dougtoppin/presentation-aws-stepfunctions

Presentation on using AWS Step Functions as a simple reminder service

presentation-aws-stepfunctions

The AWS Step Functions service can be used to orchestrate your activities as well as numerous other functions.

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This is an example of using a Step Function in conjunction with a Lambda function to implement a reminder service.

Resources

This exercise should have no cost assuming that the resource accesses do not exceed the base limits. The AWS resources created have no inherent fixed price. Cost is based on per request usage. Note this implies that they should not be publicly accessible without protections on unintended accesses.

• CloudFormation stack - no cost https://aws.amazon.com/cloudformation/pricing/
• Step Function - https://aws.amazon.com/step-functions/pricing/
• Lambda function - https://aws.amazon.com/lambda/pricing/
• SNS topic - https://aws.amazon.com/sns/pricing/

This assumes that the roles lambda_basic_execution and service-role/StatesExecutionRole-us-east-1 already exist in your account.

Usage

A single CloudFormation stack is used to create all of the resources needed for this application. This is beneficial in that it documents everything required as well as being able to create and delete all resources with a single command.

Specify an email address for an SNS notification to be sent to when reminder messages are sent.

Create the CloudFormation stack and AWS resources:
    make -e EMAIL=email@example.com create-cf

Note, you may need to confirm the subscription created to the new SNS topic.
That is required for sending reminders to work as expected.

Create a reminder as a test:
    make run-cf

Delete the CloudFormation stack and all AWS resources:
    make delete-cf

To set the STACKNAME environment variable in the Makefile and therefore all resources include it in the invocation like the following

 
make EMAIL=dougtoppin@gmail.com  STACKNAME=remindmetest2 create-cf

make STACKNAME=remindmetest2 run-cf

make STACKNAME=remindmetest2 delete-cf

## Maintenance

The Makefile *validate* command uses *cloudformation validate* and 
*cfn-lint* to validate the CloudFormation template.
Validation can be helpful in finding errors in the template more quickly
than waiting for CloudFormation to encounter and report them.

Install *cfn-lint* as follows using a virtual environment and then use validate.

virtualenv _env source _env/bin/activate

pip install cfn-lint

make validate

deactivate