`promtool update rules` discards comments

[vthriller]

What did you do?

promtool update rules rulefile

What did you expect to see?

Given the following rulefile:

# Lorem ipsum

ALERT Foo
  # whatever
  IF bar > 0
  or rate(baz [1m]) > 0 # because reasons
  #or quux > 0 # FIXME
  LABELS { severity = "crit" }

I expected to see the output silimlar to this:

# Lorem ipsum
groups:
- # whatever
  name: test
  rules:
  - alert: Foo
    expr: |
      bar > 0
      or rate(baz[1m]) > 0 # because reasons
      #or quux > 0 # FIXME
    labels:
      severity: crit

(or #or quux to be on the same level as labels: or whatever)

What did you see instead? Under which circumstances?

groups:
- name: test
  rules:
  - alert: Foo
    expr: bar > 0 or rate(baz[1m]) > 0
    labels:
      severity: crit

Environment

• System information: (irrelevant)

• Prometheus version:

promtool, version 2.0.0 (branch: HEAD, revision: 0a74f98628a0463dddc90528220c94de5032d1a0)
  build user:       root@615b82cb36b6
  build date:       20171108-07:11:59
  go version:       go1.9.2

• Alertmanager version: (irrelevant)

• Prometheus configuration file: (irrelevant)

• Alertmanager configuration file: (irrelevant)

• Logs: (none)

[brian-brazil]

This is a limitation of the YAML libraries available in Go, I'm afraid there's not much we can do about this.

[vthriller]

I'm afraid there's not much we can do about this

There's little to no reason (value escaping?) to use libraries for content generation, and since the output is pretty flat, it might as well be generated by hand. But even then you'd need to hack parser to allow it to output comments in some form.

(That being said, I'm not sure if this issue affects a lot of people and is therefore worth the effort, but here it is.)

[brian-brazil]

Unless you can find a Golang yaml library that supports comments, there's nothing we can do here.

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.