BazelCon 2024: A celebration of community and the launch of Bazel 8

The Bazel community celebrated a landmark year at BazelCon 2024. With a record-breaking 330+ attendees, 125+ talk proposal submissions, and a renewed focus on community-driven development, BazelCon marked a significant step forward for the build system and its users.

BazelCon 2024: Key highlights

The 8th annual build conference was held at the Computer History Museum in Mountain View, CA, on October 14 - 15, 2024. This was the first BazelCon not solely organized by Google; instead, it was organized by The Linux Foundation together with sponsors Google, BuildBuddy, EngFlow, NativeLink, AspectBuild, Gradle, Modus Create, and VirtusLab. The conference welcomed build enthusiasts from around the world to explore the latest advancements in build technologies, share learnings, and connect with each other.

The conference kicked off with an opening keynote delivered by Mícheál Ó Foghlú and Tobias Werth (Google), Alex Eagle (Aspect Build Systems), Helen Altshuler (EngFlow), and Chuck Grindel (Reveal Technology). The keynote highlighted the vital role of community contributions and charted a course for a future where Bazel thrives through shared stewardship.

Following the keynote, John Field and Tobias Werth (Engineering Managers at Google) delivered a state-of-the-union address, celebrating the year's top contributors and highlighting key achievements within the Bazel ecosystem.

Over the course of the conference, members of the Bazel community showcased their expertise and shared key insights through a series of live presentations. Some highlights include:

• Spotify's compelling Bazel adoption journey
• EngFlow's insightful post-mortems on remote execution
• Explorations of cutting-edge features like BuildBuddy's "Remote Bazel”

Take a look at our playlist of BazelCon 2024 Talks at your convenience.

In addition to main stage talks, BazelCon provided ample opportunities for attendees to connect and collaborate. Birds of a Feather sessions fostered lively discussions on topics ranging from generating SBOM using Bazel, to IDE integrations, to external dependency management, allowing community members to provide direct feedback and shape the future of Bazel. Make sure to check out raw BazelCon '24 Birds of a Feather notes from these sessions.

BazelCon 2024 also served as the launchpad for Bazel 8, a long-term support (LTS) release that brings significant enhancements to modularity, performance, and dependency management.

What’s new in Bazel 8?

• Starlark-powered modularity: Many core language rules traditionally shipped with Bazel are now Starlarkified and split into their own modules, including all Android, Java, Protocol Buffers, Python, and shell rules.
• WORKSPACE deprecation: The legacy WORKSPACE mechanism for external dependency management is disabled by default in Bazel 8, and is slated for removal in Bazel 9. Bzlmod, the default since Bazel 7, is the recommended solution going forward.
• Symbolic macros: Bazel 8 introduces a new way to write macros for build files, addressing many pitfalls and footguns of legacy macros. Symbolic macros offer better visibility encapsulation, type safety, and are amenable to lazy evaluation, coming in a future Bazel release.

Read the full release notes for Bazel 8.

Stay connected with the Bazel community

We extend our gratitude to everyone that contributed to the success of BazelCon 2024! We look forward to seeing you again next year.

To stay informed about the latest developments in the Bazel world, connect with us through the following channels:

• Bazel blog
• GitHub
• Slack
• Mailing list
• X (Twitter)

We encourage you to share your Bazel projects and experiences with us at product@bazel.build. We're always excited to hear from you!

By Keerthana Kumar and Xudong Yang, on behalf of the Google Bazel Team

A look back at BazelCon '23 and the launch of Bazel 7

In October ‘23, the Google Bazel team hosted the 7th annual BazelCon, a gathering for the Bazel community and broader Build ecosystem. We welcomed enterprise users and program partners, companies building businesses on top of Bazel, as well as enthusiasts curious to learn more about this space. This year, BazelCon made its debut outside North America and was hosted in the Google Munich office.

BazelCon recap

The Bazel ecosystem is growing. This year, we had over 200 in-person external attendees, over 3K livestream views, and a record number of 120 proposals submitted by the community.

We started the conference with a keynote address by Mícheál Ó Foghlú (Engineering Director at Google), followed by a state-of-the-union address by John Field and Tobias Werth (Engineering Managers at Google).

The Bazel community showcased a series of technical and lightning main-stage talks. To highlight a few:

• BMW shared insights into how they released several “Bazel cars”

• JetBrains^* announced the preview release of their new Bazel plugin for their IDEs

• Booking.com walked through their journey of adopting Bazel, thereby reducing CI time from 22 minutes to under 2 minutes and container image size by 80%

Take a look at published recordings of all of these talks at your own leisure.

