Allow Int values and parse as Seconds for Durations

The timeout values could be accidentally set as ints by a user
rather than golang durations. This meant that "5" gets parsed
to 5ms not 5s. Now we try and parse non duration strings as
seconds.

This has been tested by creating a function with the old binary,
setting the timeouts for read, write and exec to "5" and 5.
These are interpreted as 0s.

New binary swapped in and re-deployed, this then worked as our
waits were less than the 5 seconds, when expanded over 5s (the waits)
then the fn was stopped

Signed-off-by: Alistair Hey <alistair@heyal.co.uk>

config/config.go

@@ -127,14 +127,26 @@ func mapEnv(env []string) map[string]string {
 }
 
 func getDuration(env map[string]string, key string, defaultValue time.Duration) time.Duration {
-	result := defaultValue
 	if val, exists := env[key]; exists {
-		parsed, _ := time.ParseDuration(val)
-		result = parsed
+		return parseIntOrDurationValue(val, defaultValue)
+	}
+
+	return defaultValue
+}
 
+func parseIntOrDurationValue(val string, fallback time.Duration) time.Duration {
+	if len(val) > 0 {
+		parsedVal, parseErr := strconv.Atoi(val)
+		if parseErr == nil && parsedVal >= 0 {
+			return time.Duration(parsedVal) * time.Second
+		}
 	}
 
-	return result
+	duration, durationErr := time.ParseDuration(val)
+	if durationErr != nil {
+		return fallback
+	}
+	return duration
 }
 
 func getInt(env map[string]string, key string, defaultValue int) int {

config/config_test.go

@@ -262,3 +262,88 @@ func Test_Timeouts(t *testing.T) {
 	}
 
 }
+
+func Test_TestNonDurationValue_getDuration(t *testing.T) {
+	want := 10 * time.Second
+	env := map[string]string{"time": "10"}
+	got := getDuration(env, "time", 5*time.Second)
+
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_TestDurationValue_getDuration(t *testing.T) {
+	want := 10 * time.Second
+	env := map[string]string{"time": "10s"}
+	got := getDuration(env, "time", 5*time.Second)
+
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+func Test_TestNonParsableValue_getDuration(t *testing.T) {
+	want := 5 * time.Second
+	env := map[string]string{"time": "this is bad"}
+	got := getDuration(env, "time", 5*time.Second)
+
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_TestMissingMapValue_getDuration(t *testing.T) {
+	want := 5 * time.Second
+	env := map[string]string{"time_is_missing": "10"}
+	got := getDuration(env, "time", 5*time.Second)
+
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_IntAsString_parseIntOrDurationValue(t *testing.T) {
+	want := 10 * time.Second
+
+	got := parseIntOrDurationValue("10", 5*time.Second)
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_Duration_parseIntOrDurationValue(t *testing.T) {
+	want := 10 * time.Second
+
+	got := parseIntOrDurationValue("10s", 5*time.Second)
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+
+}
+
+func Test_EmptyString_parseIntOrDurationValue(t *testing.T) {
+	want := 5 * time.Second
+
+	got := parseIntOrDurationValue("", 5*time.Second)
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_ZeroAsString_parseIntOrDurationValue(t *testing.T) {
+	want := 0 * time.Second
+
+	got := parseIntOrDurationValue("0", 5*time.Second)
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}
+
+func Test_NonParsableString_parseIntOrDurationValue(t *testing.T) {
+	want := 5 * time.Second
+
+	got := parseIntOrDurationValue("this is not good", 5*time.Second)
+	if want != got {
+		t.Error(fmt.Sprintf("want: %q got: %q", want, got))
+	}
+}