metrics(list) --
An array of MetricDataQuery structures, used in an alarm based on a metric math expression. Each structure either retrieves a metric or performs a math expression. One item in the Metrics array is the math expression that the alarm watches. This expression by designated by having ReturnData set to true.
(dict) --
This structure is used in both GetMetricData and PutMetricAlarm . The supported use of this structure is different for those two operations.
When used in GetMetricData , it indicates the metric data to return, and whether this call is just retrieving a batch set of data for one metric, or is performing a Metrics Insights query or a math expression. A single GetMetricData call can include up to 500 MetricDataQuery structures.
When used in PutMetricAlarm , it enables you to create an alarm based on a metric math expression. Each MetricDataQuery in the array specifies either a metric to retrieve, or a math expression to be performed on retrieved metrics. A single PutMetricAlarm call can include up to 20 MetricDataQuery structures in the array. The 20 structures can include as many as 10 structures that contain a MetricStat parameter to retrieve a metric, and as many as 10 structures that contain the Expression parameter to perform a math expression. Of those Expression structures, one must have true as the value for ReturnData . The result of this expression is the value the alarm watches.
Any expression used in a PutMetricAlarm operation must return a single time series. For more information, see Metric Math Syntax and Functions in the Amazon CloudWatch User Guide .
Some of the parameters of this structure also have different uses whether you are using this structure in a GetMetricData operation or a PutMetricAlarm operation. These differences are explained in the following parameter list.
Id (string) --
A short name used to tie this object to the results in the response. This name must be unique within a single call to GetMetricData . If you are performing math expressions on this set of data, this name represents that data and can serve as a variable in the mathematical expression. The valid characters are letters, numbers, and underscore. The first character must be a lowercase letter.
MetricStat (dict) --
The metric to be returned, along with statistics, period, and units. Use this parameter only if this object is retrieving a metric and not performing a math expression on returned data.
Within one MetricDataQuery object, you must specify either Expression or MetricStat but not both.
Metric (dict) --
The metric to return, including the metric name, namespace, and dimensions.
Namespace (string) --
The namespace of the metric.
MetricName (string) --
The name of the metric. This is a required field.
Dimensions (list) --
The dimensions for the metric.
(dict) --
A dimension is a name/value pair that is part of the identity of a metric. Because dimensions are part of the unique identifier for a metric, whenever you add a unique name/value pair to one of your metrics, you are creating a new variation of that metric. For example, many Amazon EC2 metrics publish InstanceId as a dimension name, and the actual instance ID as the value for that dimension.
You can assign up to 30 dimensions to a metric.
Name (string) --
The name of the dimension. Dimension names must contain only ASCII characters, must include at least one non-whitespace character, and cannot start with a colon ( : ).
Value (string) --
The value of the dimension. Dimension values must contain only ASCII characters and must include at least one non-whitespace character.
Period (integer) --
The granularity, in seconds, of the returned data points. For metrics with regular resolution, a period can be as short as one minute (60 seconds) and must be a multiple of 60. For high-resolution metrics that are collected at intervals of less than one minute, the period can be 1, 5, 10, 30, 60, or any multiple of 60. High-resolution metrics are those metrics stored by a PutMetricData call that includes a StorageResolution of 1 second.
If the StartTime parameter specifies a time stamp that is greater than 3 hours ago, you must specify the period as follows or no data points in that time range is returned:
Stat (string) --
The statistic to return. It can include any CloudWatch statistic or extended statistic.
Unit (string) --
When you are using a Put operation, this defines what unit you want to use when storing the metric.
In a Get operation, if you omit Unit then all data that was collected with any unit is returned, along with the corresponding units that were specified when the data was reported to CloudWatch. If you specify a unit, the operation returns only data that was collected with that unit specified. If you specify a unit that does not match the data collected, the results of the operation are null. CloudWatch does not perform unit conversions.
Expression (string) --
This field can contain either a Metrics Insights query, or a metric math expression to be performed on the returned data. For more information about Metrics Insights queries, see Metrics Insights query components and syntax in the Amazon CloudWatch User Guide .
A math expression can use the Id of the other metrics or queries to refer to those metrics, and can also use the Id of other expressions to use the result of those expressions. For more information about metric math expressions, see Metric Math Syntax and Functions in the Amazon CloudWatch User Guide .
Within each MetricDataQuery object, you must specify either Expression or MetricStat but not both.
Label (string) --
A human-readable label for this metric or expression. This is especially useful if this is an expression, so that you know what the value represents. If the metric or expression is shown in a CloudWatch dashboard widget, the label is shown. If Label is omitted, CloudWatch generates a default.
You can put dynamic expressions into a label, so that it is more descriptive. For more information, see Using Dynamic Labels.
ReturnData (boolean) --
When used in GetMetricData , this option indicates whether to return the timestamps and raw data values of this metric. If you are performing this call just to do math expressions and do not also need the raw data returned, you can specify false . If you omit this, the default of true is used.
When used in PutMetricAlarm , specify true for the one expression result to use as the alarm. For all other metrics and expressions in the same PutMetricAlarm operation, specify ReturnData as False.
Period (integer) --
The granularity, in seconds, of the returned data points. For metrics with regular resolution, a period can be as short as one minute (60 seconds) and must be a multiple of 60. For high-resolution metrics that are collected at intervals of less than one minute, the period can be 1, 5, 10, 30, 60, or any multiple of 60. High-resolution metrics are those metrics stored by a PutMetricData operation that includes a StorageResolution of 1 second .
AccountId (string) --
The ID of the account where the metrics are located.
If you are performing a GetMetricData operation in a monitoring account, use this to specify which account to retrieve this metric from.
If you are performing a PutMetricAlarm operation, use this to specify which account contains the metric that the alarm is watching.