rules_helm

Chart-as-a-module: build, lint, and publish Helm charts in Bazel — the Helm analog of how this org already does container images (rules_oci) and protos.

Helm itself is fetched hermetically (a pinned per-platform binary from get.helm.sh), so bazel build-ing a chart needs nothing installed on the host.

Rules

Rule	Kind	What it does
helm_chart	build action	Packages a chart directory into <name>.tgz.
helm_lint	build action	helm lint (fails the build); cacheable marker output.
helm_push	bazel run	helm push <tgz> oci://<repository>.

Use

MODULE.bazel:

bazel_dep(name = "rules_helm", version = "0.1.0")

BUILD.bazel next to a chart:

load("@rules_helm//helm:defs.bzl", "helm_chart", "helm_lint", "helm_push")

_SRCS = ["values.yaml"] + glob(["templates/**", ".helmignore"])

helm_chart(
    name = "chart",
    chart_yaml = "Chart.yaml",
    srcs = _SRCS,
    version = "1.2.3",        # optional; defaults to Chart.yaml
    app_version = "1.2.3",    # optional; defaults to Chart.yaml
)

helm_lint(name = "lint", chart_yaml = "Chart.yaml", srcs = _SRCS)

helm_push(name = "push", chart = ":chart", repository = "ghcr.io/fastverk/charts")

bazel build //path/to:chart        # -> bazel-bin/path/to/chart.tgz
bazel build //path/to:lint         # fails if the chart doesn't lint
helm registry login ghcr.io ...    # auth once (CI uses GITHUB_TOKEN)
bazel run   //path/to:push         # publishes the .tgz

srcs must list every file helm should package — the action runs in a sandbox containing only the declared inputs. helm_chart is for leaf charts; a chart with subchart dependencies must have its charts/ vendored (helm dependency build) and the vendored archives passed in srcs.

Bumping helm

Two edits in helm/repositories.bzl: HELM_VERSION and the four HELM_SHA256 lines. Refresh a checksum with:

curl -fsSL https://get.helm.sh/helm-v<ver>-<platform>.tar.gz.sha256sum

This v0.1.0 downloads only the host platform's binary (chart packaging always runs host-native). A future revision can graduate this to a full multi-platform Bazel toolchain for exec-platform selection (RBE).

Publishing this module

Tag a release and run the registry tool (same flow as the other fastverk rules_* modules):

git tag v0.1.0 && git push origin v0.1.0
# in repos/bazel-registry:
bazel run //tools/rels -- release --repo fastverk/rules_helm --version 0.1.0