Allow specifying alternative "success" codes in gitiles requests.

This is needed in the release recipes because there are times when we
want to check that a file is _not_ there yet (i.e. 404 response).

R=agable@chromium.org, dnj@chromium.org

Change-Id: Iedf646d6c73ebf898e90afd2009840b1e5c5b1ab
Reviewed-on: https://chromium-review.googlesource.com/709916Reviewed-by: Paweł Hajdan Jr. <phajdan.jr@chromium.org>
Commit-Queue: Michael Moss <mmoss@chromium.org>

gerrit_util.py

@@ -358,9 +358,15 @@ def ReadHttpResponse(conn, accept_statuses=frozenset([200])):
     # If response.status < 500 then the result is final; break retry loop.
     # If the response is 404, it might be because of replication lag, so
     # keep trying anyway.
-    if response.status < 500 and response.status != 404:
+    if ((response.status < 500 and response.status != 404)
+        or response.status in accept_statuses):
       LOGGER.debug('got response %d for %s %s', response.status,
                    conn.req_params['method'], conn.req_params['uri'])
+      # If 404 was in accept_statuses, then it's expected that the file might
+      # not exist, so don't return the gitiles error page because that's not the
+      # "content" that was actually requested.
+      if response.status == 404:
+        contents = ''
       break
     # A status >=500 is assumed to be a possible transient error; retry.
     http_version = 'HTTP/%s' % ('1.1' if response.version == 11 else '1.0')

recipes/README.recipes.md

@@ -502,7 +502,7 @@ DEPRECATED. Consider using gerrit.get_change_description instead.
 
 Module for polling a git repository using the Gitiles web interface.
 
-— **def [commit\_log](/recipes/recipe_modules/gitiles/api.py#97)(self, url, commit, step_name=None, attempts=None):**
+— **def [commit\_log](/recipes/recipe_modules/gitiles/api.py#102)(self, url, commit, step_name=None, attempts=None):**
 
 Returns: (dict) the Gitiles commit log structure for a given commit.
 
@@ -512,7 +512,7 @@ Args:
   step_name (str): If not None, override the step name.
   attempts (int): Number of times to try the request before failing.
 
-— **def [download\_file](/recipes/recipe_modules/gitiles/api.py#113)(self, repository_url, file_path, branch='master', step_name=None, attempts=None, \*\*kwargs):**
+— **def [download\_file](/recipes/recipe_modules/gitiles/api.py#118)(self, repository_url, file_path, branch='master', step_name=None, attempts=None, \*\*kwargs):**
 
 Downloads raw file content from a Gitiles repository.
 
@@ -526,7 +526,7 @@ Args:
 Returns:
   Raw file content.
 
-— **def [log](/recipes/recipe_modules/gitiles/api.py#51)(self, url, ref, limit=0, cursor=None, step_name=None, attempts=None, \*\*kwargs):**
+— **def [log](/recipes/recipe_modules/gitiles/api.py#56)(self, url, ref, limit=0, cursor=None, step_name=None, attempts=None, \*\*kwargs):**
 
 Returns the most recent commits under the given ref with properties.
 
@@ -549,7 +549,7 @@ Returns:
   Cursor can be used for subsequent calls to log for paging. If None,
   signals that there are no more commits to fetch.
 
-— **def [refs](/recipes/recipe_modules/gitiles/api.py#39)(self, url, step_name='refs', attempts=None):**
+— **def [refs](/recipes/recipe_modules/gitiles/api.py#44)(self, url, step_name='refs', attempts=None):**
 
 Returns a list of refs in the remote repository.
 ### *recipe_modules* / [gsutil](/recipes/recipe_modules/gsutil)
@@ -800,9 +800,9 @@ like checkout or compile), and some of these tests have failed.
 — **def [RunSteps](/recipes/recipe_modules/git_cl/examples/full.py#17)(api):**
 ### *recipes* / [gitiles:examples/full](/recipes/recipe_modules/gitiles/examples/full.py)
 
