Empty metrics on metrics tests

[lwsanty]

Sometimes during metrics tests from PR #73 empty metrics are written
https://travis-ci.com/src-d/gitcollector/jobs/235932304

--- FAIL: TestPostgres (5.66s)
    --- FAIL: TestPostgres/testPostgresSendMetricsSuccess (0.22s)
        require.go:157: 
                Error Trace:    postgres_test.go:97
                                                        postgres_test.go:63
                Error:          Not equal: 
                                expected: []integration.metric{integration.metric{org:"git-fixtures", discovered:8, downloaded:7, updated:0, failed:1}}
                                actual  : []integration.metric{integration.metric{org:"git-fixtures", discovered:0, downloaded:0, updated:0, failed:0}}
                                
                                Diff:
                                --- Expected
                                +++ Actual
                                @@ -3,6 +3,6 @@
                                   org: (string) (len=12) "git-fixtures",
                                -  discovered: (int) 8,
                                -  downloaded: (int) 7,
                                +  discovered: (int) 0,
                                +  downloaded: (int) 0,
                                   updated: (int) 0,
                                -  failed: (int) 1
                                +  failed: (int) 0
                                  }

I suspect gitcollector in data loss
Cannot reproduce locally

Need more info

Update
OK, seems like the reason is the following

[2019-09-17T14:30:38.901550957+03:00]  WARN discovery stopped: rate limit requests exceeded: GET https://api.github.com/orgs/git-fixtures/repos?per_page=100: 403 API rate limit exceeded for 212.7.22.138. (But here's the good news: Authenticated requests get a higher rate limit. Check out the documentation for more details.) [rate reset in 60m00s] source=subcmd/download.go:226

This will be fixed in CI as soon as #74 and https://github.com/src-d/infrastructure/issues/1154 will be closed

I have a doubt about this behavior, because it may confuse users, maybe it would be better to add errors field to metrics schema so it would be more clear why all metrics are 0?

wdyt @mcarmonaa @jfontan ?

[mcarmonaa]

If I recall correctly 🤔, it was a requirement that the exported data is just numbers so to know more about errors is necessary check the logs.