Lambda

This document contains information about the Lambda service supported in Handel. This Handel service provisions an Lambda function. You can reference this function in other services as an event consumer, which will invoke the function when events occur.

Service Limitations

The following Lambda features are not currently supported in this service:

• Encrypting environment variables with KMS keys

Parameters

Parameter	Type	Required	Default	Description
type	string	Yes		This must always be lambda for this service type.
path_to_code	string	Yes		The location of your code to upload to Lambda. This can be a directory (which will be zipped up) or a single file (such as a deployable Java WAR file or pre-existing zip file)
handler	string	Yes		The handler function in your code that is the entry-point to the Lambda.
runtime	string	Yes		The Lambda runtime that will execute your code
description	string	No	Handel-created function	The configuration description of your function
memory	number	No	128	The amount of memory to allocate for your function
timeout	number	No	3	The timeout in seconds for your function. Max 300
vpc	boolean	No	false	If true, the lambda will be deployed inside your VPC. Inside your VPC, it will be able to communicate with resources like RDS databases and ElastiCache clusters.
environment_variables	EnvironmentVariables	No		Any environment variables you want to inject into your code.
tags	Resource Tags	No		Any tags you want to apply to your Lambda

EnvironmentVariables

The EnvironmentVariables element is defined by the following schema:

environment_variables:
  <YOUR_ENV_NAME>: <your_env_value>

<YOUR_ENV_NAME> is a string that will be the name of the injected environment variable. <your_env_value> is its value. You may specify an arbitrary number of environment variables in this section.

Example Handel File

version: 1

name: my-lambda

environments:
  dev:
    webapp:
      type: lambda
      path_to_code: .
      handler: index.handler
      runtime: nodejs6.10
      environment_variables:
        MY_ENV: myEnvValue
      tags:
        mytag: mytagvalue

Running a scheduled Lambda

To run a scheduled Lambda, you can use this service in conjunction with the CloudWatch Events service. See the Scheduled Lambda on the CloudWatch Events service for details on how to do this.

Depending on this service

The Lambda service outputs the following environment variables:

Environment Variable	Description
<SERVICE_NAME>_FUNCTION_NAME	The name of the created Lambda function
<SERVICE_NAME>_FUCNTION_ARN	The ARN of the created Lambda function

See Environment Variable Names for information about how the service name is included in the environment variable name.

Events produced by this service

The Lambda service does not currently produce events for other Handel services to consume.

Events consumed by this service

The Lambda service can consume events from the following service types:

• Alexa Skill Kit
• CloudWatch Events
• DynamoDB
• IoT
• S3
• SNS