bviz

A graphical Bazel build visualization and inspection tool.

Seeing what a Bazel build actually did is hard. bviz reads the outputs Bazel generates, such as query results, the trace profile and the build event log, and lets you explore them visually.

bviz is early in development. Expect rough edges, and expect the interface and command line to change.

Features

bviz reads these Bazel outputs, alone or together:

• query, cquery and aquery results: one merged target and action graph to explore, search and filter, with views of why one target depends on another and what each dependency brings in.
• Trace profile: a timeline of the build, flame graphs and statistics of where the time went, and its critical path.
• Build event log: the build's console output and the outcome of each target.
• Execution log: where the time of each spawn went.

Install

Download bviz for arm64 or x86_64 Linux or macOS from the latest release, or the latest build of main from the nightly release.

	Linux	macOS
Architecture	arm64, x86_64	arm64, x86_64
Operating system	glibc 2.28 or newer	macOS 14 or newer
Display	a Wayland session
Graphics	a Vulkan driver	Metal

On an X11 session, run bviz inside a nested Wayland compositor such as cage: cage -- bviz --profile build.profile.gz.

The arm64 Linux and the macOS binaries are cross-compiled on x86_64 Linux and are not tested in CI. The macOS binaries are not signed, and macOS blocks an unsigned download until you clear its quarantine flag: xattr -d com.apple.quarantine bviz.

bviz reads the outputs of Bazel 8.0 or newer.

To build from source, see CONTRIBUTING.md.

Quick start

In a Bazel workspace, profile a build and open the profile:

bazel build --profile=/tmp/build.profile.gz //...
bviz --profile /tmp/build.profile.gz

Usage

bviz bazelrc generates a Bazel config with every flag bviz needs. From the workspace root:

mkdir -p .bviz && bviz bazelrc > .bviz/bazelrc
echo 'try-import %workspace%/.bviz/bazelrc' >> .bazelrc

Then follow the instructions at the top of .bviz/bazelrc.

Each input flag takes the file one Bazel invocation writes. The bazelrc adds further flags that give the views more to show.

bviz flag	Written by
--profile FILE	bazel build --profile=FILE
--bep FILE	bazel build --build_event_binary_file=FILE
--exec_log FILE	bazel build --execution_log_compact_file=FILE
--query FILE	bazel query --output=streamed_proto ... > FILE
--cquery FILE	bazel cquery --output=streamed_proto --transitions=lite ... > FILE
--aquery FILE	bazel aquery --output=streamed_proto ... > FILE

Getting help

Report bugs and ask questions in the issue tracker.

Contributing

See CONTRIBUTING.md.

Acknowledgements

bviz draws with gpui, the UI framework of the Zed editor, and lays out graphs with elk-rs, a Rust port of the Eclipse Layout Kernel.

License

bviz is licensed under the Apache License 2.0; see LICENSE. The third-party works it bundles or derives from, and their terms, are listed in NOTICE.

Bazel is a trademark of Google LLC. bviz is not affiliated with or endorsed by Google.