Migrate to grpc-js

[fbiville]

Fixes #113

[fbiville]

Biggest changes:

• proto has to be loaded at runtime
• plain old Javascript objects are generated for the gRPC data types (no accessor methods generated)
• gRPC maps are generated as an plain old objects
• server.bind -> server.bindAsync
• cancelWithStatus -> sendError

Possible source of worry (i.e. investigation needed):

• output frames payloads are always wrapped in Buffer (see https://github.com/projectriff/node-function-invoker/pull/181/files#diff-9d5cdba041794f2e2a88cab243212e23)
• sometimes empty headers in test are valued as {}, sometimes they are skipped

[scothis]

Do you have a sense of the performance impact? if any

[fbiville]

I managed to successfully deploy and run the function on the core runtime (I have a strange issue with Knative).

[fbiville]

Do you have a sense of the performance impact? if any

I have spent a significant time getting a proper riff install on a PKS cluster, so I have not started looking at this particular aspect yet.

The Docker image fbiville/builder is available for consumption FYI.

[murgatroid99]

Hi,
I'm the grpc maintainer; I got here following the link from that issue about server.bind and I realized that I could help you simplify this migration. First, you can actually continue using the same proto Message classes you are currently using. The most recent version of grpc-tools has an option "generate_package_definition" that makes it generate a file that outputs the same kind of object that protoLoader.load outputs, so you can pass that into grpc.loadPackageDefinition. Using that option just requires changing part of your grpc-tools invocation like this: --grpc_out=generate_package_definition:./codegen.

Second, this doesn't necessarily help with this migration exactly but it explains why this part changed: the intended way of having a server end a call with a non-OK status is to call stream.emit('error', status). Seeing your code I realize that that's not obvious and it would be better to have something like stream.endWithStatus(statusObject).

[fbiville]

@murgatroid99 thanks for the feedback (apologies for the delay, I was in "staycation" until today).

Regarding the emission of errors, does this mean that:

grpcStream.call.sendError({
    code: grpc.status.INVALID_ARGUMENT,
    details: `${errors.reserved_prefixes.NOT_ACCEPTABLE}: ${err.cause}`,
});

can be replaced with:

grpcStream.emit('error', {
    code: grpc.status.INVALID_ARGUMENT,
    details: `${errors.reserved_prefixes.NOT_ACCEPTABLE}: ${err.cause}`,
});

?

I tried to follow your advice and open another draft PR, however I now face several issues:

• the server does not work and I get The server does not implement the method /streaming.Riff/Invoke. I assume something must be wrong with the way I load the generated package definition?
  - I am confused as to how instantiate the gRPC client, none of my attempts worked.

[fbiville]

Converting this PR to draft. I'll try to open another one with aforementioned suggestions.

[murgatroid99]

@fbiville That is what I meant about emitting errors.

I don't see anything wrong with how you're importing the package definition and I don't know why it would be returning UNIMPLEMENTED errors.