fix(remote-read): return err instead of nil

[Dentrax]

Signed-off-by: Furkan [email protected]

What this PR does

For example, an invalid URL http://10.11.12.13:30090/prometheus/api/v1/read returns 404.

I'd expect an exit 1 and fatal log here, but it returns success instead.

$ go run cmd/mimirtool/main.go remote-read stats --address http://10.11.12.13:30090 --selector '{__name__!=""}'

INFO[0000] Created remote read client using endpoint 'http://10.11.12.13:30090/prometheus/api/v1/read'
INFO[0000] Querying time from=2022-09-27T08:48:54+03:00 to=2022-09-27T09:48:54+03:00 with selector={__name__!=""}
main: error: remote server http://10.11.12.13:30090/prometheus/api/v1/read returned HTTP status 404 Not Found: 404 page not found, try --help
exit status 1

Actual Behavior

$ go run cmd/mimirtool/main.go remote-read stats --address http://10.10.10.10:30090 --selector '{__name__=~"istio.*"}' --remote-read-path /api/v1/read --log.level debug --read-timeout 60s

INFO[0000] log level set to debug
INFO[0000] Created remote read client using endpoint 'http://10.10.10.10:30090/api/v1/read'
INFO[0000] Querying time from=2022-01-18T16:01:52+03:00 to=2022-01-18T17:01:52+03:00 with selector={__name__=~"istio.*"}

$ echo $?
0

Expected Behavior

INFO[0000] log level set to debug                       
INFO[0000] Created remote read client using endpoint 'http://10.10.10.10:30090/api/v1/read' 
INFO[0000] Querying time from=2022-01-18T16:39:20+03:00 to=2022-01-18T17:39:20+03:00 with selector={__name__=~"istio.*"} 
___2remote_read_stats: error: remote server http://10.10.10.10:30090/api/v1/read returned HTTP status 400 Bad Request: exceeded sample limit (50000000), try --help

Process finished with the exit code 1

Which issue(s) this PR fixes or relates to

Fixes grafana/cortex-tools#260

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[aknuds1]

Please re-write the PR description so it clearly states what the PR does, and why (for example, it doesn't change the golangci-lint settings any longer).

[Dentrax]

Please re-write the PR description so it clearly states what the PR does, and why (for example, it doesn't change the golangci-lint settings any longer).

Sorry, a bit confused between two PRs since submitted both at the same time. It should be fine now.

[56quarters]

Thanks! LGTM, just one comment about the changelog.