Add 'stat' to gsutil module.

In support of the signing rework we're going to want to have
the signers keep track of the calculated hash to ensure that
we don't have a TOCTOU type issue. This commit adds the stat
command to the gsutil module so that we can ask gs a files hash.

Change-Id: Ib35d1541292a18fbfc26fab50f594c682ba4109d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1754262
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: George Engelbrecht <engeg@google.com>

recipes/README.recipes.md

@@ -651,7 +651,7 @@ Arguments:
 
 — **def [cat](/recipes/recipe_modules/gsutil/api.py#108)(self, url, args=None, \*\*kwargs):**
 
-— **def [copy](/recipes/recipe_modules/gsutil/api.py#115)(self, source_bucket, source, dest_bucket, dest, args=None, link_name='gsutil.copy', metadata=None, unauthenticated_url=False, \*\*kwargs):**
+— **def [copy](/recipes/recipe_modules/gsutil/api.py#122)(self, source_bucket, source, dest_bucket, dest, args=None, link_name='gsutil.copy', metadata=None, unauthenticated_url=False, \*\*kwargs):**
 
 — **def [download](/recipes/recipe_modules/gsutil/api.py#94)(self, bucket, source, dest, args=None, \*\*kwargs):**
 
@@ -659,11 +659,13 @@ Arguments:
 
 &emsp; **@property**<br>&mdash; **def [gsutil\_py\_path](/recipes/recipe_modules/gsutil/api.py#10)(self):**
 
-&mdash; **def [list](/recipes/recipe_modules/gsutil/api.py#132)(self, url, args=None, \*\*kwargs):**
+&mdash; **def [list](/recipes/recipe_modules/gsutil/api.py#139)(self, url, args=None, \*\*kwargs):**
 
-&mdash; **def [remove\_url](/recipes/recipe_modules/gsutil/api.py#146)(self, url, args=None, \*\*kwargs):**
+&mdash; **def [remove\_url](/recipes/recipe_modules/gsutil/api.py#153)(self, url, args=None, \*\*kwargs):**
 
-&mdash; **def [signurl](/recipes/recipe_modules/gsutil/api.py#139)(self, private_key_file, bucket, dest, args=None, \*\*kwargs):**
+&mdash; **def [signurl](/recipes/recipe_modules/gsutil/api.py#146)(self, private_key_file, bucket, dest, args=None, \*\*kwargs):**
+
+&mdash; **def [stat](/recipes/recipe_modules/gsutil/api.py#115)(self, url, args=None, \*\*kwargs):**
 
 &mdash; **def [upload](/recipes/recipe_modules/gsutil/api.py#78)(self, source, bucket, dest, args=None, link_name='gsutil.upload', metadata=None, unauthenticated_url=False, \*\*kwargs):**
 ### *recipe_modules* / [infra\_paths](/recipes/recipe_modules/infra_paths)

recipes/recipe_modules/gsutil/api.py

@@ -112,6 +112,13 @@ class GSUtilApi(recipe_api.RecipeApi):
     name = kwargs.pop('name', 'cat')
     return self(cmd, name, **kwargs)
 
+  def stat(self, url, args=None, **kwargs):
+    args = args or []
+    url = self._normalize_url(url)
+    cmd = ['stat'] + args + [url]
+    name = kwargs.pop('name', 'stat')
+    return self(cmd, name, **kwargs)
+
   def copy(self, source_bucket, source, dest_bucket, dest, args=None,
            link_name='gsutil.copy', metadata=None, unauthenticated_url=False,
            **kwargs):

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

@@ -189,6 +189,20 @@
     "infra_step": true,
     "name": "gsutil cat"
   },
+  {
+    "cmd": [
+      "python",
+      "-u",
+      "RECIPE_MODULE[depot_tools::gsutil]/resources/gsutil_smart_retry.py",
+      "--",
+      "RECIPE_REPO[depot_tools]/gsutil.py",
+      "----",
+      "stat",
+      "gs://example/foo"
+    ],
+    "infra_step": true,
+    "name": "gsutil stat"
+  },
   {
     "name": "$result"
   }

recipes/recipe_modules/gsutil/examples/full.py

@@ -72,6 +72,7 @@ def RunSteps(api):
 
   api.gsutil.cat('gs://%s/foo' % bucket)
 
+  api.gsutil.stat('gs://%s/foo' % bucket)
 
 def GenTests(api):
   yield api.test('basic')