Go terraform unrecognized import path from GCP Artifact Registry

I get an error when trying to download private go dependencies from artifact registry via terraform:

│ Error: Error waiting to create function: Error waiting for Creating function: Error code 3, message: Build failed with status: FAILURE and message: go: downloading github.com/GoogleCloudPlatform/functions-framework-go v1.9.2 │ go: downloading cloud.google.com/go/firestore v1.20.0 │ go: downloading cloud.google.com/go v0.121.6 ... │ go: downloading golang.org/x/text v0.31.0 │ go: downloading golang.org/x/crypto v0.44.0 │ go: my.package/buildingupdate imports │ europe-west1-go.pkg.dev/account-12345/go-lib/datatypes: unrecognized import path "europe-west1-go.pkg.dev/account-12345/go-lib": reading https://europe-west1-go.pkg.dev/account-12345/go-lib?go-get=1: 404 Not Found │ go: my.package/buildingupdate/functions.local/app imports │ github.com/cloudevents/sdk-go/v2: europe-west1-go.pkg.dev/account-12345/[email protected]: unrecognized import path "europe-west1-go.pkg.dev/account-12345/go-lib": reading https://europe-west1-go.pkg.dev/account-12345/go-lib?go-get=1: 404 Not Found

My terraform code looks the following:

build_config { runtime = "go125" entry_point = "Handler" source { storage_source { bucket = google_storage_bucket.bucket.name object = google_storage_bucket_object.update_building_source.name } } environment_variables = { # Proxy all requests via proxy.golang.org, use direct as fallback GOPROXY = "https://proxy.golang.org,direct" # Exclude from go proxy and fetch directly GOPRIVATE = "europe-west1-go.pkg.dev/account-12345/go-lib" # Do not check hash from gosumdb GONOSUMDB = "europe-west1-go.pkg.dev/account-12345/go-lib" } }

I also tried setting the Artifact Registry as proxy but then other public dependencies fail to download:

export GOPROXY=https://europe-west1-go.pkg.dev/account-12345/go-lib,https://proxy.golang.org,direct export GOPRIVATE=europe-west1-go.pkg.dev export GONOSUMDB=europe-west1-go.pkg.dev

Some other things I verified:
go mod tidy works locally when authenticating via artifact-registry-go-tools .

The service account that is configured to build cloud run functions has the artifact registry read role.

The artifact is present and when downloading it I see the correct modules and the code is up to date.

How can I fix my terraform script to tell the Cloud Run Builder to download the repository from AR?