Log more when loading shard output.json fails

Log more when loading shard output.json fails

When we use swarming to run steps for build bots, and
swarming fails to load the output.json for and shard, the
whole step is marked as an infra failure.

Sometimes, the shard completes successfully, but swarming
can't load the output.json for whatever reason. We're not
sure why this is happening, and hopefully this will help.

BUG=653728
Committed: https://chromium.googlesource.com/chromium/tools/build/+/f33e8e1237971cb0ca2725751eae9c133a1ff93c

[katthomas, 2016-10-11 23:37:07]

Description was changed from

==========
Log more when loading shard output.json fails

When we use swarming to run steps for build bots, and
swarming fails to load the output.json for and shard, the
whole step is marked as an infra failure.

Sometimes, the shard completes successfully, but swarming
can't load the output.json for whatever reason. We're not
sure why this is happening, and hopefully this will help.

BUG=653728
==========

to

==========
Log more when loading shard output.json fails

When we use swarming to run steps for build bots, and
swarming fails to load the output.json for and shard, the
whole step is marked as an infra failure.

Sometimes, the shard completes successfully, but swarming
can't load the output.json for whatever reason. We're not
sure why this is happening, and hopefully this will help.

BUG=653728
==========

[katthomas, 2016-10-11 23:37:07]

katthomas@google.com changed reviewers:
+ maruel@google.com

[M-A Ruel, 2016-10-12 15:08:23]

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

[M-A Ruel, 2016-10-12 15:08:23]

lgtm!

[katthomas, 2016-10-12 15:51:34]

The CQ bit was checked by katthomas@google.com

[commit-bot: I haz the power, 2016-10-12 15:51:42]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-10-12 15:55:38]

Description was changed from

==========
Log more when loading shard output.json fails

When we use swarming to run steps for build bots, and
swarming fails to load the output.json for and shard, the
whole step is marked as an infra failure.

Sometimes, the shard completes successfully, but swarming
can't load the output.json for whatever reason. We're not
sure why this is happening, and hopefully this will help.

BUG=653728
==========

to

==========
Log more when loading shard output.json fails

When we use swarming to run steps for build bots, and
swarming fails to load the output.json for and shard, the
whole step is marked as an infra failure.

Sometimes, the shard completes successfully, but swarming
can't load the output.json for whatever reason. We're not
sure why this is happening, and hopefully this will help.

BUG=653728

Committed:
https://chromium.googlesource.com/chromium/tools/build/+/f33e8e1237971cb0ca27...
==========

[commit-bot: I haz the power, 2016-10-12 15:55:39]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/tools/build/+/f33e8e1237971cb0ca27...