...
It is also worth to mention the way Apache CXF attaches the description to spans. With regards to the client integration, the description becomes a full URL being invoked prefixed by HTTP method, for example: GET http://localhost:8282/books. On the server side integration, the description becomes a relative JAX-RS resource path prefixed by HTTP method, f.e.: GET books, POST book/123
Configuring Client
TBD
Configuring Server
There are a couple of ways the JAX-RS client could be configured, depending on the client implementation. Apache CXF provides its own WebClient which could be configured just like that (in future versions, there would be a simpler ways to do that using client specific features):
Code Block | ||
---|---|---|
| ||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("web-client");
Response response = WebClient
.create("http://localhost:9000/catalog", Arrays.asList(new OpenTelemetryClientProvider(openTelemetry, tracer))
.accept(MediaType.APPLICATION_JSON)
.get(); |
The configuration based on using the standard JAX-RS Client is very similar:
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("jaxrs-client");
final OpenTelemetryClientProvider provider = new OpenTelemetryClientProvider(openTelemetry, tracer);
final Client client = ClientBuilder.newClient().register(provider);
final Response response = client
.target("http://localhost:9000/catalog")
.request()
.accept(MediaType.APPLICATION_JSON)
.get(); |
Configuring Server
Server configuration is a bit simpler than the client one thanks to the feature class available, OpenTelemetryFeature. Depending on the way the Apache CXF is used to configure JAX-RS services, it could be part of JAX-RS application configuration, for example:
Code Block | ||||
---|---|---|---|---|
| ||||
@ApplicationPath("/")
public class CatalogApplication extends Application {
@Override
public Set<Object> getSingletons() {
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("tracer");
return new HashSet<>(
Arrays.asList(
new OpenTelemetryFeature(openTelemetry, tracer)
)
);
}
} |
Or it could be configured using JAXRSServerFactoryBean as well, for example:
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("tracer");
final JAXRSServerFactoryBean factory = RuntimeDelegate.getInstance().createEndpoint(/* application instance */, JAXRSServerFactoryBean.class);
factory.setProvider(new OpenTelemetryFeature(openTelemetry, tracer));
...
return factory.create(); |
Once the span processor(s) and sampler are properly configured, all generated spans are going to be collected and available for analysis and/or visualization.TBD
Distributed Tracing In Action: Usage Scenarios
TBDIn the following subsections we are going to walk through many different scenarios to illustrate the distributed tracing in action, starting from the simplest ones and finishing with asynchronous JAX-RS services. All examples assume that configuration has been done (see please Configuring Client and Configuring Server sections above).
Example #1: Client and Server with default distributed tracing configured
In the first example we are going to see the effect of using default configuration on the client and on the server, with only OpenTelemetryClientProvider and OpenTelemetryProvider registered. The JAX-RS resource endpoint is pretty basic stubbed method:
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public Collection<Book> getBooks() {
return Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
);
} |
The client is as simple as that:
Code Block | ||||
---|---|---|---|---|
| ||||
final Response response = client
.target("http://localhost:8282/books")
.request()
.accept(MediaType.APPLICATION_JSON)
.get(); |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name tracer-server) is going to generate the following sample traces (taken from Jaeger UI):
TBD
Example #2: Client and Server with nested trace
In this example server-side implementation of the JAX-RS service is going to call an external system (simulated as a simple delay of 500ms) within its own span. The client-side code stays unchanged.
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public Collection<Book> getBooks(@Context final TracerContext tracer) throws Exception {
try(final Scope scope = tracer.startSpan("Calling External System")) {
// Simulating a delay of 500ms required to call external system
Thread.sleep(500);
return Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
);
}
} |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name tracer-server) is going to generate the following sample traces (taken from Jaeger UI):
TBD
Example #3: Client and Server trace with annotations
...
In this example server-side implementation of the JAX-RS service is going to add timeline to the active span. The client-side code stays unchanged.
