【ETCD】【源码阅读】深入分析 applierV3backend.Put`方法源码

本文链接：https://blog.youkuaiyun.com/zhangshenglu1/article/details/144535841

该方法是 applierV3backend 类型中负责处理 Put 操作的核心逻辑，Put 操作将键值对写入存储，同时支持设置租约、忽略值或租约、获取前值等功能。

文章目录

一、完整源码

func (a *applierV3backend) Put(ctx context.Context, txn mvcc.TxnWrite, p *pb.PutRequest) (resp *pb.PutResponse, trace *traceutil.Trace, err error) {
   
	resp = &pb.PutResponse{
   }
	resp.Header = &pb.ResponseHeader{
   }
	trace = traceutil.Get(ctx)
	// create put tracing if the trace in context is empty
	if trace.IsEmpty() {
   
		trace = traceutil.New("put",
			a.s.Logger(),
			traceutil.Field{
   Key: "key", Value: string(p.Key)},
			traceutil.Field{
   Key: "req_size", Value: p.Size()},
		)
	}
	val, leaseID := p.Value, lease.LeaseID(p.Lease)
	if txn == nil {
   
		if leaseID != lease.NoLease {
   
			if l := a.s.lessor.Lookup(leaseID); l == nil {
   
				return nil, nil, lease.ErrLeaseNotFound
			}
		}
		txn = a.s.KV().Write(trace)
		defer txn