Package brave.http

Class HttpServerHandler<Req,Resp>

java.lang.Object

brave.http.HttpServerHandler<Req,Resp>

Type Parameters:

Req - the native http request type of the server.

Resp - the native http response type of the server.

public final class HttpServerHandler<Req,Resp>
extends Object

This standardizes a way to instrument http servers, particularly in a way that encourages use of portable customizations via HttpRequestParser and HttpResponseParser.

Synchronous interception is the most straight forward instrumentation.

You generally need to:

1. Extract any trace IDs from headers and start the span
2. Put the span in scope so things like log integration works
3. Process the request
4. Catch any errors
5. Complete the span

 HttpServerRequestWrapper wrapper = new HttpServerRequestWrapper(request);
 Span span = handler.handleReceive(wrapper); // 1.
 Result result = null;
 Throwable error = null;
 try (Scope ws = currentTraceContext.newScope(span.context())) { // 2.
   return result = process(request); // 3.
 } catch (RuntimeException | Error e) {
   error = e; // 4.
   throw e;
 } finally {
   HttpServerResponseWrapper response = result != null
     ? new HttpServerResponseWrapper(wrapper, result, error)
     : null;
   handler.handleSend(response, error, span); // 5.
 }
 

Since:

4.3

Method Summary

Modifier and Type	Method	Description
static HttpServerHandler<HttpServerRequest,HttpServerResponse>	create(HttpTracing httpTracing)
static <Req, Resp> HttpServerHandler<Req,Resp>	create(HttpTracing httpTracing, HttpServerAdapter<Req,Resp> adapter)	Deprecated. Since 5.7, use create(HttpTracing) as it is more portable.
Span	handleReceive(HttpServerRequest request)	Conditionally joins a span, or starts a new trace, depending on if a trace context was extracted from the request.
<C> Span	handleReceive(TraceContext.Extractor<C> extractor, C carrier, Req request)	Deprecated. Since 5.7, use handleReceive(HttpServerRequest)
Span	handleReceive(TraceContext.Extractor<Req> extractor, Req request)	Deprecated. Since 5.7, use handleReceive(HttpServerRequest)
void	handleSend(Resp response, Throwable error, Span span)	Finishes the server span after assigning it tags according to the response or error.

Methods inherited from class java.lang.Object

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

Method Details

create

public static HttpServerHandler<HttpServerRequest,HttpServerResponse> create(HttpTracing httpTracing)

Since:

5.7

create

@Deprecated public static <Req, Resp> HttpServerHandler<Req,Resp> create(HttpTracing httpTracing, HttpServerAdapter<Req,Resp> adapter)

Deprecated.

Since 5.7, use create(HttpTracing) as it is more portable.

Since:

4.3

handleReceive

public Span handleReceive(HttpServerRequest request)

Conditionally joins a span, or starts a new trace, depending on if a trace context was extracted from the request. Tags are added before the span is started.

This is typically called before the request is processed by the actual library.

Since:

5.7

See Also:

HttpTracing.serverRequestSampler(), HttpTracing.serverRequestParser()

handleReceive

@Deprecated public Span handleReceive(TraceContext.Extractor<Req> extractor, Req request)

Deprecated.

Since 5.7, use handleReceive(HttpServerRequest)

Since:

4.3

handleReceive

@Deprecated public <C> Span handleReceive(TraceContext.Extractor<C> extractor, C carrier, Req request)

Deprecated.

Since 5.7, use handleReceive(HttpServerRequest)

Since:

4.3

handleSend

public void handleSend(@Nullable Resp response, @Nullable Throwable error, Span span)

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

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

Note: Either the response or error parameters may be null, but not both.

Since:

4.3

See Also:

HttpTracing.serverResponseParser()