[Telemetry] Add tracing_agent API.

[Telemetry] Add tracing_agent API.

Committed: https://crrev.com/210ff34516a975b9f4addd5be54d34290d7a6475
Cr-Commit-Position: refs/heads/master@{#312704}

[nednguyen, 2015-01-18 02:41:33]

Patchset #1 (id:1) has been deleted

[nednguyen, 2015-01-18 14:58:30]

Patchset #1 (id:20001) has been deleted

[nednguyen, 2015-01-18 14:59:29]

nednguyen@google.com changed reviewers:
+ chrishenry@google.com, dtu@chromium.org, nduca@chromium.org,
sullivan@chromium.org

[yurys, 2015-01-19 06:25:24]

yurys@chromium.org changed reviewers:
+ yurys@chromium.org

[yurys, 2015-01-19 06:25:25]

Is there a bug describing the purpose of adding this API and whether it relates
to removal of inspector_timeline.py? With this patch Telemetry starts using both
deprecated "Timeline" domain and "Tracing" and it is not quite clear what's the
plan on removing the former (see crbug.com/448318).

[nduca, 2015-01-20 19:49:47]

please make this more general

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/platform/tracing_agent/__init__.py (right):

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_agent/__init__.py:15: def
__init__(self, platform_backend):
i dont like that the construction is tied to the started-ness, and construction
does IsSupported implciitly.

Lets do this:

Constructor always succeeds, gets the platform backend
IsSupported is something you can call.
Start is an explicit method that gets the tracing start arguments
(categoryfilter, options)
Stop is an explicit method

We construct the agents when the backend starts. We reuse the agents across
runs, not create new ones.

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/platform/tracing_controller_backend.py
(right):

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_controller_backend.py:17:
self._current_chrome_tracing_agent = None
one big list please

all_agent_classes = telemetyr.util.Discover(agent subclasses)
all_supported_classes = [x for x in all_agent_classes if
x.IsSupported(self.platformbackend)]
self._supported_agents = [x() for x in all_supported_classes]


now just implement your few public check methods as:
  s = [x for x in self._supported_agents if isinstance(x,
ChromeDisplayTracingAgent)
  return len(s) != 0

then make the rest of this class work on a list of agents

[nednguyen, 2015-01-21 21:45:46]

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/platform/tracing_agent/__init__.py (right):

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_agent/__init__.py:15: def
__init__(self, platform_backend):
On 2015/01/20 19:49:47, nduca wrote:
> i dont like that the construction is tied to the started-ness, and
construction
> does IsSupported implciitly.
> 
> Lets do this:
> 
> Constructor always succeeds, gets the platform backend
> IsSupported is something you can call.
> Start is an explicit method that gets the tracing start arguments
> (categoryfilter, options)
> Stop is an explicit method
> 
> We construct the agents when the backend starts. We reuse the agents across
> runs, not create new ones.

Done.

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/platform/tracing_controller_backend.py
(right):

https://codereview.chromium.org/853353005/diff/40001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_controller_backend.py:17:
self._current_chrome_tracing_agent = None
On 2015/01/20 19:49:47, nduca wrote:
> one big list please
> 
> all_agent_classes = telemetyr.util.Discover(agent subclasses)
> all_supported_classes = [x for x in all_agent_classes if
> x.IsSupported(self.platformbackend)]
> self._supported_agents = [x() for x in all_supported_classes]
> 
> 
> now just implement your few public check methods as:
>   s = [x for x in self._supported_agents if isinstance(x,
> ChromeDisplayTracingAgent)
>   return len(s) != 0
> 
> then make the rest of this class work on a list of agents 

Done. I have to do some ugly custom handling logic for chrome_tracing_agent. Let
me know if you have better idea of how to handle this.

[nednguyen, 2015-01-21 21:47:41]

On 2015/01/19 06:25:25, yurys wrote:
> Is there a bug describing the purpose of adding this API and whether it
relates
> to removal of inspector_timeline.py? With this patch Telemetry starts using
both
> deprecated "Timeline" domain and "Tracing" and it is not quite clear what's
the
> plan on removing the former (see crbug.com/448318).

Hi Yurys, this is a mere refactoring change to tracing_controller. It shouldn't
touch "Timeline" domain, which is tied to browser/tab API?

[nduca, 2015-01-21 22:56:09]

lgtm with notes from our chat applied

https://codereview.chromium.org/853353005/diff/60001/tools/telemetry/telemetr...
File tools/telemetry/telemetry/core/platform/tracing_controller_backend.py
(right):

https://codereview.chromium.org/853353005/diff/60001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_controller_backend.py:56:
self._supported_agents.append(
Where's the code that removes this from the active list? Is there a way you can
write this so that that bug can't happen?

https://codereview.chromium.org/853353005/diff/60001/tools/telemetry/telemetr...
tools/telemetry/telemetry/core/platform/tracing_controller_backend.py:66: if
agent.IsActive():
lets remove IsActive its not adding value

[nednguyen, 2015-01-22 00:25:21]

The CQ bit was checked by nednguyen@google.com

[commit-bot: I haz the power, 2015-01-22 00:26:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/853353005/80001

[commit-bot: I haz the power, 2015-01-22 02:51:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-22 02:51:52]

Try jobs failed on following builders:
  linux_chromium_rel_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

Try jobs failed on following builders:
  linux_chromium_rel_ng on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[nednguyen, 2015-01-22 19:26:51]

The CQ bit was checked by nednguyen@google.com

[commit-bot: I haz the power, 2015-01-22 19:27:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/853353005/100001

[commit-bot: I haz the power, 2015-01-22 21:27:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-22 21:27:44]

Try jobs failed on following builders:
  win_gpu on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu/builds/11...)
  win_gpu_triggered_tests on tryserver.chromium.gpu
(http://build.chromium.org/p/tryserver.chromium.gpu/builders/win_gpu_triggered...)

[nednguyen, 2015-01-22 21:29:36]

The CQ bit was checked by nednguyen@google.com

[commit-bot: I haz the power, 2015-01-22 21:30:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/853353005/100001

[commit-bot: I haz the power, 2015-01-23 00:15:46]

Committed patchset #4 (id:100001)

[commit-bot: I haz the power, 2015-01-23 00:16:31]

Patchset 4 (id:??) landed as
https://crrev.com/210ff34516a975b9f4addd5be54d34290d7a6475
Cr-Commit-Position: refs/heads/master@{#312704}