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Brave instrumentation for Ratpack
/*
* Copyright 2016-2019 The OpenZipkin Authors
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package ratpack.zipkin.internal;
import brave.Span;
import brave.http.HttpClientAdapter;
import brave.http.HttpClientHandler;
import brave.http.HttpSampler;
import brave.http.HttpTracing;
import brave.propagation.CurrentTraceContext;
import brave.propagation.SamplingFlags;
import brave.propagation.ThreadLocalSpan;
import brave.propagation.TraceContext;
import brave.propagation.TraceContextOrSamplingFlags;
import io.netty.buffer.ByteBufAllocator;
import java.net.URI;
import java.time.Duration;
import java.util.Optional;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
import javax.inject.Inject;
import javax.net.ssl.SSLContext;
import io.netty.handler.ssl.SslContext;
import ratpack.exec.Promise;
import ratpack.exec.Result;
import ratpack.func.Action;
import ratpack.func.Function;
import ratpack.http.HttpMethod;
import ratpack.http.MutableHeaders;
import ratpack.http.client.*;
/**
* Decorator that adds Zipkin client logging around {@link HttpClient}.
*/
public final class ZipkinHttpClientImpl implements HttpClient {
private final HttpClient delegate;
private final CurrentTraceContext currentTraceContext;
private final ThreadLocalSpan threadLocalSpan;
private final BiFunction nextThreadLocalSpan;
private final HttpClientHandler handler;
private final TraceContext.Injector injector;
@Inject
public ZipkinHttpClientImpl(final HttpClient delegate, final HttpTracing httpTracing) {
this.delegate = delegate;
this.threadLocalSpan = ThreadLocalSpan.create(httpTracing.tracing().tracer());
this.currentTraceContext = httpTracing.tracing().currentTraceContext();
this.nextThreadLocalSpan = new NextSpan(threadLocalSpan, httpTracing.clientSampler());
this.handler = HttpClientHandler.create(httpTracing, ADAPTER);
this.injector = httpTracing.tracing().propagation().injector(MutableHeaders::set);
}
@Override
public ByteBufAllocator getByteBufAllocator() {
return delegate.getByteBufAllocator();
}
@Override
public int getPoolSize() {
return delegate.getPoolSize();
}
@Override
public int getPoolQueueSize() {
return delegate.getPoolQueueSize();
}
@Override
public Duration getReadTimeout() {
return delegate.getReadTimeout();
}
@Override
public Duration getConnectTimeout() {
return delegate.getConnectTimeout();
}
@Override
public int getMaxContentLength() {
return delegate.getMaxContentLength();
}
@Override
public int getMaxResponseChunkSize() {
return delegate.getMaxResponseChunkSize();
}
@Override
public void close() {
delegate.close();
}
@Override
public HttpClient copyWith(Action action) throws Exception {
return delegate.copyWith(action);
}
@Override
public Promise request(URI uri, Action action) {
// save off the current span as the parent of a future client span
TraceContext parent = currentTraceContext.get();
// this reference is used to manually propagate the span from the request to the response
// we use this because we cannot assume a thread context exists betweeen them.
AtomicReference currentSpan = new AtomicReference<>();
return delegate.request(uri, (RequestSpec requestSpec) -> {
try {
action.execute(new WrappedRequestSpec(requestSpec, parent, currentSpan));
} finally {
// moves the span from thread local context to an atomic ref the response can read
currentSpan.set(threadLocalSpan.remove());
}
}).wiretap(response -> responseWithSpan(response, currentSpan.getAndSet(null)));
}
@Override
public Promise requestStream(URI uri, Action action) {
// save off the current span as the parent of a future client span
TraceContext parent = currentTraceContext.get();
// this reference is used to manually propagate the span from the request to the response
// we use this because we cannot assume a thread context exists betweeen them.
AtomicReference currentSpan = new AtomicReference<>();
return delegate.requestStream(uri, (RequestSpec requestSpec) -> {
// streamed request doesn't set the http method.
// start span here until a better solution presents itself.
WrappedRequestSpec captor = new WrappedRequestSpec(requestSpec, parent, currentSpan);
Span span = nextThreadLocalSpan.apply(captor, parent);
try {
handler.handleSend(injector, captor.getHeaders(), captor, span);
action.execute(new WrappedRequestSpec(requestSpec, parent, currentSpan));
} finally {
// moves the span from thread local context to an atomic ref the response can read
currentSpan.set(threadLocalSpan.remove());
}
}).wiretap(response -> streamedResponseWithSpan(response, currentSpan.getAndSet(null)));
}
@Override
public Promise get(final URI uri, final Action requestConfigurer) {
return request(uri, requestConfigurer.prepend(RequestSpec::get));
}
@Override
public Promise post(final URI uri, final Action requestConfigurer) {
return request(uri, requestConfigurer.prepend(RequestSpec::post));
}
private void streamedResponseWithSpan(Result response, Span currentSpan) {
if (currentSpan == null) return;
Integer statusCode = (response.isError() || response.getValue() == null)
? null : response.getValue().getStatusCode();
handler.handleReceive(statusCode, response.getThrowable(), currentSpan);
}
private void responseWithSpan(Result response, Span currentSpan) {
if (currentSpan == null) return;
Integer statusCode = (response.isError() || response.getValue() == null)
? null : response.getValue().getStatusCode();
handler.handleReceive(statusCode, response.getThrowable(), currentSpan);
}
static final HttpClientAdapter ADAPTER =
new HttpClientAdapter() {
@Override public String method(WrappedRequestSpec request) {
HttpMethod method = Optional.ofNullable(request.getCapturedMethod()).orElse(HttpMethod.GET);
return method.getName();
}
@Override public String path(WrappedRequestSpec request) {
return request.getUri().getPath();
}
@Override public String url(WrappedRequestSpec request) {
return request.getUri().toString();
}
@Override public String requestHeader(WrappedRequestSpec request, String name) {
return request.getHeaders().get(name);
}
// integer because ReceivedResponse and StreamedResponse share no common interface
@Override public Integer statusCode(Integer response) {
return response;
}
};
/**
* RequestSpec wrapper that captures the method type, sets up redirect handling
* and starts new spans when a method type is set.
