init commit

.gitignore

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+.DS_Store

go.mod

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+module github.com/longbridgeapp/gorm-sharding
+
+go 1.17
+
+require (
+	github.com/longbridgeapp/assert v0.1.0
+	github.com/longbridgeapp/sqlparser v0.2.0
+	github.com/stretchr/testify v1.7.0
+	gorm.io/driver/postgres v1.1.0
+	gorm.io/gorm v1.21.16
+	gorm.io/hints v0.0.0-20210614014355-b8cf5492cb94
+)
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
+	github.com/jackc/pgconn v1.9.1-0.20210724152538-d89c8390a530 // indirect
+	github.com/jackc/pgio v1.0.0 // indirect
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgproto3/v2 v2.1.1 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20200714003250-2b9c44734f2b // indirect
+	github.com/jackc/pgtype v1.8.1 // indirect
+	github.com/jackc/pgx/v4 v4.12.1-0.20210724153913-640aa07df17c // indirect
+	github.com/jinzhu/inflection v1.0.0 // indirect
+	github.com/jinzhu/now v1.1.2 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	golang.org/x/crypto v0.0.0-20210711020723-a769d52b0f97 // indirect
+	golang.org/x/text v0.3.6 // indirect
+	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
+)

keygen/README.md

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+# keygen
+
+Distributed Primary Key generator.

keygen/README_zh.md

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+# keygen
+
+分布式主键生成器。

keygen/id.go

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+package keygen
+
+import (
+	"errors"
+	"log"
+	"net"
+	"sync"
+	"time"
+)
+
+// | 1bit unused | 41bits timestamp | 6bits worker ｜9bits table ｜ 7bits sequence |
+const (
+	timeLeft   = uint8(22)
+	workerLeft = uint8(16)
+	tableLeft  = uint8(7)
+	twepoch    = int64(1624204800000) // start from 2021-06-21
+	seqMax     = 127
+)
+
+type Sequence struct {
+	number    int64
+	timestamp int64
+	sync.Mutex
+}
+
+func (s *Sequence) next(timestamp int64) int64 {
+	s.Lock()
+	defer s.Unlock()
+
+	if timestamp > s.timestamp {
+		s.timestamp = timestamp
+		s.number = 1
+	} else {
+		s.number = s.number + 1
+	}
+
+	return s.number
+}
+
+var sequence Sequence
+var worker int64
+
+func init() {
+	ipv4, err := getIPv4()
+	if err != nil {
+		log.Fatal(err)
+	}
+	worker = int64(ipv4[3]) % 64
+	sequence = Sequence{}
+}
+
+// Next generate a distributed Primary Key
+// tableIdx - table sharding index
+func Next(tableIdx int64) int64 {
+	var now int64
+	var seq int64
+
+	for i := 0; i <= 10; i++ {
+		now = time.Now().UnixNano() / 1e6
+		seq = sequence.next(now)
+		if seq <= seqMax {
+			break
+		}
+		time.Sleep(time.Microsecond * 100)
+	}
+
+	return int64(((now - twepoch) << timeLeft) |
+		(worker << workerLeft) |
+		(tableIdx << tableLeft) |
+		seq)
+}
+
+// getWorkerNumber get the worker number from id
+func getWorkerNumber(id int64) int {
+	return int(id >> int64(workerLeft) & 63)
+}
+
+// TableIdx get the table index from id
+// Give a ID return idx of table shard
+func TableIdx(id int64) int {
+	return int(id >> int64(tableLeft) & 511)
+}
+
+// getIPv4 get the IPv4 address
+func getIPv4() (ip net.IP, err error) {
+	addrs, err := net.InterfaceAddrs()
+	if err != nil {
+		return
+	}
+
+	for _, a := range addrs {
+		if ipnet, ok := a.(*net.IPNet); ok && !ipnet.IP.IsLoopback() {
+			ipv4 := ipnet.IP.To4()
+			if ipv4 != nil {
+				return ipv4, nil
+			}
+		}
+	}
+
+	return nil, errors.New("can not get ipv4")
+}