Move pool to util

util/pool/default.go

@@ -0,0 +1,114 @@
+package pool
+
+import (
+	"sync"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/micro/go-micro/transport"
+)
+
+type pool struct {
+	size int
+	ttl  time.Duration
+	tr   transport.Transport
+
+	sync.Mutex
+	conns map[string][]*poolConn
+}
+
+type poolConn struct {
+	transport.Client
+	id      string
+	created time.Time
+}
+
+func newPool(options Options) *pool {
+	return &pool{
+		size:  options.Size,
+		tr:    options.Transport,
+		ttl:   options.TTL,
+		conns: make(map[string][]*poolConn),
+	}
+}
+
+func (p *pool) Close() error {
+	p.Lock()
+	for k, c := range p.conns {
+		for _, conn := range c {
+			conn.Client.Close()
+		}
+		delete(p.conns, k)
+	}
+	p.Unlock()
+	return nil
+}
+
+// NoOp the Close since we manage it
+func (p *poolConn) Close() error {
+	return nil
+}
+
+func (p *poolConn) Id() string {
+	return p.id
+}
+
+func (p *poolConn) Created() time.Time {
+	return p.created
+}
+
+func (p *pool) Get(addr string, opts ...transport.DialOption) (Conn, error) {
+	p.Lock()
+	conns := p.conns[addr]
+
+	// while we have conns check age and then return one
+	// otherwise we'll create a new conn
+	for len(conns) > 0 {
+		conn := conns[len(conns)-1]
+		conns = conns[:len(conns)-1]
+		p.conns[addr] = conns
+
+		// if conn is old kill it and move on
+		if d := time.Since(conn.Created()); d > p.ttl {
+			conn.Client.Close()
+			continue
+		}
+
+		// we got a good conn, lets unlock and return it
+		p.Unlock()
+
+		return conn, nil
+	}
+
+	p.Unlock()
+
+	// create new conn
+	c, err := p.tr.Dial(addr, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return &poolConn{
+		Client:  c,
+		id:      uuid.New().String(),
+		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()
+	}
+
+	// otherwise put it back for reuse
+	p.Lock()
+	conns := p.conns[conn.Remote()]
+	if len(conns) >= p.size {
+		p.Unlock()
+		return conn.(*poolConn).Client.Close()
+	}
+	p.conns[conn.Remote()] = append(conns, conn.(*poolConn))
+	p.Unlock()
+
+	return nil
+}