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public Collection<Book> getBooks(@Context final TracerContext tracer) throws Exception {
tracer.timeline("Preparing Books");
// Simulating some work using a delay of 100ms
Thread.sleep(100);
return Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
);
} |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name traceser-server) is going to generate the following sample traces (taken from Jaeger UI):
Info |
---|
Please notice that timelines are treated as logs events in Jaeger. |
Example #4: Client and Server with binary annotations (key/value)
In this example server-side implementation of the JAX-RS service is going to add key/value annotations to the active span. The client-side code stays unchanged.
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public Collection<Book> getBooks(@Context final TracerContext tracer) throws Exception {
final Collection<Book> books = Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
);
tracer.annotate("# of books", Integer.toString(books.size()));
return books;
} |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name tracer-server) is going to generate the following sample server trace properties (taken from Jaeger UI):
TBD
Example #5: Client and Server with parallel trace (involving thread pools)
In this example server-side implementation of the JAX-RS service is going to offload some work into thread pool and then return the response to the client, simulating parallel execution. The client-side code stays unchanged.
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } ) @GET public Collection<Book> getBooks(@Context final TracerContext tracer) throws Exception { final Future<Book> book1 = executor.submit( tracer.wrap("Getting Book 1", new Traceable<Book>() { public Book call(final TracerContext context) throws Exception { // Simulating a delay of 100ms required to call external system Thread.sleep(100); return new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi"); } }) ); final Future<Book> book2 = executor.submit( tracer.wrap("Getting Book 2", new Traceable<Book>() { public Book call(final TracerContext context) throws Exception { // Simulating a delay of 100ms required to call external system Thread.sleep(200); return new Book("Developing Web Services with Apache CXF and Axis2", "Kent Ka Iok Tong"); } }) ); return Arrays.asList(book1.get() |
...
, book2.get());
} |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (process name tracer-server) is going to generate the following sample traces (taken from Jaeger UI):
TBD
Example #6: Client and Server with asynchronous JAX-RS service (server-side)
In this example server-side implementation of the JAX-RS service is going to be executed asynchronously. It poses a challenge from the tracing prospective as request and response are processed in different threads (in general). At the moment, Apache CXF does not support the transparent tracing spans management (except for default use case) but provides the simple ways to do that (by letting to transfer spans from thread to thread). The client-side code stays unchanged.
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public void getBooks(@Suspended final AsyncResponse response, @Context final TracerContext tracer) throws Exception {
tracer.continueSpan(new Traceable<Future<Void>>() {
public Future<Void> call(final TracerContext context) throws Exception {
return executor.submit(
tracer.wrap("Getting Book", new Traceable<Void>() {
public Void call(final TracerContext context) throws Exception {
// Simulating a processing delay of 50ms
Thread.sleep(50);
response.resume(
Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
)
);
return null;
}
})
);
}
});
} |
The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name tracer-server)
...
is going to generate the following sample traces (taken from Jaeger UI):
TBD
Example #7: Client and Server with asynchronous invocation (client-side)
In this example server-side implementation of the JAX-RS service is going to be the default one:
Code Block | ||||
---|---|---|---|---|
| ||||
@Produces( { MediaType.APPLICATION_JSON } )
@GET
public Collection<Book> getBooks() {
return Arrays.asList(
new Book("Apache CXF Web Service Development", "Naveen Balani, Rajeev Hathi")
);
} |
While the JAX-RS client implementation is going to perform the asynchronous invocation:
Code Block | ||||
---|---|---|---|---|
| ||||
final Future<Response> future = client .target("http://localhost:8282/books") .request() .accept(MediaType.APPLICATION_JSON) .async() .get(); |
In this respect, there is no difference from the caller prospective however a bit more work is going under the hood to transfer the active tracing span from JAX-RS client request filter to client response filter as in general those are executed in different threads (similarly to server-side asynchronous JAX-RS resource invocation)
...
