Dash: Add dependencies between objects

[tylerauerbeck]

Wanted to start the conversation here to see if this is something we would want to include in dash.

In my experience there can sometimes be objects that need to wait until something else is available. There are a number of ways to get around this now (manually, we can use include_tags and exclude_tags and in pipelines we can do the same, then write custom logic to wait for certain things to become available). But are dependencies something that we want to handle inside of dash itself?

Areas I can see this being useful are for things like:

• waiting for other objects/components to become available
• skipping just specific components on failures (instead of failing an entire run)

Wanted to gather some feedback before thinking about how to include this further.

[etsauer]

@tylerauerbeck can you give some examples of this? its not something I have encountered much in the field.

[tylerauerbeck]

@etsauer

So I think I might walk this back a little. We may be digging in a bit too far on building in the waiting for other objects to become available. This should probably be handled by things like pre-steps and post-steps.

I still think that second use case might be useful though. I'm thinking something like the following:

We have an application (I'll use Kubevirt as an example):

• CRDs
• Operator
• CRs

If the CRD's fail (for one reason or another), we obviously want to skip the operator and the CRs because they won't be all that useful without the CRD's. But maybe there are other things in our inventory that deploy just fine regardless of this other app that's having issues (i.e. there's nothing wrong with the entire inventory, just those few items).

So maybe something that looks like:

version: 3.0

context: global-context
namespace: global-default
resource_groups: 
  - name: Group 1 
    namespace: group1-stuff
    resources:
      - name: A CRD
        namespace: this-deployment
        type: openshift
        template: my-crd-template
        params: some-crd-params
      - name: my-operator
        namespace: this-deployment
        type: openshift
        template: my-operator-template
        params: my-operator-params
        dependencies:
        - A CRD