Create proper wrapper scripts to decouple from swarm_client.

scripts/slave/swarming/get_swarm_results.py

Index: scripts/slave/swarming/get_swarm_results.py
diff --git a/scripts/slave/swarming/get_swarm_results.py b/scripts/slave/swarming/get_swarm_results.py
index a9886ee26479e278be97ee3fd40fde8d4913fa76..57eb7e7f324be5a72967e4063d35703df658ea9c 100755
--- a/scripts/slave/swarming/get_swarm_results.py
+++ b/scripts/slave/swarming/get_swarm_results.py
@@ -5,8 +5,10 @@
 
 """Takes in a test name and retrives all the output that the swarm server
 has produced for tests with that name. This is expected to be called as a
-build step."""
+build step.
+"""
 
+import optparse
 import os
 import sys
 
@@ -78,14 +80,31 @@ def gen_summary_output(failed_tests, exit_code, shards_remaining):
   return out, exit_code
 
 
-def GetSwarmResults(
-    swarm_get_results, swarm_base_url, test_keys, timeout, max_threads):
+def v0(client, options, test_name):

[Isaac (away), 2013/08/20 22:22:33]

v0?  Can you add a comment for what this does?

[M-A Ruel, 2013/08/23 02:18:33]

There will be multiple version handler, this is what handles all the older
versions of the client code.

+  sys.path.insert(0, client)

[Isaac (away), 2013/08/20 22:22:33]

This will repeatedly extend sys.path with each call.

Guard with "if sys.path[0] != client" ?

Also: can you verify get_swarm_results is reexeced with each build (i.e. that
this import won't get cached)?

[M-A Ruel, 2013/08/23 02:18:33]

This function is only called once indirectly by main(). This file is not a
library.
I don't understand what you mean.

[Isaac (away), 2013/08/26 02:35:46]

I mean, can you verify that if you change swarm_get_results, the new version
will be used for subsequent builds, even though we're importing here.

[M-A Ruel, 2013/08/26 14:15:39]

My next CL is to delete swarm_get_results;
https://codereview.chromium.org/22980008 so this ensures it'll be a non-issue.
We don't want to do importing anymore, from now on it will be a
subprocess.call().

+  import swarm_get_results  # pylint: disable=F0401
+
+  timeout = swarm_get_results.DEFAULT_SHARD_WAIT_TIME
+  test_keys = swarm_get_results.get_test_keys(
+      options.swarming, test_name, timeout)
+  if not test_keys:
+    print >> sys.stderr, 'No test keys to get results with.'
+    return 1
+
+  options.shards = int(options.shards)

[Isaac (away), 2013/08/20 22:22:33]

not needed if you add type='int' to parser below.

[M-A Ruel, 2013/08/23 02:18:33]

Done.

+  if options.shards == -1:
+    options.shards = len(test_keys)
+  elif len(test_keys) < options.shards:
+    print >> sys.stderr, ('Warning: Test should have %d shards, but only %d '
+                          'test keys were found' % (options.shards,
+                                                    len(test_keys)))
+
   gtest_parser = gtest_utils.GTestLogParser()
   exit_code = None
   shards_remaining = range(len(test_keys))
   first_result = True
   for index, result in swarm_get_results.yield_results(
-      swarm_base_url, test_keys, timeout, max_threads):
+      options.swarming, test_keys, timeout, None):
     assert index == result['config_instance_index']
     if first_result and result['num_config_instances'] != len(test_keys):
       # There are more test_keys than actual shards.
@@ -104,35 +123,41 @@ def GetSwarmResults(
   return exit_code
 
 
+def determine_version_and_run_handler(client, options, test_name):
+  """Executes the proper handler based on the code layout and --version
+  support.
+  """
+  # TODO(maruel): Determine version when needed.
+  return v0(client, options, test_name)
+
+
 def main():
+  """Note: this is solely to run the current master's code and can totally
+  differ from the underlying script flags.
+
+  To update these flags:
+  - Update the following code to support both the previous flag and the new
+    flag.
+  - Change scripts/master/factory/swarm_commands.py to pass the new flag.
+  - Restart all the masters using swarming.
+  - Remove the old flag from this code.
+  """
   client = swarming_utils.find_client(os.getcwd())
   if not client:
     print >> sys.stderr, 'Failed to find swarm(ing)_client'
     return 1
 
-  # TODO(maruel): Do not import, reproduce the same flags and forward to a
-  # subprocess.call() instead.
-  sys.path.insert(0, client)
-  import swarm_get_results  # pylint: disable=F0401
-
-  parser, options, test_name = swarm_get_results.parse_args()
-  if not options.shards:
-    parser.error('The number of shards expected must be passed in.')
-  test_keys = swarm_get_results.get_test_keys(
-      options.url, test_name, options.timeout)
-  if not test_keys:
-    parser.error('No test keys to get results with.')
-
-  options.shards = int(options.shards)
-  if options.shards == -1:
-    options.shards = len(test_keys)
-  elif len(test_keys) < options.shards:
-    print >> sys.stderr, ('Warning: Test should have %d shards, but only %d '
-                          'test keys were found' % (options.shards,
-                                                    len(test_keys)))
-
-  return GetSwarmResults(
-      swarm_get_results, options.url, test_keys, options.timeout, None)
+  parser = optparse.OptionParser()
+  parser.add_option('-u', '--swarming', help='Swarm server')
+  parser.add_option('-s', '--shards', help='Number of shards')

[Isaac (away), 2013/08/20 22:22:33]

type='int'?

[M-A Ruel, 2013/08/23 02:18:33]

Done.

+  (options, args) = parser.parse_args()
+  if not args:
+    parser.error('Must specify one test name.')
+  elif len(args) > 1:
+    parser.error('Must specify only one test name.')
+  options.swarming = options.swarming.rstrip('/')
+
+  return determine_version_and_run_handler(client, options, args[0])
 
 
 if __name__ == '__main__':