Pass comments generated by lookout-tool review call to stdout

[zurk]

Right now I need to parse the lookout-tool logs to get Analyzer comments and rely on internal implementation logic (https://github.com/src-d/lookout/blob/master/server/server.go#L559).
For example something like
go run cmd/lookout-sdk/*.go review --log-format=json 2>&1 | jq 'select(.msg == "file comment")' can work.

I think that comments can be interpreted as lookout-tool review output and passed to stdout.
It can be in the same log format (JSON/not JSON).

So in ideal case, I just want to run
go run cmd/lookout-sdk/*.go review --log-format=json > comments.json and get comment per line in JSON format.

[smacker]

There is a limitation in go-log: src-d/go-log#11
Go-log doesn't have a maintainer to give feedback/review/merge so I just return this issue to TODO.

[carlosms]

ping @smola so you are aware of the missing maintainer issue.

[smola]

We actually might want to have a JSON poster, alternative to the log one. As we discussed recently, to enable different evaluation and testing use cases. So logs would still go to stderr, but results can be posted as JSON to stdout.

[smacker]

@smola what is the difference between JSON poster and log poster with --format=json?

[smola]

@smacker Logs are written to stdout (no matter the format), while JSON poster would post to stdout. It's kind of differentiating between logging and output. For example: lookout ... > output.json would still output logs either in JSON or human readable, but post the meat of the review to the file.

[smola]

But it's true that the log poster could be used, just with a different setup (JSON + stdout) than the general logger?

[smacker]

We have LogPoster struct which implements Poster interface.
The constructor of it requires go-log.Logger instance. It can be a general one or a separate one.

main.go decides what to pass there.
Currently, it's log.DefaultLogger but the initial solution for this issue was just to pass log.New().Output(os.Stdout) (it would use DefaultFactory which is set by go-cli)

This way:

• we don't duplicate code to do the same posting
• results of analyzer go to stdout always, no matter does user prefer json format or not. Which makes it easy to pipe. For example to test that an analyzer returned N comments you just need to do ./lookout-sdk review | wc -l. Now this command returns 0 always which doesn't look correct to me.

[dpordomingo]

If I'm not wrong, this requirement would be satisfied by #624
(and wc -l would also work)

$ lookout-sdk review --from HEAD^ 2> log.err | wc -l
5

$ lookout-sdk review --from HEAD^ 2> log.err
{"analyzer-name":"","file":"cmd/lookout-sdk/push.go","text":"The file has increased in 2 lines."}
{"analyzer-name":"","file":"cmd/lookout-sdk/push.go","line":27,"text":"This line exceeded 120 chars."}
{"analyzer-name":"","file":"cmd/lookout-sdk/review.go","text":"The file has increased in 2 lines."}
{"analyzer-name":"","file":"cmd/lookout-sdk/review.go","line":23,"text":"This line exceeded 120 chars."}
{"analyzer-name":"","file":"cmd/sdk-test/bblfsh_test.go","line":146,"text":"This line exceeded 120 chars."}

[smacker]

Imo by default lookout-sdk review should continue print normal response and switch to the json only of the user asks.