mozrunner starts 'adb logcat' processes but doesn't manage them

RESOLVED FIXED in Firefox 64


9 months ago
9 months ago


(Reporter: gbrown, Assigned: gbrown)


Version 3
Dependency tree / graph

Firefox Tracking Flags

(firefox64 fixed)



(1 attachment)

start_logcat() launches an adb process and returns the proc. connect() calls start_logcat and stores the return value, but doesn't do anything with it.

The wptrunner uses both of these mechanisms, performs no cleanup, and connects multiple times. As a result, after a few test groups have been completed, there are multiple logcat processes running, half of them logging to files, half of them logging to stdout. In addition, when run from mozharness, the mozharness script collects logcat for the duration of the task, and makes the log available as a test artifact.

If we are keeping logcat management in mozrunner, it should be delegated to existing support in mozdevice, rather than launching an adb process. Also, we need to make sure these logcats are not only started, but stopped.

However, I think it might be better to remove all the logcat functionality from mozrunner. There's no need for additional logcat'ing in mozharness tasks. Locally, developers usually run logcat manually.
Assignee: nobody → gbrown
The existing logcat collection code in mozrunner is problematic. Rather than fix it, I'd prefer to remove it. In CI, mozharness scripts already collect the full logcat. When running locally, testers/developers can usually achieve better results by running logcat independent of the test harness, either using 'adb logcat' from the command line, using an ide, or using a specialized logcat tool.
Attachment #9015638 - Flags: review?(dburns)
Blocks: 1495430
Attachment #9015638 - Flags: review?(dburns) → review+
Pushed by
Remove logcat functionality from mozrunner; r=automatedtester
Priority: -- → P1
Closed: 9 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla64
Created web-platform-tests PR for changes under testing/web-platform/tests
Can't merge web-platform-tests PR due to failing upstream checks:
Github PR
* Taskcluster (pull_request) (
Upstream PR merged
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