example for #6 (#24)

examples/02-closeAndReopen/main.go

@@ -1,4 +1,5 @@
 // Tail a file, print its contents, close it and reopen it.
+//
 // In this example you can add lines to the syslog log by using the logger
 // command. Exit with Ctrl+C.
 package main

examples/03-consumeJSON/main.go

@@ -0,0 +1,54 @@
+// Consume and unmarshall JSON.
+//
+// In this example JSON lines are added by createJSON in a tight loop.
+// Each line is unmarshalled and a field printed.
+// Exit with Ctrl+C.
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/nxadm/tail"
+	"io/ioutil"
+	"os"
+	"strconv"
+)
+
+type jsonStruct struct {
+	Counter string `json:"counter"`
+}
+
+func main() {
+	file, err := ioutil.TempFile(os.TempDir(), "")
+	if err != nil {
+		panic(err)
+	}
+	fmt.Println(file.Name())
+	defer file.Close()
+	defer os.Remove(file.Name())
+
+	t, err := tail.TailFile(file.Name(), tail.Config{Follow: true})
+	if err != nil {
+		panic(err)
+	}
+
+	go createJSON(file)
+	var js jsonStruct
+	for line := range t.Lines {
+		fmt.Printf("JSON: " + line.Text + "\n")
+
+		err := json.Unmarshal([]byte(line.Text), &js)
+		if err != nil {
+			panic(err)
+		}
+		fmt.Printf("JSON counter field: " + js.Counter + "\n")
+	}
+}
+
+func createJSON(file *os.File) {
+	var counter int
+	for {
+		file.WriteString("{ \"counter\": \"" + strconv.Itoa(counter) + "\"}\n")
+		counter++
+	}
+}