Add support for swarming priority and expiration in the test spec

scripts/slave/recipe_modules/swarming/api.py

Index: scripts/slave/recipe_modules/swarming/api.py
diff --git a/scripts/slave/recipe_modules/swarming/api.py b/scripts/slave/recipe_modules/swarming/api.py
index af138e6d97b830dee776e58a4e61b4ccb2d6ba46..b6890c6ea720fc35743e5cf78923ab7e844998cd 100644
--- a/scripts/slave/recipe_modules/swarming/api.py
+++ b/scripts/slave/recipe_modules/swarming/api.py
@@ -12,6 +12,15 @@ from recipe_engine import recipe_api
 # Minimally supported version of swarming.py script (reported by --version).
 MINIMAL_SWARMING_VERSION = (0, 4, 10)
 
+NAMED_PRIORITIES = {

[Paweł Hajdan Jr., 2016/03/23 15:08:04]

Wasn't the idea for these to be relative rather than absolute?

[Sergiy Byelozyorov, 2016/03/23 15:09:53]

I was only briefed by Ken on what exactly we were planning to do, so I may have
missed the point. Relative to what?

[Ken Russell (switch to Gerrit), 2016/03/23 17:11:29]

Each entry in the src/testing/buildbot JSON files describes launching the test
both on the CQ and the waterfalls, but the priorities for those jobs computed by
the recipe code are different. If we want to be able to choose a "lower"
priority for one particular long-running test, then "lower" for example needs to
mean "lower with respect to the default priority for either a presubmit or
non-presubmit job, depending on what type this job is."

[Ken Russell (switch to Gerrit), 2016/03/23 17:12:45]

(I hadn't figured out what the sliding scale should be for precommit and
non-precommit jobs. Both should have some range of priorities that are
selectable via these keywords.)

[Sergiy Byelozyorov, 2016/03/23 18:08:24]

Let me see if I understand this on an example of a gpu_tests step. Normally on
CQ it is scheduled with 30 and on waterfall with 25. So if one sets
priority_adjustment to higher for this test, then we'll deduct X from the
priority when running on CQ, but keep the priority for waterfall. This way, if X
is 5, we'll make CQ schedule gpu_tests with same priority (30-5=25) as on
waterfall, and, if X is 10, then with higher priority (30-10=20) than waterfall.

[Ken Russell (switch to Gerrit), 2016/03/23 21:35:42]

The intent is that the priority_adjustment apply to the jobs on both the CQ and
waterfall. So if the CQ schedules jobs between priorities 25 and 35, and the
waterfall between priorities 20 and 30, then the "default" priority would set it
to 30 for a CQ job and 25 for a waterfall job. "higher" priority might set it to
27 for a CQ job and 22 for a waterfall job.

[Sergiy Byelozyorov, 2016/03/24 17:30:51]

Done.

+  'highest': 10,   # higest possible priority
+  'higher': 25,    # used by most masters
+  'normal': 30,    # used by CQ
+  'lower': 35,     # used by chromium.fyi
+  'default': 200,  # very low, should be increased depending on the type of task
+  'lowest': 255,   # lowest possible priority
+}
+
 
 def parse_time(value):
   """Converts serialized time from the API to datetime.datetime."""
@@ -103,9 +112,7 @@ class SwarmingApi(recipe_api.RecipeApi):
     self._default_hard_timeout = 60*60
     self._default_idempotent = False
     self._default_io_timeout = 20*60
-    # The default priority is extremely low and should be increased dependending
-    # on the type of task.
-    self._default_priority = 200
+    self._default_priority = NAMED_PRIORITIES['default']
     self._default_tags = set()
     self._default_user = None
     self._pending_tasks = set()
@@ -276,7 +283,7 @@ class SwarmingApi(recipe_api.RecipeApi):
 
   @default_priority.setter
   def default_priority(self, value):
-    assert 1 <= value <= 255
+    assert NAMED_PRIORITIES['highest'] <= value <= NAMED_PRIORITIES['lowest']
     self._default_priority = value
 
   def add_default_tag(self, tag):
@@ -581,6 +588,12 @@ class SwarmingApi(recipe_api.RecipeApi):
   # To keep compatibility with some build_internal code. To be removed as well.
   collect_each = collect
 
+  def parse_priority_adjustment(self, adjustment):
+    if isinstance(adjustment, basestring) and adjustment in NAMED_PRIORITIES:
+      return NAMED_PRIORITIES[adjustment]
+
+    return None
+
   @staticmethod
   def _display_pending(summary_json, step_presentation):
     """Shows max pending time in seconds across all shards if it exceeds 10s."""