Package com.elastisys.autoscaler.metricstreamers.cloudwatch.config

Class CloudWatchMetricStreamDefinition

java.lang.Object

com.elastisys.autoscaler.metricstreamers.cloudwatch.config.CloudWatchMetricStreamDefinition

public class CloudWatchMetricStreamDefinition
extends java.lang.Object

Represents a metric stream definition published for subscription by a CloudWatchMetricStreamer. CloudWatchMetricStreamDefinitions are configured through a CloudWatchMetricStreamerConfig.

For more details on the meaning of the different parameters, refer to the CloudWatch concepts introduction, the Amazon CloudWatch API specification and the CloudWatch Metrics, Namespaces, and Dimensions Reference.

See Also:

CloudWatchMetricStreamerConfig, CloudWatchMetricStreamer

Field Summary

Fields

Modifier and Type	Field	Description
static long	CLOUDWATCH_MAX_DATA_POINTS	The maximum number of data points that can be requested in a single call to the CloudWatch API.
static java.lang.Boolean	DEFAULT_RATE_CONVERSION

Constructor Summary

Constructors

Constructor

Description

CloudWatchMetricStreamDefinition(java.lang.String id, java.lang.String namespace, java.lang.String metric, CloudWatchStatistic statistic, com.elastisys.scale.commons.json.types.TimeInterval period, java.lang.Boolean convertToRate, java.util.Map<java.lang.String,java.lang.String> dimensions, com.elastisys.scale.commons.json.types.TimeInterval dataSettlingTime, com.elastisys.scale.commons.json.types.TimeInterval queryChunkSize)

Constructs a new CloudWatchMetricStreamDefinition.

Method Summary

Modifier and Type	Method	Description
boolean	equals(java.lang.Object obj)
com.elastisys.scale.commons.json.types.TimeInterval	getDataSettlingTime()	Returns the minimum age of requested data points.
java.util.Map<java.lang.String,java.lang.String>	getDimensions()	Returns the dimensions (key-value pairs) used to narrow down the set of streamed metric values.
java.lang.String	getId()	Returns the id of the metric stream.
java.lang.String	getMetric()	Returns the CloudWatch metric that the metric stream retrieves MetricValues for.
java.lang.String	getNamespace()	Returns the Amazon CloudWatch namespace of the metric to fetch.
com.elastisys.scale.commons.json.types.TimeInterval	getPeriod()	Returns Specifies the time period over which to apply the statistic and, hence, the spacing between data points in the aggregated data.
com.elastisys.scale.commons.json.types.TimeInterval	getQueryChunkSize()	The maximum time period that a single query will attempt to fetch in a single call.
CloudWatchStatistic	getStatistic()	Returns the aggregation method to apply to the set of metric values.
int	hashCode()
boolean	isConvertToRate()	When true the stream will feed the change rate of the metric rather than the absolute values of the metric.
java.lang.String	toString()
void	validate()	Validates that this CloudWatchMetricStreamDefinition contains sufficient information to allow a valid AWS CloudWatch query to be built.
CloudWatchMetricStreamDefinition	withPeriod(com.elastisys.scale.commons.json.types.TimeInterval period)	Creates a field-by-field copy of this object with the period field substituted in the returned clone.
CloudWatchMetricStreamDefinition	withStatistic(CloudWatchStatistic statistic)	Creates a field-by-field copy of this object with the statistic field substituted in the returned clone.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

CLOUDWATCH_MAX_DATA_POINTS

public static final long CLOUDWATCH_MAX_DATA_POINTS

The maximum number of data points that can be requested in a single call to the CloudWatch API.

See Also:

Constant Field Values

DEFAULT_RATE_CONVERSION

public static final java.lang.Boolean DEFAULT_RATE_CONVERSION

Constructor Detail

CloudWatchMetricStreamDefinition

public CloudWatchMetricStreamDefinition(java.lang.String id,
                                        java.lang.String namespace,
                                        java.lang.String metric,
                                        CloudWatchStatistic statistic,
                                        com.elastisys.scale.commons.json.types.TimeInterval period,
                                        java.lang.Boolean convertToRate,
                                        java.util.Map<java.lang.String,java.lang.String> dimensions,
                                        com.elastisys.scale.commons.json.types.TimeInterval dataSettlingTime,
                                        com.elastisys.scale.commons.json.types.TimeInterval queryChunkSize)

Constructs a new CloudWatchMetricStreamDefinition.

See the CloudWatch concepts for an explanation of the parameters.

