Better connection pool handling (#2725)

* [fix] etcd config source prefix issue (#2389)

* http transport data race issue (#2436)

* [fix] #2431 http transport data race issue

* [feature] Ability to close connection while receiving.
Ability to send messages while receiving.
Icreased r channel limit to 100 to more fluently communication.
Do not dropp sent request if r channel is full.

* [fix] Use pool connection close timeout

* [fix] replace Close with private function

* [fix] Do not close the transport client twice in stream connection , the transport client is closed in the rpc codec

* [fix] tests

---------

Co-authored-by: Johnson C <chengqiaosheng@gmail.com>

client/options.go

@@ -27,6 +27,8 @@ var (
 	DefaultPoolSize = 100
 	// DefaultPoolTTL sets the connection pool ttl.
 	DefaultPoolTTL = time.Minute
+	// DefaultPoolCloseTimeout sets the connection pool colse timeout.
+	DefaultPoolCloseTimeout = time.Second
 )
 
 // Options are the Client options.
@@ -63,8 +65,9 @@ type Options struct {
 	Wrappers []Wrapper
 
 	// Connection Pool
-	PoolSize int
-	PoolTTL  time.Duration
+	PoolSize         int
+	PoolTTL          time.Duration
+	PoolCloseTimeout time.Duration
 }
 
 // CallOptions are options used to make calls to a server.
@@ -140,13 +143,14 @@ func NewOptions(options ...Option) Options {
 			ConnectionTimeout: DefaultConnectionTimeout,
 			DialTimeout:       transport.DefaultDialTimeout,
 		},
-		PoolSize:  DefaultPoolSize,
-		PoolTTL:   DefaultPoolTTL,
-		Broker:    broker.DefaultBroker,
-		Selector:  selector.DefaultSelector,
-		Registry:  registry.DefaultRegistry,
-		Transport: transport.DefaultTransport,
-		Logger:    logger.DefaultLogger,
+		PoolSize:         DefaultPoolSize,
+		PoolTTL:          DefaultPoolTTL,
+		PoolCloseTimeout: DefaultPoolCloseTimeout,
+		Broker:           broker.DefaultBroker,
+		Selector:         selector.DefaultSelector,
+		Registry:         registry.DefaultRegistry,
+		Transport:        transport.DefaultTransport,
+		Logger:           logger.DefaultLogger,
 	}
 
 	for _, o := range options {
@@ -191,6 +195,13 @@ func PoolTTL(d time.Duration) Option {
 	}
 }
 
+// PoolCloseTimeout sets the connection pool close timeout.
+func PoolCloseTimeout(d time.Duration) Option {
+	return func(o *Options) {
+		o.PoolCloseTimeout = d
+	}
+}
+
 // Registry to find nodes for a given service.
 func Registry(r registry.Registry) Option {
 	return func(o *Options) {

client/rpc_client.go

@@ -46,6 +46,7 @@ func newRPCClient(opt ...Option) Client {
 		pool.Size(opts.PoolSize),
 		pool.TTL(opts.PoolTTL),
 		pool.Transport(opts.Transport),
+		pool.CloseTimeout(opts.PoolCloseTimeout),
 	)
 
 	rc := &rpcClient{
@@ -148,7 +149,10 @@ func (r *rpcClient) call(
 
 	c, err := r.pool.Get(address, dOpts...)
 	if err != nil {
-		return merrors.InternalServerError("go.micro.client", "connection error: %v", err)
+		if c == nil {
+			return merrors.InternalServerError("go.micro.client", "connection error: %v", err)
+		}
+		logger.Log(log.ErrorLevel, "failed to close pool", err)
 	}
 
 	seq := atomic.AddUint64(&r.seq, 1) - 1

cmd/cmd.go

@@ -565,6 +565,14 @@ func (c *cmd) Before(ctx *cli.Context) error {
 		clientOpts = append(clientOpts, client.PoolTTL(d))
 	}
 
+	if t := ctx.String("client_pool_close_timeout"); len(t) > 0 {
+		d, err := time.ParseDuration(t)
+		if err != nil {
+			return fmt.Errorf("failed to parse client_pool_close_timeout: %v", t)
+		}
+		clientOpts = append(clientOpts, client.PoolCloseTimeout(d))
+	}
+
 	// We have some command line opts for the server.
 	// Lets set it up
 	if len(serverOpts) > 0 {

util/pool/default.go

@@ -1,6 +1,7 @@
 package pool
 
 import (
+	"errors"
 	"sync"
 	"time"
 
