/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.cxf.tracing.htrace;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.cxf.common.logging.LogUtils;
import org.apache.cxf.helpers.CastUtils;
import org.apache.cxf.phase.PhaseInterceptorChain;
import org.apache.cxf.tracing.AbstractTracingProvider;
import org.apache.htrace.core.SpanId;
import org.apache.htrace.core.TraceScope;
import org.apache.htrace.core.Tracer;
public abstract class AbstractHTraceProvider extends AbstractTracingProvider {
protected static final Logger LOG = LogUtils.getL7dLogger(AbstractHTraceProvider.class);
protected static final String TRACE_SPAN = "org.apache.cxf.tracing.htrace.span";
private final Tracer tracer;
public AbstractHTraceProvider(final Tracer tracer) {
this.tracer = tracer;
}
protected TraceScopeHolder<TraceScope> startTraceSpan(final Map<String, List<String>> requestHeaders,
String path, String method) {
// Try to extract the Span Id value from the request header
final SpanId spanId = getFirstValueOrDefault(requestHeaders, getSpanIdHeader(), SpanId.INVALID);
TraceScope traceScope = null;
if (SpanId.INVALID.equals(spanId)) {
traceScope = tracer.newScope(buildSpanDescription(path, method));
} else {
traceScope = tracer.newScope(buildSpanDescription(path, method), spanId);
}
// If the service resource is using asynchronous processing mode, the trace
// scope will be closed in another thread and as such should be detached.
boolean detached = false;
if (isAsyncResponse()) {
traceScope.detach();
propagateContinuationSpan(traceScope);
detached = true;
}
return new TraceScopeHolder<TraceScope>(traceScope, detached);
}
protected void stopTraceSpan(final Map<String, List<String>> requestHeaders,
final Map<String, List<Object>> responseHeaders,
final TraceScopeHolder<TraceScope> holder) {
final String spanIdHeader = getSpanIdHeader();
// Transfer tracing headers into the response headers
if (requestHeaders.containsKey(spanIdHeader)) {
responseHeaders.put(spanIdHeader, CastUtils.cast(requestHeaders.get(spanIdHeader)));
}
if (holder == null) {
return;
}
final TraceScope span = holder.getScope();
if (span != null) {
// If the service resource is using asynchronous processing mode, the trace
// scope has been created in another thread and should be re-attached to the current
// one.
if (holder.isDetached()) {
span.reattach();
span.close();
} else {
span.close();
}
}
}
private void propagateContinuationSpan(final TraceScope continuationScope) {
PhaseInterceptorChain.getCurrentMessage().put(TraceScope.class, continuationScope);
}
protected boolean isAsyncResponse() {
return !PhaseInterceptorChain.getCurrentMessage().getExchange().isSynchronous();
}
private static SpanId getFirstValueOrDefault(final Map<String, List<String>> headers,
final String header, final SpanId defaultValue) {
List<String> value = headers.get(header);
if (value != null && !value.isEmpty()) {
try {
return SpanId.fromString(value.get(0));
} catch (NumberFormatException ex) {
LOG.log(Level.FINE, String.format("Unable to parse '%s' header value to Span Id", header), ex);
}
}
return defaultValue;
}
}