Package brave.http

Class HttpClientHandler<Req,Resp>

java.lang.Object

brave.http.HttpClientHandler<Req,Resp>

Type Parameters:

Req - the native http request type of the client.

Resp - the native http response type of the client.

public final class HttpClientHandler<Req,Resp>
extends java.lang.Object

This standardizes a way to instrument http clients, particularly in a way that encourages use of portable customizations via HttpClientParser.

This is an example of synchronous instrumentation:

 Span span = handler.handleSend(injector, request);
 Throwable error = null;
 try (Tracer.SpanInScope ws = tracer.withSpanInScope(span)) {
   // any downstream code can see Tracer.currentSpan() or use Tracer.currentSpanCustomizer()
   response = invoke(request);
 } catch (RuntimeException | Error e) {
   error = e;
   throw e;
 } finally {
   handler.handleReceive(response, error, span);
 }
 

Since:

4.3

Method Summary

Modifier and Type	Method	Description
static <Req,Resp> HttpClientHandler<Req,Resp>	create(HttpTracing httpTracing, HttpClientAdapter<Req,Resp> adapter)
void	handleReceive(Resp response, java.lang.Throwable error, Span span)	Finishes the client span after assigning it tags according to the response or error.
<C> Span	handleSend(TraceContext.Injector<C> injector, C carrier, Req request)	Like handleSend(TraceContext.Injector, Object), except for when the carrier of trace data is not the same as the request.
<C> Span	handleSend(TraceContext.Injector<C> injector, C carrier, Req request, Span span)	Like handleSend(TraceContext.Injector, Object, Object), except explicitly controls the span representing the request.
Span	handleSend(TraceContext.Injector<Req> injector, Req request)	Starts the client span after assigning it a name and tags.
Span	handleSend(TraceContext.Injector<Req> injector, Req request, Span span)	Like handleSend(TraceContext.Injector, Object), except explicitly controls the span representing the request.
Span	nextSpan(Req request)	Creates a potentially noop span representing this request.

Methods inherited from class java.lang.Object

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

Method Detail

create

public static <Req,Resp> HttpClientHandler<Req,Resp> create(HttpTracing httpTracing,
                                                            HttpClientAdapter<Req,Resp> adapter)

handleSend

public Span handleSend(TraceContext.Injector<Req> injector,
                       Req request)

Starts the client span after assigning it a name and tags. This injects the trace context onto the request before returning.

Call this before sending the request on the wire.

handleSend

public <C> Span handleSend(TraceContext.Injector<C> injector,
                           C carrier,
                           Req request)

Like handleSend(TraceContext.Injector, Object), except for when the carrier of trace data is not the same as the request.

See Also:

HttpClientParser.request(HttpAdapter, Object, SpanCustomizer)

handleSend

public Span handleSend(TraceContext.Injector<Req> injector,
                       Req request,
                       Span span)

Like handleSend(TraceContext.Injector, Object), except explicitly controls the span representing the request.

Since:

4.4

handleSend

public <C> Span handleSend(TraceContext.Injector<C> injector,
                           C carrier,
                           Req request,
                           Span span)

Like handleSend(TraceContext.Injector, Object, Object), except explicitly controls the span representing the request.

Since:

4.4

nextSpan

public Span nextSpan(Req request)

Creates a potentially noop span representing this request. This is used when you need to provision a span in a different scope than where the request is executed.

Since:

4.4

handleReceive

public void handleReceive(@Nullable
                          Resp response,
                          @Nullable
                          java.lang.Throwable error,
                          Span span)

Finishes the client span after assigning it tags according to the response or error.

This is typically called once the response headers are received, and after the span is no longer in scope.

See Also:

HttpClientParser.response(HttpAdapter, Object, Throwable, SpanCustomizer)