FixityEventRule

This project contains one Lambda function lambda_function.py that queries Athena table and execute Step functions tasks and a CloudWatch rule that triggers a Lambda function sns.py to email recipient with fixity report. Source code and supporting files for this serverless application - FixityEventRule - that you can deploy with the SAM CLI or Cloudformation. It includes the following files and folders.

• fixitycheck - Code for this application's Lambda function.
• events - Invocation events that you can use to invoke the function.
• tests - Unit tests for this application code.
• template.yaml - A template that defines this application's AWS resources.

The application uses several AWS resources, including Lambda functions, Athena, AWS SNS, CloudWatch, and Step Functions. These resources are defined in the template.yaml file in this project.

Architecure Overview

Fixity Check:

1. Cloudwatch executes FixityEventRule Lambda function daily.
2. FixityEventRule queries Athena, generate step functions tasks, and executes step functions.
3. Step functions do fixity checks for the preservation files stores in S3 and store fixity check results to S3.

Email fixity report:

1. Cloudwatch executes FixityEventRule Lambda function daily.
2. FixityEventRule queries Athena, generate summary report, and email to recipient through SNS.

See DLP Fixity Service for the detail implementation of the AWS step functions serverless fixity for digital preservation compliance.

See Athena for Athena database setup.

Deploy the FixityEventRule application

Deploy FixityEventRule application using CloudFormation stack

Step 1: Launch CloudFormation stack

Click Next to continue

Step 2: Specify stack details

Name	Description
Stack name	any valid name
DatabaseName	Athena Database Name
TableName	Athena Table Name
ResultBucket	S3 Bucket that stores Athena query result
FixityOutputBucket	S3 Bucket that stores Fixity output result
StateMachineName	a valid State Machine Name
WorkGroupName	a valid Athena WorkGroup Name
SNSTopic	a valid SNS Topic Name
GlueManagedPolicyName	Glue ManagedPolicy Name
Email	a valid email
DayPeriod	90
REGION	a valid AWS region. e.g. us-east-1

Step 3: Configure stack options

Leave it as is and click Next

Step 4: Review

Make sure all checkboxes under Capabilities section are CHECKED

Click Create stack

Deploy FixityEventRule application using SAM CLI

To use the SAM CLI, you need the following tools.

• SAM CLI - Install the SAM CLI
• Python 3 installed
• Docker - Install Docker community edition

To build and deploy your application for the first time, run the following in your shell:

sam build --use-container

Above command will build the source of the application. The SAM CLI installs dependencies defined in requirements.txt, creates a deployment package, and saves it in the .aws-sam/build folder.

To package the application, run the following in your shell:

sam package --output-template-file packaged.yaml --s3-bucket BUCKETNAME

Above command will package the application and upload it to the S3 bucket you specified.

Run the following in your shell to deploy the application to AWS:

sam deploy --template-file packaged.yaml --stack-name STACKNAME --s3-bucket BUCKETNAME --parameter-overrides 'DatabaseName=databasename TableName=tablename ResultBucket=bucketname FixityOutputBucket=bucketname StateMachineName=statemachinename WorkGroupName=workgroupname SNSTopic=SNSTopic GlueManagedPolicyName=PolicyName Email=Email DayPeriod=90 Region=us-east-1' --capabilities CAPABILITY_IAM CAPABILITY_NAMED_IAM --region us-east-1

Environment variables

Key	Value
DatabaseName	Athena Database Name
TableName	Athena Table Name
ResultBucket	S3 Bucket that stores Athena query result
FixityOutputBucket	S3 Bucket that stores Fixity output result
StateMachineName	State Machine Name
WorkGroupName	Athena WorkGroup Name
SNSTopic	SNS Topic Name
GlueManagedPolicyName	Glue ManagedPolicy Name
Email	email
DayPeriod	90
REGION	us-east-1

• Stack Name: The name of the stack to deploy to CloudFormation. This should be unique to your account and region, and a good starting point would be something matching your project name.
• AWS Region: The AWS region you want to deploy your app to.

Run the lamdba function through bash

aws lambda invoke --function-name LambdaFunctioName out --log-type Tail --query 'LogResult' --output text |  base64 -d

Unit tests

Tests are defined in the tests folder in this project. Use PIP to install the pytest and run unit tests.

FixityEventRule$ pip install pytest pytest-mock --user
FixityEventRule$ python -m pytest tests/ -v

Cleanup

To delete the sample application that you created, use the AWS CLI. Assuming you used your project name for the stack name, you can run the following:

aws cloudformation delete-stack --stack-name FixityEventRule