aws-core-utils

aws-core-utils v3.0.1

Core utilities for working with Amazon Web Services (AWS), including ARNs, regions, stages, Lambdas, AWS errors, stream events, Kinesis, DynamoDB.DocumentClients, etc.

Currently includes:

• arns.js
  • Utilities for working with Amazon Resource Names (ARNs)
• aws-errors.js
  • Utilities for working with AWS errors.
• dynamodb-doc-clients.js
  • Utilities for working with AWS.DynamoDB.DocumentClients and a module-scope cache of AWS.DynamoDB.DocumentClient instances by region for Lambda.
• kinesis-utils.js
  • Utilities for working with AWS.Kinesis and a module-scope cache of AWS.Kinesis instances by region for Lambda.
• lambdas.js
  • Utilities for working with AWS Lambda, which enable extraction of function names, versions and, most importantly, aliases from AWS contexts and their invoked function ARNs.
• regions.js
  • Utilities for resolving the AWS region from various sources (primarily for AWS Lambda usage).
• stages.js
  • Utilities for resolving or deriving the current stage (e.g. dev, qa, prod) from various sources (primarily for AWS Lambda usage).
  • Utilities for configuration of stage handling.
  • Configurable and default functions for generating stage-qualified stream and resource names.
  • Configurable and default functions for extracting stages from stage-qualified stream and resource names.
• stream-events.js
  • Utilities for extracting information from AWS Kinesis and AWS DynamoDB stream events.

This module is exported as a Node.js module.

Installation

Using npm:

$ {sudo -H} npm i -g npm
$ npm i --save aws-core-utils

In Node.js:

• To use the AWS ARN utilities

const arns = require('aws-core-utils/arns');

const arnComponent = arns.getArnComponent(arn, index);
const arnPartition = arns.getArnPartition(arn);
const arnService = arns.getArnService(arn);
const arnRegion = arns.getArnRegion(arn);
const arnAccountId = arns.getArnAccountId(arn);
const arnResources = arns.getArnResources(arn);

• To use the AWS errors utilities

const awsErrors = require('aws-core-utils/aws-errors');

• To get the current AWS region & configure it on a context

const regions = require('aws-core-utils/regions');

// To get the current AWS region
const region = regions.getRegion();

// To configure a context with the current AWS region
regions.configureRegion(context, failFast)

• To use the DynamoDB.DocumentClient utilities to cache and configure an AWS DynamoDB.DocumentClient instance per region

const dynamoDBDocClients = require('aws-core-utils/dynamodb-doc-clients');

// Preamble to create a context and configure logging on the context
const context = {};
const logging = require('logging-utils');
logging.configureDefaultLogging(context); // or your own custom logging configuration (see logging-utils README.md)

// Define the DynamoDB.DocumentClient's constructor options that you want to use, e.g.
const dynamoDBDocClientOptions = {
  // See http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB/DocumentClient.html#constructor-property
  // and http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/DynamoDB.html#constructor-property
  maxRetries: 0
  // ...
};

// To create and cache a new AWS DynamoDB.DocumentClient instance with the given DynamoDB.DocumentClient constructor 
// options for either the current region or the region specified in the given options OR reuse a previously cached 
// DynamoDB.DocumentClient instance (if any) that is compatible with the given options
const dynamoDBDocClient = dynamoDBDocClients.setDynamoDBDocClient(dynamoDBDocClientOptions, context);

// To configure a new AWS.DynamoDB.DocumentClient instance (or re-use a cached instance) on a context 
dynamoDBDocClients.configureDynamoDBDocClient(context, dynamoDBDocClientOptions);
console.log(context.dynamoDBDocClient);

// To get a previously set or configured AWS DynamoDB.DocumentClient instance for the current AWS region
const dynamoDBDocClient1 = dynamoDBDocClients.getDynamoDBDocClient();
// ... or for a specified region
const dynamoDBDocClient2 = dynamoDBDocClients.getDynamoDBDocClient('us-west-2');

// To get the original options that were used to construct a cached AWS DynamoDB.DocumentClient instance for the current or specified AWS region
const optionsUsed1 = dynamoDBDocClients.getDynamoDBDocClientOptionsUsed();
const optionsUsed2 = dynamoDBDocClients.getDynamoDBDocClientOptionsUsed('us-west-1');

