A 3rd party Dropwizard bundle, that enhances Dropwizard capabilities to support not only JAX-RS resources but also websockets endpoints using the JSR-356 API.
The websockets endpoints will be instrumented the same way Dropwizards does with JAX-RS resources, and their metrics will be exposed in the same way. This includes:
- Counters of current open sessions.
- Counters and rate meters for new connections.
- Counters and rate meters for messages reviewed by the endpoint.
- Timers and statistics for session duration.
Add the Maven dependency:
<dependency> <groupId>com.liveperson</groupId> <artifactId>dropwizard-websockets</artifactId> <version></version> </dependency>In your code you should add the WebsocketBundle in the initialization stage of the Application. Give the bundle your endpoints classes (or ServerEndpoindConfig in case of programmatic endpoints) as parameters:
public void initialize(Bootstrap<Configuration> bootstrap) { bootstrap.addBundle(new WebsocketBundle(MyWebSocket1.class, MyWebSocket2.class)); }Or, if you prefer, you can register the endpoint before the running stage:
public void initialize(Bootstrap<Configuration> bootstrap) { websocketBundle = new WebsocketBundle(); bootstrap.addBundle(websocketBundle); } @Override public void run(Configuration configuration, Environment environment) throws Exception { // Using BasicServerEndpointConfig lets you inject objects to the websocket endpoint: final BasicServerEndpointConfig bsec = new BasicServerEndpointConfig(EchoServer.class, "/extends-ws"); // bsec.getUserProperties().put(Environment.class.getName(), environment); // Then you can get it from the Session object // - obj = session.getUserProperties().get("objectName"); websocketBundle.addEndpoint(bsec); }That's all. A full example can be found in the tests classes.
In order to collect metrics on your endpoints, you should annotate them with metrics annotations:
@Metered @Timed @ExceptionMetered @ServerEndpoint("/annotated-ws") public static class AnnotatedEchoServer { @OnOpen public void myOnOpen(final Session session) throws IOException { session.getAsyncRemote().sendText("welcome"); } @OnMessage public void myOnMsg(final Session session, String message) { session.getAsyncRemote().sendText(message.toUpperCase()); } @OnClose public void myOnClose(final Session session, CloseReason cr) { } }Then you'll be able to see your metrics as follows:
{ "counters" : { "io.dropwizard.websockets.MyApp$AnnotatedEchoServer.openConnections" : { "count" : 2 } }, "meters" : { "io.dropwizard.websockets.MyApp$AnnotatedEchoServer.OnError" : { "count" : 0, "m15_rate" : 0.0, "m1_rate" : 0.0, "m5_rate" : 0.0, "mean_rate" : 0.0, "units" : "events/second" }, "io.dropwizard.websockets.MyApp$AnnotatedEchoServer.OnMessage" : { "count" : 3, "m15_rate" : 0.6, "m1_rate" : 0.6, "m5_rate" : 0.6, "mean_rate" : 0.3194501069682357, "units" : "events/second" } }, "timers" : { "io.dropwizard.websockets.MyApp$AnnotatedEchoServer" : { "count" : 1, "max" : 0.101819137, "mean" : 0.101819137, "min" : 0.101819137, "p50" : 0.101819137, "p75" : 0.101819137, "p95" : 0.101819137, "p98" : 0.101819137, "p99" : 0.101819137, "p999" : 0.101819137, "stddev" : 0.0, "m15_rate" : 0.2, "m1_rate" : 0.2, "m5_rate" : 0.2, "mean_rate" : 0.10647618704871187, "duration_units" : "seconds", "rate_units" : "calls/second" } } }See also dropwizard-websocket-jee7-bundle.
