breaking(go): update flow streaming protocol to SSE

[hugoaguirre]

OK

curl -X POST -H "Accept: text/event-stream" http://localhost:3400/streamy -d '{"data":5}'
data: {"count":0}\n\n
data: {"count":1}\n\n
data: {"count":2}\n\n
data: {"count":3}\n\n
data: {"count":4}\n\n
data: {"result": "done: 5, streamed: 5 times"}\n\n

ERROR

curl -X POST -H "Accept: text/event-stream" http://localhost:3400/streamy -d '{"data":5}'                                                                       
data: {"message": {"count":0}}\n\n
data: {"message": {"count":1}}\n\n
data: {"message": {"count":2}}\n\n
data: {"message": {"count":3}}\n\n
data: {"message": {"count":4}}\n\n
data: {"error": {"status": "INTERNAL", "message": "stream flow error", "details": "this is a dummy error"}}\n\n         

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[pavelgj]

I wonder if it would be better to use genkit/client library here for the test?

[hugoaguirre]

Ah, good idea. Could you illuminate me on why using genkit/client would be better for this? Is it for compatibility reasons?

Using the raw request, we can inspect headers and response payloads to ensure the proper formatting.

[pavelgj]

you're not testing the streamed data?

[hugoaguirre]

Yes. My understanding is that this file should be used for test cases for the flow server, unless this label is for something else that I'm not aware of.

Should I change it to something more specific? e.g. app: stream_flows

[apascal07]

I think Pavel means that you're not consuming the whole stream, just one chunk. Now that I think about it, you do need to consume the stream so you can check the final response.

[hugoaguirre]

Got it. I'll add the expected stream values and test against them 😄