Description: Demo of things Joe learned while messing around with Lambdas

• We needed a way to provision certificates in the new AWS account
  • We didn't have Rundeck to help us out
  • There would be more overhead and cost to exploring ECS or EKS
  • Lambdas are usually cheap to run
• We already have lambdas in production, but no one is currently supporting/owning them from a standardization and deployment perspective

• Install awscli and configure an account named lambda-demo with the default region us-east-1:
  • aws configure --profile lambda-demo
• Install Docker
• Install Terraform

• Make sure you have access to the docker-python-lambda-builder repo before starting

• Start 80s Synthwave Music: make start-music

• Docker was necessary because the AWS documentation wants you to provision an Amazon Linux EC2 instance
  • Instead I created docker-python-lambda-builder which will take an app and its dependencies and zip them
• Download/Build the lambda builder container: make docker-init
• After the build has finished, package the lambda: make lambda-build
  • This will zip the application and dependencies

• Terraform will create the structure needed to support the lambda in AWS
  • Lambda
  • IAM Role
  • IAM Policy
• Initialize Terraform: make tf-init
• Use Terraform to provision new lambda: make tf-apply
  • You will be prompted to review and confirm the changes

• After terraform has completed, you can invoke the function and its handler: make lambda-invoke
  • Think of the handler as a substitute of main in python

• You decide you want to make changes to your function, simply go to the lambda folder and edit app.py
• After making changes, rebuild the lambda packages, upload the lambda, and invoke the function: make lambda-build lambda-upload lambda-invoke or make lambda-refresh

• Log into the AWS console for the account you specified in awscli
• Navigate to the Lambda control panel
• Click on the function that you just created demo_testservice_stg_useast1_example_com
• Here you can review the function code
  • Note: If the function is deemed too big by AWS, you will not be able to use this IDE.
• You can also change the handler to the test_handler specified in app.py
• Press the Save button on the top right corner, click the empty drop-down menu to the left of the Test button and select Configure test event
• Give the Event name a name and then press Create
• You can now press the Test button
• Review the Execution results in the console to see what happened with the test_handler
• You can also see more robust logs by pressing the Logs link next to the Execution results

• Destroy lambda resources: make tf-destroy
• Confirm deletion by submitting yes Sample Destroy Output

$ make tf-destroy
terraform destroy terraform/
data.template_file.lambda_assume_role: Refreshing state...
aws_iam_role.lambda_role: Refreshing state... (ID: demo_testservice_stg_useast1_example_com)
aws_lambda_function.lambda_demo: Refreshing state... (ID: demo_testservice_stg_useast1_example_com)

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  - destroy

Terraform will perform the following actions:

  - aws_iam_role.lambda_role

  - aws_lambda_function.lambda_demo


Plan: 0 to add, 0 to change, 2 to destroy.

Do you really want to destroy all resources?
  Terraform will destroy all your managed infrastructure, as shown above.
  There is no undo. Only 'yes' will be accepted to confirm.

  Enter a value: yes

aws_lambda_function.lambda_demo: Destroying... (ID: demo_testservice_stg_useast1_example_com)
aws_lambda_function.lambda_demo: Destruction complete after 5s
aws_iam_role.lambda_role: Destroying... (ID: demo_testservice_stg_useast1_example_com)
aws_iam_role.lambda_role: Still destroying... (ID: demo_testservice_stg_useast1_example_com, 10s elapsed)
aws_iam_role.lambda_role: Destruction complete after 11s

• Remove docker images: make docker-cleanup

• Lambdas aren't always fun to debug
• Keep Lambdas small, don't implement more than a few functions
• Lambdas/Serverless won't fix all problems. It actually introduces new problems too

• There are a bunch more things that lambdas can do
  • Interface with other AWS resources
  • We didn't even touch on the API Gateway
• Deployment pipelines need to be figured out for each runtime (python/ruby/nodejs)
• Terraform is great for provisioning the resources, but not great for updating the lambda after initialization
• Lambdas are great for monitoring checks