&1)"
 then
   exit 1;
 fi
@@ -71,4 +76,3 @@ do
 done
 
 exit 0
-