Package io.helidon.tracing.jersey.client

Class ClientTracingFilter

java.lang.Object

io.helidon.tracing.jersey.client.ClientTracingFilter

All Implemented Interfaces:

ClientRequestFilter, ClientResponseFilter

public class ClientTracingFilter
extends Object
implements ClientRequestFilter, ClientResponseFilter

This filter adds tracing information the the associated JAX-RS client call based on the provided properties.

In order to inject the tracing information properly, Tracer and an optional parent SpanContext needs to be resolved. In case we are in scope of inbound JAX-RS request, the client also uses inbound HTTP headers to determine correct headers for outbound call.

The Tracer gets resolved in the following order:

1. From request property TRACER_PROPERTY_NAME
2. From JAX-RS server, when the client is invoked in scope of a JAX-RS inbound request and appropriate filter is configured (see helidon-tracing-jersey and helidon-microprofile-tracing modules)
3. From GlobalTracer.get()

The parent SpanContext is resolved as follows

1. From request property CURRENT_SPAN_CONTEXT_PROPERTY_NAME
2. From JAX-RS server, when the client is invoked in scope of a JAX-rs inbound request

Inbound HTTP headers are resolved from JAX-RS server.

For each client call, a new Span with operation name "jersey-client-call" is created based on the resolved Tracer and an optional parent Span. The span information is also propagated to the outbound request using HTTP headers injected by tracer.

Example 1 - client within a JAX-RS resource (with tracing integration configured on server):

 public String someMethod(@Uri(BACKEND) WebTarget target) {
   Response response = target.request().get();
   // process the response
 }
 

Example 2 - standalone client (with access to tracer and span), assuming we have a WebTarget ready as target

 target.request()
   .property(TracingClientFilter.TRACER_PROPERTY_NAME, tracer)
   .property(TracingClientFilter.CURRENT_SPAN_CONTEXT_PROPERTY_NAME, spanContext)
   .get();
 

Field Summary

Fields

Modifier and Type	Field and Description
static String	CURRENT_SPAN_CONTEXT_PROPERTY_NAME The SpanContext property name.
static String	SPAN_OPERATION_NAME Operation name of a span created for outbound calls.
static String	TRACER_PROPERTY_NAME The Tracer property name.
static String	X_OT_SPAN_CONTEXT Header used by Envoy proxy.
static String	X_REQUEST_ID Header used by routers.

Constructor Summary

Constructors

Constructor and Description
ClientTracingFilter() Default constructor so this filter can be registered with Jersey as a class.

Method Summary

Modifier and Type	Method and Description
void	filter(ClientRequestContext requestContext)
void	filter(ClientRequestContext requestContext, ClientResponseContext responseContext)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

TRACER_PROPERTY_NAME

public static final String TRACER_PROPERTY_NAME

The Tracer property name.

See Also:

Constant Field Values

CURRENT_SPAN_CONTEXT_PROPERTY_NAME

public static final String CURRENT_SPAN_CONTEXT_PROPERTY_NAME

The SpanContext property name.

See Also:

Constant Field Values

SPAN_OPERATION_NAME

public static final String SPAN_OPERATION_NAME

Operation name of a span created for outbound calls.

See Also:

Constant Field Values

X_OT_SPAN_CONTEXT

public static final String X_OT_SPAN_CONTEXT

Header used by Envoy proxy. Automatically propagated when within Jersey and when using helidon-microprofile-tracing module.

See Also:

Constant Field Values

X_REQUEST_ID

public static final String X_REQUEST_ID

Header used by routers. Automatically propagated when within Jersey and when using helidon-microprofile-tracing module.

See Also:

Constant Field Values

Constructor Detail

ClientTracingFilter

public ClientTracingFilter()

Default constructor so this filter can be registered with Jersey as a class. Required by integrated platform.

Method Detail

filter

public void filter(ClientRequestContext requestContext)

Specified by:

filter in interface ClientRequestFilter

filter

public void filter(ClientRequestContext requestContext,
                   ClientResponseContext responseContext)

Specified by:

filter in interface ClientResponseFilter