fix: use Pods CIDR from the Cluster spec

Author: dkoshkin

pkg/handlers/cni/calico/handler.go

@@ -283,13 +283,15 @@ func generateProviderCNICRS(
 		},
 	)
 
-	podSubnet, podSubnetSpecified := cluster.GetAnnotations()[cni.PodSubnetAnnotationKey]
+	podSubnet, err := cni.PodCIDR(cluster)
+	if err != nil {
+		return nil, err
+	}
 
 	var b bytes.Buffer
 
 	for _, o := range parsed {
-		if podSubnetSpecified &&
-			podSubnet != "" &&
+		if podSubnet != "" &&
 			o.GetObjectKind().GroupVersionKind().GroupKind() == calicoInstallationGK {
 			obj := o.(*unstructured.Unstructured).Object
 

pkg/handlers/cni/cluster.go

@@ -0,0 +1,31 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package cni
+
+import (
+	"errors"
+
+	capiv1 "sigs.k8s.io/cluster-api/api/v1beta1"
+)
+
+var ErrMultiplePodsCIDRBlocks = errors.New("cluster has more than 1 Pods network CIDR blocks")
+
+// PodCIDR will return the Pods network CIDR.
+// If not set returns an empty string.
+// If more than 1 CIDRBlocks is defined will return an error.
+func PodCIDR(cluster *capiv1.Cluster) (string, error) {
+	var subnets []string
+	if cluster.Spec.ClusterNetwork != nil &&
+		cluster.Spec.ClusterNetwork.Pods != nil {
+		subnets = cluster.Spec.ClusterNetwork.Pods.CIDRBlocks
+	}
+	switch {
+	case len(subnets) == 1:
+		return cluster.Spec.ClusterNetwork.Pods.CIDRBlocks[0], nil
+	case len(subnets) > 1:
+		return "", ErrMultiplePodsCIDRBlocks
+	default:
+		return "", nil
+	}
+}

pkg/handlers/cni/cluster_test.go

@@ -0,0 +1,76 @@
+// Copyright 2023 D2iQ, Inc. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package cni
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/cluster-api/api/v1beta1"
+)
+
+func Test_PodCIDR(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name     string
+		cluster  *v1beta1.Cluster
+		wantCIDR string
+		wantErr  error
+	}{
+		{
+			name: "no Pods CIDR set",
+			cluster: &v1beta1.Cluster{
+				Spec: v1beta1.ClusterSpec{},
+			},
+		},
+		{
+			name: "no Pods CIDR set, but Services CIDR is set",
+			cluster: &v1beta1.Cluster{
+				Spec: v1beta1.ClusterSpec{
+					ClusterNetwork: &v1beta1.ClusterNetwork{
+						Services: &v1beta1.NetworkRanges{
+							CIDRBlocks: []string{"192.168.0.1/16"},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "Pods CIDR set",
+			cluster: &v1beta1.Cluster{
+				Spec: v1beta1.ClusterSpec{
+					ClusterNetwork: &v1beta1.ClusterNetwork{
+						Pods: &v1beta1.NetworkRanges{
+							CIDRBlocks: []string{"192.168.0.1/16"},
+						},
+					},
+				},
+			},
+			wantCIDR: "192.168.0.1/16",
+		},
+		{
+			name: "error: multiple Pods CIDRs set",
+			cluster: &v1beta1.Cluster{
+				Spec: v1beta1.ClusterSpec{
+					ClusterNetwork: &v1beta1.ClusterNetwork{
+						Pods: &v1beta1.NetworkRanges{
+							CIDRBlocks: []string{"192.168.0.1/16", "10.0.0.1/16"},
+						},
+					},
+				},
+			},
+			wantErr: ErrMultiplePodsCIDRBlocks,
+		},
+	}
+	for idx := range tests {
+		tt := tests[idx]
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			cidr, err := PodCIDR(tt.cluster)
+			assert.ErrorIs(t, err, tt.wantErr)
+			assert.Equal(t, tt.wantCIDR, cidr)
+		})
+	}
+}

pkg/handlers/cni/constants.go

@@ -7,6 +7,4 @@ import "github.com/d2iq-labs/capi-runtime-extensions/pkg/handlers"
 
 const (
 	CNIProviderLabelKey = handlers.MetadataDomain + "/cni"
-
-	PodSubnetAnnotationKey = handlers.MetadataDomain + "/pod-subnet"
 )