【ETCD】【源码阅读】深入分析 storeTxnWrite.Put方法源码

该方法是 storeTxnWrite 类型中的核心方法，负责将键值对存储到数据库，同时处理键的元数据（如版本、修订号、租约）并管理租约关联。

一、完整代码

func (tw *storeTxnWrite) put(key, value []byte, leaseID lease.LeaseID) {
   
   
	rev := tw.beginRev + 1
	c := rev
	oldLease := lease.NoLease

	// if the key exists before, use its previous created and
	// get its previous leaseID
	_, created, ver, err := tw.s.kvindex.Get(key, rev)
	if err == nil {
   
   
		c = created.main
		oldLease = tw.s.le.GetLease(lease.LeaseItem{
   
   Key: string(key)})
		tw.trace.Step("get key's previous created_revision and leaseID")
	}
	ibytes := newRevBytes()
	idxRev := revision{
   
   main: rev, sub: int64(len(tw.changes))}
	revToBytes(idxRev, ibytes)

	ver = ver + 1
	kv := mvccpb.KeyValue{
   
   
		Key:            key,
		Value:          value,
		CreateRevision: c,
		ModRevision:    rev,
		Version:        ver,
		Lease:          int64(leaseID),
	}

	d, err := kv.Marshal()
	if err != nil {
   
   
		tw.storeTxnRead.s.lg.Fatal(
			"failed to marshal mvccpb.KeyValue",
			zap.