Class MikroMetric

Description

MikroMetric is a Lambda-oriented lightweight wrapper for producing AWS CloudWatch Embedded Metric Format-compatible metric logs.

Example

// ES5 format
const { MikroMetric } = require('mikrometric');
// ES6 format
import { MikroMetric } from 'mikrometric';

const mikroMetric = MikroMetric.start({ namespace: 'MyNamespace', serviceName: 'MyServiceName' });

mikroMetric.putDimension('User', 'Sam Person');
mikroMetric.putMetric('Duration', 83, 'Milliseconds');
mikroMetric.setProperty('CorrelationId', '8d5a0ba6-05e0-4c9b-bc7c-9164ea1bdedd');

mikroMetric.flush();

Constructors

`Private` constructor

new MikroMetric(namespace, serviceName, event?, context?): MikroMetric
Parameters
- namespace: string
- serviceName: string
- Optional event: any
- Optional context: any
Returns MikroMetric
- Defined in domain/entities/MikroMetric.ts:47

Properties

`Static` `Private` context

context: any

`Static` `Private` correlationId

correlationId: string

`Static` `Private` event

event: any

`Static` `Private` instance

instance: MikroMetric

`Static` `Private` metadataConfig

metadataConfig: StaticMetadataConfigInput | Record<string, any> = {}

`Static` `Private` metric

metric: MetricBaseObject

`Static` `Private` namespace

namespace: string

`Static` `Private` serviceName

serviceName: string

Methods

`Private` canAddMoreItemsToArray

canAddMoreItemsToArray(array, maximumLength): void
Parameters
- array: any[]
- maximumLength: number
Returns void
Description
Validate if the length of an array is within acceptable bounds.
- Defined in domain/entities/MikroMetric.ts:264

`Private` createBaseMetricObject

createBaseMetricObject(): MetricBaseObject
Returns MetricBaseObject
Description
Create the base AWS EMF object shape.

See
- https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Embedded_Metric_Format_Specification.html
- https://docs.aws.amazon.com/lambda/latest/dg/configuration-envvars.html
- Defined in domain/entities/MikroMetric.ts:205

`Private` createDynamicMetadata

createDynamicMetadata(): DynamicMetadata
Returns DynamicMetadata
Description
Get dynamic metadata with aws-metadata-utils and add some extra bits on top.
- Defined in domain/entities/MikroMetric.ts:240

`Private` createMetricObject

createMetricObject(): MetricObject
Returns MetricObject
Description
Create the metric object.
- Defined in domain/entities/MikroMetric.ts:224

`Private` filterMetadata

filterMetadata(metadata): any
Parameters
- metadata: Record<string, any>
Returns any
Description
Filter metadata from empties.
- Defined in domain/entities/MikroMetric.ts:279

flush

flush(): MetricObject
Returns MetricObject
Description
"Flush" your metric log, which in plain English means "send it". The log will be picked up by CloudWatch Metrics automatically through the log format.

Example
```
mikroMetric.flush();
```
- Defined in domain/entities/MikroMetric.ts:192

getNamespace

getNamespace(): string
Returns string
Description
Get the current namespace.
- Defined in domain/entities/MikroMetric.ts:120

getServiceName

getServiceName(): string
Returns string
Description
Get the current service name.
- Defined in domain/entities/MikroMetric.ts:127

`Private` hasNonAsciiCharacters

hasNonAsciiCharacters(stringToTest): void
Parameters
- stringToTest: string
Returns void
Description
Check if a string contains any non-ASCII characters.
- Defined in domain/entities/MikroMetric.ts:256

`Private` isLengthWithinBounds

isLengthWithinBounds(value, maximumLength): void
Parameters
- value: string
- maximumLength: number
Returns void
Description
Validate if the length of a string is within acceptable bounds.
- Defined in domain/entities/MikroMetric.ts:271

putDimension

putDimension(key, value): void
Parameters
- key: string
- value: string
Returns void
Description
Put a dimension onto the metric log.

From the AWS docs: "A dimension is a name/value pair that is part of the identity of a metric. You can assign up to 30 dimensions to a metric".

