Traffic tags and URLs removed from Cloud Run traffic definition

[jakubmiarka]

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Description

When any change to Cloud Run resource (google_cloud_run_service) is triggered, the apply removes existing values from the Traffic property of the service definition.

In our set-up we use Terraform to manage the Cloud Run deployment (env vars, IAM, resources ...) but we use Cloud Build to deploy new revisions. For these revisions we assign a traffic tag using gcloud CLI. The YAML definition after a few deployments looks like:

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
    ...
spec:
  template:
    metadata:
        ...
    spec:
      ...
  traffic:
  - revisionName: api-00001-kaz
    tag: dev-46351b6
  - revisionName: api-00002-goq
    tag: dev-7791b74
status:
  ...
  traffic:
  - revisionName: api-00001-kaz
    tag: dev-46351b6
    url: https://dev-46351b6---api-abcd-nw.a.run.app
  - revisionName: api-00002-goq
    tag: dev-7791b74
    url: https://dev-7791b74---api-abcd-nw.a.run.app
  url: https://api-abcd-nw.a.run.app
  address:
    url: https://api-abcd-nw.a.run.app

When terraform runs on an unrelated change (such as a change in env var), the plan shows only the env var change. However, when apply runs it removes all the tag and url properties, so the traffic then looks like:

...
traffic:
  - revisionName: api-00001-kaz
  - revisionName: api-00002-goq
...

and we lose our traffic tags and ability to hit/test specific revisions.

From a quick look, I believe the root cause is a mismatch in the schema of the traffic object. Google docs define it as

{
  "configurationName": string,
  "revisionName": string,
  "percent": integer,
  "tag": string,
  "latestRevision": boolean,
  "url": string
}

However, the provider seems to only have:

{
  "revisionName": string,
  "percent": integer,
  "latestRevision": boolean
}

as per the code here. And I suspect when this function runs it strips out everything except the 3 known properties:

terraform-provider-google/google/resource_cloud_run_service.go

Lines 1018 to 1022 in 20c4bfc

	transformed = append(transformed, map[string]interface{}{
	"revision_name": flattenCloudRunServiceSpecTrafficRevisionName(original["revisionName"], d, config),
	"percent": flattenCloudRunServiceSpecTrafficPercent(original["percent"], d, config),
	"latest_revision": flattenCloudRunServiceSpecTrafficLatestRevision(original["latestRevision"], d, config),
	})

Can the TF's schema be updated to match the GCP's one? Any suggested workarounds in the meantime?

New or Affected Resource(s)

• google_cloud_run_service

[george-oakling]

Today I found out this is blocking us to determine which version had originally the traffic so we can leave it as it is, if we want just to cold start new containers...is it difficult to implement? I would like to participate if needed :)

[george-oakling]

Hi! Can we expect this to be enhanced any time soon? How can I help to push this a bit? :) @rileykarson

[george-oakling]

Any news on this issue?

[github-actions]

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