AWS Cost Notification Module

Purpose

This terraform module sends a daily cost report and the cost delta in a 7 day rolling period, scheduled on a CRON to a slack or teams channel of your choice.

The module also reports on the top 5 services attributing to the daily cost. Its a very rudimentary means of managing the cost of your AWS bill, but it does provide a 1000 ft view of the current expenses for the previous day. More on this module can be found on our blog on Medium.

Lambda deployment package

The Lambda function is deployed using a .zip deployment package. The package is contained within this module and also attached to the GitHub release.

You may choose one of the following options for the deployment:

1. default: If no s3_* variables are specified, then the package is used by the lambda directly.
2. recommended: s3_bucket can be specified to upload the package to the S3 bucket, for the lambda to use.
   • s3_prefix can be specified to override the default location.
   • upload_deployment_to_s3=false can be specified to disable the upload, in which case the package must be placed on s3 manually.

Examples

See examples dropdown on Terraform Cloud, or browse here.

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Documentation

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Inputs

Name	Description	Type	Default	Required
account_name	Name of your account to Identify your account in the notification message	string	n/a	yes
amber_threshold	Percentage exceeded threshold to send an amber alert and notify the slack channel	string	"20"	no
cloudwatch_logs_retention_in_days	Specifies the number of days you want to retain log events in the specified log group. Possible values are: 1, 3, 5, 7, 14, 30, 60, 90, 120, 150, 180, 365, 400, 545, 731, 1827, and 3653.	number	14	no
create_role	Controls whether IAM role for Lambda Function should be created	bool	true	no
emails_for_notifications	List of emails to receive cost notifier notifications	list(string)	[]	no
kms_key_arn	The alias, alias ARN, key ID, or key ARN of an AWS KMS key used to encrypt all resources.	string	null	no
lambda_description	Lambda function description.	string	"This function sends AWS cost notifications. Source: github.com/cloudandthings/terraform-aws-costnotifier"	no
lambda_role	IAM role ARN attached to the Lambda Function. This governs both who / what can invoke your Lambda Function, as well as what resources our Lambda Function has access to. See Lambda Permission Model for more details.	string	""	no
lambda_runtime	The lambda runtime to use. One of: ["python3.9", "python3.8", "python3.7"]	string	"python3.8"	no
naming_prefix	Naming prefix used to name all resources	string	n/a	yes
notification_schedule	CRON expression to schedule notification	string	"cron(0 20 ? * MON-SUN *)"	no
permissions_boundary	ARN of the policy that is used to set the permissions boundary for the role.	string	null	no
red_threshold	Percentage exceeded threshold to send a red alert and notify the slack channel	string	"50"	no
s3_bucket	S3 bucket for deployment package.	string	null	no
s3_key	S3 object key for deployment package. Otherwise, defaults to var.naming_prefix/local.deployment_filename.	string	null	no
security_group_ids	List of VPC security group IDs associated with the Lambda function.	list(string)	[]	no
subnet_ids	List of VPC subnet IDs associated with the Lambda function.	list(string)	[]	no
tags	A mapping of tags to assign to the resources.	map(string)	{}	no
upload_deployment_to_s3	If true, the deployment package within this module repo will be copied to S3. If false then the S3 object must be uploaded separately. Ignored if s3_bucket is null.	bool	true	no
webhook_type	Either "slack" or "teams".	string	"slack"	no
webhook_urls	Webhook URLs to receive daily cost notifications on either Slack or Teams	list(string)	n/a	yes

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Modules

Name	Source	Version
billing_notifier_lambda	terraform-aws-modules/lambda/aws	4.9.0

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Outputs

Name	Description
cost_notfier_lambda_name	Created lambda's name

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Providers

Name	Version
aws	~> 4.9

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Requirements

Name	Version
terraform	>= 0.15.0
aws	~> 4.9
null	~> 3.1

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Resources

Name	Type
aws_cloudwatch_event_rule.billing_notifier_lambda_event_rule	resource
aws_cloudwatch_event_target.billing_notifier_lambda_event_target	resource
aws_lambda_permission.billing_notifier_lambda_permission	resource
aws_s3_object.deployment	resource
aws_sns_topic.cost_notifier	resource
aws_sns_topic_subscription.cost_notifier	resource
aws_caller_identity.current	data source

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