From 38a66817e61966dd34c754fe0c863b9d565087f9 Mon Sep 17 00:00:00 2001
From: Asim <asim@chuhnk.me>
Date: Mon, 6 Jun 2016 23:37:52 +0100
Subject: [PATCH] Add a conn lifetime for the pool

---
 client/rpc_pool.go | 47 ++++++++++++++++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 14 deletions(-)

diff --git a/client/rpc_pool.go b/client/rpc_pool.go
index 7bdf6929..a550c601 100644
--- a/client/rpc_pool.go
+++ b/client/rpc_pool.go
@@ -2,6 +2,7 @@ package client
 
 import (
 	"sync"
+	"time"
 
 	"github.com/micro/go-micro/transport"
 )
@@ -15,10 +16,14 @@ type pool struct {
 
 type poolConn struct {
 	transport.Client
+	created int64
 }
 
 var (
+	// only hold on to this many conns
 	maxIdleConn = 2
+	// only hold on to the conn for this period
+	maxLifeTime = int64(60)
 )
 
 func newPool() *pool {
@@ -34,32 +39,46 @@ func (p *poolConn) Close() error {
 
 func (p *pool) getConn(addr string, tr transport.Transport, opts ...transport.DialOption) (*poolConn, error) {
 	p.Lock()
-	conns, ok := p.conns[addr]
-	// no free conn
-	if !ok || len(conns) == 0 {
-		p.Unlock()
-		// create new conn
-		c, err := tr.Dial(addr, opts...)
-		if err != nil {
-			return nil, err
+	conns := p.conns[addr]
+	now := time.Now().Unix()
+
+	// 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 := now - conn.created; d > maxLifeTime {
+			conn.Client.Close()
+			continue
 		}
-		return &poolConn{c}, nil
+
+		// we got a good conn, lets unlock and return it
+		p.Unlock()
+
+		return conn, nil
 	}
 
-	conn := conns[len(conns)-1]
-	p.conns[addr] = conns[:len(conns)-1]
 	p.Unlock()
-	return conn, nil
+
+	// create new conn
+	c, err := tr.Dial(addr, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return &poolConn{c, time.Now().Unix()}, nil
 }
 
 func (p *pool) release(addr string, conn *poolConn, err error) {
-	// don't store the conn
+	// don't store the conn if it has errored
 	if err != nil {
 		conn.Client.Close()
 		return
 	}
 
-	// otherwise put it back
+	// otherwise put it back for reuse
 	p.Lock()
 	conns := p.conns[addr]
 	if len(conns) >= maxIdleConn {