// To delete and remove a cached DynamoDB.DocumentClient instance from the cache
const deleted = dynamoDBDocClients.deleteDynamoDBDocClient('eu-west-1');

• To use the Kinesis utilities to cache and configure an AWS Kinesis instance per region

const kinesisUtils = require('aws-core-utils/kinesis-utils');

// Preamble to create a context and configure logging on the context
const context = {};
const logging = require('logging-utils');
logging.configureDefaultLogging(context); // or your own custom logging configuration (see logging-utils README.md)

// Define the Kinesis constructor options that you want to use, e.g.
const kinesisOptions = {
  // See http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/Kinesis.html#constructor-property for full details
  maxRetries: 0
  // ...
};

// To create and cache a new AWS Kinesis instance with the given Kinesis constructor options for either the current 
// region or the region specified in the given options OR reuse a previously cached Kinesis instance (if any) that is 
// compatible with the given options
const kinesis = kinesisUtils.setKinesis(kinesisOptions, context);

// To configure a new AWS.Kinesis instance (or re-use a cached instance) on a context 
kinesisUtils.configureKinesis(context, kinesisOptions);
console.log(context.kinesis);

// To get a previously set or configured AWS Kinesis instance for the current AWS region
const kinesis1 = kinesisUtils.getKinesis();
// ... or for a specified region
const kinesis2 = kinesisUtils.getKinesis('us-west-2');

// To get the original options that were used to construct a cached AWS Kinesis instance for the current or specified AWS region
const optionsUsed1 = kinesisUtils.getKinesisOptionsUsed();
const optionsUsed2 = kinesisUtils.getKinesisOptionsUsed('us-west-1');

// To delete and remove a cached Kinesis instance from the cache
const deleted = kinesisUtils.deleteKinesis('eu-west-1');

• To use the Lambda utilities

const lambdas = require('aws-core-utils/lambdas');

// Fail a Lambda's callback with a standard error and preserve HTTP status codes (for non-API Gateway Lambdas) 
// See core-functions/app-errors.js for standard errors to use
lambdas.failCallback(lambdaCallback, error, awsContext, message, code);

// Fail an API Gateway-exposed Lambda's callback with a standard error and preserve HTTP status codes
lambdas.failCallbackForApiGateway(lambdaCallback, error, awsContext, message, code, allowedHttpStatusCodes);

// To resolve the Lambda alias from an AWS Lambda context
const alias = lambdas.getAlias(awsContext);

// To extract other details from an AWS Lambda context
const functionName = lambdas.getFunctionName(awsContext);
const functionVersion = lambdas.getFunctionVersion(awsContext);
const functionNameVersionAndAlias = lambdas.getFunctionNameVersionAndAlias(awsContext);
const invokedFunctionArn = lambdas.getInvokedFunctionArn(awsContext);
const invokedFunctionArnFunctionName = lambdas.getInvokedFunctionArnFunctionName(awsContext);

• To use the stage utilities

// To configure stage-handling, which determines the behaviour of the functions numbered 1 to 6 below
const stages = require('aws-core-utils/stages');
const config = require('./config.json'); // ... or your own config file

// ... EITHER using the default stage handling configuration partially customised via config.stageHandlingOptions
stages.configureDefaultStageHandling(context, config.stageHandlingOptions, forceConfiguration); 

// ... OR using your own custom stage-handling configuration
const stageHandlingSettings = stages.getDefaultStageHandlingSettings(config.stageHandlingOptions);
// Optionally override the default stage handling functions with your own custom functions
// stageHandlingSettings.customToStage = undefined;
// stageHandlingSettings.convertAliasToStage = stages.DEFAULTS.convertAliasToStage;
// stageHandlingSettings.injectStageIntoStreamName = stages.DEFAULTS.toStageSuffixedStreamName;
// stageHandlingSettings.extractStageFromStreamName = stages.DEFAULTS.extractStageFromSuffixedStreamName;
// stageHandlingSettings.injectStageIntoResourceName = stages.DEFAULTS.toStageSuffixedResourceName;
// stageHandlingSettings.extractStageFromResourceName = stages.DEFAULTS.extractStageFromSuffixedResourceName;
stages.configureStageHandling(context, stageHandlingSettings, forceConfiguration);

