feat: add helm-util (#328)

Author: Duologic

helm-util/README.md

@@ -0,0 +1,44 @@
+# helm-util
+
+Provides utilities for using helm in jsonnet.
+
+## Helmraiser
+
+Helmraiser refers to a Go package that provides helmTemplate native function through Tanka for generating a Jsonnet
+library from any Helm chart. The goal of this function is to keep track of upstream changes in a Helm chart while
+retaining Jsonnet changes (read: mixins) on top of them.
+
+## Example usage
+
+```
+jb install github.com/grafana/jsonnet-libs/helm-util
+```
+
+```
+local helm = import 'github.com/grafana/jsonnet-libs/helm-util/helm.libsonnet';
+
+{
+  version:: 'v0.16.0',
+
+  values:: {
+    installCRDs: true,
+    global: {
+      podSecurityPolicy: {
+        enabled: true,
+        useAppArmor: false,
+      },
+    },
+  },
+
+  chart: helm.template(
+    name='cert-manager',
+    chart='jetstack/cert-manager',
+    conf={
+      values: $.values,
+      flags: [
+        '--version=%s % $.version',
+      ],
+    },
+  ),
+}
+```

helm-util/helm.libsonnet

@@ -0,0 +1,81 @@
+local d = import 'github.com/sh0rez/docsonnet/doc-util/main.libsonnet';
+{
+  local this = self,
+
+  '#':: d.pkg(
+    name='helm-util',
+    url='github.com/grafana/jsonnet-libs/helm-util/helm.libsonnet',
+    help='`helm-util` provides utilities for using helm in jsonnet',
+  ),
+
+  // This common label is usually set to 'Helm', this is not true anymore.
+  // You can override this with any value you choose.
+  // https://helm.sh/docs/chart_best_practices/labels/#standard-labels
+  defaultLabels:: { 'app.kubernetes.io/managed-by': 'Helmraiser' },
+
+  '#template':: d.fn(
+    |||
+      `template` expands the Helm Chart to it's underlying resources and returns them in an `Object`,
+      so they can be consumed and modified from within Jsonnet.
+
+      This functionality requires Helmraiser support in Jsonnet (e.g. using Grafana Tanka) and also
+      the `helm` binary installed on your `$PATH`.
+    |||,
+    [
+      d.arg('name', d.T.string),
+      d.arg('chart', d.T.string),
+      d.arg('conf', d.T.object),
+    ]
+  ),
+  template(name, chart, conf={})::
+    this.patchLabels(
+      std.native('helmTemplate')(name, chart, conf),
+      defaultLabels
+    ),
+
+  '#patchKubernetesObjects':: d.fn(
+    '`patchKubernetesObjects` finds all Kubernetes objects and patches them`',
+    [
+      d.arg('object', d.T.object),
+      d.arg('patch', d.T.object),
+    ]
+  ),
+  patchKubernetesObjects(object, patch)::
+    if std.isObject(object)
+    then
+      // a Kubernetes object is characterized by having an apiVersion and Kind
+      if std.objectHas(object, 'apiVersion') && std.objectHas(object, 'kind')
+      then object + patch
+      else
+        std.mapWithKey(
+          function(key, obj)
+            this.patchKubernetesObjects(obj, patch),
+          object
+        )
+    else if std.isArray(object)
+    then
+      std.map(
+        function(obj)
+          this.patchKubernetesObjects(obj, patch),
+        object
+      )
+    else object,
+
+  '#patchLabels':: d.fn(
+    '`patchLabels` finds all Kubernetes objects and adds labels',
+    [
+      d.arg('object', d.T.object),
+      d.arg('labels', d.T.object),
+    ]
+  ),
+  patchLabels(object, labels={})::
+    this.patchKubernetesObjects(
+      object,
+      {
+        metadata+: {
+          labels+: labels,
+        },
+      }
+    ),
+
+}