Aws-lambda-helper NPM

aws-lambda-helper

Collection of helper methods for lambda

Installation

$ npm install aws-lambda-helper --save

Usage

  var AwsHelper = require('aws-lambda-helper');

  exports.handler = function(event, context) {
    ...
    //Initialise the helper by passing in the context
    AwsHelper.init(context);
    ...
  }

Invoke a Lamda function

  var AwsHelper = require('aws-lambda-helper');

  exports.handler = function(event, context){
    // assume : context.invokedFunctionArn = invokedFunctionArn: 'arn:aws:lambda:eu-west-1:123456789:function:mylambda:prod'

    //Initialise the helper by passing in the context
    AwsHelper.init(context);

    console.log(AwsHelper.env); //prints: prod
    console.log(AwsHelper.region); //prints: eu-west-1
    console.log(AwsHelper.account); //prints: 123456789

    var params = {
        FunctionName: 'MyAmazingLambda',
        Payload: { 'hello': 'world' },
        Qualifier: ''
      };
    AwsHelper.Lambda.invoke(params, function (err, data) {
      AwsHelper.failOnError(err, event, context);
      context.succeed(data);
    });
  }

Logging JSON messages

var AwsHelper = require('aws-lambda-helper');

exports.handler = function(event, context){
  // assume : context.invokedFunctionArn = invokedFunctionArn: 'arn:aws:lambda:eu-west-1:123456789:function:mylambda:prod'

  //Initialise the helper by passing in the context
  AwsHelper.init(context, event);

  var log = AwsHelper.Logger('example');

  log.info();     // Returns a boolean: is the "info" level enabled?
  // This is equivalent to `log.isInfoEnabled()` or
  // `log.isEnabledFor(INFO)` in log4j.

  log.info('hi');                     // Log a simple string message (or number).
  log.info('hi %s', bob, anotherVar); // Uses `util.format` for msg formatting.

  log.info({foo: 'bar'}, 'hi');
  // The first field can optionally be a "fields" object, which
  // is merged into the log record.

  log.info(err);  // Special case to log an `Error` instance to the record.
  // This adds an "err" field with exception details
  // (including the stack) and sets "msg" to the exception
  // message.
  log.info(err, 'more on this: %s', more);
  // ... or you can specify the "msg".

  log.info({foo: 'bar', err: err}, 'some msg about this error');
  // To pass in an Error *and* other fields, use the `err`
  // field name for the Error instance.
}

Pushing Data Back to Client(s) Via WebSocket Server

var params = {
  id: sessionId, // the id provided by the WebSocket Server AKA "connectionId"
  bucketId: 12345, // the id of this rticular search request
  userId: 'UniqueFingerprint', // the super long string that uniquely identifies a client
  items: [{  // your list of one or more tiles or packages go here
    url: '/userId/connectionId/bucketId/itemId', // url for S3 object.
  }] // note: url should not have .json in it.
};
AwsHelper.pushResultToClient(params, function (err, res) {
  console.log(err, res); // do what ever you want after the result is pushed
});

Retrieving a Search Result (Artile Tile or Package)

When a user shares a result tile (e.g. an article or package) we retrieve the result they saw from S3:

var params = {
  url: '/userId/connectionId/bucketId/itemId', // supplied by front-end
};
AwsHelper.getRecordFromS3(params, function (err, json) {
  console.log(err, json); // handle error or use json
});

Environment Variables

You will require an the following Environment Variables to push results to S3 and retrieve them later:

export WEBSOCKET_SERVER_URL=get_this_from_codeship
export AWS_S3_SEARCH_RESULT_BUCKET=get_this_from_codeship
export SEARCH_RESULT_TOPIC=arn:aws:sns:eu-west-1:123456789:my-awesome-topic

(see below for complete list of required Environment Variables)