check for correct kustomization in multi-doc yaml

Signed-off-by: Somtochi Onyekwere <somtochionyekwere@gmail.com>

internal/build/build.go

@@ -23,6 +23,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"os"
 	"sync"
 	"time"
@@ -250,12 +251,19 @@ func (b *Builder) unMarshallKustomization() (*kustomizev1.Kustomization, error)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read kustomization file %s: %w", b.kustomizationFile, err)
 	}
-
 	k := &kustomizev1.Kustomization{}
 	decoder := k8syaml.NewYAMLOrJSONDecoder(bytes.NewBuffer(data), len(data))
-	err = decoder.Decode(k)
-	if err != nil {
-		return nil, fmt.Errorf("failed to unmarshall kustomization file %s: %w", b.kustomizationFile, err)
+	// check for kustomization in yaml with the same name and namespace
+	for !(k.Name == b.name && (k.Namespace == b.namespace || k.Namespace == "")) {
+		err = decoder.Decode(k)
+		if err != nil {
+			if err == io.EOF {
+				return nil, fmt.Errorf("failed find kustomization with name '%s' and namespace '%s' in file '%s'",
+					b.name, b.namespace, b.kustomizationFile)
+			} else {
+				return nil, fmt.Errorf("failed to unmarshall kustomization file %s: %w", b.kustomizationFile, err)
+			}
+		}
 	}
 	return k, nil
 }

internal/build/build_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package build
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -157,3 +158,60 @@ type: kubernetes.io/dockerconfigjson
 		})
 	}
 }
+
+func Test_unMarshallKustomization(t *testing.T) {
+	tests := []struct {
+		name        string
+		localKsFile string
+		wantErr     bool
+		errString   string
+	}{
+		{
+			name:        "valid kustomization",
+			localKsFile: "testdata/local-kustomization/valid.yaml",
+		},
+		{
+			name:        "Multi-doc yaml containing kustomization and other resources",
+			localKsFile: "testdata/local-kustomization/multi-doc-valid.yaml",
+		},
+		{
+			name:        "no namespace",
+			localKsFile: "testdata/local-kustomization/no-ns.yaml",
+		},
+		{
+			name:        "kustomization with a different name",
+			localKsFile: "testdata/local-kustomization/different-name.yaml",
+			wantErr:     true,
+			errString:   "failed find kustomization with name",
+		},
+	}
+
+	b := &Builder{
+		name:      "podinfo",
+		namespace: "flux-system",
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			b.kustomizationFile = tt.localKsFile
+			ks, err := b.unMarshallKustomization()
+			if !tt.wantErr {
+				if err != nil {
+					t.Fatalf("unexpected err '%s'", err)
+				}
+
+				if ks.Name != b.name && ks.Namespace != b.namespace {
+					t.Errorf("expected kustomization '%s/%s' to match '%s/%s'",
+						ks.Name, ks.Namespace, b.name, b.namespace)
+				}
+			} else {
+				if err == nil {
+					t.Fatal("expected error but got nil")
+				}
+
+				if !strings.Contains(err.Error(), tt.errString) {
+					t.Errorf("expected error '%s' to contain string '%s'", err.Error(), tt.errString)
+				}
+			}
+		})
+	}
+}

internal/build/testdata/local-kustomization/different-name.yaml

@@ -0,0 +1,7 @@
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+kind: Kustomization
+metadata:
+  name: infra
+  namespace: flux-system
+spec:
+  path: "./clusters/test-build"

internal/build/testdata/local-kustomization/multi-doc-valid.yaml

@@ -0,0 +1,32 @@
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+kind: Kustomization
+metadata:
+  name: infra-namespace
+  namespace: flux-system
+  labels:
+    component.kutara.io/part-of: definitions
+spec:
+  path: "./k8s/base/infra"
+  prune: true
+---
+---
+apiVersion: source.toolkit.fluxcd.io/v1beta2
+kind: GitRepository
+metadata:
+  name: podinfo
+  namespace: flux-system
+spec:
+  interval: 30s
+  ref:
+    branch: master
+  url: https://github.com/stefanprodan/podinfo
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+kind: Kustomization
+metadata:
+  name: podinfo
+  namespace: flux-system
+spec:
+  path: "./clusters/test-build"
+---

internal/build/testdata/local-kustomization/no-ns.yaml

@@ -0,0 +1,6 @@
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+kind: Kustomization
+metadata:
+  name: podinfo
+spec:
+  path: "./clusters/test-build"

internal/build/testdata/local-kustomization/valid.yaml

@@ -0,0 +1,7 @@
+apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
+kind: Kustomization
+metadata:
+  name: podinfo
+  namespace: flux-system
+spec:
+  path: "./clusters/test-build"