Example
```
mikroMetric.putDimension('User', 'Sam Person');
```
See
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch_concepts.html#Dimension
- Defined in domain/entities/MikroMetric.ts:140

putMetric

putMetric(key, value, unit?): void
Parameters
- key: string
- value: string | number
- Optional unit: Unit
Returns void
Description
Put a metric onto the metric log.

Example
```
mikroMetric.putMetric('Duration', 83, 'Milliseconds');
```
See
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Embedded_Metric_Format_Specification.html#CloudWatch_Embedded_Metric_Format_Specification_structure_metricdefinition
- Defined in domain/entities/MikroMetric.ts:159

reset

reset(): void
Returns void
Description
Reset to fresh state.

Example
```
mikroMetric.reset();
```
- Defined in domain/entities/MikroMetric.ts:92

setCorrelationId

setCorrelationId(correlationId): void
Parameters
- correlationId: string
Returns void
Description
Set correlation ID manually, for example for use in cross-boundary calls.

This value will be propagated to all future metrics.
- Defined in domain/entities/MikroMetric.ts:101

setNamespace

setNamespace(namespace): void
Parameters
- namespace: string
Returns void
Description
Set the namespace for the metric log.

Example
```
mikroMetric.setNamespace('MyNamespace');
```
- Defined in domain/entities/MikroMetric.ts:110

setProperty

setProperty(key, value): void
Parameters
- key: string
- value: PropertyValue
Returns void
Description
Set a property onto the metric log.

These will be shown in CloudWatch Logs (Insights) but not in CloudWatch Metrics.

Example
```
mikroMetric.setProperty('RequestId', '422b1569-16f6-4a03-b8f0-fe3fd9b100f8');
```
- Defined in domain/entities/MikroMetric.ts:179

`Private` sortOutput

sortOutput(input): any
Parameters
- input: Record<string, any>
Returns any
Description
Alphabetically sort the fields in the log object.
- Defined in domain/entities/MikroMetric.ts:293

`Static` start

start(input?): MikroMetric
Parameters
- Optional input: MikroMetricInput
Returns MikroMetric
Description
This instantiates MikroMetric. In order to be able to "remember" event and context we use a singleton pattern to reuse the same logical instance.

Example
```
mikroMetric.start({ namespace: 'MyNamespace', serviceName: 'MyService' });
```
- Defined in domain/entities/MikroMetric.ts:64

Class MikroMetric

Description

Example

Index

Constructors

Properties

Methods

Constructors

Private constructor

Parameters

namespace: string

serviceName: string

Optional event: any

Optional context: any

Returns MikroMetric

Properties

Static Private context

Static Private correlationId

Static Private event

Static Private instance

Static Private metadataConfig

Static Private metric

Static Private namespace

Static Private serviceName

Methods

Private canAddMoreItemsToArray

Parameters

array: any[]

maximumLength: number

Returns void

Description

Private createBaseMetricObject

Returns MetricBaseObject

Description

See

Private createDynamicMetadata

Returns DynamicMetadata

Description

Private createMetricObject

Returns MetricObject

Description

Private filterMetadata

Parameters

metadata: Record<string, any>

Returns any

Description

flush

Returns MetricObject

Description

Example

getNamespace

Returns string

Description

getServiceName

Returns string

Description

Private hasNonAsciiCharacters

Parameters

stringToTest: string

Returns void

Description

Private isLengthWithinBounds

Parameters

value: string

maximumLength: number

Returns void

Description

putDimension

Parameters

key: string

value: string

Returns void

Description

Example

See

putMetric

Parameters

key: string

value: string | number

Optional unit: Unit

`Private` constructor

`Optional` event: any

`Optional` context: any

`Static` `Private` context

`Static` `Private` correlationId

`Static` `Private` event

`Static` `Private` instance

`Static` `Private` metadataConfig

`Static` `Private` metric

`Static` `Private` namespace

`Static` `Private` serviceName

`Private` canAddMoreItemsToArray

`Private` createBaseMetricObject

`Private` createDynamicMetadata

`Private` createMetricObject

`Private` filterMetadata

`Private` hasNonAsciiCharacters

`Private` isLengthWithinBounds

`Optional` unit: Unit

`Private` sortOutput

`Static` start

`Optional` input: MikroMetricInput