. The actual invocation of the request by the client (with service name tracer-client) and consequent invocation of the service on the server side (service name tracer-server) is going to generate the following sample traces (taken from Jaeger UI):
TBD
Distributed Tracing with OpenTelemetry and JAX-WS support
TBD
Distributed Tracing with OpenTelemetry and OSGi
TBD
Spring XML-Configuration
TBD
Using non-JAX-RS clients
Distributed tracing in the Apache CXF is build primarily around JAX-RS 2.x implementation. However, JAX-WS is also supported but it requires to write some boiler-plate code and use OpenTelemetry Java SDK directly (the JAX-WS integration is going to be enhanced in the future). Essentially, from the server-side prospective the in/out interceptors, OpenTelemetryStartInterceptor and OpenTelemetryStopInterceptor respectively, should be configured as part of interceptor chains, either manually or using OpenTelemetryFeature. For example:
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("tracer");
final JaxWsServerFactoryBean sf = new JaxWsServerFactoryBean();
...
sf.getFeatures().add(new OpenTelemetryFeature(openTelemetry, tracer));
...
sf.create(); |
Similarly to the server-side, client-side needs own set of out/in interceptors, OpenTelemetryClientStartInterceptor and OpenTelemetryClientStopInterceptor (or OpenTelemetryClientFeature). Please notice the difference from server-side: OpenTelemetryClientStartInterceptor becomes out-interceptor while OpenTelemetryClientStopInterceptor becomes in-interceptor. For example:
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final Tracer tracer = openTelemetry.getTracer("tracer");
final JaxWsProxyFactoryBean sf = new JaxWsProxyFactoryBean();
...
sf.getFeatures().add(new OpenTelemetryClientFeature(openTelemetry, tracer));
...
sf.create(); |
As it was mentioned before, you may use GlobalOpenTelemetry utility class to pass the tracer around so, for example, any JAX-WS service will be able to retrieve the current tracer by invoking GlobalOpenTelemetry.get() method.
Distributed Tracing with OpenTelemetry and OSGi
Most of the distributed tracers compatible with OpenTelemetry API could be deployed into OSGi container and as such, the integration is fully available for Apache CXF services running inside the container. For a complete example please take a look on jax_rs_tracing_opentelemetry_osgi sample project, but here is the typical OSGi Blueprint snippet in case logging span exporter.
Code Block | ||||
---|---|---|---|---|
| ||||
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:cxf="http://cxf.apache.org/blueprint/core"
xmlns:jaxrs="http://cxf.apache.org/blueprint/jaxrs"
xsi:schemaLocation="http://www.osgi.org/xmlns/blueprint/v1.0.0 http://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd
http://cxf.apache.org/blueprint/core http://cxf.apache.org/schemas/blueprint/core.xsd
http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/blueprint/jaxrs.xsd">
<bean id="tracingFeature" class="org.apache.cxf.tracing.opentelemetry.jaxrs.OpenTelemetryFeature">
<argument index="0">
<bean factory-ref="withPropagators" factory-method="build"/>
</argument>
<argument index="1" value="tracer" />
</bean>
<bean id="openTelemetrySdk" class="io.opentelemetry.sdk.OpenTelemetrySdk" factory-method="builder" />
<bean id="sdkTracerProvider" class="io.opentelemetry.sdk.trace.SdkTracerProvider" factory-method="builder" />
<bean id="withSampler" factory-ref="sdkTracerProvider" factory-method="setSampler">
<argument index="0">
<bean class="io.opentelemetry.sdk.trace.samplers.Sampler" factory-method="alwaysOn" />
</argument>
</bean>
<bean id="processor" class="io.opentelemetry.sdk.trace.export.BatchSpanProcessor" factory-method="builder">
<argument index="0">
<bean class="io.opentelemetry.exporter.logging.LoggingSpanExporter" factory-method="create" />
</argument>
</bean>
<bean id="withSpanProcessor" factory-ref="sdkTracerProvider" factory-method="addSpanProcessor">
<argument index="0">
<bean factory-ref="processor" factory-method="build"/>
</argument>
</bean>
<bean id="withTracerProvider" factory-ref="openTelemetrySdk" factory-method="setTracerProvider">
<argument index="0">
<bean factory-ref="withSpanProcessor" factory-method="build"/>
</argument>
</bean>
<bean id="withPropagators" factory-ref="withTracerProvider" factory-method="setPropagators">
<argument index="0">
<bean class="io.opentelemetry.context.propagation.ContextPropagators" factory-method="create">
<argument index="0">
<bean class="io.opentelemetry.api.trace.propagation.W3CTraceContextPropagator" factory-method="getInstance" />
</argument>
</bean>
</argument>
</bean>
<cxf:bus>
<cxf:features>
<cxf:logging />
</cxf:features>
</cxf:bus>
<jaxrs:server id="catalogServer" address="/">
<jaxrs:serviceBeans>
...
