Alert rules parser breaks on valid input

[RichiH]

I just broke Prometheus at 35C3 with the following rule:

  - alert: APHighAssociations                       
    expr: {__name__=~"AP_Data_radio._Clients"} > 150                                                                                                           
    for: 15m                                        
    labels:                                         
      severity: sev3                                
    annotations:                                    
      summary: "AP {{ $labels.host }} has more than 150 clients"
      description: "AP {{$labels.host}} has had more than 150 clients for 15 minutes."

It works when expanding on the regex:

  - alert: APHighAssociations
    expr: (AP_Data_radio0_Clients > 150) or (AP_Data_radio1_Clients > 150)
    for: 15m
    labels:
      severity: sev3
    annotations:
      summary: "AP {{ $labels.host }} has more than 150 clients"
      description: "AP {{$labels.host}} has had more than 150 clients for 15 minutes."

Verified with 2.6.0

[RichiH]

PS:

% ./promtool check rules first_rules.yml
Checking test.yml
  FAILED:
yaml: line XX: did not find expected comment or line break
%

[brian-brazil]

That's not valid yaml.

[RichiH]

I can attach the full yaml, but just copy that section, or anything with curlies, really. Sent by mobile; please excuse my brevity.

…

On Fri, Dec 28, 2018, 12:53 Brian Brazil ***@***.*** wrote: That's not valid yaml. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#5047 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAuEIwIwgaCk5TpqfL3kqZ0Vk0G9QobOks5u9gZEgaJpZM4Zjw3x> .

[brian-brazil]

I did, it's still not valid YAML. You need to quote it.

[beorn7]

To be more concrete: Strings starting with { need to be quoted in YAML.

[RichiH]

Aye, thanks.