promtool convert alert rules don't respect the go template

[DreamRivulet]

What did you do?
I use the promtool to convert old 1.8 version alert rules to new yaml format.

What did you expect to see?
template like {{ var }} should not be split into multi-line.

What did you see instead? Under which circumstances?
template {{ var }} are split like:

..., This is a alert template {{ var 
  }}

when string is long.

Environment

• System information:

  Linux 4.4.0-130-generic x86_64

• Prometheus version:

  promtool, version 2.5.0 (branch: HEAD, revision: 67dc912ac8b24f94a1fc478f352d25179c94ab9b)
  build user:       root@578ab108d0b9
  build date:       20181106-11:40:44
  go version:       go1.11.1

[brian-brazil]

Does this change the resulting output label?

[DreamRivulet]

yes, the alert template will not work when span newlines, see: go template.

[DreamRivulet]

It's better that promtool can respect the go template when converting alert rules into yaml format, i see promtool uses https://github.com/go-yaml/yaml to do the marshal, but i didn't find any place which will split the string into multi-lines.

[simonpasquier]

Can you share the original alert rule file?

[DreamRivulet]

## alert.rules ##
  ALERT WorkerFailedAlert
    IF changes(worker_fail_count [300m]) > 3
    LABELS {
      severity = "warning",
      workerID = "{{ $labels.workerID }}",
      alert_key = "This is a test to prove that promtool fails , {{ $labels.workerID }}"
    }

Above is a simple old format alert rule, you can use the promtool to convert it, then you will get the following output:

groups:
- name: test.rules
  rules:
  - alert: WorkerFailedAlert
    expr: changes(worker_fail_count[5h]) > 3
    labels:
      alert_key: This is a test to prove that promtool fails , {{ $labels.workerID
        }}
      severity: warning
      workerID: '{{ $labels.workerID }}'

[codesome]

Related go-yaml/yaml#166

[DreamRivulet]

It looks like the fix will merged into go-yaml v3 version, will promtool upgrade the go-yaml to v3 when it's available ?

[brian-brazil]

This code no longer exists in current master. If the yaml library is producing output that it itself can't parse, we should probably add that information to that bug.