function handler()

in index.js [218:285]
26 lines of code
9 McCabe index (conditional complexity)

function handler(event, context) {
    // add the context and event to the function that closes the lambda
    // invocation
    var finish = onCompletion.bind(undefined, context, event);

    /** End Runtime Functions */
    if (debug) {
        console.log(JSON.stringify(event));
    }

    // fail the function if the wrong event source type is being sent, or if
    // there is no data, etc
    var noProcessStatus = ERROR;
    var noProcessReason;

    if (!event.Records || event.Records.length === 0) {
        noProcessReason = "Event contains no Data";
        // not fatal - just got an empty event
        noProcessStatus = OK;
    } else {
        // there are records in this event
        var serviceName;
        if (event.Records[0].eventSource === KINESIS_SERVICE_NAME || event.Records[0].eventSource === DDB_SERVICE_NAME) {
            serviceName = event.Records[0].eventSource;
        } else {
            noProcessReason = "Invalid Event Source " + event.Records[0].eventSource;
        }

        // currently hard coded around the 1.0 kinesis event schema
        if (event.Records[0].kinesis && event.Records[0].kinesis.kinesisSchemaVersion !== "1.0") {
            noProcessReason = "Unsupported Kinesis Event Schema Version " + event.Records[0].kinesis.kinesisSchemaVersion;
        }
    }

    if (noProcessReason) {
        // terminate if there were any non process reasons
        finish(noProcessStatus, ERROR, noProcessReason);
    } else {
        init(function (err) {
            if (err) {
                finish(err, ERROR);
            } else {
                // parse the stream name out of the event
                var streamName = exports.getStreamName(event.Records[0].eventSourceARN);

                // create the processor to handle each record
                var processor = exports.processEvent.bind(undefined, event, serviceName, streamName, function (err) {
                    if (err) {
                        finish(err, ERROR, "Error Processing Records");
                    } else {
                        finish(undefined, OK);
                    }
                });

                if (deliveryStreamMapping.length === 0 || !deliveryStreamMapping[streamName]) {
                    // no delivery stream cached so far, so add this stream's
                    // tag
                    // value
                    // to the delivery map, and continue with processEvent
                    exports.buildDeliveryMap(streamName, serviceName, context, event, processor);
                } else {
                    // delivery stream is cached so just invoke the processor
                    processor();
                }
            }
        });
    }
}