modifying readFileContentInLoop to display iteratively file content and eventually check initial content

hack/verify-flags/excluded-flags.txt

@@ -24,3 +24,4 @@ up_to
 valid_flag
 retry_time
 file_content_in_loop
+break_on_expected_content

test/images/mount-tester-user/Dockerfile

@@ -12,5 +12,5 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM gcr.io/google_containers/mounttest:0.5
+FROM gcr.io/google_containers/mounttest:0.6
 USER 1001

test/images/mount-tester-user/Makefile

@@ -1,4 +1,4 @@
-TAG = 0.3
+TAG = 0.4
 PREFIX = gcr.io/google_containers
 
 all: push

test/images/mount-tester/Makefile

@@ -1,4 +1,4 @@
-TAG = 0.5
+TAG = 0.6
 PREFIX = gcr.io/google_containers
 
 all: push

test/images/mount-tester/mt.go

@@ -37,6 +37,7 @@ var (
 	readFileContentPath       = ""
 	readFileContentInLoopPath = ""
 	retryDuration             = 180
+	breakOnExpectedContent    = true
 )
 
 func init() {
@@ -51,6 +52,7 @@ func init() {
 	flag.StringVar(&readFileContentPath, "file_content", "", "Path to read the file content from")
 	flag.StringVar(&readFileContentInLoopPath, "file_content_in_loop", "", "Path to read the file content in loop from")
 	flag.IntVar(&retryDuration, "retry_time", 180, "Retry time during the loop")
+	flag.BoolVar(&breakOnExpectedContent, "break_on_expected_content", true, "Break out of loop on expected content, (use with --file_content_in_loop flag only)")
 }
 
 // This program performs some tests on the filesystem as dictated by the
@@ -120,7 +122,7 @@ func main() {
 		errs = append(errs, err)
 	}
 
-	err = readFileContentInLoop(readFileContentInLoopPath, retryDuration)
+	err = readFileContentInLoop(readFileContentInLoopPath, retryDuration, breakOnExpectedContent)
 	if err != nil {
 		errs = append(errs, err)
 	}
@@ -217,13 +219,14 @@ func readFileContent(path string) error {
 	return nil
 }
 
+const initialContent string = "mount-tester new file\n"
+
 func readWriteNewFile(path string, perm os.FileMode) error {
 	if path == "" {
 		return nil
 	}
 
-	content := "mount-tester new file\n"
-	err := ioutil.WriteFile(path, []byte(content), perm)
+	err := ioutil.WriteFile(path, []byte(initialContent), perm)
 	if err != nil {
 		fmt.Printf("error writing new file %q: %v\n", path, err)
 		return err
@@ -232,19 +235,14 @@ func readWriteNewFile(path string, perm os.FileMode) error {
 	return readFileContent(path)
 }
 
-func readFileContentInLoop(path string, retryDuration int) error {
+func readFileContentInLoop(path string, retryDuration int, breakOnExpectedContent bool) error {
 	if path == "" {
 		return nil
 	}
-	var content []byte
-	content = testFileContent(path, retryDuration)
-
-	fmt.Printf("content of file %q: %v\n", path, string(content))
-
-	return nil
+	return testFileContent(path, retryDuration, breakOnExpectedContent)
 }
 
-func testFileContent(filePath string, retryDuration int) []byte {
+func testFileContent(filePath string, retryDuration int, breakOnExpectedContent bool) error {
 	var (
 		contentBytes []byte
 		err          error
@@ -253,18 +251,18 @@ func testFileContent(filePath string, retryDuration int) []byte {
 	retryTime := time.Second * time.Duration(retryDuration)
 	for start := time.Now(); time.Since(start) < retryTime; time.Sleep(2 * time.Second) {
 		contentBytes, err = ioutil.ReadFile(filePath)
-		if err == nil {
-			//Expected content "mount-tester new file\n", length 22
-			if len(contentBytes) == 22 {
-				break
-			} else {
-				fmt.Printf("Unexpected length of file: found %d, expected %d.Retry", len(contentBytes), 22)
+		if err != nil {
+			fmt.Printf("Error reading file %s: %v, retrying\n", filePath, err)
+			continue
+		}
+		fmt.Printf("content of file %q: %v\n", filePath, string(contentBytes))
+		if breakOnExpectedContent {
+			if string(contentBytes) != initialContent {
+				fmt.Printf("Unexpected content. Expected: %s. Retrying", initialContent)
+				continue
 			}
-		} else {
-			fmt.Printf("Error read file %s: %v, retry", filePath, err)
+			break
 		}
-
 	}
-
-	return contentBytes
+	return err
 }