bazel-paq

Bazel rule for hashing targets.

Easily track and deploy build deltas.

An optimization for monorepo releases.

Purpose

Reduce bazel build deployments to unreleased targets.

Requires cache of build target hashes.

Usage

Module

Not supported in this release.

Workspace

Add http_archive to WORKSPACE file in respective project repository.

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "bazel_paq",
    sha256 = "369d2fb4b3d8375e4ec93cfcd86fab11885ba552fc533b1e40802f873a385f55",
    strip_prefix = "bazel-paq-1.0.1",
    url = "https://github.com/gregl83/bazel-paq/archive/refs/tags/v1.0.1.tar.gz",
)

load("@bazel_paq//:deps.bzl", "bazel_paq_dependencies")

bazel_paq_dependencies()

Invoke paq rule in BUILD file for each repository target as needed.

load("@bazel_paq//:defs.bzl", "paq")

# Produces file named `hash.paq` in bazel-bin target directory.
paq(
    name = "hash",
    source = ":<file-or-dir-build-target>",
)

Rule Output

Invoking the paq bazel rule outputs a file named using the rule name argument value and the .paq filename extension.

Output paq files are valid JSON and contain a single blake3 hash in double quotes for a supplied bazel target.

Hashing Algorithm

A rust powered executable named paq uses blake3 to hash either a single file or directory.

Output hashes can be validated by installing paq and using it to hash build targets in bazel's bazel-bin directory.

For more information see the paq project repository.

Examples

See examples directory for bazel build targets using bazel-paq.

Using Bazel Paq in Releases

1. Read target hash from .paq file.

2. Read target release hash stored in cache.

3. Compare target and target release hashes.

   a. Equal - Skip already released target.

   b. Unequal - Release new target.

4. Store target release hash in cache using target hash value.

License

MIT