journal: SendVals with arbitrary auto-converting functions

journal/journal_unix.go

@@ -129,6 +129,24 @@ func fdIsJournalStream(fd int) (bool, error) {
 // (http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html)
 // for more details.  vars may be nil.
 func Send(message string, priority Priority, vars map[string]string) error {
+	return send(message, priority, func(b *bytes.Buffer) {
+		for k, v := range vars {
+			appendVariable(b, k, v)
+		}
+	})
+}
+
+// Send a message to the local systemd journal. Optional values may be
+// provided as a list of Value variablese.
+func SendVals(message string, priority Priority, values ...Value) error {
+	return send(message, priority, func(b *bytes.Buffer) {
+		for _, v := range values {
+			appendVariable(b, v.Name(), v.Value())
+		}
+	})
+}
+
+func send(message string, priority Priority, varFunc func(data *bytes.Buffer)) error {
 	conn := getOrInitConn()
 	if conn == nil {
 		return errors.New("could not initialize socket to journald")
@@ -142,9 +160,7 @@ func Send(message string, priority Priority, vars map[string]string) error {
 	data := new(bytes.Buffer)
 	appendVariable(data, "PRIORITY", strconv.Itoa(int(priority)))
 	appendVariable(data, "MESSAGE", message)
-	for k, v := range vars {
-		appendVariable(data, k, v)
-	}
+	varFunc(data)
 
 	_, _, err := conn.WriteMsgUnix(data.Bytes(), nil, socketAddr)
 	if err == nil {

journal/journal_unix_test.go

@@ -127,6 +127,24 @@ func TestStderrIsJournalStream(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
+
+		err = journal.Send(message, journal.PriInfo, map[string]string{"KEY": "VALUE"})
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = journal.SendVals(message, journal.PriInfo)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		err = journal.SendVals(message, journal.PriInfo,
+			journal.String("KEY", "VALUE"),
+			journal.Int("INT_KEY", 1),
+		)
+		if err != nil {
+			t.Fatal(err)
+		}
 	}
 }
 

journal/values.go

@@ -0,0 +1,80 @@
+package journal
+
+import (
+	"strconv"
+	"time"
+)
+
+// Value represents a key-value pair that can be logged to the journal.
+type Value interface {
+	// Name must be composed of uppercase letters, numbers,
+	// and underscores, but must not start with an underscore. Within these
+	// restrictions, any arbitrary field name may be used.  Some names have special
+	// significance: see the journalctl documentation
+	// (http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html)
+	// for more details.
+	Name() string
+
+	// Value must be a string representation of the value.
+	Value() string
+}
+
+type value struct {
+	name  string
+	value string
+}
+
+var _ = Value(&value{})
+
+func (s value) Name() string {
+	return s.name
+}
+
+func (s value) Value() string {
+	return s.value
+}
+
+// String returns a Value for a string value.
+func String(name, Value string) Value {
+	return &value{name, Value}
+}
+
+// Int returns a Value for an int.
+func Int(name string, Value int) Value {
+	return &value{name, strconv.Itoa(Value)}
+}
+
+// Int64 returns a Value for an int64.
+func Int64(name string, Value int64) Value {
+	return &value{name, strconv.FormatInt(Value, 10)}
+}
+
+// Uint64 returns a Value for a uint64.
+func Uint64(name string, Value uint64) Value {
+	return &value{name, strconv.FormatUint(Value, 10)}
+}
+
+// Float64 returns a Value for a floating-point number.
+func Float64(name string, Value float64) Value {
+	return &value{name, strconv.FormatFloat(Value, 'g', -1, 64)}
+}
+
+// Bool returns a Value for a bool.
+func Bool(name string, Value bool) Value {
+	return &value{name, strconv.FormatBool(Value)}
+}
+
+// Time returns a Value for a time.Time.
+func Time(name string, Value time.Time) Value {
+	return &value{name, Value.Format(time.RFC3339Nano)}
+}
+
+// Duration returns a Value for a time.Duration.
+func Duration(name string, Value time.Duration) Value {
+	return &value{name, Value.String()}
+}
+
+// Error returns a Value for an error.
+func Error(name string, Value error) Value {
+	return &value{name, Value.Error()}
+}