Terraform AWS Lambda module: scheduler/cron

Terraform AWS module which creates Lambda resource with attached CloudWatch scheduler.

It integrates Lambda function with CloudWatch cron expression using EventBridge.

Simply put, thanks to this module, you can schedule your code to run at a specific time.

Usage

module "cron" {
  source = "git@github.com:uridium/terraform-aws-lambda-scheduler.git"

  function_name  = "plower"
  handler        = "lambda.handler"
  runtime        = "python3.9"
  layer_enabled  = true
  code_directory = "/opt/lambda"
  input          = "{\"firstName\": \"John\", \"lastName\": \"Doe\"}"

  vars = {
    foo = "bar"
  }

  tags = {
    Env = "Stage"
  }

  cron = "cron(01 06 ? * MON-FRI *)"
}

Development

This module uses pre-commit hook to identify simple issues before pushing code to the remote repository, and relies on .pre-commit-config.yaml file.

To use it simply run:

pip install pre-commit
pre-commit install

Now pre-commit will run automatically on every git commit.

Notes

• code_directory specifies a directory where you keep your entire Lambda code
• If you want to create a layer, simply put it into layer/<runtime> directory and set layer_enabled to true

Examples

• Displays Hello World with Python, no VPC
• Displays Hello World with Python, no VPC, uses remote state file and locking
• Displays HTTP headers with Nodejs, VPC
• Displays HTTP headers with Python, VPC
• Displays HTTP headers with Python, no VPC, container image

Requirements

Name	Version
terraform	>= 1.2
archive	>= 2.3.0
aws	>= 4.0

Resources

Name	Type
aws_cloudwatch_event_rule.this	resource
aws_cloudwatch_event_target.this	resource
aws_cloudwatch_log_group.this	resource
aws_iam_role.this	resource
aws_iam_role_policy_attachment.lambda	resource
aws_iam_role_policy_attachment.xray	resource
aws_lambda_function.this	resource
aws_lambda_layer_version.this	resource
aws_lambda_permission.this	resource
archive_file.function_zip	data source
archive_file.layer_zip	data source
aws_iam_policy_document.this	data source

Inputs

Name	Description	Type	Default	Required
code_directory	A relative or full path to the directory with your Lambda Function (and Layer if you use it) code. For example: /opt/lambda	string	null	no
cron	The scheduling expression. For example: cron(0 20 * * ? *) or rate(5 minutes)	string	n/a	yes
description	Description of what your Lambda Function does	string	"Generated by Terraform"	no
function_name	A unique name for your Lambda Function	string	n/a	yes
handler	The function entrypoint in your code	string	null	no
image_uri	ECR image URI containing the function's deployment package	string	false	no
input	Valid JSON text passed to the target	string	null	no
layer_enabled	Create a Lambda Layer Version resource	bool	false	no
memory_size	The amount of memory in MB your Lambda Function can use at runtime	number	128	no
package_type	Lambda deployment package type	string	"Zip"	no
runtime	The identifier of the function's runtime	string	null	no
security_group_ids	A list of security group IDs associated with the Lambda function	list(string)	[]	no
subnet_ids	A list of subnet IDs associated with the Lambda function	list(string)	[]	no
tags	A map of tags to assign to the object	map(string)	null	no
timeout	The amount of time your Lambda Function has to run in seconds	number	3	no
tracing_mode	Define X-Ray tracing mode to record timing and error information for a subset of invocations	string	"PassThrough"	no
vars	The Lambda environment's configuration settings	map(string)	null	no

Outputs

Name	Description
lambda_function_arn	The ARN of the Lambda Function
lambda_function_filename	The filename of the function zip archive
lambda_function_handler	The filename.handler-method value in your function
lambda_function_image_uri	A list of subnets and security groups associated tiwht the Lambda Function
lambda_function_last_modified	The time when the Lambda Function was modified
lambda_function_name	The name of the Lambda Function
lambda_function_role	IAM role attached to the Lambda Function
lambda_function_runtime	The identifier of the Lambda Function's runtime
lambda_function_source_code_hash	A base64-encoded SHA256 hash of the package file
lambda_function_source_code_size	The size in bytes of the function .zip file
lambda_function_version	Latest published version of your Lambda Function
lambda_function_vpc_config	A list of subnets and security groups associated tiwht the Lambda Function