Allow skipping Pri header.

rfc3164/machine.go.rl

@@ -88,9 +88,14 @@ action err_prival {
 }
 
 action err_pri {
-	m.err = fmt.Errorf(errPri, m.p)
-	fhold;
-	fgoto fail;
+	if(!m.allowSkipPri) {
+		m.err = fmt.Errorf(errPri, m.p)
+		fhold;
+		fgoto fail;
+	} else {
+		fhold;
+		fgoto STATE_NO_PRI;
+	}	
 }
 
 action err_timestamp {
@@ -158,23 +163,30 @@ msg = (tag content? ':' sp)? mex;
 
 fail := (any - [\n\r])* @err{ fgoto main; };
 
-main := pri (timestamp | (rfc3339 when { m.rfc3339 })) sp hostname sp msg;
+sysmessage = (timestamp | (rfc3339 when { m.rfc3339 })) sp hostname sp msg;
+
+myfsm := (
+	STATE_NO_PRI: sysmessage             
+);
+
+main := pri sysmessage;
 
 }%%
 
 %% write data noerror noprefix;
 
 type machine struct {
-	data         []byte
-	cs           int
-	p, pe, eof   int
-	pb           int
-	err          error
-	bestEffort   bool
-	yyyy         int
-	rfc3339      bool
-	loc          *time.Location
-	timezone     *time.Location
+	data           []byte
+	cs             int
+	p, pe, eof     int
+	pb             int
+	err            error
+	bestEffort     bool
+	yyyy           int
+	rfc3339        bool
+	allowSkipPri   bool
+	loc            *time.Location
+	timezone       *time.Location
 }
 
 // NewMachine creates a new FSM able to parse RFC3164 syslog messages.
@@ -194,6 +206,11 @@ func NewMachine(options ...syslog.MachineOption) syslog.Machine {
 	return m
 }
 
+// WithNoPri sets the skip PRI flag to allow messages without PRI header.
+func (m *machine) WithAllowSkipPri() {
+	m.allowSkipPri = true
+}
+
 // WithBestEffort enables best effort mode.
 func (m *machine) WithBestEffort() {
 	m.bestEffort = true
@@ -259,5 +276,4 @@ func (m *machine) Parse(input []byte) (syslog.Message, error) {
 	}
 
 	return output.export(), nil
-}
-
+}

rfc3164/machine_test.go

@@ -12,17 +12,19 @@ import (
 // todo > add support for testing `best effort` mode
 
 type testCase struct {
-	input        []byte
-	valid        bool
-	value        syslog.Message
-	errorString  string
-	partialValue syslog.Message
+	input         []byte
+	valid         bool
+	shouldSkipPri bool
+	value         syslog.Message
+	errorString   string
+	partialValue  syslog.Message
 }
 
