Add support for [custom_parameter] in custom alert configuration

[ondrej337]

Describe the feature request

Hi Gatus Team,
I'd like to request a feature enhancement for Gatus alerts.

Currently, custom alerts allow for flexible configuration, but it would be extremely useful to support a [custom_parameter] field that can be passed into the alert definition. This would enable users to inject dynamic or contextual data into alerts, such as environment tags, service metadata, or custom routing keys.

Proposed Use Case:
`
alerting:
custom:
url: "https://test.com/services/health"
method: "POST"
body: |
{
"text": "[CUSTOM_PARAMETER]"
}
endpoints:

• name: website
  url: "https://twin.sh/health"
  conditions:
  • "[STATUS] == 200"
    alerts:
  • type: custom
    custom_parameter: "production"
    `
    Let me know if this is feasible or if you'd prefer a different implementation approach. Happy to help test or contribute if needed!

Thanks for the great work on Gatus
Ondrej

Why do you personally want this feature to be implemented?

No response

How long have you been using this project?

No response

Additional information

No response

[TwiN]

Did you look into provider overrides?
You could just override the custom body in the endpoint alert instead.

P.S. I'm doing this solo (though there are contributors that regularly contribute), so there's no team involved 😆

[ondrej337]

Thanks for the heads-up—and major respect for running this solo. Yes, I'm aware of that, but if I have a large number of different endpoints, using a single parameter would be a much simpler and cleaner solution. It would save time and reduce duplication compared to overriding the alert body for each endpoint individually.

[TwiN]

In your example, wouldn't you just have to override the body, which is also just one parameter (albeit multi-line)?

I understand a custom parameter would be easier, but from a configuration perspective, I feel it adds more complexity in exchange for no new feature outside of convenience. After all, provider overrides was implemented to deal specifically with the issue you mentioned.