@@ -12,37 +13,40 @@ import (
 type pool struct {
 	tr transport.Transport
 
-	conns map[string][]*poolConn
-	size  int
-	ttl   time.Duration
-
-	sync.Mutex
+	closeTimeout time.Duration
+	conns        map[string][]*poolConn
+	mu           sync.Mutex
+	size         int
+	ttl          time.Duration
 }
 
 type poolConn struct {
-	created time.Time
 	transport.Client
-	id string
+
+	closeTimeout time.Duration
+	created      time.Time
+	id           string
 }
 
 func newPool(options Options) *pool {
 	return &pool{
-		size:  options.Size,
-		tr:    options.Transport,
-		ttl:   options.TTL,
-		conns: make(map[string][]*poolConn),
+		size:         options.Size,
+		tr:           options.Transport,
+		ttl:          options.TTL,
+		closeTimeout: options.CloseTimeout,
+		conns:        make(map[string][]*poolConn),
 	}
 }
 
 func (p *pool) Close() error {
-	p.Lock()
-	defer p.Unlock()
+	p.mu.Lock()
+	defer p.mu.Unlock()
 
 	var err error
 
 	for k, c := range p.conns {
 		for _, conn := range c {
-			if nerr := conn.Client.Close(); nerr != nil {
+			if nerr := conn.close(); nerr != nil {
 				err = nerr
 			}
 		}
@@ -67,7 +71,7 @@ func (p *poolConn) Created() time.Time {
 }
 
 func (p *pool) Get(addr string, opts ...transport.DialOption) (Conn, error) {
-	p.Lock()
+	p.mu.Lock()
 	conns := p.conns[addr]
 
 	// While we have conns check age and then return one
@@ -79,22 +83,30 @@ func (p *pool) Get(addr string, opts ...transport.DialOption) (Conn, error) {
 
 		// If conn is old kill it and move on
 		if d := time.Since(conn.Created()); d > p.ttl {
-			if err := conn.Client.Close(); err != nil {
-				p.Unlock()
-				return nil, err
+			if err := conn.close(); err != nil {
+				p.mu.Unlock()
+				c, errConn := p.newConn(addr, opts)
+				if errConn != nil {
+					return nil, errConn
+				}
+				return c, err
 			}
 
 			continue
 		}
 
 		// We got a good conn, lets unlock and return it
-		p.Unlock()
+		p.mu.Unlock()
 
 		return conn, nil
 	}
 
-	p.Unlock()
+	p.mu.Unlock()
 
+	return p.newConn(addr, opts)
+}
+
+func (p *pool) newConn(addr string, opts []transport.DialOption) (Conn, error) {
 	// create new conn
 	c, err := p.tr.Dial(addr, opts...)
 	if err != nil {
@@ -102,28 +114,46 @@ func (p *pool) Get(addr string, opts ...transport.DialOption) (Conn, error) {
 	}
 
 	return &poolConn{
-		Client:  c,
-		id:      uuid.New().String(),
-		created: time.Now(),
+		Client:       c,
+		id:           uuid.New().String(),
+		closeTimeout: p.closeTimeout,
+		created:      time.Now(),
 	}, nil
 }
 
 func (p *pool) Release(conn Conn, err error) error {
 	// don't store the conn if it has errored
 	if err != nil {
-		return conn.(*poolConn).Client.Close()
+		return conn.(*poolConn).close()
 	}
 
 	// otherwise put it back for reuse
-	p.Lock()
-	defer p.Unlock()
+	p.mu.Lock()
+	defer p.mu.Unlock()
 
 	conns := p.conns[conn.Remote()]
 	if len(conns) >= p.size {
-		return conn.(*poolConn).Client.Close()
+		return conn.(*poolConn).close()
 	}
 
 	p.conns[conn.Remote()] = append(conns, conn.(*poolConn))
 
 	return nil
 }
+
+func (p *poolConn) close() error {
+	ch := make(chan error)
+	go func() {
+		defer close(ch)
+		ch <- p.Client.Close()
+	}()
+	t := time.NewTimer(p.closeTimeout)
+	var err error
+	select {
+	case <-t.C:
+		err = errors.New("unable to close in time")
+	case err = <-ch:
+		t.Stop()
+	}
+	return err
+}

util/pool/default_test.go

@@ -73,12 +73,12 @@ func testPool(t *testing.T, size int, ttl time.Duration) {
 		// release the conn
 		p.Release(c, nil)
 
-		p.Lock()
+		p.mu.Lock()
 		if i := len(p.conns[l.Addr()]); i > size {
-			p.Unlock()
+			p.mu.Unlock()
 			t.Fatalf("pool size %d is greater than expected %d", i, size)
 		}
-		p.Unlock()
+		p.mu.Unlock()
 	}
 }
 

util/pool/options.go

@@ -7,9 +7,10 @@ import (
 )
 
 type Options struct {
-	Transport transport.Transport
-	TTL       time.Duration
-	Size      int
+	Transport    transport.Transport
+	TTL          time.Duration
+	CloseTimeout time.Duration
+	Size         int
 }
 
 type Option func(*Options)
@@ -31,3 +32,9 @@ func TTL(t time.Duration) Option {
 		o.TTL = t
 	}
 }
+
+func CloseTimeout(t time.Duration) Option {
+	return func(o *Options) {
+		o.CloseTimeout = t
+	}
+}