Notification infrastructure and print notifier

[dwhswenson]

This PR adds some of the notification infrastructure (some source already in src/cloud_cron/notifications/base.py) as well as a first concrete implementation in the PrintNotificationHandler. This example implementation just prints the example notification (making it visible in CloudWatch logs for the print notifier lambda function).

This also migrates SNS topics to FIFO SNS topics, which is necessary to connect to a FIFO SQS queue.

[Copilot]

Pull request overview

This PR introduces notification infrastructure for cloud-cron, adding a reusable notification handler framework and a concrete print-based implementation for testing. It also migrates SNS topics to FIFO to enable integration with FIFO SQS queues, which is required for message deduplication.

Changes:

• Adds PrintNotificationHandler that extends the base NotificationHandler to print rendered Jinja2 templates to CloudWatch logs
• Migrates SNS topics to FIFO by automatically appending .fifo suffix and adding MessageGroupId support to SNS publish operations
• Introduces reusable Terraform modules: notification-plumbing for SNS→SQS→Lambda wiring and print-notification for the print handler deployment

Reviewed changes

Copilot reviewed 23 out of 23 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/cloud_cron/notifications/print_handler.py	New handler that prints rendered templates for testing notification pipeline
src/cloud_cron/notifications/__init__.py	Exports the new PrintNotificationHandler class
src/cloud_cron/lambda_task.py	Adds load_sns_message_group_id() function and includes MessageGroupId in SNS publish calls
tests/notifications/test_print_handler.py	Tests for PrintNotificationHandler's template rendering and output
tests/test_lambda_task.py	Tests for load_sns_message_group_id() and updated SNS publish assertions
modules/sns-topics/main.tf	Converts SNS topics to FIFO by auto-appending .fifo suffix and enabling content-based deduplication
modules/notification-plumbing/main.tf	New reusable module for SNS→SQS FIFO→Lambda event source mapping with IAM policy output
modules/notification-plumbing/variables.tf	Input validation for FIFO topic ARN and queue name
modules/notification-plumbing/outputs.tf	Exports queue ARNs, subscription details, and Lambda IAM policy JSON
modules/notification-plumbing/README.md	Documentation for notification plumbing module usage
modules/print-notification/main.tf	Lambda function, IAM roles/policies, and plumbing integration for print handler
modules/print-notification/variables.tf	Configuration for Lambda image, template file, and queue settings
modules/print-notification/outputs.tf	Exports Lambda ARN, queue details, and subscription ARN
modules/print-notification/README.md	Documentation for print notification module usage
examples/basic/main.tf	Integrates print notification module with example SNS topic
examples/basic/variables.tf	Adds print_repository_name variable for container repository
examples/basic/templates/print.txt	Jinja2 template for print notification output
examples/basic/print-notifier/handler.py	Lambda handler entry point using PrintNotificationHandler
examples/basic/print-notifier/Dockerfile	Container image definition for print notification Lambda
PLAN.md	Updates Phase 4 tasks to reflect completed notification plumbing work
IDEA.md	Updates notification channel description to reflect per-channel containers

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[ethanholz]

This all looks correct but I can't really tell without testing this on real infrastructure. Have you run any tofu plan/tofu apply to this works as you expect?

[dwhswenson]

This all looks correct but I can't really tell without testing this on real infrastructure. Have you run any tofu plan/tofu apply to this works as you expect?

Getting this once an hour in CloudWatch logs on AWS (since.... too long? note -- locally managed state for now; in the future we'll add tests that this at least deploys correctly)

I'll call that passing!

[ethanholz]

Looks good! Let's merge that in then!