Improve logging after the switch to github.com/go-kit/kit/log

[pelov]

Description

After the switch to github.com/go-kit/kit/log the current log output doesn't look very readable. The switch doesn't require simply using level.Debug(logger).Log but also formatting the logs using key value pairs.

How Has This Been Tested?

Looked briefly at the log output in a real instance and they look better but haven't checked carefully every log line, so feel free to test it yourself and suggest improvements.

[pelov]

Fixes #262.

[Yannig]

Hi. Can you try to rebase your work with latest version?

[vutkin]

Hi @pelov, could you please bump version to 4.2 and do a rebase from master?

[gjrlopes]

Hi @Yannig

This improvement was lost in the 0.5.1 version.
Due this the log have several lines without "msg" key and with "(MISSING)" as value. Check log messages below:

{
  "Launching connection: ": "***@192.168.1.100:1521/XE",
  "caller": "collector.go:326",
  "level": "debug",
  "ts": "2023-11-15T11:56:26.179Z"
}

{
  "caller": "collector.go:332",
  "level": "debug",
  "set max idle connections to ": 0,
  "ts": "2023-11-15T11:56:26.179Z"
}

{
  "caller": "collector.go:334",
  "level": "debug",
  "set max open connections to ": 10,
  "ts": "2023-11-15T11:56:26.179Z"
}

{
  "Successfully loaded custom metrics from: /tmp/custom-metrics.toml": "(MISSING)",
  "caller": "collector.go:389",
  "level": "info",
  "ts": "2023-11-15T11:56:27.575Z"
}

{
  "About to scrape metric: ": "(MISSING)",
  "caller": "collector.go:283",
  "level": "debug",
  "ts": "2023-11-15T11:56:27.575Z"
}

{
  "(Ignored unless Histogram type)": "(MISSING)",
  "- Metric MetricsBuckets: ": null,
  "caller": "collector.go:287",
  "level": "debug",
  "ts": "2023-11-15T11:56:27.575Z"
}

Example from 0.4.4:

{
  "caller": "main.go:364",
  "level": "debug",
  "msg": "Query result looks like",
  "ts": "2023-11-15T12:15:14.325Z",
  "value": 2090
}

Same message from 0.5.1:

{
  "Query result looks like: ": 17170432,
  "caller": "collector.go:426",
  "level": "debug",
  "ts": "2023-11-15T11:56:28.417Z"
}

Is it possible to reimplement it and release a new version?
Best regards