From e0a4d183013977b5836ae8b06182f747330a243e Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Mon, 11 Sep 2017 09:07:14 +0000
Subject: [PATCH 1/2] Allow http keep-alive setting to be overridden in config

---
 config/config.go        | 2 ++
 util/httputil/client.go | 6 +++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/config/config.go b/config/config.go
index 18eba3a5d..626fd3d1e 100644
--- a/config/config.go
+++ b/config/config.go
@@ -526,6 +526,8 @@ type HTTPClientConfig struct {
 	ProxyURL URL `yaml:"proxy_url,omitempty"`
 	// TLSConfig to use to connect to the targets.
 	TLSConfig TLSConfig `yaml:"tls_config,omitempty"`
+	// If set, override whether to use HTTP KeepAlive - defaults OFF
+	KeepAlive *bool `yaml:"keep_alive,omitempty"`
 
 	// Catches all undefined fields and must be empty after parsing.
 	XXX map[string]interface{} `yaml:",inline"`
diff --git a/util/httputil/client.go b/util/httputil/client.go
index f89ea688e..1c48030d4 100644
--- a/util/httputil/client.go
+++ b/util/httputil/client.go
@@ -36,11 +36,15 @@ func NewClientFromConfig(cfg config.HTTPClientConfig) (*http.Client, error) {
 	if err != nil {
 		return nil, err
 	}
+	disableKeepAlives := true // hard-coded default unless overridden in config
+	if cfg.KeepAlive != nil {
+		disableKeepAlives = !*cfg.KeepAlive
+	}
 	// The only timeout we care about is the configured scrape timeout.
 	// It is applied on request. So we leave out any timings here.
 	var rt http.RoundTripper = &http.Transport{
 		Proxy:             http.ProxyURL(cfg.ProxyURL.URL),
-		DisableKeepAlives: true,
+		DisableKeepAlives: disableKeepAlives,
 		TLSClientConfig:   tlsConfig,
 	}
 

From 9d6b945e415b52c04eba9790da42f072a8cbc0f0 Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Mon, 11 Sep 2017 09:08:26 +0000
Subject: [PATCH 2/2] Default HTTP keep-alive ON for remote read/write

---
 config/config.go         | 2 +-
 storage/remote/client.go | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/config/config.go b/config/config.go
index 626fd3d1e..401bee4f4 100644
--- a/config/config.go
+++ b/config/config.go
@@ -526,7 +526,7 @@ type HTTPClientConfig struct {
 	ProxyURL URL `yaml:"proxy_url,omitempty"`
 	// TLSConfig to use to connect to the targets.
 	TLSConfig TLSConfig `yaml:"tls_config,omitempty"`
-	// If set, override whether to use HTTP KeepAlive - defaults OFF
+	// If set, override whether to use HTTP KeepAlive - scraping defaults OFF, remote read/write defaults ON
 	KeepAlive *bool `yaml:"keep_alive,omitempty"`
 
 	// Catches all undefined fields and must be empty after parsing.
diff --git a/storage/remote/client.go b/storage/remote/client.go
index fc60cfba6..1a20dc43a 100644
--- a/storage/remote/client.go
+++ b/storage/remote/client.go
@@ -51,6 +51,11 @@ type clientConfig struct {
 
 // NewClient creates a new Client.
 func NewClient(index int, conf *clientConfig) (*Client, error) {
+	// If not specified in config, allow HTTP connections for remote API to use keep-alive
+	if conf.httpClientConfig.KeepAlive == nil {
+		val := true
+		conf.httpClientConfig.KeepAlive = &val
+	}
 	httpClient, err := httputil.NewClientFromConfig(conf.httpClientConfig)
 	if err != nil {
 		return nil, err