*/
// not a static type as it shares many references with the enclosing class
final class WrappedRequestSpec implements RequestSpec {
private final RequestSpec delegate;
private final TraceContext parent;
private final AtomicReference currentSpan;
private HttpMethod capturedMethod;
WrappedRequestSpec(
RequestSpec delegate,
TraceContext parent,
AtomicReference currentSpan
) {
this.delegate = delegate;
this.parent = parent;
this.currentSpan = currentSpan;
this.delegate.onRedirect(this::redirectHandler);
}
/**
* Default redirect handler that ensures the span is marked as received before
* a new span is created.
*/
private Action redirectHandler(ReceivedResponse response) {
Span span = currentSpan.getAndSet(null);
handler.handleReceive(response.getStatusCode(), null, span);
return (s) -> new WrappedRequestSpec(s, parent, currentSpan);
}
@Override
public RequestSpec redirects(int maxRedirects) {
this.delegate.redirects(maxRedirects);
return this;
}
@Override
public int getRedirects() {
return delegate.getRedirects();
}
@Override
public RequestSpec onRedirect(Function> function) {
Function> wrapped =
(ReceivedResponse response) -> redirectHandler(response).append(function.apply(response));
this.delegate.onRedirect(wrapped);
return this;
}
@Override
public RequestSpec sslContext(SSLContext sslContext) {
this.delegate.sslContext(sslContext);
return this;
}
@Override
public SslContext getSslContext() {
return delegate.getSslContext();
}
@Override
public RequestSpec sslContext(SslContext sslContext) {
return delegate.sslContext(sslContext);
}
@Override
public MutableHeaders getHeaders() {
return this.delegate.getHeaders();
}
@Override
public RequestSpec maxContentLength(int numBytes) {
this.delegate.maxContentLength(numBytes);
return this;
}
@Override
public int getMaxContentLength() {
return delegate.getMaxContentLength();
}
@Override
public RequestSpec responseMaxChunkSize(int i) {
this.delegate.responseMaxChunkSize(i);
return this;
}
@Override
public RequestSpec headers(Action action) throws Exception {
this.delegate.headers(action);
return this;
}
@Override
public RequestSpec method(HttpMethod method) {
this.capturedMethod = method;
Span currentSpan = nextThreadLocalSpan.apply(this, parent);
handler.handleSend(injector, this.getHeaders(), this, currentSpan);
this.delegate.method(method);
return this;
}
@Override
public HttpMethod getMethod() {
return delegate.getMethod();
}
@Override
public RequestSpec decompressResponse(boolean shouldDecompress) {
this.delegate.decompressResponse(shouldDecompress);
return this;
}
@Override
public boolean getDecompressResponse() {
return delegate.getDecompressResponse();
}
@Override
public URI getUri() {
return this.delegate.getUri();
}
@Override
public RequestSpec connectTimeout(Duration duration) {
this.delegate.connectTimeout(duration);
return this;
}
@Override
public Duration getConnectTimeout() {
return delegate.getConnectTimeout();
}
@Override
public RequestSpec readTimeout(Duration duration) {
this.delegate.readTimeout(duration);
return this;
}
@Override
public Duration getReadTimeout() {
return delegate.getReadTimeout();
}
@Override
public Body getBody() {
return this.delegate.getBody();
}
@Override
public RequestSpec body(Action action) throws Exception {
this.delegate.body(action);
return this;
}
public HttpMethod getCapturedMethod() {
return capturedMethod;
}
}
/** This is a partial function that applies the last parent when creating a new span */
static class NextSpan implements BiFunction {
final ThreadLocalSpan span;
final HttpSampler sampler;
NextSpan(ThreadLocalSpan span, HttpSampler sampler) {
this.span = span;
this.sampler = sampler;
}
@Override public Span apply(WrappedRequestSpec req, TraceContext parent) {
if (parent != null) return span.next(TraceContextOrSamplingFlags.create(parent));
Boolean sampled = sampler.trySample(ADAPTER, req);
return span.next(TraceContextOrSamplingFlags.create(
new SamplingFlags.Builder().sampled(sampled).build())
);
}
}
}