Add is_first_class_gcs migration file

If is_first_class_gcs file exists with contents '1'
- GCS hooks will download content and then overwrite the file with '0'
- First class GCS deps will download as necessary by checking the hash
file.

If there is no is_first_class_gcs file or its content is '0' for a GCS hook:
- Hook will run normally and, if content is downloaded, an is_first_class_gcs
file will be written with '0'

If there is no is_first_class_gcs file or its content is '0' for a first
class gcs dep:
- Content will be downloaded and is_first_class_gcs will be set to '1'

Verified locally with migrating and unmigrating a GCS hook.
TODO: update other GCS hook scripts in chromium/src to check migration
file.

Bug: b/324418194
Change-Id: Ida8541cb70839b86e99115bcabfc38bc87e40136
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5368250
Reviewed-by: Joanna Wang <jojwang@chromium.org>
Commit-Queue: Stephanie Kim <kimstephanie@google.com>

download_from_google_storage.py

@@ -38,6 +38,9 @@ PLATFORM_MAPPING = {
     'zos': 'zos',
 }
 
+# (b/328065301): Remove when all GCS hooks are migrated to first class deps
+MIGRATION_TOGGLE_FILE_NAME = 'is_first_class_gcs'
+
 
 class InvalidFileError(IOError):
     pass
@@ -255,6 +258,12 @@ def _downloader_worker_thread(thread_num,
         input_sha1_sum, output_filename = q.get()
         if input_sha1_sum is None:
             return
+        working_dir = os.path.dirname(output_filename)
+        if not working_dir:
+            raise Exception(
+                'Unable to construct a working_dir from the output_filename.')
+        migration_file_name = os.path.join(working_dir,
+                                           MIGRATION_TOGGLE_FILE_NAME)
         extract_dir = None
         if extract:
             if not output_filename.endswith('.tar.gz'):
@@ -284,6 +293,14 @@ def _downloader_worker_thread(thread_num,
                               're-downloading...' %
                               (thread_num, output_filename))
                     skip = False
+            # (b/328065301): Remove when all GCS hooks are migrated to first
+            # class deps
+            # If the directory was created by a first class GCS
+            # dep, remove the migration file and re-download using the
+            # latest hook.
+            is_first_class_gcs = os.path.exists(migration_file_name)
+            if is_first_class_gcs:
+                skip = False
             if skip:
                 continue
 
@@ -371,6 +388,8 @@ def _downloader_worker_thread(thread_num,
                 with open(extract_dir + '.tmp', 'a'):
                     tar.extractall(path=dirname)
                 os.remove(extract_dir + '.tmp')
+        if os.path.exists(migration_file_name):
+            os.remove(migration_file_name)
         # Set executable bit.
         if sys.platform == 'cygwin':
             # Under cygwin, mark all files as executable. The executable flag in
@@ -448,7 +467,23 @@ def download_from_google_storage(input_filename, base_url, gsutil, num_threads,
 
     # Sequentially check for the most common case and see if we can bail out
     # early before making any slow calls to gsutil.
-    if not force and all(
+    if directory:
+        working_dir = input_filename
+    elif os.path.dirname(output):
+        working_dir = os.path.dirname(output)
+
+    if not working_dir:
+        raise Exception(
+            'Unable to construct a working_dir from the inputted directory'
+            ' or sha1 file name.')
+
+    # (b/328065301): Remove when all GCS hooks are migrated to first class deps
+    # If the directory was created by a first class GCS
+    # dep, remove the migration file and re-download using the
+    # latest hook.
+    migration_file = os.path.join(working_dir, MIGRATION_TOGGLE_FILE_NAME)
+    is_first_class_gcs = os.path.exists(migration_file)
+    if not force and not is_first_class_gcs and all(
             _data_exists(sha1, path, extract) for sha1, path in input_data):
         return 0
 

gclient.py

@@ -2548,9 +2548,8 @@ class GcsDependency(Dependency):
 
