Add support for RFC 2579 DateAndTime (#322)

Extract a UNIX timestamp from RFC 2579 DateAndTime textual conversions.
* Add support to the generator.
* Add support to the collector.
* Update snmp.yml with new DateAndTime metrics.
* Refactor type walkNode in generator/tree.go.

Signed-off-by: Ben Kochie <[email protected]>

collector.go

@@ -14,6 +14,7 @@
 package main
 
 import (
+	"encoding/binary"
 	"fmt"
 	"net"
 	"strconv"
@@ -234,7 +235,55 @@ func getPduValue(pdu *gosnmp.SnmpPDU) float64 {
 	}
 }
 
+// parseDateAndTime extracts a UNIX timestamp from an RFC 2579 DateAndTime.
+func parseDateAndTime(pdu *gosnmp.SnmpPDU) (float64, error) {
+	var (
+		v   []byte
+		tz  *time.Location
+		err error
+	)
+	// DateAndTime should be a slice of bytes.
+	switch pduType := pdu.Value.(type) {
+	case []byte:
+		v = pdu.Value.([]byte)
+	default:
+		return 0, fmt.Errorf("invalid DateAndTime type %v", pduType)
+	}
+	pduLength := len(v)
+	// DateAndTime can be 8 or 11 bytes depending if the time zone is included.
+	switch pduLength {
+	case 8:
+		// No time zone included, assume UTC.
+		tz = time.UTC
+	case 11:
+		// Extract the timezone from the last 3 bytes.
+		locString := fmt.Sprintf("%s%02d%02d", string(v[8]), uint8(v[9]), uint8(v[10]))
+		loc, err := time.Parse("-0700", locString)
+		if err != nil {
+			return 0, fmt.Errorf("error parsing location string: %q, error: %s", locString, err)
+		}
+		tz = loc.Location()
+	default:
+		return 0, fmt.Errorf("invalid DateAndTime length %v", pduLength)
+	}
+	if err != nil {
+		return 0, fmt.Errorf("unable to parse DateAndTime %q, error: %s", v, err)
+	}
+	// Build the date from the various fields and time zone.
+	t := time.Date(
+		int(binary.BigEndian.Uint16(v[0:2])),
+		time.Month(uint8(v[2])),
+		int(uint8(v[3])),
+		int(uint8(v[4])),
+		int(uint8(v[5])),
+		int(uint8(v[6])),
+		int(uint8(v[7]))*1e+8,
+		tz)
+	return float64(t.Unix()), nil
+}
+
 func pduToSamples(indexOids []int, pdu *gosnmp.SnmpPDU, metric *config.Metric, oidToPdu map[string]gosnmp.SnmpPDU) []prometheus.Metric {
+	var err error
 	// The part of the OID that is the indexes.
 	labels := indexesToLabels(indexOids, metric, oidToPdu)
 
@@ -255,6 +304,13 @@ func pduToSamples(indexOids []int, pdu *gosnmp.SnmpPDU, metric *config.Metric, o
 		t = prometheus.GaugeValue
 	case "Float", "Double":
 		t = prometheus.GaugeValue
+	case "DateAndTime":
+		t = prometheus.GaugeValue
+		value, err = parseDateAndTime(pdu)
+		if err != nil {
+			log.Debugf("error parsing DateAndTime: %s", err)
+			return []prometheus.Metric{}
+		}
 	default:
 		// It's some form of string.
 		t = prometheus.GaugeValue

collector_test.go

@@ -14,6 +14,7 @@
 package main
 
 import (
+	"errors"
 	"reflect"
 	"regexp"
 	"testing"
@@ -497,6 +498,41 @@ func TestPduValueAsString(t *testing.T) {
 	}
 }
 
+func TestParseDateAndTime(t *testing.T) {
+	cases := []struct {
+		pdu    *gosnmp.SnmpPDU
+		result float64
+		err    error
+	}{
+		// No timezone, use UTC
+		{
+			pdu:    &gosnmp.SnmpPDU{Value: []byte{7, 226, 8, 15, 8, 1, 15, 0}},
+			result: 1534320075,
+			err:    nil,
+		},
+		// +0200
+		{
+			pdu:    &gosnmp.SnmpPDU{Value: []byte{7, 226, 8, 15, 8, 1, 15, 0, 43, 2, 0}},
+			result: 1534312875,
+			err:    nil,
+		},
+		{
+			pdu:    &gosnmp.SnmpPDU{Value: []byte{0}},
+			result: 0,
+			err:    errors.New("invalid DateAndTime length 1"),
+		},
+	}
+	for _, c := range cases {
+		got, err := parseDateAndTime(c.pdu)
+		if !reflect.DeepEqual(err, c.err) {
+			t.Errorf("parseDateAndTime(%v) error: got %v, want %v", c.pdu, err, c.err)
+		}
+		if !reflect.DeepEqual(got, c.result) {
+			t.Errorf("parseDateAndTime(%v) result: got %v, want %v", c.pdu, got, c.result)
+		}
+	}
+}
+
 func TestIndexesToLabels(t *testing.T) {
 	cases := []struct {
 		oid      []int

generator/README.md

@@ -105,6 +105,7 @@ modules:
                              #   gauge:   An integer with type gauge.
                              #   counter: An integer with type counter.
                              #   OctetString: A bit string, rendered as 0xff34.
+                             #   DateAndTime: An RFC 2579 DateAndTime byte sequence. If the device has no time zone data, UTC is used.
                              #   DisplayString: An ASCII or UTF-8 string.
                              #   PhysAddress48: A 48 bit MAC address, rendered as 00:01:02:03:04:ff.
                              #   Float: A 32 bit floating-point value with type gauge.

