Merge pull request #29 from scorptec68/master

For RFC5424 APP-NAME is limited to 48 chars - so truncate it

formatter.go

@@ -6,6 +6,8 @@ import (
 	"time"
 )
 
+const appNameMaxLength = 48 // limit to 48 chars as per RFC5424
+
 // Formatter is a type of function that takes the consituent parts of a
 // syslog message and returns a formatted string. A different Formatter is
 // defined for each different syslog protocol we support.
@@ -37,11 +39,19 @@ func RFC3164Formatter(p Priority, hostname, tag, content string) string {
 	return msg
 }
 
+// if string's length is greater than max, then use the last part
+func truncateStartStr(s string, max int) string {
+	if (len(s) > max) {
+		return s[len(s) - max:]
+	}
+	return s
+}
+
 // RFC5424Formatter provides an RFC 5424 compliant message.
 func RFC5424Formatter(p Priority, hostname, tag, content string) string {
 	timestamp := time.Now().Format(time.RFC3339)
 	pid := os.Getpid()
-	appName := os.Args[0]
+	appName := truncateStartStr(os.Args[0], appNameMaxLength)
 	msg := fmt.Sprintf("<%d>%d %s %s %s %d %s - %s",
 		p, 1, timestamp, hostname, appName, pid, tag, content)
 	return msg

formatter_test.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"testing"
 	"time"
+	"strings"
 )
 
 func TestDefaultFormatter(t *testing.T) {
@@ -37,8 +38,20 @@ func TestRFC3164Formatter(t *testing.T) {
 func TestRFC5424Formatter(t *testing.T) {
 	out := RFC5424Formatter(LOG_ERR, "hostname", "tag", "content")
 	expected := fmt.Sprintf("<%d>%d %s %s %s %d %s - %s",
-		LOG_ERR, 1, time.Now().Format(time.RFC3339), "hostname", os.Args[0], os.Getpid(), "tag", "content")
+		LOG_ERR, 1, time.Now().Format(time.RFC3339), "hostname", truncateStartStr(os.Args[0], appNameMaxLength),
+			os.Getpid(), "tag", "content")
 	if out != expected {
 		t.Errorf("expected %v got %v", expected, out)
 	}
 }
+
+func TestTruncateStartStr(t *testing.T) {
+	out := truncateStartStr("abcde", 3)
+	if strings.Compare(out, "cde" ) != 0 {
+		t.Errorf("expected \"cde\" got %v", out)
+	}
+	out = truncateStartStr("abcde", 5)
+	if strings.Compare(out, "abcde" ) != 0 {
+		t.Errorf("expected \"abcde\" got %v", out)
+	}
+}