com.google.apphosting.api

Class CloudTrace

java.lang.Object

com.google.apphosting.api.CloudTrace

public abstract class CloudTrace
extends Object

Holds the current trace context visible to user code. If present, this object will be stored under the KEY-variable in an Environment's property. This class is used to share the current trace context between run time and user code. It is not responsible for managing contexts. It only keeps the most current context for a given thread.

Constructor Summary

Constructors

Constructor and Description
CloudTrace(ApiProxy.Environment env) Creates a new CloudTrace object and binds it to a given Environment.

Method Summary

Modifier and Type	Method and Description
static void	endSpan(ApiProxy.Environment env, CloudTraceContext context, CloudTraceContext parent) Ends the span for the given context.
protected abstract void	endSpanImpl(CloudTraceContext context)
static @Nullable CloudTraceContext	getCurrentContext(ApiProxy.Environment env) Returns the current trace context for the given environment and the current thread.
protected abstract @Nullable CloudTraceContext	getDefaultContext() Returns the default context when a thread-specific one doesn't exist.
static void	setCurrentContext(ApiProxy.Environment env, @Nullable CloudTraceContext context) Sets the current trace context for the current environment and the current thread.
static void	setLabel(ApiProxy.Environment env, CloudTraceContext context, String key, String value) Sets a key:value label on the span for the given context.
protected abstract void	setLabelImpl(CloudTraceContext context, String key, String value)
static @Nullable CloudTraceContext	startChildSpan(ApiProxy.Environment env, CloudTraceContext context, String name) Starts a new span as the child of the given context.
protected abstract @Nullable CloudTraceContext	startChildSpanImpl(CloudTraceContext context, String name)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CloudTrace

public CloudTrace(ApiProxy.Environment env)

Creates a new CloudTrace object and binds it to a given Environment.

Parameters:

env - the environment object to bind this object to.

Method Detail

getCurrentContext

public static @Nullable CloudTraceContext getCurrentContext(ApiProxy.Environment env)

Returns the current trace context for the given environment and the current thread.

Parameters:

env - the current environment.

setCurrentContext

public static void setCurrentContext(ApiProxy.Environment env,
                                     @Nullable CloudTraceContext context)

Sets the current trace context for the current environment and the current thread.

Parameters:

env - the current environment.

context - the current trace context.

getDefaultContext

protected abstract @Nullable CloudTraceContext getDefaultContext()

Returns the default context when a thread-specific one doesn't exist.

startChildSpan

public static @Nullable CloudTraceContext startChildSpan(ApiProxy.Environment env,
                                                         CloudTraceContext context,
                                                         String name)

Starts a new span as the child of the given context. The given context must match the current context in the environment. After the call, the returned context becomes current.

Parameters:

env - the environment object to get the current context from.

context - parent context of the child span. Must match the current context.

name - name of the child span.

Returns:

context of the child span or null if the environment does not have trace context.

setLabel

public static void setLabel(ApiProxy.Environment env,
                            CloudTraceContext context,
                            String key,
                            String value)

Sets a key:value label on the span for the given context. The given context must match the current context in the environment.

Parameters:

env - the environment object to get the current context.

context - context of the span. Must match the current context.

key - key of the label.

value - value of the label.

endSpan

public static void endSpan(ApiProxy.Environment env,
                           CloudTraceContext context,
                           CloudTraceContext parent)

Ends the span for the given context. The given context must match the current context in the environment. After the call, the parent context becomes current.

Parameters:

env - the environment object to get the current context.

context - context of the span. Must match the current context.

parent - parent context of the span. It becomes the current context after the call.

startChildSpanImpl

protected abstract @Nullable CloudTraceContext startChildSpanImpl(CloudTraceContext context,
                                                                  String name)

setLabelImpl

protected abstract void setLabelImpl(CloudTraceContext context,
                                     String key,
                                     String value)

endSpanImpl

protected abstract void endSpanImpl(CloudTraceContext context)