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GCP PubSub

Topic And Subscription ID

GCP PubSub event source can listen to a PubSub with given topic, or subscriptionID. Here is the logic with different topic and subscriptionID combination.

Topic Provided/Existing Sub ID Provided/Existing Actions
Yes/Yes Yes/Yes Validate if given topic matches subsciption's topic
Yes/Yes Yes/No Create a subscription with given ID
Yes/Yes No/- Create or re-use subscription with auto generated subID
Yes/No Yes/No Create a topic and a subscription with given subID
Yes/No Yes/Yes Invalid
Yes/No No/- Create a topic, create or re-use subscription w/ auto generated subID
No/- Yes/Yes OK
No/- Yes/No Invalid

Workload Identity

If you have configured Workload Identity and want to use it for a PubSub EventSource, leave credentialSecret nil.

Full spec is available here.

See a PubSub EventSource example.

Running With PubSub Emulator

You can point this event source at the PubSub Emulator by configuring the PUBSUB_EMULATOR_HOST environment variable for the event source pod. This can be configured on the EventSource resource under the spec.template.container.env key. This option is also documented in the PubSub EventSource example.