[Feature Request] support json/protobuf payloads for workflow gate

[robcao]

Is your feature request related to a problem? Please describe.

Users using protobuf messages for workflow inputs want to be able to use protobuf messages as inputs to the workflow gate. json/protobuf is supported by things like the temporal cli and ui, and should also be supported by the worker controller.

Describe the solution you'd like

Add an additional optional field called ProtoMessageType to GateWorkflowConfig (and the WorkerDeployment CRD). When this field is populated alongside an input payload, the client should send the payload as a json/protobuf payload, instead of a json/plain payload, like this

var arg interface{}
if len(wf.input) > 0 {
    if wf.protoMessageType != "" {
        arg = converter.NewRawValue(&commonpb.Payload{
            Metadata: map[string][]byte{
                converter.MetadataEncoding:    []byte(converter.MetadataEncodingProtoJSON),
                converter.MetadataMessageType: []byte(wf.protoMessageType),
            },
            Data: wf.input,
        })
    } else {
        arg = json.RawMessage(wf.input)
    }
}

Additional context

We are happy to help contribute this if we can agree on the shape of the change

[jaypipes]

@robcao I think I would rather add a new ProtoMessage optional field to the already-existing GateInputSource struct that is the field type of the GateWorkflowConfig.InputFrom field which is used when GateWorkflowConfig.Input cannot be used due to encrypted values.

[robcao]

@jaypipes

Does that imply we will have to use a ConfigMap or Secret to store the actual payload? We are fine with that, although it seems like an additional requirement for protobuf payloads (but we are okay with that)

[jaypipes]

@jaypipes

Does that imply we will have to use a ConfigMap or Secret to store the actual payload? We are fine with that, although it seems like an additional requirement for protobuf payloads (but we are okay with that)

@robcao No, not at all! :) I was just suggesting instead of adding ProtoMessageType field to the GateWorkflowConfig struct, instead add a ProtoMessage field to the GateInputSource struct, since that is already where we handle the "polymorphism" for the different payload types.

[jaypipes]

I'm happy to throw together an example PR for this if you'd like.