How to write not condition in alert manager route matches?

[Radha R4]

How to write not condition in alert manager route matches? I want to execute this condition only when severity is not critical..

routes
    - match_re:
          severity: ^(?!critical)
      receiver: teams-channel-webhook-high-priority

I tried the above regex condition .But it didnt work.

I also tried with

not_match_re:


  severity: critical




Even that didnt work.

I want to match conditions when serverity is not critical.How to write this condition?

[Brian Candler]

You can make a nested tree of routes, which in effect gives you an "if ... then ... else ..." capability.

  routes:

    - ... something to do always

      continue: true

    - match:

        severity: critical

      routes:

        - ... things to do when critical

        - ...

    - ... things to do when not critical

    - ...

Leaving out the "match" condition entirely makes a rule match always.

Note that "continue: true" carries on to the next rule after a match, but only at the same level.  It will only fall out to the parent ruleset if no matches occur.

Or of course, you can explicitly match all non-critical severities e.g. match_re: severity: 'debug|informational|warning'

As to why what you wrote before didn't work:

1. The supported regex syntax for go's re2 library is defined here:

https://github.com/google/re2/wiki/Syntax

The (?!...) form is not implemented, due to the non-backtracking design of re2.

2. I don't know why you thought "not_match_re" would work, but it's not defined here:

https://prometheus.io/docs/alerting/configuration/

I would have hoped that alertmanager would fail to start when given unknown config tag.  If it didn't, then that could be a bug.

[Radha R4]

Thankyou so much Brian for the details response...Its now clear to me :)

I was only testing using routing tree editor.and found it didnt work

https://prometheus.io/webtools/alerting/routing-tree-editor/

[Brian Candler]

I didn't know about that tool - looks like it could be useful (if it works).

If you show what YAML you pasted into that, and what label set you tested with, maybe we can see what's wrong - either the tool or the YAML.