generator/tree.go

@@ -90,8 +90,9 @@ func prepareTree(nodes *Node) map[string]*Node {
 	// is technically only ASCII.
 	displayStringRe := regexp.MustCompile(`^\d+[at]$`)
 
-	// Set type on MAC addresses and strings.
+	// Apply various tweaks to the types.
 	walkNode(nodes, func(n *Node) {
+		// Set type on MAC addresses and strings.
 		// RFC 2579
 		switch n.Hint {
 		case "1x:":
@@ -106,13 +107,16 @@ func prepareTree(nodes *Node) map[string]*Node {
 		if n.TextualConvention == "DisplayString" {
 			n.Type = "DisplayString"
 		}
-	})
 
-	// Promote Opaque Float/Double textual convention to type.
-	walkNode(nodes, func(n *Node) {
+		// Promote Opaque Float/Double textual convention to type.
 		if n.TextualConvention == "Float" || n.TextualConvention == "Double" {
 			n.Type = n.TextualConvention
 		}
+
+		// Convert RFC 2579 DateAndTime textual conversion to type.
+		if n.TextualConvention == "DateAndTime" {
+			n.Type = "DateAndTime"
+		}
 	})
 
 	return nameToNode
@@ -130,6 +134,8 @@ func metricType(t string) (string, bool) {
 		return "IpAddr", true
 	case "PhysAddress48", "DisplayString", "Float", "Double":
 		return t, true
+	case "DateAndTime":
+		return t, true
 	default:
 		// Unsupported type.
 		return "", false

generator/tree_test.go

@@ -119,6 +119,11 @@ func TestTreePrepare(t *testing.T) {
 			in:  &Node{Oid: "1", Type: "OPAQUE", TextualConvention: "Double"},
 			out: &Node{Oid: "1", Type: "Double", TextualConvention: "Double"},
 		},
+		// RFC 2579 DateAndTime.
+		{
+			in:  &Node{Oid: "1", Type: "DisplayString", TextualConvention: "DateAndTime"},
+			out: &Node{Oid: "1", Type: "DateAndTime", TextualConvention: "DateAndTime"},
+		},
 	}
 	for i, c := range cases {
 		// Indexes always end up initilized.
@@ -312,6 +317,7 @@ func TestGenerateConfigModule(t *testing.T) {
 					{Oid: "1.100", Access: "ACCESS_READONLY", Label: "MacAddress", Type: "OCTETSTR", Hint: "1x:"},
 					{Oid: "1.200", Access: "ACCESS_READONLY", Label: "Float", Type: "OPAQUE", TextualConvention: "Float"},
 					{Oid: "1.201", Access: "ACCESS_READONLY", Label: "Double", Type: "OPAQUE", TextualConvention: "Double"},
+					{Oid: "1.202", Access: "ACCESS_READONLY", Label: "DateAndTime", Type: "DisplayString", TextualConvention: "DateAndTime"},
 				}},
 			cfg: &ModuleConfig{
 				Walk: []string{"root", "1.3"},
@@ -409,6 +415,12 @@ func TestGenerateConfigModule(t *testing.T) {
 						Type: "Double",
 						Help: " - 1.201",
 					},
+					{
+						Name: "DateAndTime",
+						Oid:  "1.202",
+						Type: "DateAndTime",
+						Help: " - 1.202",
+					},
 				},
 			},
 		},

snmp.yml

@@ -5788,7 +5788,7 @@ paloalto_fw:
     help: The amount of time since this host was last initialized - 1.3.6.1.2.1.25.1.1
   - name: hrSystemDate
     oid: 1.3.6.1.2.1.25.1.2
-    type: DisplayString
+    type: DateAndTime
     help: The host's notion of the local date and time of day. - 1.3.6.1.2.1.25.1.2
   - name: hrSystemInitialLoadDevice
     oid: 1.3.6.1.2.1.25.1.3
@@ -6047,15 +6047,15 @@ paloalto_fw:
       type: gauge
   - name: hrFSLastFullBackupDate
     oid: 1.3.6.1.2.1.25.3.8.1.8
-    type: DisplayString
+    type: DateAndTime
     help: The last date at which this complete file system was copied to another storage
       device for backup - 1.3.6.1.2.1.25.3.8.1.8
     indexes:
     - labelname: hrFSIndex
       type: gauge
   - name: hrFSLastPartialBackupDate
     oid: 1.3.6.1.2.1.25.3.8.1.9
-    type: DisplayString
+    type: DateAndTime
     help: The last date at which a portion of this file system was copied to another
       storage device for backup - 1.3.6.1.2.1.25.3.8.1.9
     indexes: