TechPrufer
Get started
Spotify
Spotify logoSpotify · Feature trail

Build System Migration

6 posts · Sep 2019 – Sep 2023

What this trail covers

Spotify has successfully migrated its iOS application to the Bazel build system, replacing the legacy Xcode build system. This migration aimed to improve developer productivity by significantly reducing build and CI times, enhancing the feedback loop for engineers. The process involved a phased rollout, side-by-side operation of both systems, and the development of tooling to ensure parity and safety. The integration with Xcode was achieved through rules_xcodeproj, and the release process was adapted. This post details the initial success of integrating Rome, an open-source artifact caching tool, with Artifactory to cache Carthage dependencies, resulting in a 50% reduction in CI build times for the Spotify for Artists app. Future work includes extending this to more projects and addressing local debugging limitations with cached binaries.

All Spotify trails
  1. Switching Build Systems, SeamlesslyThis post details the technical challenges and solutions involved in migrating Spotify's iOS application from the Xcode build system to Bazel. It covers the motivation for adopting Bazel (faster builds, improved developer productivity), the strategy for a seamless migration (side-by-side operation, custom Ruby DSL for project declarations, automated BUILD.bazel file generation), the impact on build times (reduction from ~80 minutes to ~20 minutes for CI feedback loop), the cost of maintaining dual systems, the integration with Xcode via rules_xcodeproj for local development, and the rigorous process for releasing with Bazel, including side-by-side build comparisons and phased rollouts. It highlights the use of Bazel's remote cache and remote execution (RBE) and tools like BuildBuddy for insights and optimization.
  2. Strategies and Tools for Performing Migrations on PlatformThis post details the challenges and strategies involved in performing large-scale migrations within a growing mobile codebase. It outlines key challenges such as defining scope, scaling up adoption, managing competing priorities, and ensuring accountability. Specific advice is given on how to approach these challenges, including creating product briefs, focusing on stakeholder management, leveraging automation, and using metrics and dashboards to track progress. The post highlights the migration of Spotify's mobile codebase to Bazel as a significant example of such an effort.
  3. Introducing XCRemoteCache: The iOS Remote Caching Tool that Cut Our Clean Build Times by 70%This post introduces XCRemoteCache, an open-source remote caching tool for iOS projects that reduces clean build times by 70%. It details the problem of long local build times in the Spotify iOS application, explains the principles of remote caching, and describes the design and implementation of XCRemoteCache. Key technical aspects include identifying input files using Git history and compilation outputs, handling build artifact portability with path-agnostic fingerprints and debug symbol mapping, and integrating with existing Xcode projects via a CocoaPods plugin. The post also shares real-world results from its rollout to 50% of developers and provides instructions for integration and contribution.
  4. My beatThis post details Patrick Balestra's role as a Senior iOS Engineer on the Infrastructure team, focusing on improving the iOS developer experience through tools and libraries. He highlights his transition to a new monorepo and Bazel system project aimed at unifying tooling across different developer types. The post also mentions his open-source contribution to XCMetrics, a tool for tracking Xcode build metrics to improve developer experience and productivity.
  5. Introducing XCMetrics: Our All-in-One Tool for Tracking Xcode Build MetricsThis post introduces XCMetrics, an open-sourced, all-in-one tool for collecting, displaying, and tracking Xcode build metrics. It addresses the problem of obtaining good Xcode build data by parsing xcactivitylog files and building a more full-featured system than XCLogParser. XCMetrics consists of a Swift CLI tool, a backend service, and a PostgreSQL database. It has been used to collect over one million builds and billions of compilation steps, producing over 10TB of data, and has enabled data-driven decisions to improve developer experience and productivity. The tool is designed for scale and customization with a plugin system.
  7. When in Rome: How Spotify halved build times with just one scriptThis post details the integration of the Rome open-source artifact caching tool with Spotify's Artifactory for caching Carthage dependencies. A custom Bash script was developed to enable Rome to upload and download artifacts to/from Artifactory. This integration resulted in a 50% reduction in CI build times for the Spotify for Artists app, from approximately 20 minutes to under 10 minutes. The post also highlights a limitation where developers cannot debug locally with binaries downloaded from Artifactory due to absolute paths in symbols.