statefun-e2e-tests/statefun-exactly-once-remote-e2e/src/main/python/functions.py

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from remote_module_verification_pb2 import Invoke, InvokeResult, InvokeCount

from statefun import StatefulFunctions
from statefun import RequestReplyHandler
from statefun import kafka_egress_record

import uuid

functions = StatefulFunctions()


@functions.bind("org.apache.flink.statefun.e2e.remote/counter")
def counter(context, invoke: Invoke):
    """
    Keeps count of the number of invocations, and forwards that count
    to be sent to the Kafka egress. We do the extra forwarding instead
    of directly sending to Kafka, so that we cover inter-function
    messaging in our E2E test.
    """
    invoke_count = context.state('invoke_count').unpack(InvokeCount)
    if not invoke_count:
        invoke_count = InvokeCount()
        invoke_count.count = 1
    else:
        invoke_count.count += 1
    context.state('invoke_count').pack(invoke_count)

    response = InvokeResult()
    response.id = context.address.identity
    response.invoke_count = invoke_count.count

    context.pack_and_send(
        "org.apache.flink.statefun.e2e.remote/forward-function",
        # use random keys to simulate both local handovers and
        # cross-partition messaging via the feedback loop
        uuid.uuid4().hex,
        response
    )


@functions.bind("org.apache.flink.statefun.e2e.remote/forward-function")
def forward_to_egress(context, invoke_result: InvokeResult):
    """
    Simply forwards the results to the Kafka egress.
    """
    egress_message = kafka_egress_record(
        topic="invoke-results",
        key=invoke_result.id,
        value=invoke_result
    )
    context.pack_and_send_egress(
        "org.apache.flink.statefun.e2e.remote/invoke-results",
        egress_message
    )


handler = RequestReplyHandler(functions)

#
# Serve the endpoint
#

from flask import request
from flask import make_response
from flask import Flask

app = Flask(__name__)


@app.route('/service', methods=['POST'])
def handle():
    response_data = handler(request.data)
    response = make_response(response_data)
    response.headers.set('Content-Type', 'application/octet-stream')
    return response


if __name__ == "__main__":
    app.run()