Announcing riff v0.0.7

May 13, 2018

We are happy to announce the 0.0.7 release of riff. Thank you all who worked on this effort.

go streaming

The Go function invoker now supports streaming functions. These accept an input channel and return an output channel and an optional error channel.

func Foo(input <-chan X) (<-chan Y, <-chan error) {
  out := make(chan Y)
  errs := make(chan error)

  go func() {
    defer close(out)
    defer close(errs)
    for in := range input {
      ...
    }
  }()

  return out, errs
}

Request/reply functions work just like before.

func Foo(input X) (Y, error) {
}

python streaming

The Python 3 function invoker now supports streaming functions.

For function modules with interaction_model='stream', the invoker will pass a generator yielding each message payload. The response should be a generator yielding the response payload.

interaction_model = "stream"

def bidirectional(stream):
    return (item.upper() for item in stream)

For another example, see this windowing sample.

bounded gRPC calls

The riff sidecar has been modified to support bounded gRPC calls. This is a first step toward moving streaming responsibilities like windowing and request/reply correlation out of the invokers.

Starting with the 0.0.7 release, the CLI will generate function yaml with a default window size of 1.

spec:
  protocol: grpc
  windowing:
    size: 1

The windowing.size key can be used to control the window size. Alternatively you can use windowing.time

spec:
  protocol: grpc
  windowing:
    time: 10s

Windowing can be disabled entirely for streaming functions which expect unbounded streams by removing the windowing key from the yaml. For now, this is also the recommended approach to handle sliding windows.