feat(sequence): add group sequence implementation

pkg/sequence/group/group.go

@@ -19,10 +19,20 @@ package group
 
 import (
 	"context"
+	"io"
+	"strconv"
+	"sync"
+)
+
+import (
+	"github.com/pkg/errors"
 )
 
 import (
 	"github.com/arana-db/arana/pkg/proto"
+	"github.com/arana-db/arana/pkg/runtime"
+	rcontext "github.com/arana-db/arana/pkg/runtime/context"
+	"github.com/arana-db/arana/pkg/util/log"
 )
 
 func init() {
@@ -33,22 +43,204 @@ func init() {
 
 const (
 	SequencePluginName = "group"
+
+	_stepKey                 = "step"
+	_startSequence     int64 = 1
+	_defaultGroupStrep int64 = 100
+
+	_initGroupSequenceTableSql = `
+	CREATE TABLE IF NOT EXISTS __arana_group_sequence (
+		id          int AUTO_INCREMENT COMMENT 'primary key',
+		seq_val     bigint COMMENT 'the current group start value',
+		step        int COMMENT 'the step of the group',
+		table_name  varchar(255) NOT NULL COMMENT 'arana logic table name',
+		renew_time  datetime NOT NULL COMMENT 'node renew time',
+		PRIMARY KEY(id),
+		UNIQUE KEY(table_name)
+	) ENGINE = InnoDB;
+	`
+	_initGroupSequence        = `INSERT INTO __arana_group_sequence(seq_val, step, table_name, renew_time) VALUE (?, ?, ?, now())`
+	_selectNextGroupWithXLock = `SELECT seq_val FROM __arana_group_sequence WHERE table_name = ? FOR UPDATE;`
+	_updateNextGroup          = `UPDATE __arana_group_sequence set seq_val = ?, renew_time = now() WHERE table_name = ?;`
+)
+
+var (
+	// mu Solving the competition of the initialization of Sequence related library tables
+	mu sync.Mutex
+
+	finishInitTable = false
 )
 
 type groupSequence struct {
-	workId       int32
-	currentVal   int64
-	preTimestamp int64
+	mu sync.Mutex
+
+	tableName string
+	step      int64
+
+	nextGroupStartVal  int64
+	nextGroupMaxVal    int64
+	currentGroupMaxVal int64
+	currentVal         int64
 }
 
 // Start sequence and do some initialization operations
 func (seq *groupSequence) Start(ctx context.Context, option proto.SequenceConfig) error {
+	rt := ctx.Value(proto.RuntimeCtxKey{}).(runtime.Runtime)
+	ctx = rcontext.WithRead(rcontext.WithDirect(ctx))
+
+	// init table
+	if err := seq.initTableAndKeepalive(ctx, rt); err != nil {
+		return err
+	}
+
+	// init sequence
+	if err := seq.initStep(ctx, rt, option); err != nil {
+		return err
+	}
+
+	seq.tableName = option.Name
+	return nil
+}
+
+func (seq *groupSequence) initTableAndKeepalive(ctx context.Context, rt runtime.Runtime) error {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if finishInitTable {
+		return nil
+	}
+
+	tx, err := rt.Begin(ctx)
+	if err != nil {
+		return err
+	}
+
+	defer tx.Rollback(ctx)
+
+	ret, err := tx.Exec(ctx, "", _initGroupSequenceTableSql)
+	if err != nil {
+		return err
+	}
+	_, _ = ret.RowsAffected()
+
+	if _, _, err := tx.Commit(ctx); err != nil {
+		return err
+	}
+
+	finishInitTable = true
+	return nil
+}
+
+func (seq *groupSequence) initStep(ctx context.Context, rt runtime.Runtime, option proto.SequenceConfig) error {
+	seq.mu.Lock()
+	defer seq.mu.Unlock()
+
+	var step int64
+	stepValue, ok := option.Option[_stepKey]
+	if ok {
+		tempStep, err := strconv.Atoi(stepValue)
+		if err != nil {
+			return err
+		}
+		step = int64(tempStep)
+	} else {
+		step = _defaultGroupStrep
+	}
+	seq.step = step
+
 	return nil
 }
 
-// Acquire Apply for a increase ID
+// Acquire Apply for an increase ID
 func (seq *groupSequence) Acquire(ctx context.Context) (int64, error) {
-	return 0, nil
+	seq.mu.Lock()
+	defer seq.mu.Unlock()
+
+	if seq.currentVal >= seq.currentGroupMaxVal {
+		schema := rcontext.Schema(ctx)
+		rt, err := runtime.Load(schema)
+		if err != nil {
+			log.Errorf("[sequence] load runtime.Runtime from schema=%s fail, %s", schema, err.Error())
+			return 0, err
+		}
+
+		err = seq.acquireNextGroup(ctx, rt)
+		if err != nil {
+			return 0, err
+		}
+		seq.currentVal = seq.nextGroupStartVal
+		seq.currentGroupMaxVal = seq.nextGroupMaxVal
+	} else {
+		seq.currentVal++
+	}
+
+	return seq.currentVal, nil
+}
+
+func (seq *groupSequence) acquireNextGroup(ctx context.Context, rt runtime.Runtime) error {
+	ctx = rcontext.WithDirect(ctx)
+	tx, err := rt.Begin(ctx)
+	if err != nil {
+		return err
+	}
+
+	defer tx.Rollback(ctx)
+
+	rs, err := tx.Query(ctx, "", _selectNextGroupWithXLock, seq.tableName)
+	if err != nil {
+		return err
+	}
+
+	ds, err := rs.Dataset()
+	if err != nil {
+		return err
+	}
+	val := make([]proto.Value, 1)
+	row, err := ds.Next()
+	if err != nil {
+		if errors.Is(err, io.EOF) {
+			seq.nextGroupStartVal = _startSequence
+			seq.nextGroupMaxVal = _startSequence + seq.step - 1
+			rs, err := tx.Exec(ctx, "", _initGroupSequence, seq.nextGroupMaxVal+1, seq.step, seq.tableName)
+			if err != nil {
+				return err
+			}
+			_, _ = rs.RowsAffected()
+
+			_, _, err = tx.Commit(ctx)
+			if err != nil {
+				return err
+			}
+			return nil
+		}
+		return err
+	}
+	if err = row.Scan(val); err != nil {
+		return err
+	}
+	_, _ = ds.Next()
+
+	if val[0] != nil {
+		nextGroupStartVal := val[0].(int64)
+		if nextGroupStartVal%seq.step != 0 {
+			// padding left
+			nextGroupStartVal = (nextGroupStartVal/seq.step + 1) * seq.step
+		}
+		seq.nextGroupStartVal = nextGroupStartVal
+		seq.nextGroupMaxVal = seq.nextGroupStartVal + seq.step - 1
+		rs, err := tx.Exec(ctx, "", _updateNextGroup, seq.nextGroupMaxVal+1, seq.tableName)
+		if err != nil {
+			return err
+		}
+		_, _ = rs.RowsAffected()
+
+		_, _, err = tx.Commit(ctx)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
 }
 
 // Reset resets sequence info