Dependencies in Bazel
This guide explains how to manage dependencies in your Bazel projects effectively.
Understanding Dependencies
Dependencies in Bazel can be:
- Local (within your workspace)
- External (from remote repositories)
- System-level (tools and libraries)
Declaring Dependencies
In your BUILD files:
python
cc_library(
name = "my_lib",
deps = [
"//path/to/other:lib",
"@external_repo//some:lib",
],
)Managing External Dependencies
There are two main approaches to managing external dependencies in Bazel:
Using WORKSPACE (Traditional Approach)
python
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
http_archive(
name = "com_google_googletest",
urls = ["https://github.com/google/googletest/archive/release-1.11.0.zip"],
strip_prefix = "googletest-release-1.11.0",
sha256 = "...",
)Using Bzlmod (Modern Approach)
In your MODULE.bazel file:
python
module(
name = "my_project",
version = "1.0",
)
bazel_dep(name = "googletest", version = "1.11.0")Best Practices
- Use precise versions for external dependencies
- Always include SHA-256 hashes for http_archive rules
- Prefer Bzlmod over WORKSPACE for new projects (Bzlmod is the modern dependency management system)
- Keep dependencies close to where they're used
- Use recommended rules from well-maintained rule sets