Package com.github.ambry.rest

Class RestRequestMetricsTracker

java.lang.Object

com.github.ambry.rest.RestRequestMetricsTracker

public class RestRequestMetricsTracker
extends java.lang.Object

Construct to support end-to-end metrics tracking based on request type. Usually accompanies a single RestRequest i.e. there is a one-to-one mapping b/w a RestRequest and a RestRequestMetricsTracker instance.

A brief description of how the tracker works :- 1. When an object of type RestRequest (request) is instantiated, it is also expected to be associated with a unique instance of RestRequestMetricsTracker (tracker). This unique instance is returned on every call to RestRequest.getMetricsTracker(). Therefore there is one-to-one mapping between an instance of RestRequest and an instance of RestRequestMetricsTracker. 2. When the tracker is instantiated, the type of the request is usually not available. Therefore, the RestRequestMetrics (metrics) object associated with the tracker tracks "unknown" requests. 3. As the request passes through the NIO framework and the scaling framework, metrics associated with these layers are tracked and stored but not updated in the metrics object. 4. When the request reaches the RestRequestService, it is usually identified as a specific type and a custom metrics object that tracks that specific type of request is "injected" into the tracker associated with the request. 5. When the response for the request is complete and the request is "closed", the metrics that are stored are updated in the metrics object (injected or default).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	RestRequestMetricsTracker.NioMetricsTracker	Tracker for updating NIO related metrics.
static class	RestRequestMetricsTracker.ScalingMetricsTracker	Helper for updating scaling related metrics.

Field Summary

Fields

Modifier and Type	Field	Description
protected static java.lang.String	DEFAULT_REQUEST_TYPE
RestRequestMetricsTracker.NioMetricsTracker	nioMetricsTracker	NIO related metrics tracker instance.
RestRequestMetricsTracker.ScalingMetricsTracker	scalingMetricsTracker	Scaling related metrics tracker instance.

Constructor Summary

Constructors

Constructor	Description
RestRequestMetricsTracker()

Method Summary

Modifier and Type	Method	Description
long	getRoundTripTimeInMs()
long	getTimeToFirstByteInMs()
void	injectContainerMetrics(ContainerMetrics containerMetrics)
void	injectMetrics(RestRequestMetrics restRequestMetrics)	Injects a RestRequestMetrics that can be used to track the metrics of the RestRequest that this instance of RestRequestMetricsTracker is attached to.
boolean	isSatisfied()	Return whether the rest request is satisfied or not.
void	markFailure()	Marks that the request is failed so that metrics can be tracked.
void	markUnsatisfied()	Marks that the request is unsatisfied so that metrics can be tracked.
void	recordMetrics()	Records the metrics.
static void	setDefaults(com.codahale.metrics.MetricRegistry metricRegistry)	Creates a default RestRequestMetrics in case injectMetrics(RestRequestMetrics) is never called on an instance of RestRequestMetricsTracker.
void	setResponseStatus(ResponseStatus responseStatus)

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_REQUEST_TYPE

protected static final java.lang.String DEFAULT_REQUEST_TYPE

See Also:

Constant Field Values

nioMetricsTracker

public final RestRequestMetricsTracker.NioMetricsTracker nioMetricsTracker

NIO related metrics tracker instance.

scalingMetricsTracker

public final RestRequestMetricsTracker.ScalingMetricsTracker scalingMetricsTracker

Scaling related metrics tracker instance.

Constructor Detail

RestRequestMetricsTracker

public RestRequestMetricsTracker()

Method Detail

markFailure

public void markFailure()

Marks that the request is failed so that metrics can be tracked.

markUnsatisfied

public void markUnsatisfied()

Marks that the request is unsatisfied so that metrics can be tracked.

isSatisfied

public boolean isSatisfied()

Return whether the rest request is satisfied or not.

Returns:

true if request is satisfied.

setResponseStatus

public void setResponseStatus(ResponseStatus responseStatus)

Parameters:

responseStatus - the ResponseStatus to be used for certain count metrics.

injectMetrics

public void injectMetrics(RestRequestMetrics restRequestMetrics)

Injects a RestRequestMetrics that can be used to track the metrics of the RestRequest that this instance of RestRequestMetricsTracker is attached to.

Parameters:

restRequestMetrics - the RestRequestMetrics instance to use to track the metrics of the RestRequest that this instance of RestRequestMetricsTracker is attached to.

injectContainerMetrics

public void injectContainerMetrics(ContainerMetrics containerMetrics)

recordMetrics

public void recordMetrics()

Records the metrics.

This method is expected to called when the RestRequest, that this instance of RestRequestMetricsTracker is attached to, finishes.

getRoundTripTimeInMs

public long getRoundTripTimeInMs()

Returns:

round trip time of this request in milliseconds

getTimeToFirstByteInMs

public long getTimeToFirstByteInMs()

Returns:

time to first byte of this request in milliseconds

setDefaults

public static void setDefaults(com.codahale.metrics.MetricRegistry metricRegistry)

Creates a default RestRequestMetrics in case injectMetrics(RestRequestMetrics) is never called on an instance of RestRequestMetricsTracker.

Parameters:

metricRegistry - the MetricRegistry to use to register the created metrics.