Motivation

SRVCOM-1799 introduced basic gRPC support, which usually is sufficient for most scenarios. However, to fully support gRPC also streaming scenarios should be implemented. More information can be found in the documentation. [1] [2]

Goal

Implement streaming scenarios of gRPC services, namely:

• Server-side streaming
• Client-side streaming
• Bidirectional streaming

Scenarios

As a developer, I need my workflow to also call a gRPC streaming service using one of the following options:

• The workflow sends a single request and receives a stream of responses from the server.
• The workflow streams requests and receives a single response from the server.
• The workflow streams requests and receives a stream of responses from the server.

Expected outcomes

• Workflows can use operation state with gRPC functions referencing gRPC streaming endpoints.
• Integration tests exist verifying each supported scenario.
• A guide and an example exist which show how to use serverless workflow with gRPC scenarios.

[1] https://grpc.io/docs/what-is-grpc/core-concepts/
[2] https://grpc.io/docs/languages/java/basics/