// ... OR using completely customised stage handling settings
const settings = {
    customToStage: myCustomToStageFunction, // or undefined if not needed
    convertAliasToStage: myConvertAliasToStageFunction, // or undefined to knockout using aliases as stages

    injectStageIntoStreamName: myInjectStageIntoStreamNameFunction, 
    extractStageFromStreamName: myExtractStageFromStreamNameFunction,
    streamNameStageSeparator: myStreamNameStageSeparator,

    injectStageIntoResourceName: myInjectStageIntoResourceNameFunction,
    extractStageFromResourceName: myExtractStageFromResourceNameFunction,
    resourceNameStageSeparator: myResourceNameStageSeparator,

    injectInCase: myInjectInCase,
    extractInCase: myExtractInCase,

    defaultStage: myDefaultStage, // or undefined
}
stages.configureStageHandling(context, settings, forceConfiguration);


// To check if stage handling is configured
const configured = stages.isStageHandlingConfigured(context);

// To look up stage handling settings and functions
const setting = stages.getStageHandlingSetting(context, settingName);
const fn = stages.getStageHandlingFunction(context, functionSettingName);

// 1. To resolve / derive a stage from an AWS event
const context = {};
const stage = stages.resolveStage(event, awsContext, context);

// 2. To configure a context with a resolved stage 
stages.configureStage(context, event, awsContext, failFast)

// 3. To qualify an unqualified stream name with a stage
const unqualifiedStreamName = 'TestStream';
const stageQualifiedStreamName = stages.toStageQualifiedStreamName(unqualifiedStreamName, stage, context);

// 4. To extract a stage from a qualified stream name
const qualifiedStreamName = 'TestStream_PROD';
const stage2 = stages.extractStageFromQualifiedStreamName(qualifiedStreamName, context);

// 5. To qualify an unqualified resource name with a stage
const unqualifiedResourceName = 'TestResource';
const stageQualifiedResourceName = stages.toStageQualifiedResourceName(unqualifiedResourceName, stage, context);

// 6. To extract a stage from a qualified resource name
const qualifiedResourceName = 'TestResource_QA';
const stage3 = stages.extractStageFromQualifiedResourceName(qualifiedResourceName, context);

• To use the stream event utilities

const streamEvents = require('aws-core-utils/stream-events');

// To extract stream names form AWS event source ARNs 
const eventSourceARNs = streamEvents.getEventSourceARNs(event);
const eventSourceStreamNames = streamEvents.getEventSourceStreamNames(event);
const eventSourceStreamName = streamEvents.getEventSourceStreamName(record);

// Simple checks to validate existance of some of the properties of Kinesis & DynamoDB stream event records
try {
  streamEvents.validateStreamEventRecord(record);
  streamEvents.validateKinesisStreamEventRecord(record);
  streamEvents.validateDynamoDBStreamEventRecord(record);
} catch (err) { 
  // ... 
}

Unit tests

This module's unit tests were developed with and must be run with tape. The unit tests have been tested on Node.js v4.3.2.

Install tape globally if you want to run multiple tests at once:

$ npm install tape -g

Run all unit tests with:

$ npm test

or with tape:

$ tape test/*.js

See the package source for more details.

Changes

3.0.1

• Changes to stages.js module:
  • Added a convenience configureStageHandlingIfNotConfigured function
  • Changed configureDefaultStageHandlingIfNotConfigured function to use new configureStageHandlingIfNotConfigured function
• Updated logging-utils dependency to version 2.0.3

3.0.0

• Changes to stages.js module:
  • Added typedef for StageHandlingOptions to better define parameters and return types
  • Changed getDefaultStageHandlingSettings function to accept an options argument of type StageHandlingOptions instead of an arbitrary config object and to also load default options from config.json
  • Changed configureDefaultStageHandling function to accept a new options argument of type StageHandlingOptions to enable optional, partial overriding of default stage handling settings
  • Changed stageHandlingSettings to stageHandlingOptions in config.json
  • Fixed require logging-utils link
• Updated logging-utils dependency to version 2.0.1

2.1.4

• Updated JsDoc comments in dynamodb-doc-clients and kinesis-utils modules.

