Megacheck

[mjtrangoni]

Hi @wrouesnel,

I did some changes here, adding some features and fixing others too.

• Update some vendoring using govendor.
• Use promu as build tool.
• Use more Prometheus Libraries.
• Add a megacheck target and fix four issues detected by this tool.
• Update travisCI go version.

See how it with promu looks like,

$ ./postgres_exporter
INFO[0000] Starting postgres_exporter (version=0.3.0, branch=megacheck, revision=b06b38b0031589a66f677de0c44abcec41c03050)  source="postgres_exporter.go:971"
INFO[0000] Build context (go=go1.8.3, user=trangoni@sargas, date=20170606-08:35:25)  source="postgres_exporter.go:972"
FATA[0000] couldn't find environment variable DATA_SOURCE_NAME  source="postgres_exporter.go:976"
 $ ./postgres_exporter -version
lustre_exporter, version 0.3.0 (branch: megacheck, revision: b06b38b0031589a66f677de0c44abcec41c03050)
  build user:       trangoni@sargas
  build date:       20170606-08:35:25
  go version:       go1.8.3

I hope you find this well, and I am open for changes and code-review, too.

[coveralls]

Coverage decreased (-1.2%) to 50.647% when pulling 1904ba9 on mjtrangoni:megacheck into 1fa394d on wrouesnel:master.

[wrouesnel]

Thanks for the PR! I've actually been standardizing on gometalinter for my projects though (see https://github.com/wrouesnel/self-contained-go-project for the template I'm starting to use) so I'll probably do that instead of megacheck.

Definitely want to bring promu in to be more inline with the Prometheus ecosystem though.

[mjtrangoni]

Ok, should I rebase something or should I drop this PR completely?

megacheck is still warning one issue,

$ megacheck ./... | grep -v vendor
postgres_exporter_test.go:16:2: field e is unused (U1000)

[wrouesnel]

It's a good motivator and I'll be incorporating it's changes, but I'm more in favor of metalinter which does the same sort of thing but with a bigger tool range.