Merge pull request #58 from weaveworks/docs-for-cluster-generator

Documentation and fixes.

Author: bigkevmcd

controllers/gitopsset_controller.go

@@ -80,7 +80,7 @@ func (r *GitOpsSetReconciler) event(obj *templatesv1.GitOpsSet, severity, msg st
 	r.EventRecorder.Event(obj, eventtype, reason, msg)
 }
 
-//+kubebuilder:rbac:groups=templa3tes.weave.works,resources=gitopssets,verbs=get;list;watch;create;update;patch;delete
+//+kubebuilder:rbac:groups=templates.weave.works,resources=gitopssets,verbs=get;list;watch;create;update;patch;delete
 //+kubebuilder:rbac:groups=templates.weave.works,resources=gitopssets/status,verbs=get;update;patch
 //+kubebuilder:rbac:groups=templates.weave.works,resources=gitopssets/finalizers,verbs=update
 //+kubebuilder:rbac:groups=source.toolkit.fluxcd.io,resources=gitrepositories,verbs=get;list;watch

controllers/templates/generators/cluster/cluster.go

@@ -42,39 +42,41 @@ func (g *ClusterGenerator) Generate(ctx context.Context, sg *templatesv1.GitOpsS
 	}
 	g.Logger.Info("generating params from Cluster generator")
 
-	var paramsList []map[string]any
-
 	selector, err := metav1.LabelSelectorAsSelector(&sg.Cluster.Selector)
 	if err != nil {
 		return nil, fmt.Errorf("unable to convert selector: %w", err)
 	}
 
-	if selector.Empty() {
-		g.Logger.Info("empty GitOpsSetGenerator cluster selector: no clusters are selected")
-		return nil, nil
-	}
-
-	clusterList := clustersv1.GitopsClusterList{}
 	listOptions := client.ListOptions{LabelSelector: selector}
 
+	clusterList := clustersv1.GitopsClusterList{}
 	err = g.Client.List(ctx, &clusterList, &listOptions)
 	if err != nil {
 		return nil, err
 	}
 
+	var paramsList []map[string]any
 	for _, cluster := range clusterList.Items {
 		params := map[string]any{
 			"ClusterName":        cluster.Name,
 			"ClusterNamespace":   cluster.Namespace,
-			"ClusterLabels":      cluster.Labels,
-			"ClusterAnnotations": cluster.Annotations,
+			"ClusterLabels":      mapOrEmptyMap(cluster.Labels),
+			"ClusterAnnotations": mapOrEmptyMap(cluster.Annotations),
 		}
 		paramsList = append(paramsList, params)
 	}
 
 	return paramsList, nil
 }
 
+func mapOrEmptyMap(src map[string]string) map[string]string {
+	if src == nil {
+		return map[string]string{}
+	}
+
+	return src
+}
+
 // Interval is an implementation of the Generator interface.
 func (g *ClusterGenerator) Interval(sg *templatesv1.GitOpsSetGenerator) time.Duration {
 	return generators.NoRequeueInterval

controllers/templates/generators/cluster/cluster_test.go

@@ -3,7 +3,6 @@ package cluster
 import (
 	"context"
 	"testing"
-	"time"
 
