com.datadoghq.trace.DDTracer Maven / Gradle / Ivy
package com.datadoghq.trace;
import com.datadoghq.trace.integration.AbstractDecorator;
import com.datadoghq.trace.propagation.Codec;
import com.datadoghq.trace.propagation.HTTPCodec;
import com.datadoghq.trace.sampling.AllSampler;
import com.datadoghq.trace.sampling.Sampler;
import com.datadoghq.trace.writer.LoggingWriter;
import com.datadoghq.trace.writer.Writer;
import com.fasterxml.jackson.annotation.JsonIgnore;
import io.opentracing.ActiveSpan;
import io.opentracing.ActiveSpanSource;
import io.opentracing.BaseSpan;
import io.opentracing.SpanContext;
import io.opentracing.propagation.Format;
import io.opentracing.util.ThreadLocalActiveSpanSource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.concurrent.ThreadLocalRandom;
import lombok.extern.slf4j.Slf4j;
/** DDTracer makes it easy to send traces and span to DD using the OpenTracing integration. */
@Slf4j
public class DDTracer extends ThreadLocalActiveSpanSource implements io.opentracing.Tracer {
public static final String UNASSIGNED_DEFAULT_SERVICE_NAME = "unnamed-java-app";
public static final Writer UNASSIGNED_WRITER = new LoggingWriter();
public static final Sampler UNASSIGNED_SAMPLER = new AllSampler();
/** Writer is an charge of reporting traces and spans to the desired endpoint */
private final Writer writer;
/** Sampler defines the sampling policy in order to reduce the number of traces for instance */
private final Sampler sampler;
/** Default service name if none provided on the trace or span */
private final String defaultServiceName;
/** Span context decorators */
private final Map> spanContextDecorators = new HashMap<>();
private final CodecRegistry registry;
private final Map services = new HashMap<>();
/** Default constructor, trace/spans are logged, no trace/span dropped */
public DDTracer() {
this(UNASSIGNED_WRITER);
}
public DDTracer(final Writer writer) {
this(writer, new AllSampler());
}
public DDTracer(final Writer writer, final Sampler sampler) {
this(UNASSIGNED_DEFAULT_SERVICE_NAME, writer, sampler);
}
public DDTracer(final String defaultServiceName, final Writer writer, final Sampler sampler) {
this.defaultServiceName = defaultServiceName;
this.writer = writer;
this.writer.start();
this.sampler = sampler;
registry = new CodecRegistry();
registry.register(Format.Builtin.HTTP_HEADERS, new HTTPCodec());
log.debug(
"New tracer instance, default-service={}, writer={}, sampler={}",
defaultServiceName,
writer.getClass().getSimpleName(),
sampler.getClass().getSimpleName());
}
/**
* Returns the list of span context decorators
*
* @return the list of span context decorators
*/
public List getSpanContextDecorators(final String tag) {
return spanContextDecorators.get(tag);
}
/**
* Add a new decorator in the list ({@link AbstractDecorator})
*
* @param decorator The decorator in the list
*/
public void addDecorator(final AbstractDecorator decorator) {
List list = spanContextDecorators.get(decorator.getMatchingTag());
if (list == null) {
list = new ArrayList<>();
}
list.add(decorator);
spanContextDecorators.put(decorator.getMatchingTag(), list);
}
@Override
public DDSpanBuilder buildSpan(final String operationName) {
return new DDSpanBuilder(operationName, this);
}
@Override
public void inject(final SpanContext spanContext, final Format format, final T carrier) {
final Codec codec = registry.get(format);
if (codec == null) {
log.warn("Unsupported format for propagation - {}", format.getClass().getName());
} else {
codec.inject((DDSpanContext) spanContext, carrier);
}
}
@Override
public SpanContext extract(final Format format, final T carrier) {
final Codec codec = registry.get(format);
if (codec == null) {
log.warn("Unsupported format for propagation - {}", format.getClass().getName());
} else {
return codec.extract(carrier);
}
return null;
}
/**
* We use the sampler to know if the trace has to be reported/written. The sampler is called on
* the first span (root span) of the trace. If the trace is marked as a sample, we report it.
*
* @param trace a list of the spans related to the same trace
*/
public void write(final Queue> trace) {
if (trace.isEmpty()) {
return;
}
if (this.sampler.sample(trace.peek())) {
this.writer.write(new ArrayList<>(trace));
}
}
public void close() {
writer.close();
}
@Override
public String toString() {
return "DDTracer{" + "writer=" + writer + ", sampler=" + sampler + '}';
}
/**
* Register additional information about a service. Service additional information are a Datadog
* feature only. Services are reported through a specific Datadog endpoint.
