net/http: add Transport.IdleConnTimeout

Don't keep idle HTTP client connections open forever. Add a new knob,
Transport.IdleConnTimeout, and make the default be 90 seconds. I
figure 90 seconds is more than a minute, and less than infinite, and I
figure enough code has things waking up once a minute polling APIs.

This also removes the Transport's idleCount field which was unused and
redundant with the size of the idleLRU map (which was actually used).

Change-Id: Ibb698a9a9a26f28e00a20fe7ed23f4afb20c2322
Reviewed-on: https://go-review.googlesource.com/22670
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 13 insertions, 6 deletions

diff --git a/src/net/http/export_test.go b/src/net/http/export_test.go
index d1baed896a..3ebc51b19e 100644
--- a/src/net/http/export_test.go
+++ b/src/net/http/export_test.go
@@ -81,9 +81,6 @@ func (t *Transport) IdleConnKeysForTesting() (keys []string) {
 	keys = make([]string, 0)
 	t.idleMu.Lock()
 	defer t.idleMu.Unlock()
-	if t.idleConn == nil {
-		return
-	}
 	for key := range t.idleConn {
 		keys = append(keys, key.String())
 	}
@@ -91,12 +88,22 @@ func (t *Transport) IdleConnKeysForTesting() (keys []string) {
 	return
 }
 
-func (t *Transport) IdleConnCountForTesting(cacheKey string) int {
+func (t *Transport) IdleConnStrsForTesting() []string {
+	var ret []string
 	t.idleMu.Lock()
 	defer t.idleMu.Unlock()
-	if t.idleConn == nil {
-		return 0
+	for _, conns := range t.idleConn {
+		for _, pc := range conns {
+			ret = append(ret, pc.conn.LocalAddr().String()+"/"+pc.conn.RemoteAddr().String())
+		}
 	}
+	sort.Strings(ret)
+	return ret
+}
+
+func (t *Transport) IdleConnCountForTesting(cacheKey string) int {
+	t.idleMu.Lock()
+	defer t.idleMu.Unlock()
 	for k, conns := range t.idleConn {
 		if k.String() == cacheKey {
 			return len(conns)