Merge pull request #1 from avast/log_of_err

retry return error with log of all errors

Author: JaSei

retry.go

@@ -4,6 +4,7 @@ package retry
 
 import (
 	"fmt"
+	"strings"
 	"time"
 )
 
@@ -49,11 +50,14 @@ func RetryWithOpts(retryableFunction Retryable, opts RetryOpts) error {
 func RetryCustom(retryableFunction Retryable, onRetryFunction OnRetry, opts RetryOpts) error {
 	var n uint
 
+	errorLog := make(errorLog, opts.tries)
+
 	for n < opts.tries {
 		err := retryableFunction()
 
 		if err != nil {
 			onRetryFunction(n, err)
+			errorLog[n] = err
 
 			delayTime := opts.delay * (1 << (n - 1))
 			time.Sleep((time.Duration)(delayTime) * opts.units)
@@ -64,5 +68,16 @@ func RetryCustom(retryableFunction Retryable, onRetryFunction OnRetry, opts Retr
 		n++
 	}
 
-	return fmt.Errorf("All (%d) retries fail", opts.tries)
+	return fmt.Errorf("All (%d) retries fail:\n%s", opts.tries, errorLog)
+}
+
+type errorLog []error
+
+func (log errorLog) String() string {
+	logWithNumber := make([]string, len(log))
+	for i, l := range log {
+		logWithNumber[i] = fmt.Sprintf("#%d: %s", i+1, l.Error())
+	}
+
+	return strings.Join(logWithNumber, "\n")
 }

retry_test.go

@@ -15,6 +15,19 @@ func TestCustom(t *testing.T) {
 		NewRetryOpts().Units(time.Nanosecond),
 	)
 	assert.Error(t, err)
+
+	expectedErrorFormat := `All (10) retries fail:
+#1: test
+#2: test
+#3: test
+#4: test
+#5: test
+#6: test
+#7: test
+#8: test
+#9: test
+#10: test`
+	assert.Equal(t, expectedErrorFormat, err.Error(), "retry error format")
 	assert.Equal(t, uint(45), retrySum, "right count of retry")
 
 	retrySum = 0