Grafana Oncall templates new helper filter regex_replace()

[njohnstone2]

Grafana Oncall currently supports the default jinja2 filter functions with a handful of helper functions included in this repo. I would like to propose adding a new filter to support the use of regex to replace values within a template.

Grafana alerts provide a valueString field in the payload that is sent to grafana oncall. I would like to include this value in my alerting template however customizing this field is limited to the existing jinja2 filtering functions.

Example

Given the following valueString it would be nice to have the option to strip out the var field to display a more concise summary of what values are triggering the alert.

Payload

{
  "labels": {
    "env": "prod",
    "alertname": "Prod - My Alert"
  },
  "status": "firing",
  "valueString": "[ var='B0' metric='my_metric' labels={} value=175 ]"
}

Message Template

{{- payload.message }}
{%- if "status" in payload %}
**Status**: {{ payload.status }}
{% endif -%}
{%- if "valueString" in payload -%}
**Value**: {{ payload.valueString | regex_replace("var=\'[a-zA-Z0-9]+\'", "") }}
{% endif -%}

Desired Output

Prod - My Alert
Status: firing
Value: "[ metric='my_metric' labels={} value=175 ]"

[Matvey-Kuk]

@njohnstone2 thank you for implementing this feature!

[njohnstone2]

No worries and thanks for accepting the change!

[mimahesh]

Hi i am trying to get Metric and value output separately and did same for web template but for Microsoft team Template same rule are not able to apply . is there any specific reason for that

Metric = {{payload.valueString|regex_replace("[ var='.' metric='", "")|regex_replace("'.", "")}}
Value = {{payload.valueString|regex_replace("[ var='.' metric='.' labels={.*} value=", "")|regex_replace(" ]", "")}}

[Matvey-Kuk]

@matiasb could you please check this one ☝️ ? Thank you!

[PhantomPhreak]

Here are my 2cents how to filter the valueString with added regex_replace() (which is just a re.sub() under the hood).

valueString may contain more than 1 metric, i want to get only metric name and it's value, represented as K:V, to make alert message shorter and easier to read.

Slack template:

{%- if "valueString" in payload -%}
*Metrics*:
{{ payload.valueString | regex_replace("\[( var='.+?')? metric='", "\t") | regex_replace("' labels={.+?} value=", ": ") | regex_replace("\]\,?", "\n") }}
{% endif -%}

Result: