Additional log upload improvements

[timothyb89]

#211 adds log uploads to a GCS bucket. We can make a few more small improvements that would improve quality of life a lot:

• [x] Compress (gzip) logs over a certain size, say 1 KiB. Files should be named .log.gz versus .log and have their Content-Encoding set to gzip.
• [ ] CI should post a comment on the PR that shows log status and links to files
• [ ] Add a small dashboard for each run using the manifest file. We could provide some basic info about the build and link directly to each container log.
• [ ] Look at including docker's json logs as well. They include timestamps and the stream name for each message so we could have a nice preview in the browser.

[timothyb89]

• [x] An easier way to get timestamps in logs: add -t to the docker logs call

[aadams19]

See https://github.com/monasca/monasca-docker/pull/211/commits/72e5ee14cdc7021fe41b57e9c610bf10bb6da832 for compress and timestamp fixes

[kornicameister]

@aadams19 do you want to implement all those points in #211 ?

[aadams19]

No, our plan is just do those two changes in https://github.com/monasca/monasca-docker/commit/72e5ee14cdc7021fe41b57e9c610bf10bb6da832 for now since they were fairly simple changes with high rewards. The rest we will have to revisit sometime in the future

[timothyb89]

So it looks like we failed to account for situations where secure environment variables aren't available, that is, any PR from a branch that isn't this repo (i.e. a fork, where most PRs should come from). For example: https://travis-ci.org/monasca/monasca-docker/jobs/277478462#L649

Turns out this is a fairly significant issue (really always the case with 3rd party CI). I think the quick solution is:

• Use travis's JWT addon: https://docs.travis-ci.com/user/jwt
• Make a tiny log ingester on Cloud Functions to take 1+ logs and a JWT. Post logs to that endpoint instead of uploading to GCS directly.

...that said, short term we can just print out the logs when secure vars aren't available.