Heroku Deployment

Relevant source files

The following files were used as context for generating this wiki page:

• README.md
• package.json
• config/database.yml
• config/environments/production.rb
• config/webpacker.yml
• babel.config.js

Heroku Deployment for the Actionmap application involves configuring a Ruby on Rails environment optimized for production hosting. The application serves as a platform for users to learn about representatives and local political events, utilizing a PostgreSQL backend and Webpacker for asset management.

The deployment infrastructure is designed to handle production-grade traffic by enforcing SSL, managing assets through precompilation, and utilizing environment variables for sensitive configuration like database credentials.

Sources: README.md:1-13, config/environments/production.rb:1-82

Production Environment Configuration

The production environment on Heroku is configured to maximize performance and security. Unlike development, code is not reloaded between requests, and classes are eager-loaded to allow threaded web servers to perform better.

Key Production Settings

Setting	Value	Description
cache_classes	true	Prevents reloading of code for every request.
eager_load	true	Loads the application into memory on boot.
consider_all_requests_local	false	Disables detailed error reports for end-users.
force_ssl	true	Redirects all HTTP traffic to HTTPS and uses secure cookies.
log_level	:debug	Sets the verbosity of system logs.

Sources: config/environments/production.rb:7-46

Log Management

In the Heroku environment, logs are typically routed to standard output (STDOUT). The application checks for the presence of the RAILS_LOG_TO_STDOUT environment variable to initialize the logger accordingly.

  if ENV['RAILS_LOG_TO_STDOUT'].present?
    logger = ActiveSupport::Logger.new($stdout)
    logger.formatter = config.log_formatter
    config.logger    = ActiveSupport::TaggedLogging.new(logger)
  end

Sources: config/environments/production.rb:73-77

Database Architecture

The application transitions from SQLite3 (used in development and testing) to PostgreSQL for production deployment on Heroku. The connection is managed via the DATABASE_URL environment variable or specific credential variables.

Database Connection Flow

This diagram illustrates how the application selects the database adapter based on the environment.

Configuration Parameters

The production database configuration uses the following parameters:

• Adapter: postgresql
• Encoding: unicode
• Pool Size: Determined by RAILS_MAX_THREADS (defaulting to 5).
• Password: Provided via ACTIONMAP_DATABASE_PASSWORD.

Sources: config/database.yml:19-75

Asset Pipeline and Javascript Compilation

Actionmap utilizes Webpacker to compile and serve JavaScript and specialized assets like Topojson files. In the production environment, the application relies on precompiled packs.

Webpacker Production Configuration

The production build is optimized for performance by disabling on-the-fly compilation and enabling manifest caching.

production:
    <<: *default
    compile: false
    extract_css: false
    cache_manifest: true

Sources: config/webpacker.yml:85-94

Build Environment Validation

The babel.config.js ensures that the build process is aware of the environment, throwing an error if the NODE_ENV is not set to one of the valid values: development, test, or production.

Sources: babel.config.js:1-17

Node and Yarn Engines

The application specifies version requirements for the runtime environment to ensure compatibility during the Heroku build process:

• Node: 12.x || 14.x
• Yarn: 1.22.x

Sources: package.json:7-10

External Dependencies and Integrations

The deployment depends on several frontend and mapping libraries that are bundled during the build phase.

Core Dependencies

Dependency	Purpose
d3 / topojson	Used for rendering interactive maps.
bootstrap	Provides the UI framework.
turbolinks	Optimizes page navigation.
jquery	Required for various UI interactions and plugins like select2.

Sources: package.json:12-28

Conclusion

Heroku deployment for Actionmap is centered around a standard Rails production stack. It prioritizes security through SSL enforcement and performance through PostgreSQL and precompiled Webpacker assets. Configuration is primarily driven by environment variables, ensuring that sensitive data is kept out of the source code while allowing for flexible deployment across different Heroku environments.