Parameters:

id - The id of the metric stream. This is the id that will be used by clients wishing to subscribe to MetricValues for this metric stream. Required.

namespace - The Amazon CloudWatch namespace of the metric to fetch. Required.

metric - The CloudWatch metric that the metric stream retrieves MetricValues for. Required.

statistic - The aggregation method to apply to the set of metric values. Can be any of "Sum", "Average", "Minimum", "Maximum" and "SampleCount". Required.

period - Specifies the time period over which to apply the statistic and, hence, the spacing between data points in the aggregated data. Must be at least 60 seconds and must be a multiple of 60. Required.

convertToRate - When true the stream will feed the change rate of the metric rather than the absolute values of the metric.

dimensions - The dimensions (key-value pairs) used to narrow down the set of streamed metric values. Only metric values matching the specified dimensions will be returned.

As an example, for EC2 instance metrics (namespace @code ), InstanceId can be used to only return values for a certain instance and AutoScalingGroupName to narrow down queries to only ask for metrics from a certain Auto Scaling Group. May be null.

dataSettlingTime - The minimum age of requested data points. The MetricStreamer will never request values newer than this from CloudWatch. As such, this value can be regarded as the expected "settling time" of new data points.

When requesting aggregate metric data points from CloudWatch that are recent, there is always a risk of seeing partial/incomplete results before metric values from all instances have been registered. Typically, it takes a couple of minutes for all instances to report their values to CloudWatch.

May be null. Default is to use no data settling time.

queryChunkSize - The maximum time period that a single query will attempt to fetch in a single call. A query with a longer time interval will be run incrementally, each fetching a sub-interval of this duration. This type of incremental retrieval of large QueryResultSets limits the amount of (memory) resources involved in processing large queries. May be null. Default: #MAX_QUERY_CHUNK_SIZE

Method Detail

getId

public java.lang.String getId()

Returns the id of the metric stream. This is the id that will be used by clients wishing to subscribe to MetricValues for this metric stream.

Returns:

getNamespace

public java.lang.String getNamespace()

Returns the Amazon CloudWatch namespace of the metric to fetch.

Returns:

getMetric

public java.lang.String getMetric()

Returns the CloudWatch metric that the metric stream retrieves MetricValues for.

Returns:

getDimensions

public java.util.Map<java.lang.String,java.lang.String> getDimensions()

Returns the dimensions (key-value pairs) used to narrow down the set of streamed metric values. Only metric values matching the specified dimensions will be returned.

As an example, for EC2 instance metrics (namespace @code ), InstanceId can be used to only return values for a certain instance and AutoScalingGroupName to narrow down queries to only ask for metrics from a certain Auto Scaling Group.

Returns:

getStatistic

public CloudWatchStatistic getStatistic()

Returns the aggregation method to apply to the set of metric values. Can be any of "Sum", "Average", "Minimum", "Maximum" and "SampleCount".

Returns:

getPeriod

public com.elastisys.scale.commons.json.types.TimeInterval getPeriod()

Returns Specifies the time period over which to apply the statistic and, hence, the spacing between data points in the aggregated data. Must be at least 60 seconds and must be a multiple of 60.

Returns:

isConvertToRate

public boolean isConvertToRate()

When true the stream will feed the change rate of the metric rather than the absolute values of the metric.

Returns:

getDataSettlingTime

public com.elastisys.scale.commons.json.types.TimeInterval getDataSettlingTime()

Returns the minimum age of requested data points. The MetricStreamer will never request values newer than this from CloudWatch. As such, this value can be regarded as the expected "settling time" of new data points.

When requesting aggregate metric data points from CloudWatch that are recent, there is always a risk of seeing partial/incomplete results before metric values from all instances have been registered. Typically, it takes a couple of minutes for all instances to report their values to CloudWatch.

Returns:

getQueryChunkSize

public com.elastisys.scale.commons.json.types.TimeInterval getQueryChunkSize()

The maximum time period that a single query will attempt to fetch in a single call. A query with a longer time interval will be run incrementally, each fetching a sub-interval of this duration. This type of incremental retrieval of large QueryResultSets limits the amount of (memory) resources involved in processing large queries.

Returns:

validate

public void validate()
              throws java.lang.IllegalArgumentException

Validates that this CloudWatchMetricStreamDefinition contains sufficient information to allow a valid AWS CloudWatch query to be built. If it does, the method will just return. If it is found to be invalid, a IllegalArgumentException is thrown.

Throws:

java.lang.IllegalArgumentException - If this CloudWatchMetricStreamDefinition is invalid.

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

withPeriod

public CloudWatchMetricStreamDefinition withPeriod(com.elastisys.scale.commons.json.types.TimeInterval period)

Creates a field-by-field copy of this object with the period field substituted in the returned clone.

Parameters:

period -

Returns:

withStatistic

public CloudWatchMetricStreamDefinition withStatistic(CloudWatchStatistic statistic)

Creates a field-by-field copy of this object with the statistic field substituted in the returned clone.

Parameters:

statistic -

Returns: