internal/log: fix potential integer conversion issue from parsed value (

#2289)

Co-authored-by: Katie Hockman <[email protected]>

internal/log/log.go

@@ -100,9 +100,18 @@ var (
 
 func init() {
 	if v := os.Getenv("DD_LOGGING_RATE"); v != "" {
-		if sec, err := strconv.ParseUint(v, 10, 64); err != nil {
-			Warn("Invalid value for DD_LOGGING_RATE: %v", err)
+		setLoggingRate(v)
+	}
+}
+
+func setLoggingRate(v string) {
+	if sec, err := strconv.ParseInt(v, 10, 64); err != nil {
+		Warn("Invalid value for DD_LOGGING_RATE: %v", err)
+	} else {
+		if sec < 0 {
+			Warn("Invalid value for DD_LOGGING_RATE: negative value")
 		} else {
+			// DD_LOGGING_RATE = 0 allows to log errors immediately.
 			errrate = time.Duration(sec) * time.Second
 		}
 	}

internal/log/log_test.go

@@ -140,6 +140,42 @@ func TestRecordLoggerIgnore(t *testing.T) {
 	assert.Contains(t, tp.Logs()[0], "appsec")
 }
 
+func TestSetLoggingRate(t *testing.T) {
+	testCases := []struct {
+		input  string
+		result time.Duration
+	}{
+		{
+			input:  "",
+			result: time.Minute,
+		},
+		{
+			input:  "0",
+			result: 0 * time.Second,
+		},
+		{
+			input:  "10",
+			result: 10 * time.Second,
+		},
+		{
+			input:  "-1",
+			result: time.Minute,
+		},
+		{
+			input:  "this is not a number",
+			result: time.Minute,
+		},
+	}
+	for _, tC := range testCases {
+		tC := tC
+		errrate = time.Minute // reset global variable
+		t.Run(tC.input, func(t *testing.T) {
+			setLoggingRate(tC.input)
+			assert.Equal(t, tC.result, errrate)
+		})
+	}
+}
+
 func BenchmarkError(b *testing.B) {
 	Error("k %s", "a") // warm up cache
 	for i := 0; i < b.N; i++ {