Take relative paths in account for Bucket revision

This commit changes the checksum method which is used to calculate the
revision of a Bucket source, so that the file paths are taken into
account and directory structure changes can be observed.

Signed-off-by: Hidde Beydals <hello@hidde.co>

controllers/bucket_controller.go

@@ -356,9 +356,12 @@ func (r *BucketReconciler) auth(ctx context.Context, bucket sourcev1.Bucket) (*m
 	return minio.New(bucket.Spec.Endpoint, &opt)
 }
 
+// checksum calculates the SHA1 checksum of the given root directory.
+// It traverses the given root directory and calculates the checksum for any found file, and returns the SHA1 sum of the
+// list with relative file paths and their checksums.
 func (r *BucketReconciler) checksum(root string) (string, error) {
-	checksum := ""
-	err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
+	sum := sha1.New()
+	if err := filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
@@ -369,14 +372,16 @@ func (r *BucketReconciler) checksum(root string) (string, error) {
 		if err != nil {
 			return err
 		}
-		checksum += fmt.Sprintf("%x", sha1.Sum(data))
+		relPath, err := filepath.Rel(root, path)
+		if err != nil {
+			return err
+		}
+		sum.Write([]byte(fmt.Sprintf("%x  %s\n", sha1.Sum(data), relPath)))
 		return nil
-	})
-	if err != nil {
+	}); err != nil {
 		return "", err
 	}
-
-	return fmt.Sprintf("%x", sha1.Sum([]byte(checksum))), nil
+	return fmt.Sprintf("%x", sum.Sum(nil)), nil
 }
 
 // resetStatus returns a modified v1beta1.Bucket and a boolean indicating

controllers/bucket_controller_test.go

@@ -0,0 +1,83 @@
+/*
+Copyright 2021 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package controllers
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestBucketReconciler_checksum(t *testing.T) {
+	tests := []struct {
+		name       string
+		beforeFunc func(root string)
+		want       string
+		wantErr    bool
+	}{
+		{
+			name: "empty root",
+			want: "da39a3ee5e6b4b0d3255bfef95601890afd80709",
+		},
+		{
+			name: "with file",
+			beforeFunc: func(root string) {
+				mockFile(root, "a/b/c.txt", "a dummy string")
+			},
+			want: "309a5e6e96b4a7eea0d1cfaabf1be8ec1c063fa0",
+		},
+		{
+			name: "with file in different path",
+			beforeFunc: func(root string) {
+				mockFile(root, "a/b.txt", "a dummy string")
+			},
+			want: "e28c62b5cc488849950c4355dddc5523712616d4",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			root, err := ioutil.TempDir("", "bucket-checksum-")
+			if err != nil {
+				t.Fatal(err)
+			}
+			defer os.RemoveAll(root)
+			if tt.beforeFunc != nil {
+				tt.beforeFunc(root)
+			}
+			got, err := (&BucketReconciler{}).checksum(root)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("checksum() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if got != tt.want {
+				t.Errorf("checksum() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func mockFile(root, path, content string) error {
+	filePath := filepath.Join(root, path)
+	if err := os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
+		panic(err)
+	}
+	if err := ioutil.WriteFile(filePath, []byte(content), 0644); err != nil {
+		panic(err)
+	}
+	return nil
+}