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@HelloGrayson
Last active August 29, 2015 14:24
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tchannel .call api change
# raw
response = yield tchannel.call(
argscheme="raw",
service="someservice",
endpoint="something",
body="RAWRESPONSE",
headers={
'X-Source': 'geo'
},
ttl=1000
)
# json
response = yield tchannel.call(
argscheme = "json"
service="someservice",
endpoint="maps",
body="{
'lat': 100,
'lng': 140
}",
headers={
'X-Source': 'geo'
},
ttl=1000
)
# thrift
Foo = get_tchannel_thrift(FooThrift, 'fooservice')
response = yield tchannel.call(
argscheme="thrift",
"some_binary",
headers={
'X-Source': 'geo'
},
ttl=1000
)
response = yield tchannel.call_thrift(
Foo.getBar(Foo.BarResponse("hi")),
headers={
'X-Source': 'geo'
},
timeout=5000
)
response = yield tchannel.as_thrift().call(
Foo.getBar(Foo.BarResponse("hi")),
headers={
'X-Source': 'geo'
},
timeout=5000
)
response = yield tchannel.thrift.call(
Foo.getBar(Foo.BarResponse("hi")),
headers={
'X-Source': 'geo'
},
timeout=5000
)
future = tchannel_sync.call(
Foo.baz(True),
headers={
'X-Source': 'geo'
},
ttl=1000
)
@HelloGrayson
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Finagle's is brutal:

  1. create filters
  2. add to stack
  3. write current stack to header buffer
  4. use builder to create client with stack
  5. filter stack applies to each request

So with a trace filter they can set zipkin headers for each request.

val tracer = mock[Tracer]
//tracer.sampleTrace(any(classManifest[TraceId])) returns Some(true)
when(tracer.sampleTrace(any(classOf[TraceId]))).thenReturn(Some(true))

val filter = new TTwitterClientFilter("service", true, None, protocolFactory)
val buffer = new OutputBuffer(protocolFactory)
buffer().writeMessageBegin(
  new TMessage(ThriftTracing.CanTraceMethodName, TMessageType.CALL, 0))
val options = new thrift.ConnectionOptions
options.write(buffer())
buffer().writeMessageEnd()

val tracing = new TracingFilter[ThriftClientRequest, Array[Byte]](tracer, "TTwitterClientFilterTest")
val service = mock[Service[ThriftClientRequest, Array[Byte]]]
val _request = ArgumentCaptor.forClass(classOf[ThriftClientRequest])
when(service(_request.capture)).thenReturn(Future(Array[Byte]()))

val stack = tracing andThen filter
stack(new ThriftClientRequest(buffer.toArray, false), service)

val header = new thrift.RequestHeader
InputBuffer.peelMessage(_request.getValue.message, header, protocolFactory)

assert(header.isSampled)

sources:

@jc-fireball
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Wow. no Finagle.

@abhinav
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abhinav commented Jul 28, 2015

Based on discussion earlier, this is how we expect the client-side streaming API to look:


Response streaming

We'll introduce a stream method on the TChannel object and its argscheme-specific proxies that will accept the same arguments as call. Instead of a standard response, it'll return a streaming response object which provides a .read() method.

response = tchannel.stream(service='foo', endpoint='bar', body='listItems')
headers = response.headers
try:
    while True:
        chunk = yield response.read()
        process(chunk)
except EndOfStream:
    pass

Request streaming

We'll have a body_producer parameter on both call and stream. body_producer may be passed in lieu of the body. It will be a function that accepts a write function and calls it to write to the stream. The function must be a coroutine, or return a function that resolves to None when it finishes writing.

@gen.coroutine
def producer(write):
    for line in some_file:
        yield write(line)

response = yield tchannel.call(endpoint='foo', service='bar', body_producer=producer)

# Bidirectional streaming:

response = yield tchannel.stream(endpoint='foo', service='bar', body_producer=producer)
try:
    while True:
        chunk = yield response.read()
        process(chunk)
except EndOfStream:
    pass

@blampe
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blampe commented Jul 28, 2015

Suggestion: make the streamed response iterable, e.g. for thing in response.

@HelloGrayson
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@blampe +1

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