bcr_postsubmit.py is a script used for Bazel Central Registry (BCR) postsubmit operations. It synchronizes the bazel_registry.json and the modules/ directory from the main branch of the Bazel Central Registry to the BCR's public cloud storage bucket.
bcr_presubmit.py is a script used for Bazel Central Registry (BCR) presubmit operations. This script primarily handles the preparation and execution of tests for new modules or updated versions of modules being added to the Bazel Central Registry.
This script powers the BCR Presubmit pipeline, which respects:
CI_RESOURCE_PERCENTAGE: (Optional) Specifies the percentage of CI machine resources to use for running tests. Default is 30%. ATTENTION: please do NOT overwhelm CI during busy hours.bcr_compatibility.py is a script used for testing compatibility between any versions of Bazel and BCR modules, and optionally with given incompatible flags.
A new build can be triggered via the BCR Bazel Compatibility Test pipeline with the following environment variables:
MODULE_SELECTIONS: (Mandatory) A comma-separated list of module patterns to be tested in the format <module_pattern>@<version_pattern>. A module is selected if it matches any of the given patterns.
The <module_pattern> can include wildcards (*) to match multiple modules (e.g. rules_*).
The <version_pattern> can be:
1.2.3)latest to select the latest version>=1.0.0, <2.0.0)Examples: rules_cc@0.0.13,rules_java@latest, rules_*@latest, protobuf@<29.0-rc1
SELECT_TOP_BCR_MODULES: (Optional) Set this env var to select the top N most important modules from the BCR for testing (based on their PageRank values). This will override the MODULE_SELECTIONS env var.
SMOKE_TEST_PERCENTAGE: (Optional) Specifies a percentage of selected modules to be randomly sampled for smoke testing.
For example, if MODULE_SELECTIONS=rules_*@latest and SMOKE_TEST_PERCENTAGE=10, then 10% of modules with name starting with rules_ will be randomly selected.
USE_BAZEL_VERSION: (Optional) Specifies the Bazel version to be used. The script will override Bazel version for all task configs.
USE_BAZELISK_MIGRATE: (Optional) Set this env var to 1 to enable testing incompatible flags with Bazelisk's --migrate feature. A report will be generated for the pipeline if this feature is enabled.
INCOMPATIBLE_FLAGS: (Optional) Specifies the list of incompatible flags to be tested with Bazelisk. By default incompatible flags are fetched by parsing titles of open Bazel Github issues with incompatible-change and migration-ready labels. Make sure the Bazel version you select support those flags.
CI_RESOURCE_PERCENTAGE: (Optional) Specifies the percentage of CI machine resources to use for running tests. Default is 30%. ATTENTION: please do NOT overwhelm CI during busy hours.
bcr_downstream.py is a script used for testing whether a new or updated BCR module version breaks downstream modules that directly depend on it. It vendors the target module via bazel vendor, overrides it in each direct downstream module's workspace via --override_module, and selects the top direct dependents ranked by BCR PageRank.
Downstream tasks are skipped if their Bazel major version is not among the major versions tested in the target module‘s presubmit.yml (e.g. a target tested with 8.x and 9.* skips downstream 6.x and 7.* tasks). If the target module is also tested with a symbolic version tracking the newest Bazel (e.g. rolling), major versions newer than its highest pinned one are kept as well. No filtering is applied if the target module doesn’t pin any Bazel version, and downstream tasks using symbolic versions (e.g. latest, rolling) are always kept. If a Bazel version is set explicitly (USE_BAZEL_VERSION or use_bazel_version, see below), all downstream tasks run with that version and none of them are skipped. The target module is vendored with the same Bazel version as each downstream task (or 7.x for tasks using Bazel 6, which doesn't support bazel vendor).
A build can be triggered on a BCR PR by attaching the run-downstream-test label, or manually via the BCR Downstream Test pipeline with the following environment variables:
TARGET_MODULE: (Optional) The target module in <module_pattern>@<version_pattern> format (e.g. rules_cc@0.1.1, protobuf@latest), which must match a single module version. If omitted, the target module is auto-detected from git diff main...HEAD. A build can only test one module version, so set this to choose one if a PR changes several module versions.SELECT_TOP_BCR_MODULES: (Optional) Maximum number of direct downstream modules to select based on descending global BCR PageRank score (via //tools:module_analyzer). Default is 50.MODULE_SELECTIONS: (Optional) A comma-separated list of downstream module patterns to test explicitly (e.g. grpc@latest,rules_go@latest). Overrides SELECT_TOP_BCR_MODULES when set.SMOKE_TEST_PERCENTAGE: (Optional) Percentage of selected downstream modules to randomly sample for smoke testing.EXCLUDE_DEV_DEPS: (Optional) Set to 1 or true to exclude dev_dependency = True dependencies when discovering direct downstream modules and computing PageRank. Default is false.USE_BAZEL_VERSION: (Optional) Specifies the Bazel version to be used. If set, the script overrides the Bazel version for all downstream task configs; otherwise, the Bazel versions specified in each downstream module's presubmit.yml are respected.CI_RESOURCE_PERCENTAGE: (Optional) Percentage of CI machine resources per queue allocated to the bcr-downstream-test-queue-* concurrency group. Default is 10 (10%).A target module can also configure SELECT_TOP_BCR_MODULES, MODULE_SELECTIONS, SMOKE_TEST_PERCENTAGE, EXCLUDE_DEV_DEPS and USE_BAZEL_VERSION in its presubmit.yml file under the top-level bcr_downstream_test field, using the lowercase option names. The environment variables take precedence when set. For example:
bcr_downstream_test: # Test the top 20 direct dependents, ignoring dev dependencies. select_top_bcr_modules: 20 exclude_dev_deps: true # Or test the given downstream modules instead. # module_selections: ["grpc@latest", "rules_go@latest"] use_bazel_version: 8.x