     def IsDownloadNeeded(self, output_dir, output_file):
         """Check if download and extract is needed."""
-        download_needed = False
         if not os.path.exists(output_file):
-            download_needed = True
+            return True
 
         hash_file = os.path.join(output_dir, 'hash')
         existing_hash = None
@@ -2559,13 +2558,21 @@ class GcsDependency(Dependency):
                 with open(hash_file, 'r') as f:
                     existing_hash = f.read().rstrip()
             except IOError:
-                download_needed = True
+                return True
         else:
-            download_needed = True
+            return True
+
+        # (b/328065301): Remove is_first_class_gcs_file logic when all GCS
+        # hooks are migrated to first class deps
+        is_first_class_gcs_file = os.path.join(
+            output_dir, download_from_google_storage.MIGRATION_TOGGLE_FILE_NAME)
+        is_first_class_gcs = os.path.exists(is_first_class_gcs_file)
+        if not is_first_class_gcs:
+            return True
 
         if existing_hash != self.sha256sum:
-            download_needed = True
-        return download_needed
+            return True
+        return False
 
     def GetSha256Sum(self, filename):
         sha = hashlib.sha256()
@@ -2654,6 +2661,11 @@ class GcsDependency(Dependency):
             with tarfile.open(output_file, 'r:*') as tar:
                 tar.extractall(path=output_dir)
         self.WriteFilenameHash(calculated_sha256sum, hash_file)
+        migration_toggle_file = os.path.join(
+            output_dir, download_from_google_storage.MIGRATION_TOGGLE_FILE_NAME)
+        with open(migration_toggle_file, 'w') as f:
+            f.write(str(1))
+            f.write('\n')
 
     #override
     def GetScmName(self):

tests/gclient_gcs_smoketest.py

@@ -39,16 +39,22 @@ class GClientSmokeGcs(gclient_smoketest_base.GClientSmokeBase):
             'abcd123\n',
             'src/another_gcs_dep/llvmfile.tar.gz':
             'tarfile',
+            'src/another_gcs_dep/is_first_class_gcs':
+            '1\n',
             'src/another_gcs_dep/extracted_dir/extracted_file':
             'extracted text',
             'src/gcs_dep/deadbeef':
             'tarfile',
             'src/gcs_dep/hash':
             'abcd123\n',
+            'src/gcs_dep/is_first_class_gcs':
+            '1\n',
             'src/gcs_dep/extracted_dir/extracted_file':
             'extracted text',
             'src/gcs_dep_with_output_file/hash':
             'abcd123\n',
+            'src/gcs_dep_with_output_file/is_first_class_gcs':
+            '1\n',
             'src/gcs_dep_with_output_file/clang-format-no-extract':
             'non-extractable file',
         })
@@ -77,6 +83,7 @@ class GClientSmokeGcs(gclient_smoketest_base.GClientSmokeBase):
         tree.update({
             'src/repo12/extracted_dir/extracted_file': 'extracted text',
             'src/repo12/hash': 'abcd123\n',
+            'src/repo12/is_first_class_gcs': '1\n',
             'src/repo12/path_to_file.tar.gz': 'tarfile',
         })
         self.assertTree(tree)
@@ -94,6 +101,7 @@ class GClientSmokeGcs(gclient_smoketest_base.GClientSmokeBase):
         tree.update({
             'src/repo12/extracted_dir/extracted_file': 'extracted text',
             'src/repo12/hash': 'abcd123\n',
+            'src/repo12/is_first_class_gcs': '1\n',
             'src/repo12/path_to_file.tar.gz': 'tarfile',
         })
         self.assertTree(tree)
@@ -109,6 +117,7 @@ class GClientSmokeGcs(gclient_smoketest_base.GClientSmokeBase):
         tree.update({
             'src/repo12/extracted_dir/extracted_file': 'extracted text',
             'src/repo12/hash': 'abcd123\n',
+            'src/repo12/is_first_class_gcs': '1\n',
             'src/repo12/path_to_file.tar.gz': 'tarfile',
         })
         self.assertTree(tree)