server: Move server files to 'server' directory.

26 git mv mvcc wal auth etcdserver etcdmain proxy embed/ lease/ server 36 git mv go.mod go.sum server
2024-09-27 06:25:44 +00:00 · 2020-10-20 23:05:17 +02:00
parent eee8dec0c3
commit 4a5e9d1261
316 changed files with 0 additions and 0 deletions
--- a/server/proxy/tcpproxy/userspace.go
+++ b/server/proxy/tcpproxy/userspace.go
@@ -0,0 +1,231 @@
+// Copyright 2016 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tcpproxy
+
+import (
+	"fmt"
+	"io"
+	"math/rand"
+	"net"
+	"sync"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+type remote struct {
+	mu       sync.Mutex
+	srv      *net.SRV
+	addr     string
+	inactive bool
+}
+
+func (r *remote) inactivate() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.inactive = true
+}
+
+func (r *remote) tryReactivate() error {
+	conn, err := net.Dial("tcp", r.addr)
+	if err != nil {
+		return err
+	}
+	conn.Close()
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.inactive = false
+	return nil
+}
+
+func (r *remote) isActive() bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return !r.inactive
+}
+
+type TCPProxy struct {
+	Logger          *zap.Logger
+	Listener        net.Listener
+	Endpoints       []*net.SRV
+	MonitorInterval time.Duration
+
+	donec chan struct{}
+
+	mu        sync.Mutex // guards the following fields
+	remotes   []*remote
+	pickCount int // for round robin
+}
+
+func (tp *TCPProxy) Run() error {
+	tp.donec = make(chan struct{})
+	if tp.MonitorInterval == 0 {
+		tp.MonitorInterval = 5 * time.Minute
+	}
+	for _, srv := range tp.Endpoints {
+		addr := fmt.Sprintf("%s:%d", srv.Target, srv.Port)
+		tp.remotes = append(tp.remotes, &remote{srv: srv, addr: addr})
+	}
+
+	eps := []string{}
+	for _, ep := range tp.Endpoints {
+		eps = append(eps, fmt.Sprintf("%s:%d", ep.Target, ep.Port))
+	}
+	if tp.Logger != nil {
+		tp.Logger.Info("ready to proxy client requests", zap.Strings("endpoints", eps))
+	}
+
+	go tp.runMonitor()
+	for {
+		in, err := tp.Listener.Accept()
+		if err != nil {
+			return err
+		}
+
+		go tp.serve(in)
+	}
+}
+
+func (tp *TCPProxy) pick() *remote {
+	var weighted []*remote
+	var unweighted []*remote
+
+	bestPr := uint16(65535)
+	w := 0
+	// find best priority class
+	for _, r := range tp.remotes {
+		switch {
+		case !r.isActive():
+		case r.srv.Priority < bestPr:
+			bestPr = r.srv.Priority
+			w = 0
+			weighted = nil
+			unweighted = nil
+			fallthrough
+		case r.srv.Priority == bestPr:
+			if r.srv.Weight > 0 {
+				weighted = append(weighted, r)
+				w += int(r.srv.Weight)
+			} else {
+				unweighted = append(unweighted, r)
+			}
+		}
+	}
+	if weighted != nil {
+		if len(unweighted) > 0 && rand.Intn(100) == 1 {
+			// In the presence of records containing weights greater
+			// than 0, records with weight 0 should have a very small
+			// chance of being selected.
+			r := unweighted[tp.pickCount%len(unweighted)]
+			tp.pickCount++
+			return r
+		}
+		// choose a uniform random number between 0 and the sum computed
+		// (inclusive), and select the RR whose running sum value is the
+		// first in the selected order
+		choose := rand.Intn(w)
+		for i := 0; i < len(weighted); i++ {
+			choose -= int(weighted[i].srv.Weight)
+			if choose <= 0 {
+				return weighted[i]
+			}
+		}
+	}
+	if unweighted != nil {
+		for i := 0; i < len(tp.remotes); i++ {
+			picked := tp.remotes[tp.pickCount%len(tp.remotes)]
+			tp.pickCount++
+			if picked.isActive() {
+				return picked
+			}
+		}
+	}
+	return nil
+}
+
+func (tp *TCPProxy) serve(in net.Conn) {
+	var (
+		err error
+		out net.Conn
+	)
+
+	for {
+		tp.mu.Lock()
+		remote := tp.pick()
+		tp.mu.Unlock()
+		if remote == nil {
+			break
+		}
+		// TODO: add timeout
+		out, err = net.Dial("tcp", remote.addr)
+		if err == nil {
+			break
+		}
+		remote.inactivate()
+		if tp.Logger != nil {
+			tp.Logger.Warn("deactivated endpoint", zap.String("address", remote.addr), zap.Duration("interval", tp.MonitorInterval), zap.Error(err))
+		}
+	}
+
+	if out == nil {
+		in.Close()
+		return
+	}
+
+	go func() {
+		io.Copy(in, out)
+		in.Close()
+		out.Close()
+	}()
+
+	io.Copy(out, in)
+	out.Close()
+	in.Close()
+}
+
+func (tp *TCPProxy) runMonitor() {
+	for {
+		select {
+		case <-time.After(tp.MonitorInterval):
+			tp.mu.Lock()
+			for _, rem := range tp.remotes {
+				if rem.isActive() {
+					continue
+				}
+				go func(r *remote) {
+					if err := r.tryReactivate(); err != nil {
+						if tp.Logger != nil {
+							tp.Logger.Warn("failed to activate endpoint (stay inactive for another interval)", zap.String("address", r.addr), zap.Duration("interval", tp.MonitorInterval), zap.Error(err))
+						}
+					} else {
+						if tp.Logger != nil {
+							tp.Logger.Info("activated", zap.String("address", r.addr))
+						}
+					}
+				}(rem)
+			}
+			tp.mu.Unlock()
+		case <-tp.donec:
+			return
+		}
+	}
+}
+
+func (tp *TCPProxy) Stop() {
+	// graceful shutdown?
+	// shutdown current connections?
+	tp.Listener.Close()
+	close(tp.donec)
+}