-[DEPS](/recipes/recipe_modules/gitiles/examples/full.py#5): [gitiles](#recipe_modules-gitiles), [recipe\_engine/properties][recipe_engine/recipe_modules/properties]
+[DEPS](/recipes/recipe_modules/gitiles/examples/full.py#5): [gitiles](#recipe_modules-gitiles), [recipe\_engine/json][recipe_engine/recipe_modules/json], [recipe\_engine/properties][recipe_engine/recipe_modules/properties]
 
-— **def [RunSteps](/recipes/recipe_modules/gitiles/examples/full.py#11)(api):**
+— **def [RunSteps](/recipes/recipe_modules/gitiles/examples/full.py#12)(api):**
 ### *recipes* / [gsutil:examples/full](/recipes/recipe_modules/gsutil/examples/full.py)
 
 [DEPS](/recipes/recipe_modules/gsutil/examples/full.py#5): [gsutil](#recipe_modules-gsutil), [recipe\_engine/path][recipe_engine/recipe_modules/path]

recipes/recipe_modules/gitiles/api.py

@@ -32,6 +32,11 @@ class Gitiles(recipe_api.RecipeApi):
       args.extend(['--log-limit', log_limit])
     if log_start is not None:
       args.extend(['--log-start', log_start])
+    accept_statuses = kwargs.pop('accept_statuses', None)
+    if accept_statuses:
+      args.extend([
+          '--accept-statuses',
+          ','.join([str(s) for s in accept_statuses])])
     a = self.m.python(
         step_name, self.resource('gerrit_client.py'), args, **kwargs)
     return a

recipes/recipe_modules/gitiles/examples/full.expected/basic.json

@@ -529,6 +529,24 @@
     ],
     "name": "fetch master:OWNERS"
   },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[depot_tools::gitiles]/resources/gerrit_client.py",
+      "--json-file",
+      "/path/to/tmp/json",
+      "--url",
+      "https://chromium.googlesource.com/chromium/src/+/master/NONEXISTENT",
+      "--format",
+      "text",
+      "--attempts",
+      "1",
+      "--accept-statuses",
+      "404"
+    ],
+    "name": "fetch master:NONEXISTENT"
+  },
   {
     "name": "$result",
     "recipe_result": null,

recipes/recipe_modules/gitiles/examples/full.py

@@ -18,6 +18,8 @@ def RunSteps(api):
 
   data = api.gitiles.download_file(url, 'OWNERS', attempts=5)
   assert data == 'foobar'
+  data = api.gitiles.download_file(url, 'NONEXISTENT', attempts=1,
+                                   accept_statuses=[404])
 
 
 def GenTests(api):
@@ -58,4 +60,8 @@ def GenTests(api):
           'fetch master:OWNERS',
           api.gitiles.make_encoded_file('foobar')
       )
+      + api.step_data(
+          'fetch master:NONEXISTENT',
+          api.gitiles.make_encoded_file('')
+      )
   )

recipes/recipe_modules/gitiles/resources/gerrit_client.py

@@ -113,19 +113,22 @@ def main(arguments):
                  'instead.')
   query_params['format'] = args.format
 
+  kwargs = {}
+  accept_statuses = frozenset([int(s) for s in args.accept_statuses.split(',')])
+  if accept_statuses:
+    kwargs['accept_statuses'] = accept_statuses
+
   # Choose handler.
   if args.format == 'json':
     def handler(conn):
-      return ReadHttpJsonResponse(conn)
+      return ReadHttpJsonResponse(conn, **kwargs)
   elif args.format == 'text':
     # Text fetching will pack the text into structured JSON.
     def handler(conn):
-      result = ReadHttpResponse(conn).read()
-      if not result:
-        return None
+      result = ReadHttpResponse(conn, **kwargs).read()
       # Wrap in a structured JSON for export to recipe module.
       return {
-          'value': result,
+          'value': result or None,
       }
 
   if args.log_start:
@@ -183,6 +186,10 @@ def create_argparser():
            'This value can be typically be taken from json result of previous '
            'call to log, which returns next page start commit as "next" key. '
            'Only for https://<hostname>/<repo>/+log/... gitiles request.')
+  parser.add_argument(
+      '--accept-statuses', type=str, default='200',
+      help='Comma-separated list of Status codes to accept as "successful" '
+           'HTTP responses.')
   return parser