</jaxrs:serviceBeans>
<jaxrs:providers>
<ref component-id="tracingFeature" />
</jaxrs:providers>
</jaxrs:server>
</blueprint> |
Info |
---|
As of now, OpenTelemetry does not provide dedicated OSGi bundles and the service loader mechanism is not working very well. It is very likely that you may need to declare own span exporters. |
Accessing OpenTelemetry APIs
The Apache CXF abstracts as much of the tracer-specific APIs behind TracerContext as possible. However, sometimes there is a need to get access to OpenTelemetry APIs in order to leverages the rich set of available instrumentations. To make it possible, TracerContext has a dedicated unwrap method which returns underlying Tracer instance. The snippet below shows off how to use this API and use OpenTelemetry instrumentation for OpenFeign client through OpenTracing shim (as of today, OpenFeign client does not provide native support for OpenTelemetry).
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
// Use OpenTelemetru OpenTracing shim for Feign OpenTracing integration
GlobalTracer.registerIfAbsent(OpenTracingShim.createTracerShim(openTelemetry)); |
Code Block | ||||
---|---|---|---|---|
| ||||
@GET
@Path("/search")
@Produces(MediaType.APPLICATION_JSON)
public JsonObject search(@QueryParam("q") final String query, @Context final TracerContext tracing) throws Exception {
final GoogleBooksApi api = Feign.builder()
.client(new TracingClient(new ApacheHttpClient(), tracing.unwrap(Tracer.class)))
.target(GoogleBooksApi.class, "https://www.googleapis.com");
final Response response = api.search(query);
try (final Reader reader = response.body().asReader()) {
return Json.createReader(reader).readObject();
}
} |
The usage of tracer-specific APIs is not generally advisable (because of portability reasons) but in case there are no other options available, it is available.
Using non-JAX-RS clients
The Apache CXF uses native OpenTelemetry capabilities so the existing instrumentations for different HTTP clients work as expected. The usage of only JAX-RS client is not required. For example, the following snippet demonstrates the usage of traceble OkHttp client to call JAX-RS resources, backed by Apache CXF and OpenTelemetry OkHttp3 instrumentation.
Code Block | ||||
---|---|---|---|---|
| ||||
final SdkTracerProvider sdkTracerProvider = SdkTracerProvider
.builder()
...
.build();
final OpenTelemetry openTelemetry = OpenTelemetrySdk
.builder()
.setTracerProvider(sdkTracerProvider)
...
.buildAndRegisterGlobal();
final OkHttpClient client = OkHttpClient.Builder().build();
final Call.Factory factory = OkHttpTelemetry.builder(openTelemetry).build().newCallFactory(client));
final Request request = new Request.Builder()
.url("http://localhost:9000/catalog")
.header("Accept", "application/json")
.build();
try (final Response response = factory.newCall(request).execute()) {
// Do something with response.body()
} |
Samples
- https://github.com/apache/cxf/tree/3.6.x-fixes/distribution/src/main/release/samples/jax_rs/tracing_opentelemetry_osgi
- https://github.com/apache/cxf/tree/main/distribution/src/main/release/samples/jax_rs/tracing_opentelemetry
- https://github.com/apache/cxf/tree/main/distribution/src/main/release/samples/jax_rs/tracing_opentelemetry_camel
...