JSON logger with %v generate bad value

[StephaneBrillant]

At 2 places the %v macro is used with the logger and is not supported

thanos/cmd/thanos/query.go

Line 559 in 46d0106

level.Warn(logger).Log("msg", "Duplicate store address is provided - %v", addr)

thanos/cmd/thanos/rule.go

Line 724 in 46d0106

level.Warn(logger).Log("msg", "duplicate query address is provided - %v", u.String())

What happened:
Logs generates result in dynamic key with MISSING value.
ex:

{"msg":"Duplicate store address is provided - %v","test":"(MISSING)"}

What you expected to happen:
Json logging play well with ElasticSearch type mapping. No dynamic key with MISSING value is reported

Proposed fix
Replace %v by string concatenation
ex: logger.Log("msg", "Duplicate store address is provided - " + addr)

[yeya24]

Thanks for catching this! Would you like to open a pr to fix it?

We can just change it to level.Warn(logger).Log("msg", "Duplicate store address is provided", "addr", addr).

I am wondering if there is already a static linter for this.