Enhanced Feature Request: Automated Topic/Subscription Registration for Spring Cloud Pub/Sub with Emulator

Dear Google Cloud Platform Team,

I hope this message finds you well. I would like to propose an enhancement for Spring Cloud Pub/Sub on the Google Cloud Platform, specifically in the context of utilizing the emulator.

As it stands, it would be highly advantageous if Spring Cloud Pub/Sub could automatically register a topic/subscription when the emulator host is set to localhost (e.g., spring.cloud.gcp.pubsub.emulator-host=localhost:8085). My suggestion is to leverage the REST API to dynamically create these topics/subscriptions based on specified application properties during the application's startup process.

The motivation behind this request stems from the seamless experience provided by Kafka, where similar functionality is already in place. Enabling this feature would streamline the development process, allowing users to effortlessly initiate their projects. This enhancement becomes particularly valuable when utilizing the emulator container image, eliminating the need for users to resort to creating custom scripts for manual configuration.

I believe that implementing this enhancement would significantly improve the user experience, making Spring Cloud Pub/Sub with the emulator even more user-friendly and efficient.

Thank you for considering this feature request, and I appreciate your ongoing efforts to enhance the Google Cloud Platform.

Best Regards,

Andrew Polemeni

Review the emulator-host application property and the requested startup REST API behavior first. Clarify the application properties and startup lifecycle needed, then verify that topics and subscriptions are created automatically when the emulator runs at localhost:8085.

Written by the indexing model from the issue text.