In addition to hearing from presenters, conference attendees also had the opportunity to engage with each other in smaller, more interactive forums. Through live Q&A with the Bazel team and several Birds of a Feather sessions on topics ranging from authoring rulesets, to collecting usage data responsibly, to IDE integrations, the Bazel community was able to provide direct feedback to the team and spark productive discussions. Make sure to check out published notes from these sessions.

At BazelCon, we also proudly announced the initial release candidate for Bazel 7, which has since launched.

What’s new in Bazel 7?

Bazel 7 is the latest major release on the long-term support (LTS) track. Many multi-year efforts have landed in this release. For example:

Bzlmod: Bzlmod, Bazel's new modular external dependency management system, is now enabled by default (i.e. --enable_bzlmod defaults to true). If your project doesn't have a MODULE.bazel file, Bazel will create an empty one for you. The old WORKSPACE mechanism will continue to work alongside the new Bzlmod-managed system. Learn more about what’s changed since Bazel 6 and what’s coming up in Bazel 8 and 9.

Build without the Bytes (BwoB): Build without the Bytes for builds using remote execution is now enabled by default (i.e. --remote_download_outputs defaults to toplevel). Bazel will no longer try to download any intermediate outputs from the remote server, but only the outputs of requested top-level targets instead. This significantly improves remote build performance. Learn more about BwoB.

Merged analysis and execution (Skymeld): Project Skymeld aims to improve multi-target build performance by removing the boundary between the analysis and execution phases and allowing targets to be independently executed as soon as their analysis finishes.

Platform-based toolchain resolution for Android and C++: This change helps streamline the toolchain resolution API across all rulesets, obviating the need for language-specific flags. It also removes technical debt by having Android and C++ rules use the same toolchain resolution logic as other rulesets. Full details for Android developers are available in the Android Platforms announcement.

Read the full release notes for Bazel 7.

 

Stay up-to-date with Bazel

We are thankful to everyone who played a role in making BazelCon ‘23 a big success - speakers, contributors, attendees, the planning committee, and more. We look forward to seeing you again next year!

In the meantime, follow along as we work together towards Bazel 8:

• Bazel blog
• GitHub
• Mailing list
• Slack
• X (formerly known as Twitter)

If you have any questions or feedback, or would like to share something you’ve built, reach out to product@bazel.build. We would love to hear from you!

By the Google Bazel team

^*Copyright © 2023 JetBrains s.r.o. JetBrains and IntelliJ are registered trademarks of JetBrains s.r.o

Get ready for BazelCon 2020

With only 24 hours to go, BazelCon 2020 is shaping up to be a much anticipated gathering for the Bazel community and broader Build ecosystem. With over 1000 attendees, presentations by Googlers, as well as talks from industry Build leaders from Twitter, Dropbox, Uber, Pinterest, GrabTaxi, and more, we hope BazelCon 2020 will provide an opportunity for knowledge sharing, networking, and community building.

I am very excited by the keynote announcements, the migration stories at Twitter, Pinterest, and CarGurus, as well as technical deep dives on Bazel persistent workers, incompatible target skipping, migrating from Gradle to Bazel, and more. The “sold out” Birds of a Feather sessions and the Live Q&A with the Bazel team will bring the community together to discuss design docs, look at landings, and provide feedback on the direction of Bazel and the entire ecosystem.

We are also pleased to announce that, starting with the next major release (4.0), Bazel will support Long Term Support (LTS) releases as well as regular Rolling releases.

Some benefits of this new release cadence are:

• Bazel will release stable, supported LTS releases on a predictable schedule with a long window without breaking changes
• Bazel contributors / rules owners can prepare to support future LTS releases via rolling releases.
• Bazel users can choose the release cadence that works best for them, since we will offer both LTS releases and rolling releases.

Long Term Support (LTS) releases:

• We will create an LTS release every ~9 months => new LTS release branch, increment major version number.
• Each LTS release will include all new features, bug fixes and (breaking) changes since the last major version.
• Bazel will actively support each LTS branch for 9 months with critical bug fixes, but no new features.
• Thereafter, Bazel will provide maintenance for two additional years with only security and OS compatibility fixes.
• Bazel Federation reboot: Bazel will provide strong guidance about the ruleset versions that should be used with each Bazel release so that each user will not have to manage interoperability themselves.

Make sure that you register at http://goo.gle/bazelcon to be a part of the excitement of the premier build conference!

See you all at BazelCon 2020!

By Joe Hicks and the entire Bazel Team at Google