io.opentelemetry.api.incubator.propagation.ExtendedContextPropagators Maven / Gradle / Ivy
/*
* Copyright The OpenTelemetry Authors
* SPDX-License-Identifier: Apache-2.0
*/
package io.opentelemetry.api.incubator.propagation;
import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.context.Context;
import io.opentelemetry.context.propagation.ContextPropagators;
import io.opentelemetry.context.propagation.TextMapGetter;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Utility class to simplify context propagation.
*
* The README
* explains the use cases in more detail.
*/
public final class ExtendedContextPropagators {
private ExtendedContextPropagators() {}
private static final TextMapGetter> TEXT_MAP_GETTER =
new TextMapGetter>() {
@Override
public Set keys(Map carrier) {
return carrier.keySet();
}
@Override
@Nullable
public String get(@Nullable Map carrier, String key) {
return carrier == null ? null : carrier.get(key);
}
};
/**
* Injects the current context into a string map, which can then be added to HTTP headers or the
* metadata of a message.
*
* @param propagators provide the propagators from {@link OpenTelemetry#getPropagators()}
*/
public static Map getTextMapPropagationContext(ContextPropagators propagators) {
Map carrier = new HashMap<>();
propagators
.getTextMapPropagator()
.inject(
Context.current(),
carrier,
(map, key, value) -> {
if (map != null) {
map.put(key, value);
}
});
return Collections.unmodifiableMap(carrier);
}
/**
* Extract the context from a string map, which you get from HTTP headers of the metadata of a
* message you're processing.
*
* @param carrier the string map
* @param propagators provide the propagators from {@link OpenTelemetry#getPropagators()}
*/
public static Context extractTextMapPropagationContext(
Map carrier, ContextPropagators propagators) {
Context current = Context.current();
if (carrier == null) {
return current;
}
CaseInsensitiveMap caseInsensitiveMap = new CaseInsensitiveMap(carrier);
return propagators.getTextMapPropagator().extract(current, caseInsensitiveMap, TEXT_MAP_GETTER);
}
}