io.micrometer.tracing.CurrentTraceContext Maven / Gradle / Ivy
/**
* Copyright 2022 the original author or 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
*
* https://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 io.micrometer.tracing;
import io.micrometer.common.lang.Nullable;
import java.io.Closeable;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
/**
* This API was heavily influenced by Brave. Parts of its documentation were taken
* directly from Brave.
*
* This makes a given span the current span by placing it in scope (usually but not always
* a thread local scope).
*
* @author OpenZipkin Brave Authors
* @author Marcin Grzejszczak
* @since 1.0.0
*/
public interface CurrentTraceContext {
/**
* A noop implementation.
*/
CurrentTraceContext NOOP = new CurrentTraceContext() {
@Override
public TraceContext context() {
return TraceContext.NOOP;
}
@Override
public Scope newScope(TraceContext context) {
return () -> {
};
}
@Override
public Scope maybeScope(TraceContext context) {
return () -> {
};
}
@Override
public Callable wrap(Callable task) {
return task;
}
@Override
public Runnable wrap(Runnable task) {
return task;
}
@Override
public Executor wrap(Executor delegate) {
return delegate;
}
@Override
public ExecutorService wrap(ExecutorService delegate) {
return delegate;
}
};
/**
* @return current {@link TraceContext} or {@code null} if not set.
*/
@Nullable
TraceContext context();
/**
* Sets the current span in scope until the returned object is closed. It is a
* programming error to drop or never close the result. Using try-with-resources is
* preferred for this reason.
* @param context span to place into scope or {@code null} to clear the scope
* @return the scope with the span set
*/
CurrentTraceContext.Scope newScope(@Nullable TraceContext context);
/**
* Like {@link #newScope(TraceContext)}, except returns a noop scope if the given
* context is already in scope.
* @param context span to place into scope or {@code null} to clear the scope
* @return the scope with the span set
*/
CurrentTraceContext.Scope maybeScope(@Nullable TraceContext context);
/**
* Wraps a task in a trace representation.
* @param task task to wrap
* @param task return type
* @return wrapped task
*/
Callable wrap(Callable task);
/**
* Wraps a task in a trace representation.
* @param task task to wrap
* @return wrapped task
*/
Runnable wrap(Runnable task);
/**
* Wraps an executor in a trace representation.
* @param delegate executor to wrap
* @return wrapped executor
*/
Executor wrap(Executor delegate);
/**
* Wraps an executor service in a trace representation.
* @param delegate executor service to wrap
* @return wrapped executor service
*/
ExecutorService wrap(ExecutorService delegate);
/**
* Scope of a span. Needs to be closed so that resources are let go (e.g. MDC is
* cleared).
*/
interface Scope extends Closeable {
/**
* A noop implementation.
*/
Scope NOOP = () -> {
};
@Override
void close();
}
}