tests/src/integration/message-hub/src/receive-messages.js

// Licensed to the Apache Software Foundation (ASF) under one or more contributor
// license agreements; and to You under the Apache License, Version 2.0.

/*
 This function is bound to a trigger and is initiated when the message arrives
 via OpenWhisk feed connected to Message Hub. Note that many messages can come in
 as a large batch. Example input:

{
  "messages": [{
    "partition": 0,
    "key": null,
    "offset": 252,
    "topic": "in-topic",
    "value": {
      "events": [{
        "eventType": "update",
        "id": "1",
        "timestamp": "2017-09-01T11:11:11.111+02",
        "payload": {
          "category": 4,
          "name": "Harvey",
          "location": "Houston"
        }
      }, {
        ...
      }]
    }
  }, {
    ...
  }]
}


Expected output (merge all events from multiple 'messages' into one big 'events'):
{
  "events": [{
        "eventType": "update",
        "id": "1",
        "timestamp": "2017-09-01T11:11:11.111+02",
        "payload": {
          "category": 4,
          "name": "Harvey",
          "location": "Houston"
        }
  }, {
    ...
  }]
}
**/

function main(params) {
    console.log("DEBUG: Received the following message as input: " + JSON.stringify(params));

    return new Promise(function(resolve, reject) {
        if (!params.messages || !params.messages[0] ||
            !params.messages[0].value || !params.messages[0].value.events) {
            reject("Invalid arguments. Must include 'messages' JSON array with 'value' field");
        }
        var msgs = params.messages;
        var out = [];
        for (var i = 0; i < msgs.length; i++) {
            var msg = msgs[i];
            for (var j = 0; j < msg.value.events.length; j++) {
                out.push(msg.value.events[j]);
            }
        }
        resolve({
            "events": out
        });
    });
}