2.1.3

• Added a new dynamodb-doc-clients module to enable creation and configuration of AWS DynamoDB.DocumentClient instances and caching of a DynamoDB.DocumentClient instance per region. Note that this new module is an almost exact replica of the kinesis-utils module, but for getting, setting and caching DynamoDB.DocumentClient instances instead of Kinesis instances.
  • Added setDynamoDBDocClient, getDynamoDBDocClient, getDynamoDBDocClientOptionsUsed, deleteDynamoDBDocClient and configureDynamoDBDocClient functions and unit tests for same.

2.1.2

• Updated core-functions dependency to version 2.0.3
• Updated logging-utils dependency to version 1.0.6

2.1.1

• Added getDefaultStageHandlingSettings function to get the default stage handling settings

2.1.0

• Changes to stages module:
  • Changed API of configureStageHandling function to accept a setting object instead of the multiple fixed parameters, to simplify configuration of new, custom settings.
  • Minor changes and fixes to code & unit tests to accommodate this change.
• Major overhaul of kinesis-utils module to enable full configuration of an AWS Kinesis instance and caching of a Kinesis instance per region.
  • Added setKinesis, getKinesis, getKinesisOptionsUsed & deleteKinesis functions and unit tests for same.
  • Rewrote and changed API of configureKinesis function to use the new setKinesis function and patched its unit tests.
• Technically should have been a 3.0.0 release semantically speaking, since I changed the APIs of two existing functions, but it did not seem warranted.

2.0.1

• Added new kinesis-utils module to provide basic configuration and caching of an AWS.Kinesis instance for Lambda
• Changes to stream-events module:
  • Added validateStreamEventRecord function to check if a record is either a valid Kinesis or DynamoDB stream event record
  • Added validateKinesisStreamEventRecord function to check if a record is a valid Kinesis stream event record
  • Added validateDynamoDBStreamEventRecord function to check if a record is a valid DynamoDB stream event record
  • Added unit tests for new functions
• Minor change to setRegionIfNotSet to eliminate unnecessary logging when regions are the same
• Updated core-functions dependency to version 2.0.2
• Updated logging-utils dependency to version 1.0.5

2.0.0

• Major changes to stages:
  • Changed existing configuration API from resolveStage-specific configuration to general stage handling configuration.
    • Added support for a custom to stage function.
    • Added support for configuration of stream and resource name qualification.
  • Added configureStage function.
  • Added configurable toStageQualifiedStreamName and default toStageSuffixedStreamName functions.
  • Added configurable extractStageFromQualifiedStreamName and default extractStageFromSuffixedStreamName functions.
  • Added configurable toStageQualifiedResourceName and default toStageSuffixedResourceName functions.
  • Added configurable extractStageFromQualifiedResourceName and default extractStageFromSuffixedResourceName functions.
  • Changed and added unit tests for revamped stages module.
• Changes to regions:
  • Added configureRegion function.
  • Added optional, hidden failFast argument to getRegion function needed for configureRegion function.
• Changes to aws-errors:
  • Fixed incorrect usage in comments.
  • Moved exported object's methods bodies to module-level functions.
• Changes to lambdas:
  • Added failCallback function to fail non-API Gateway Lambda callbacks with standard app errors to facilitate mapping of errors to HTTP status codes
  • Added failCallbackForApiGateway function to fail API Gateway Lambda callbacks with standard app errors to facilitate mapping of errors to HTTP status codes
• Added stream-events module and unit tests for it.
• Updated core-functions dependency to version 1.2.0.
• Added logging-utils 1.0.2 dependency.

1.0.0

• Completed changes needed to release 1.0.0
• Added unit tests for stages.js
• Simplified regions.js API down to relevant methods
• Fixed defects attempting to source awsRegion and eventSourceARN from event instead of Kinesis records within event.
• Patched repository in package.json

0.9.0

• Initial commit