Java Code Examples for brave.propagation.TraceContext#findExtra()

/**
 * This version of propagation contains at least 74 characters corresponding to identifiers and
 * the sampling bit. It will also include extra fields where present.
 *
 * <p>Ex 74 characters: {@code
 * Root=1-67891233-abcdef012345678912345678;Parent=463ac35c9f6413ad;Sampled=1}
 *
 * <p>{@inheritDoc}
 */
@Override
public void inject(TraceContext traceContext, R request) {
  AmznTraceId amznTraceId = traceContext.findExtra(AmznTraceId.class);
  CharSequence customFields = amznTraceId != null ? amznTraceId.customFields : null;
  int customFieldsLength = customFields == null ? 0 : customFields.length();
  // Root=1-67891233-abcdef012345678912345678;Parent=463ac35c9f6413ad;Sampled=1
  char[] result = new char[74 + customFieldsLength];
  System.arraycopy(ROOT, 0, result, 0, 5);
  writeRoot(traceContext, result, 5);
  System.arraycopy(PARENT, 0, result, 40, 8);
  writeHexLong(result, 48, traceContext.spanId());
  System.arraycopy(SAMPLED, 0, result, 64, 9);
  Boolean sampled = traceContext.sampled();
  // Sampled status is same as B3, but ? means downstream decides (like omitting X-B3-Sampled)
  // https://github.com/aws/aws-xray-sdk-go/blob/391885218b556c43ed05a1e736a766d70fc416f1/header/header.go#L50
  result[73] = sampled == null ? '?' : sampled ? '1' : '0';
  for (int i = 0; i < customFieldsLength; i++) {
    result[i + 74] = customFields.charAt(i);
  }
  setter.put(request, AMZN_TRACE_ID_NAME, new String(result));
}
 

@Override public void inject(TraceContext context, R request) {
  delegate.inject(context, request);
  BaggageFields extra = context.findExtra(BaggageFields.class);
  if (extra == null) return;
  Map<String, String> values =
      extra.toMapFilteringFieldNames(factory.localFieldNames);
  if (values.isEmpty()) return;

  for (BaggagePropagationConfig config : factory.configs) {
    if (config.baggageCodec == BaggageCodec.NOOP) continue; // local field

    String value = config.baggageCodec.encode(values, context, request);
    if (value == null) continue;

    List<String> keys = config.baggageCodec.injectKeyNames();
    for (int i = 0, length = keys.size(); i < length; i++) {
      setter.put(request, keys.get(i), value);
    }
  }
}
 

@Test public void contextsAreIndependent() {
  TraceContext decorated = propagationFactory.decorate(context);
  BasicMapExtra extra1 = decorated.findExtra(BasicMapExtra.class);
  extra1.put("1", "one");

  context2 = propagationFactory.decorate(context2.toBuilder().addExtra(extra1).build());
  BasicMapExtra extra2 = context2.findExtra(BasicMapExtra.class);

  // Instances are not the same
  assertThat(extra1).isNotSameAs(extra2);

  // But have the same values
  assertThat(extra1).isEqualTo(extra2);

  extra1.put("1", "two");
  extra2.put("1", "three");

  // Yet downstream changes don't affect eachother
  assertThat(extra1.get("1")).isEqualTo("two");
  assertThat(extra2.get("1")).isEqualTo("three");
}
 

@Test public void contextsHaveIndependentValue() {
  TraceContext decorated = propagationFactory.decorate(context);
  BasicMapExtra extra1 = decorated.findExtra(BasicMapExtra.class);
  extra1.put("1", "two");

  // we have the same span ID, so we should couple our extra state
  assertThat(propagationFactory.decorate(decorated.toBuilder().build()).extra())
      .isEqualTo(decorated.extra());

  // we no longer have the same span ID, so we should decouple our extra state
  context2 = propagationFactory.decorate(context2.toBuilder().addExtra(extra1).build());
  BasicMapExtra extra2 = context2.findExtra(BasicMapExtra.class);

  // we have different instances of extra
  assertThat(extra1).isNotSameAs(extra2);

  // however, the values inside are the same until a write occurs
  assertThat(extra1).isEqualTo(extra2);

  // check that the change is present, but the other contexts are the same
  String beforeUpdate = extra1.get("1");
  extra1.put("1", "2");

  assertThat(extra1.get("1")).isNotEqualTo(beforeUpdate); // copy-on-write
  assertThat(extra2.get("1")).isEqualTo(beforeUpdate);
}
 

/**
 * This scenario is possible, albeit rare. {@code tracer.nextSpan(extracted} } is called when
 * there is an implicit parent. For example, you have a trace in progress when extracting extra
 * from an incoming message. Another example is where there is a span in scope due to a leak such
 * as from using {@link CurrentTraceContext.Default#inheritable()}.
 *
 * <p>Extracted extra should merge into the current extra state instead creating multiple
 * entries in {@link TraceContext#extra()}.
 */
@Test public void decorate_extractedExtra_plus_parent_merge() {
  TraceContext decorated = propagationFactory.decorate(context);
  BasicMapExtra extra1 = decorated.findExtra(BasicMapExtra.class);

  BasicMapExtra extracted = factory.create();
  extra1.put("1", "one");
  extracted.put("1", "two");
  extracted.put("2", "three");

  context2 = propagationFactory.decorate(
      context2.toBuilder().addExtra(extra1).addExtra(extracted).build());
  BasicMapExtra extra2 = context2.findExtra(BasicMapExtra.class);
  assertThat(context2.extra()).containsExactly(extra2); // merged

  assertThat(extra2.get("1")).isEqualTo("two"); // extracted should win!
  assertThat(extra2.get("2")).isEqualTo("three");

  assertExtraClaimed(context2);
}
 

@Test public void decorate_extractedExtra_plus_emptyParent() {
  TraceContext decorated = propagationFactory.decorate(context);
  BasicMapExtra extra1 = decorated.findExtra(BasicMapExtra.class);

  BasicMapExtra extracted = factory.create();
  extracted.put("2", "three");

  context2 = propagationFactory.decorate(
      context2.toBuilder().addExtra(extra1).addExtra(extracted).build());
  BasicMapExtra extra2 = context2.findExtra(BasicMapExtra.class);
  assertThat(context2.extra()).containsExactly(extra2); // merged

  assertThat(extra2.get("2")).isEqualTo("three");

  assertExtraClaimed(context2);
}
 

@Test public void decorate_parent() {
  TraceContext decorated = propagationFactory.decorate(context);
  BasicMapExtra extra1 = decorated.findExtra(BasicMapExtra.class);
  extra1.put("1", "one");

  context2 = propagationFactory.decorate(context2.toBuilder().addExtra(extra1).build());
  BasicMapExtra extra2 = context2.findExtra(BasicMapExtra.class);
  assertThat(context2.extra()).containsExactly(extra2); // didn't duplicate

  assertThat(extra2.get("1")).isEqualTo("one");

  assertExtraClaimed(context2);
}
 

@Override public void inject(TraceContext context, R request) {
  if (request instanceof GrpcClientRequest) {
    byte[] serialized = TraceContextBinaryFormat.toBytes(context);
    Metadata metadata = ((GrpcClientRequest) request).headers;
    metadata.removeAll(GRPC_TRACE_BIN);
    metadata.put(GRPC_TRACE_BIN, serialized);
    TagsBin tags = context.findExtra(TagsBin.class);
    if (tags != null) {
      metadata.removeAll(GRPC_TAGS_BIN);
      metadata.put(GRPC_TAGS_BIN, tags);
    }
  }
  delegate.inject(context, request);
}