finished dist id

ch6-cloud/ch6-07-dist-id.md

@@ -162,3 +162,62 @@ redis 127.0.0.1:6379> SADD base64_encoding_of_last16bits MzI0Mgo=
 redis 127.0.0.1:6379> SADD base64_encoding_of_last16bits MzI0Mgo=
 (integer) 0
 ```
+
+使用起来也比较简单，有一些逻辑简单的函数就略去实现了：
+
+```go
+package main
+
+import (
+    "fmt"
+    "os"
+    "time"
+
+    "github.com/sony/sonyflake"
+)
+
+func getMachineID() (uint16, error) {
+    var machineID uint16
+    var err error
+    machineID = readMachineIDFromLocalFile()
+    if machineID == 0 {
+        machineID, err = generateMachineID()
+        if err != nil {
+            return 0, err
+        }
+    }
+
+    return machineID, nil
+}
+
+func checkMachineID(machineID uint16) bool {
+    saddResult, err := saddMachineIDToRedisSet()
+    if err != nil || saddResult == 0 {
+        return true
+    }
+
+    err := saveMachineIDToLocalFile(machineID)
+    if err != nil {
+        return true
+    }
+
+    return false
+}
+
+func main() {
+    t, _ := time.Parse("2006-01-02", "2018-01-01")
+    settings := sonyflake.Settings{
+        StartTime: t,
+        MachineID: getMachineID,
+    }
+
+    sf := sonyflake.NewSonyflake(settings)
+    id, err := sf.NextID()
+    if err != nil {
+        fmt.Println(err)
+        os.Exit(1)
+    }
+
+    fmt.Println(id)
+}
+```