How to measure elapsed time with Apache Camel

Question

I need to measure how much time it takes to process external service response in Apache Camel.

I've search the web for solutions and surprisingly there was no acceptable one.

Using an EventNotifier feels too heavy weight and more framework level performance measurement tool.

So I've made my own simple solution, but I'm hoping for something better out there I've missed or at least a constructive feedback.

A solution attempt below.

Answer 1

I think that camel do this by default.

Available as of Camel 2.12 Message History is enabled by default from Camel 2.12. During routing Camel captures how the Exchange is routed, as a org.apache.camel.MessageHistory entity that is stored on the Exchange. On the org.apache.camel.MessageHistory there is information abut the route id, processor id, timestamp, and elapsed time it took to process the Exchange by the processor.

Only that you have to do is get the MessageHistory in your "doFinally" code:

List<MessageHistory> list = exchange.getProperty(Exchange.MESSAGE_HISTORY,List.class);

There you can get the the elapsed time for each route

Answer 2

This is how my business logic looks like:

from(incomingUri).routeId(ROUTE_ID)
            ...
            .doTry()
                .bean(stopwatch, "start")
                .to(externalService)
            .doCatch(NoHttpResponseException.class, ProtocolException.class, IOException.class)
                .process(externalServiceExceptionProcessor(ERROR_MESSAGE_SERVICE_NOT_RESPONDING))
            .doFinally()
                .bean(stopwatch, "stop")
            .end()
            ...

The Stopwatch bean instantition:

StopWatchBean stopwatch = new StopWatchBean(new ExchangeConsumer<Stopwatch>() {
        @Override
        public void accept(Exchange exchange, Stopwatch stopwatch) {
            Long taken = stopwatch.elapsed(MILLISECONDS);
            exchange.setProperty(RESPONSE_TIME, constant(taken));
        }
});

and class definition:

public class StopWatchBean {

    private final Stopwatch stopwatch;
    private final ExchangeConsumer<Stopwatch> onStopFunction;

    public StopWatchBean(ExchangeConsumer<Stopwatch> onStopFunction) {
        this.stopwatch = Stopwatch.createUnstarted();
        this.onStopFunction = onStopFunction;
    }

    public void stop(Exchange exchange) {
        if (!stopwatch.isRunning()) {
            return;
        }
        stopwatch.stop();
        onStopFunction.accept(exchange, stopwatch);
    }

    public void start(Exchange unused) {
        stopwatch.start();
    }

    public void reset(Exchange unused) {
        stopwatch.reset();
    }

}

The Stopwatch is from Guava and the Consumer is just a custom functional interface.

Waiting for comments.

EDIT: I've added some simple code, like:

started = System.currentTimeMillis();
...
stopped = System.currentTimeMillis();

elapsed = stopped - started;

and made some measurements, on normal case looks good:

[xxxxxxxxxProxy    ] [stopWatchStart    ] [bean[StopWatchBean{elapsed=100, stopwatch=100.8 ms}]                          ] [         1]
[xxxxxxxxxProxy    ] [toXxxxxxxxxx      ] [https://127.0.0.1:5680/xxxxxxxxx?throwExceptionOnFailure=false&bridgeEndpoint=] [       100]
[xxxxxxxxxProxy    ] [stopWatchStop     ] [bean[StopWatchBean{elapsed=100, stopwatch=100.8 ms}]                          ] [         3]

and on error/exception is different:

[xxxxxxxxxProxy    ] [stopWatchStart    ] [bean[StopWatchBean{elapsed=38, stopwatch=344.1 ms}]                           ] [         1]
[xxxxxxxxxProxy    ] [toXxxxxxxxxx      ] [https://127.0.0.1:5680/xxxxxxxxx?throwExceptionOnFailure=false&bridgeEndpoint=] [        37]
[xxxxxxxxxProxy    ] [stopWatchStop     ] [bean[StopWatchBean{elapsed=38, stopwatch=344.1 ms}]                           ] [         1]

I'm puzzled, why the difference, 38 vs 344, could it be due to Camel not taking Exception handling into account?