Polo Legacy — Deploy & Test Strategy

Development

Local Dev Server

python run.py          # or: inv run

• Flask app on port 2200 with LiveReload
• Watches src/* for changes, auto-restarts on crash (5s backoff)
• Sets ENV=dev, USE_LOCAL_DATA=true
• Uses LocalDataService (reads local_data.json instead of DynamoDB)
• Converts Lambda event/context into Flask request objects

Tailwind CSS

inv tailwind           # one-shot compile
inv tailwind --watch   # watch mode

Output: src/static/dist/main.css

Syncing Local Data

inv sync                         # all resources, all profiles
inv sync -r instances            # single resource type
inv sync -p prod,staging         # specific AWS profiles

Requires AWS CLI profile "polo" configured. Writes per-type JSON files, then combine() merges into local_data.json for the dev server.

Build

Lambda Package

inv zip                 # creates lambda_deployment.zip with deps
inv build               # SAM build
inv build -p polo       # with specific AWS profile

SAM Template (template.yaml)

• Runtime: Python 3.12
• Memory: 256 MB
• Timeout: 30 seconds
• Layers: AWS Lambda Powertools v2
• Functions:
  • PoloFunction → lambda_function.lambda_handler (API routes)
  • StaticFunction → lambda_static.lambda_handler (/static files)
• API Events:
  • /{proxy+} ANY → PoloFunction
  • / ANY → PoloFunction

Deploy

CDK Deployment

inv bootstrap -p polo                          # CDK bootstrap (first time)
inv deploy -p polo -e prod                     # deploy to production
inv deploy -p polo -e prod -s PoloStack        # specific stack
inv deploy -p polo -e prod --exclusively       # only named stack
inv destroy -p polo -e prod                    # tear down
inv destroy -p polo -e prod --force            # skip confirmation

CDK apps defined in:

• infra/app.py — main application stack
• infra/ci.py — CI/CD pipeline
• infra/destination.py — cross-account destination

Environment Variables (Production Lambda)

Required:

Variable	Value
ENV	prod
AWS_REGION	us-east-1
DYNAMODB_TABLE_NAME	prod-ResourceTable
DYNAMODB_REPORT_TABLE_NAME	prod-ReportTable
POWERTOOLS_SERVICE_NAME	polo
POWERTOOLS_METRICS_NAMESPACE	Polo
LOGOUT_URL	/auth/logout

Optional:

Variable	Purpose
USE_LOCAL_DATA	true for dev mode
SLACK_WEBHOOK_URL	Cloud Cop Slack notifications
DATA_BUCKET_NAME	S3 bucket for sync data
CORE_ACCOUNT_ID	Cross-account cost data
CORE_ROLE_ARN	Cross-account role assumption

Testing

Configuration

pytest.ini / conftest.py:

• Auto-mocks os.environ (function scope) with:
  • LOGOUT_URL=/auth/logout
  • DATA_BUCKET_NAME=test-data
  • USE_LOCAL_DATA=1

Test Commands

inv test                        # all tests
inv test --local                # local tests only (no AWS)
inv test --integration          # integration tests (requires AWS)
inv test --watch                # watch mode (pytest-watch)
inv test --coverage             # with coverage report
inv test --report               # HTML coverage report
inv test --fail-under 80        # minimum coverage threshold

Test Stack

Tool	Purpose
pytest	Test runner
moto	AWS service mocking (DynamoDB, S3, EC2, etc.)
freezegun	Time freezing for date-dependent tests
pytest-coverage	Coverage measurement
pytest-watch	File-watching test re-runner

Test Files

src/lambda_function_test.py              — API handler tests
src/lambda_cop_test.py                   — Cloud Cop tests
src/routes/common_test.py                — Route utility tests
src/services/dynamo_data_service_test.py — DynamoDB service tests
src/services/local_data_service_test.py  — Local data service tests
src/services/cost_breakdown_service_test.py — Cost calculation tests
src/services/models/instance_test.py     — Instance model tests
src/services/models/marqoindex_test.py   — Index model tests
src/services/models/all_test.py          — Everything object tests
src/services/reports/*_test.py           — Reporter tests

Test Strategy

• Unit tests: Models, services, utilities — fast, no external deps
• Mocked AWS tests: Using moto to simulate DynamoDB, S3, EC2 APIs
• Time-dependent tests: Using freezegun for report generation, TTL logic
• No E2E browser tests: Frontend is server-rendered, no Playwright/Selenium
• No snapshot tests: HTML output not snapshot-tested

CI/CD

CDK-managed pipeline (infra/ci.py). Build steps:

1. Tailwind CSS compilation
2. Lambda zip creation
3. SAM build
4. CDK synth
5. CDK deploy

Dependencies

Production (src/requirements.txt)

arrow          — datetime utilities
boto3          — AWS SDK
htmxido        — HTML generation DSL
humanize       — human-readable numbers
pytz           — timezone handling
requests       — HTTP client

Development (requirements.dev.txt)

# Infrastructure
aws-cdk-lib, aws_cdk.aws_lambda_python_alpha, constructs

# AWS
aws_lambda_powertools[tracer], boto3-stubs[*]

# Testing
pytest, pytest-coverage, pytest-watch, pytest-freezegun, moto

# Code quality
ruff, mypy, mypy-extensions

# Dev server
flask, livereload, python-dotenv, invoke

# Utilities
coverage, freezegun, ujson, setuptools