BazelCon 2024

We have been running RE for several years. In this talk, we present what we have learned - the hard way - during this time, with the hope that this will help others who are building or operating a remote execution service prevent similar issues. We will cover these themes: cloud infrastructure limits, memory management pitfalls, software architecture oh-nos, and monitoring mistakes.

Complete dependency graphs are at the heart of what gives Bazel its power and sandboxing plays a key role in keeping these graphs correct. However: Bazel's approach to sandboxing makes some concessions. With cooperation from tools this works well, but — what happens when your tools aren't well-behaved? In this talk, we detail how we — in service of migrating a 20 year old codebase to Bazel — extended Bazel and its sandbox to encode and enforce all host filesystem dependencies in Bazel's dependency graph. We'll cover the changes we had to make to use existing rulesets, how this compares with alternative solutions to this problem, lessons we learned along the way, and some takeaways for the broader ecosystem.

Bazel is well-known for its commitment to deliver both fast and correct builds at scale. However, ensuring trustworthy development and deployments to production goes beyond just accurate execution tracking. It encompasses the entire pipeline, including the integrity of the host environment, the security of third-party dependencies, and the reliability of remote caching and execution systems. In this talk, we will explore the advanced features Bazel offers for creating correct and secure builds. Additionally, we will address existing challenges in generating Software Bill of Materials (SBOMs) and maintaining reliable audit trails, so your process can achieve the highest Supply Chain Levels for Software Artifacts (SLSA) compliance.

Since last BazelCon we came up with several very exciting ideas, how to reduce memory consumption. In this talk I will present several of them: skyfocus, skeletal analysis and how to further reduce peek heap consumption. Additional saving may come from laziness: lazy macros and lazy loading.

The `glob` function is seemingly simple from a user-land perspective, but entails a lot of complexity in Bazel's implementation. This talk motivates the difficulty, discusses the history of implementing `glob` in Bazel, goes over the current approach, and mentions possible future improvements.

Birds of a Feather session for Android app developers using Bazel to discuss the Bazel Android Rules, including Starlarkification of the native rules, migration, open sourcing.

We want to demonstrate how to use Bazel to compile C++ source code across various operating systems (e.g. Linux, Windows, and macOS) and processor architectures (e.g. AMD and ARM). We will show how to - Create a Bazel C++ toolchain, that serves different host and target operating systems and architectures - Make Bazel automatically pick the right toolchain configuration based on host and target system - Compile natively as well as cross platform - Create “universal binaries” by running several toolchains in the same build, creating a single artifact, that can run on multiple architectures - Use the platform information to name packages, switch dependencies, skip targets, … We will show how to achieve all of this by using native Bazel features like multi platform builds, toolchains, transitions, and sufficiently hermetic toolchains.