*
* @param service additional service information
*/
public void addServiceInfo(final Service service) {
services.put(service.getName(), service);
// Update the writer
try {
// We don't bother to send multiple times the list of services at this time
writer.writeServices(services);
} catch (final Throwable ex) {
log.warn("Failed to report additional service information, reason: {}", ex.getMessage());
}
}
/**
* Return the list of additional service information registered
*
* @return the list of additional service information
*/
@JsonIgnore
public Map getServiceInfo() {
return services;
}
private static class CodecRegistry {
private final Map, Codec> codecs = new HashMap<>();
Codec get(final Format format) {
return (Codec) codecs.get(format);
}
public void register(final Format format, final Codec codec) {
codecs.put(format, codec);
}
}
/** Spans are built using this builder */
public class DDSpanBuilder implements SpanBuilder {
private final ActiveSpanSource spanSource;
/** Each span must have an operationName according to the opentracing specification */
private final String operationName;
// Builder attributes
private Map tags = Collections.emptyMap();
private long timestamp;
private SpanContext parent;
private String serviceName;
private String resourceName;
private boolean errorFlag;
private String spanType;
private boolean ignoreActiveSpan = false;
public DDSpanBuilder(final String operationName, final ActiveSpanSource spanSource) {
this.operationName = operationName;
this.spanSource = spanSource;
}
@Override
public SpanBuilder ignoreActiveSpan() {
this.ignoreActiveSpan = true;
return this;
}
private DDSpan startSpan() {
return new DDSpan(this.timestamp, buildSpanContext());
}
@Override
public ActiveSpan startActive() {
final DDSpan span = startSpan();
final ActiveSpan activeSpan = spanSource.makeActive(span);
log.debug("Starting a new active span: {}", span);
return activeSpan;
}
@Override
public DDSpan startManual() {
final DDSpan span = startSpan();
log.debug("Starting a new manual span: {}", span);
return span;
}
@Override
@Deprecated
public DDSpan start() {
return startManual();
}
@Override
public DDSpanBuilder withTag(final String tag, final Number number) {
return withTag(tag, (Object) number);
}
@Override
public DDSpanBuilder withTag(final String tag, final String string) {
if (tag.equals(DDTags.SERVICE_NAME)) {
return withServiceName(string);
} else if (tag.equals(DDTags.RESOURCE_NAME)) {
return withResourceName(string);
} else if (tag.equals(DDTags.SPAN_TYPE)) {
return withSpanType(string);
} else {
return withTag(tag, (Object) string);
}
}
@Override
public DDSpanBuilder withTag(final String tag, final boolean bool) {
return withTag(tag, (Object) bool);
}
@Override
public DDSpanBuilder withStartTimestamp(final long timestampMillis) {
this.timestamp = timestampMillis;
return this;
}
public DDSpanBuilder withServiceName(final String serviceName) {
this.serviceName = serviceName;
return this;
}
public DDSpanBuilder withResourceName(final String resourceName) {
this.resourceName = resourceName;
return this;
}
public DDSpanBuilder withErrorFlag() {
this.errorFlag = true;
return this;
}
public DDSpanBuilder withSpanType(final String spanType) {
this.spanType = spanType;
return this;
}
public Iterable> baggageItems() {
if (parent == null) {
return Collections.emptyList();
}
return parent.baggageItems();
}
@Override
public DDSpanBuilder asChildOf(final BaseSpan span) {
return asChildOf(span == null ? null : span.context());
}
@Override
public DDSpanBuilder asChildOf(final SpanContext spanContext) {
this.parent = spanContext;
return this;
}
@Override
public DDSpanBuilder addReference(final String referenceType, final SpanContext spanContext) {
log.debug("`addReference` method is not implemented. Doing nothing");
return this;
}
// Private methods
private DDSpanBuilder withTag(final String tag, final Object value) {
if (this.tags.isEmpty()) {
this.tags = new HashMap<>();
}
this.tags.put(tag, value);
return this;
}
private long generateNewId() {
// Ensure the generated ID is in a valid range:
return ThreadLocalRandom.current().nextLong(1, Long.MAX_VALUE);
}
/**
* Build the SpanContext, if the actual span has a parent, the following attributes must be
* propagated: - ServiceName - Baggage - Trace (a list of all spans related) - SpanType
*
* @return the context
*/
private DDSpanContext buildSpanContext() {
final long traceId;
final long spanId = generateNewId();
final long parentSpanId;
final Map baggage;
final Queue> parentTrace;
final DDSpanContext context;
SpanContext parentContext = this.parent;
if (parentContext == null && !ignoreActiveSpan) {
// use the ActiveSpan as parent unless overridden or ignored.
final ActiveSpan activeSpan = activeSpan();
if (activeSpan != null) parentContext = activeSpan.context();
}
if (parentContext instanceof DDSpanContext) {
final DDSpanContext ddsc = (DDSpanContext) parentContext;
traceId = ddsc.getTraceId();
parentSpanId = ddsc.getSpanId();
baggage = ddsc.getBaggageItems();
parentTrace = ddsc.getTrace();
if (this.serviceName == null) this.serviceName = ddsc.getServiceName();
if (this.spanType == null) this.spanType = ddsc.getSpanType();
} else {
traceId = generateNewId();
parentSpanId = 0L;
baggage = null;
parentTrace = null;
}
if (serviceName == null) {
serviceName = defaultServiceName;
}
final String operationName =
this.operationName != null ? this.operationName : this.resourceName;
// this.operationName, this.tags,
// some attributes are inherited from the parent
context =
new DDSpanContext(
traceId,
spanId,
parentSpanId,
serviceName,
operationName,
this.resourceName,
baggage,
errorFlag,
spanType,
this.tags,
parentTrace,
DDTracer.this);
return context;
}
}
}
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