Using API to retrieve applications by label

[WoodhamsR]

Hi!

I have a requirement to programmatically monitor the rollout status / application health of a subset of our applications by label. I figure the best way to do this is via the ArgoCD API (ArgoCD version v2.9.9+8281b18).

We used the docs to get a user up and running with get access on Applications:
https://argo-cd.readthedocs.io/en/stable/developer-guide/api-docs/

This seems to work fine passing no filters or passing e.g. a projects filter, as per the docs:
/swagger-ui#operation/ApplicationService_List

The selector filter is more complicated, as it's key-value-pairs. I saw on Stack Overflow that you need to send it like this:
label%3Dvalue

As soon as I add this selector (or any variation I can think of which passes the validation regex), I get no results back.

So, I would like to know please:

• Is there any further documentation or examples for the API I'm missing, especially for selectors?
• Is querying by label supported in this way?
• What is the correct syntax / what am I likely doing wrong which is filtering out all my results?

I'm just prototyping in Postman at the moment, in case that's relevant.

Many thanks in advance!

Robert

[WoodhamsR]

This is a problem with our setup (and my understanding) - we use ApplicationSets to generate these apps, so they actually have no labels!