 	"github.com/go-logr/logr"
 	"github.com/stretchr/testify/assert"
@@ -23,13 +22,11 @@ func TestClusterGenerator_Generate(t *testing.T) {
 		sg          *templatesv1.GitOpsSetGenerator
 		clusters    []runtime.Object
 		wantParams  []map[string]any
-		wantErr     bool
 		errContains string
 	}{
 		{
 			name:        "return error if sg is nil",
 			sg:          nil,
-			wantErr:     true,
 			errContains: generators.ErrEmptyGitOpsSet.Error(),
 		},
 		{
@@ -38,10 +35,58 @@ func TestClusterGenerator_Generate(t *testing.T) {
 			wantParams: nil,
 		},
 		{
-			name: "successful clusters listing",
+			name: "generator with no label selector returns all clusters",
+			sg: &templatesv1.GitOpsSetGenerator{
+				Cluster: &templatesv1.ClusterGenerator{},
+			},
+			clusters: []runtime.Object{
+				&clustersv1.GitopsCluster{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:        "cluster1",
+						Namespace:   "ns1",
+						Annotations: map[string]string{},
+						Labels:      map[string]string{"test1": "value"},
+					},
+					Spec: clustersv1.GitopsClusterSpec{},
+				},
+				&clustersv1.GitopsCluster{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:        "cluster2",
+						Namespace:   "ns2",
+						Annotations: map[string]string{},
+						Labels:      map[string]string{"test2": "value"},
+					},
+					Spec: clustersv1.GitopsClusterSpec{},
+				},
+			},
+			wantParams: []map[string]any{
+				{
+					"ClusterAnnotations": map[string]string{},
+					"ClusterLabels": map[string]string{
+						"test1": "value",
+					},
+					"ClusterName":      "cluster1",
+					"ClusterNamespace": "ns1",
+				},
+				{
+					"ClusterAnnotations": map[string]string{},
+					"ClusterLabels": map[string]string{
+						"test2": "value",
+					},
+					"ClusterName":      "cluster2",
+					"ClusterNamespace": "ns2",
+				},
+			},
+		},
+		{
+			name: "label selector filtering",
 			sg: &templatesv1.GitOpsSetGenerator{
 				Cluster: &templatesv1.ClusterGenerator{
-					Selector: *metav1.AddLabelToSelector(&metav1.LabelSelector{}, "foo", "bar"),
+					Selector: metav1.LabelSelector{
+						MatchLabels: map[string]string{
+							"foo": "bar",
+						},
+					},
 				},
 			},
 			clusters: []runtime.Object{
@@ -76,15 +121,15 @@ func TestClusterGenerator_Generate(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			c := newFakeClient(t, tt.clusters...)
 			g := NewGenerator(logr.Discard(), c)
-			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-			defer cancel()
-			gotParams, err := g.Generate(ctx, tt.sg, nil)
-			if tt.wantErr {
-				assert.Error(t, err)
+
+			gotParams, err := g.Generate(context.TODO(), tt.sg, nil)
+
+			if tt.errContains != "" {
 				assert.Contains(t, err.Error(), tt.errContains)
-			} else {
-				assert.NoError(t, err)
+				return
 			}
+
+			assert.NoError(t, err)
 			assert.Equal(t, tt.wantParams, gotParams)
 		})
 	}
@@ -93,12 +138,8 @@ func TestClusterGenerator_Generate(t *testing.T) {
 func newFakeClient(t *testing.T, objs ...runtime.Object) client.WithWatch {
 	t.Helper()
 	scheme := runtime.NewScheme()
-	if err := clustersv1.AddToScheme(scheme); err != nil {
-		t.Fatal(err)
-	}
-	if err := templatesv1.AddToScheme(scheme); err != nil {
-		t.Fatal(err)
-	}
+	assert.NoError(t, clustersv1.AddToScheme(scheme))
+	assert.NoError(t, templatesv1.AddToScheme(scheme))
 
 	return fake.NewClientBuilder().WithScheme(scheme).WithRuntimeObjects(objs...).Build()
 }

docs/README.md

@@ -136,6 +136,7 @@ We currently provide these generators:
  - [gitRepository](#gitrepository-generator)
  - [matrix](#matrix-generator)
  - [apiClient](#apiclient-generator)
+ - [cluster](#cluster-generator)
 
 ### List generator
 
@@ -627,6 +628,75 @@ Whatever result is parsed from the API endpoint will be returned as a map in a s
 
 For generation, you might need to use the `repeat` mechanism to generate repeating results.
 
+### Cluster generator
+
+The cluster generator generates from in-cluster GitOpsCluster resources.
+
+For example, this `GitOpsSet` will generate a `Kustomization` resource for each cluster matching the [Label selector](https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/).
+
+```yaml
+apiVersion: templates.weave.works/v1alpha1
+kind: GitOpsSet
+metadata:
+  name: cluster-sample
+spec:
+  generators:
+    - cluster:
+        selector:
+          matchLabels:
+            env: dev
+            team: dev-team
+  templates:
+    - content:
+        kind: Kustomization
+        apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+        metadata:
+          name: "{{ .Element.ClusterName }}-demo"
+          labels:
+            app.kubernetes.io/name: go-demo
+            app.kubernetes.io/instance: "{{ .Element.ClusterName }}"
+            com.example/team: "{{ .Element.ClusterLabels.team }}"
+        spec:
+          interval: 5m
+          path: "./examples/kustomize/environments/{{ .Element.ClusterLabels.env }}"
+          prune: true
+          sourceRef:
+            kind: GitRepository
+            name: go-demo-repo
+```
+
+The following fields are generated for each GitOpsCluster.
+
+ - `ClusterName` the name of the cluster
+ - `ClusterNamespace` the namespace that this cluster is from
+ - `ClusterLabels` the labels from the metadata field on the GitOpsCluster
+ - `ClusterAnnotations` the annotations from the metadata field on the GitOpsCluster
+
+If the selector is not provided, all clusters from all namespaces will be returned:
+
+```yaml
+apiVersion: templates.weave.works/v1alpha1
+kind: GitOpsSet
+metadata:
+  name: cluster-sample
+spec:
+  generators:
+    - cluster: {}
+```
+
+Otherwise if the selector is empty, no clusters will be generated:
+
+```yaml
+apiVersion: templates.weave.works/v1alpha1
+kind: GitOpsSet
+metadata:
+  name: cluster-sample
+spec:
+  generators:
+    - cluster:
+        selector: {}
+```
+
 ## Templating functions
 
 Currently, the [Sprig](http://masterminds.github.io/sprig/) functions are available in the templating, with some functions removed[^sprig] for security reasons.