 var testCases = []testCase{
 	{
 		[]byte(`<34>Jan 12 06:30:00 xxx apache: 1.2.3.4 - - [12/Jan/2011:06:29:59 +0100] "GET /foo/bar.html HTTP/1.1" 301 96 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; fr; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 ( .NET CLR 3.5.30729)" PID 18904 Time Taken 0`),
 		true,
+		false,
 		&SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(34),
@@ -40,6 +42,7 @@ var testCases = []testCase{
 	{
 		[]byte(`<34>Aug  7 06:30:00 xxx aaa: message from 1.2.3.4`),
 		true,
+		false,
 		&SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(34),
@@ -55,8 +58,9 @@ var testCases = []testCase{
 		nil,
 	},
 	{
-		input: []byte(`<85>Jan 24 15:50:41 ip-172-31-30-110 sudo[6040]: ec2-user : TTY=pts/0 ; PWD=/var/log ; USER=root ; COMMAND=/bin/tail secure`),
-		valid: true,
+		input:         []byte(`<85>Jan 24 15:50:41 ip-172-31-30-110 sudo[6040]: ec2-user : TTY=pts/0 ; PWD=/var/log ; USER=root ; COMMAND=/bin/tail secure`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(85),
@@ -71,8 +75,9 @@ var testCases = []testCase{
 		},
 	},
 	{
-		input: []byte(`<166>Jul  6 20:33:28 ABC-1-234567 Some message here`),
-		valid: true,
+		input:         []byte(`<166>Jul  6 20:33:28 ABC-1-234567 Some message here`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(166),
@@ -85,8 +90,9 @@ var testCases = []testCase{
 		},
 	},
 	{
-		input: []byte(`<34>Oct 11 22:14:15 mymachine su: 'su root' failed for lonvick on /dev/pts/8`),
-		valid: true,
+		input:         []byte(`<34>Oct 11 22:14:15 mymachine su: 'su root' failed for lonvick on /dev/pts/8`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(34),
@@ -100,8 +106,9 @@ var testCases = []testCase{
 		},
 	},
 	{
-		input: []byte(`<13>Feb  5 17:32:18 10.0.0.99 Use the BFG!`),
-		valid: true,
+		input:         []byte(`<13>Feb  5 17:32:18 10.0.0.99 Use the BFG!`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(13),
@@ -114,8 +121,9 @@ var testCases = []testCase{
 		},
 	},
 	{
-		input: []byte(`<165>Aug 24 05:34:00 mymachine myproc[10]: %% It's time to make the do-nuts.  %%  Ingredients: Mix=OK, Jelly=OK # Devices: Mixer=OK, Jelly_Injector=OK, Frier=OK # Transport: Conveyer1=OK, Conveyer2=OK # %%`),
-		valid: true,
+		input:         []byte(`<165>Aug 24 05:34:00 mymachine myproc[10]: %% It's time to make the do-nuts.  %%  Ingredients: Mix=OK, Jelly=OK # Devices: Mixer=OK, Jelly_Injector=OK, Frier=OK # Transport: Conveyer1=OK, Conveyer2=OK # %%`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(165),
@@ -130,8 +138,9 @@ var testCases = []testCase{
 		},
 	},
 	{
-		input: []byte(`<0>Oct 22 10:52:01 10.1.2.3 sched[0]: That's All Folks!`),
-		valid: true,
+		input:         []byte(`<0>Oct 22 10:52:01 10.1.2.3 sched[0]: That's All Folks!`),
+		valid:         true,
+		shouldSkipPri: false,
 		value: &SyslogMessage{
 			Base: syslog.Base{
 				Priority:  syslogtesting.Uint8Address(0),
@@ -145,6 +154,30 @@ var testCases = []testCase{
 			},
 		},
 	},
+	{
+		input:         []byte(`Oct 22 10:52:01 10.1.2.3 sched[0]: That's All Folks!`),
+		valid:         true,
+		shouldSkipPri: true,
+		value: &SyslogMessage{
+			Base: syslog.Base{
+				Priority:  syslogtesting.Uint8Address(0),
+				Facility:  syslogtesting.Uint8Address(0),
+				Severity:  syslogtesting.Uint8Address(0),
+				Timestamp: syslogtesting.TimeParse(time.Stamp, "Oct 22 10:52:01"),
+				Hostname:  syslogtesting.StringAddress("10.1.2.3"),
+				Appname:   syslogtesting.StringAddress("sched"),
+				ProcID:    syslogtesting.StringAddress("0"),
+				Message:   syslogtesting.StringAddress(`That's All Folks!`),
+			},
+		},
+	},
+	{
+		input:         []byte(`Oct 22 10:52:01 10.1.2.3 sched[0]: That's All Folks!`),
+		valid:         false,
+		shouldSkipPri: false,
+		value:         nil,
+		errorString:   "expecting a priority value within angle brackets [col 0]",
+	},
 	// todo > other test cases pleaaaase
 }
 
@@ -153,9 +186,16 @@ func TestMachineParse(t *testing.T) {
 		tc := tc
 		t.Run(syslogtesting.RightPad(string(tc.input), 50), func(t *testing.T) {
 			t.Parallel()
+			var merr, perr error
+			var message, partial syslog.Message
 
-			message, merr := NewMachine().Parse(tc.input)
-			partial, perr := NewMachine(WithBestEffort()).Parse(tc.input)
+			if tc.shouldSkipPri {
+				message, merr = NewMachine(WithAllowSkipPri()).Parse(tc.input)
+				partial, perr = NewMachine(WithBestEffort(), WithAllowSkipPri()).Parse(tc.input)
+			} else {
+				message, merr = NewMachine().Parse(tc.input)
+				partial, perr = NewMachine(WithBestEffort()).Parse(tc.input)
+			}
 
 			if !tc.valid {
 				assert.Nil(t, message)
@@ -172,7 +212,9 @@ func TestMachineParse(t *testing.T) {
 				assert.Equal(t, merr, perr)
 			}
 
-			assert.Equal(t, tc.value, message)
+			if tc.errorString != "" {
+				assert.Equal(t, tc.value, message)
+			}
 		})
 	}
 }

rfc3164/options.go

@@ -6,6 +6,14 @@ import (
 	syslog "github.com/influxdata/go-syslog/v3"
 )
 
+// WithNoPri sets the skip PRI flag to allow messages without PRI header.
+func WithAllowSkipPri() syslog.MachineOption {
+	return func(m syslog.Machine) syslog.Machine {
+		m.(*machine).WithAllowSkipPri()
+		return m
+	}
+}
+
 // WithBestEffort enables the best effort mode.
 func WithBestEffort() syslog.MachineOption {
 	return func(m syslog.Machine) syslog.Machine {