# Explanation Launchpad is a large platform built over many years. These pages explain the ideas behind the project, its components, and the best practices its developers follow. ## The ideas behind Launchpad Launchpad connects the people who make software with users and other developers, and offers the resources they need to make their software available. Understanding why Launchpad exists, whom it serves, and the values that guide it provides the context for everything else. - [What is Launchpad?](https://ubuntu.com/docs/launchpad/developer/explanation/ideas-behind-launchpad/scope/index.html.md#what-is-launchpad) - [About Launchpad security](https://ubuntu.com/docs/launchpad/developer/explanation/ideas-behind-launchpad/security/index.html.md#about-launchpad-security) - [Launchpad strategy](https://ubuntu.com/docs/launchpad/developer/explanation/ideas-behind-launchpad/strategy/index.html.md#launchpad-strategy) - [Launchpad values](https://ubuntu.com/docs/launchpad/developer/explanation/ideas-behind-launchpad/values/index.html.md#launchpad-values) ## Core components and setup Launchpad is made up of many components. Knowing how these pieces fit together helps you navigate the codebase, and design and test your changes. - [Parts of Launchpad](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/parts-of-launchpad/index.html.md#parts-of-launchpad) - [Publisher](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/publisher/index.html.md#explanation-publisher) - [Application framework](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/framework/index.html.md#application-framework) - [Code concepts](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/concepts/index.html.md#code-concepts) - [The Launchpad PPA](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/launchpad-ppa/index.html.md#the-launchpad-ppa) - [Navigating the tree](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/navigating/index.html.md#navigating-the-tree) - [Launchpad pip integration](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/pip/index.html.md#launchpad-pip-integration) - [Launchpad installation details](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/running-details/index.html.md#launchpad-installation-details) - [Testing](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/testing/index.html.md#testing-launchpad-changes) - [Building live filesystems](https://ubuntu.com/docs/launchpad/developer/explanation/core-components-and-set-up/building-live-filesystems/index.html.md#building-live-filesystems) ## Database Launchpad uses PostgreSQL and depends on PostgreSQL-specific features. Its schema is patched on a live system and managed by Storm, the ORM Launchpad uses. - [Database performance](https://ubuntu.com/docs/launchpad/developer/explanation/database/database-performance/index.html.md#database-performance) - [Database patching](https://ubuntu.com/docs/launchpad/developer/explanation/database/database-patching/index.html.md#database-patching) - [PostgreSQL and Launchpad](https://ubuntu.com/docs/launchpad/developer/explanation/database/postgresql/index.html.md#postgresql-and-launchpad) - [Storm migration guide](https://ubuntu.com/docs/launchpad/developer/explanation/database/storm-migration-guide/index.html.md#storm-migration-guide) - [Working with db-devel](https://ubuntu.com/docs/launchpad/developer/explanation/database/working-with-db-devel/index.html.md#working-with-db-devel) ## Developing for the Launchpad project Contributing to Launchpad means working across several branches, guarding new behaviour behind feature flags, and guiding each change through review and into production. This day-to-day development is expected to follow specific processes and conventions. - [About Launchpad branches](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/branches/index.html.md#about-launchpad-branches) - [Datetime usage guide](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/datetime-usage/index.html.md#datetime-usage-guide) - [Error explanations](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/error-explanations/index.html.md#error-explanations) - [Feature flags](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/feature-flags/index.html.md#feature-flags) - [Hacking](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/hacking/index.html.md#hacking-guide) - [Journey of a change to production](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/journey-of-a-change-to-production/index.html.md#journey-change-production) - [Pre merge reviews](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/pre-merge-reviews/index.html.md#pre-merge-reviews) - [XXX policy](https://ubuntu.com/docs/launchpad/developer/explanation/developing-for-launchpad/xxx-policy/index.html.md#xxx-policy) ## Best practices for development Launchpad aims to be fast and always available. It should also be safe to change parts of it with a low risk of breaking other parts of the system. These principles inform how its code is structured, how performance and permissions are handled, and how its templates and tests are written. - [Architectural guide](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/architecture/index.html.md#architectural-guide) - [Assertions in Launchpad](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/assertions-in-launchpad/index.html.md#assertions-in-launchpad) - [Bug triage process background](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/bug-triage-process-background/index.html.md#bug-triage-process-background) - [Charm development](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/charms/index.html.md#charm-development) - [Code import in depth](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/codeimport/index.html.md#code-import-in-depth) - [Page tests](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/page-tests/index.html.md#page-tests) - [About Launchpad performance](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/performance/index.html.md#about-launchpad-performance) - [Launchpad permissions](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/security-policy/index.html.md#launchpad-permissions) - [Template reuse](https://ubuntu.com/docs/launchpad/developer/explanation/development-best-practices/template-reuse/index.html.md#template-reuse) ## JavaScript Launchpad’s front end is written in JavaScript built on the YUI library, with its own build system and both unit and integration test frameworks. - [JavaScript build system](https://ubuntu.com/docs/launchpad/developer/explanation/javascript/javascript-buildsystem/index.html.md#javascript-build-system) - [Integration testing in JavaScript](https://ubuntu.com/docs/launchpad/developer/explanation/javascript/javascript-integration-testing/index.html.md#integration-testing-in-javascript) - [Developing with YUI Test](https://ubuntu.com/docs/launchpad/developer/explanation/javascript/javascript-unittesting/index.html.md#developing-with-yui-test) ## Static assets Launchpad’s visual style comes from CSS and images that are compiled and optimized as part of the build using CSS sprites. - [CSS](https://ubuntu.com/docs/launchpad/developer/explanation/static-assets/css/index.html.md#launchpad-css) - [CSS sprites](https://ubuntu.com/docs/launchpad/developer/explanation/static-assets/css-sprites/index.html.md#use-css-sprites) - [Favicons](https://ubuntu.com/docs/launchpad/developer/explanation/static-assets/favicon/index.html.md#launchpad-favicons) - [Images](https://ubuntu.com/docs/launchpad/developer/explanation/static-assets/images/index.html.md#launchpad-images)