HTTP Client: Introduce `dataproxy_max_idle_connections` config variable (#35864)

* Introduce dataproxy_max_idle_connections config var

* Fix according to reviewer's comments

* Fix according to reviewer's comments - round 2

* Remove unused const

* Bring back MaxIdleConnsPerHost

* Fixes according to reviewer's comments

conf/defaults.ini

@@ -166,9 +166,6 @@ max_conns_per_host = 0
 # The maximum number of idle connections that Grafana will keep alive.
 max_idle_connections = 100
 
-# The maximum number of idle connections per host that Grafana will keep alive.
-max_idle_connections_per_host = 2
-
 # How many seconds the data proxy keeps an idle connection open before timing out.
 idle_conn_timeout_seconds = 90
 

conf/sample.ini

@@ -172,9 +172,6 @@
 # The maximum number of idle connections that Grafana will keep alive.
 ;max_idle_connections = 100
 
-# The maximum number of idle connections per host that Grafana will keep alive.
-;max_idle_connections_per_host = 2
-
 # How many seconds the data proxy keeps an idle connection open before timing out.
 ;idle_conn_timeout_seconds = 90
 

docs/sources/administration/configuration.md

@@ -424,6 +424,7 @@ For more details check the [Transport.MaxConnsPerHost](https://golang.org/pkg/ne
 The maximum number of idle connections that Grafana will maintain. Default is `100`. For more details check the [Transport.MaxIdleConns](https://golang.org/pkg/net/http/#Transport.MaxIdleConns) documentation.
 
 ### max_idle_connections_per_host
+[Deprecated - use max_idle_connections instead]
 
 The maximum number of idle connections per host that Grafana will maintain. Default is `2`. For more details check the [Transport.MaxIdleConnsPerHost](https://golang.org/pkg/net/http/#Transport.MaxIdleConnsPerHost) documentation.
 

pkg/models/datasource_cache.go

@@ -84,19 +84,20 @@ func (ds *DataSource) GetHTTPTransport(provider httpclient.Provider, customMiddl
 
 func (ds *DataSource) HTTPClientOptions() sdkhttpclient.Options {
 	tlsOptions := ds.TLSOptions()
+	timeouts := &sdkhttpclient.TimeoutOptions{
+		Timeout:               ds.getTimeout(),
+		DialTimeout:           time.Duration(setting.DataProxyDialTimeout) * time.Second,
+		KeepAlive:             time.Duration(setting.DataProxyKeepAlive) * time.Second,
+		TLSHandshakeTimeout:   time.Duration(setting.DataProxyTLSHandshakeTimeout) * time.Second,
+		ExpectContinueTimeout: time.Duration(setting.DataProxyExpectContinueTimeout) * time.Second,
+		MaxConnsPerHost:       setting.DataProxyMaxConnsPerHost,
+		MaxIdleConns:          setting.DataProxyMaxIdleConns,
+		MaxIdleConnsPerHost:   setting.DataProxyMaxIdleConns,
+		IdleConnTimeout:       time.Duration(setting.DataProxyIdleConnTimeout) * time.Second,
+	}
 	opts := sdkhttpclient.Options{
-		Timeouts: &sdkhttpclient.TimeoutOptions{
-			Timeout:               ds.getTimeout(),
-			DialTimeout:           time.Duration(setting.DataProxyDialTimeout) * time.Second,
-			KeepAlive:             time.Duration(setting.DataProxyKeepAlive) * time.Second,
-			TLSHandshakeTimeout:   time.Duration(setting.DataProxyTLSHandshakeTimeout) * time.Second,
-			ExpectContinueTimeout: time.Duration(setting.DataProxyExpectContinueTimeout) * time.Second,
-			MaxConnsPerHost:       setting.DataProxyMaxConnsPerHost,
-			MaxIdleConns:          setting.DataProxyMaxIdleConns,
-			MaxIdleConnsPerHost:   setting.DataProxyMaxIdleConnsPerHost,
-			IdleConnTimeout:       time.Duration(setting.DataProxyIdleConnTimeout) * time.Second,
-		},
-		Headers: getCustomHeaders(ds.JsonData, ds.DecryptedValues()),
+		Timeouts: timeouts,
+		Headers:  getCustomHeaders(ds.JsonData, ds.DecryptedValues()),
 		Labels: map[string]string{
 			"datasource_name": ds.Name,
 			"datasource_uid":  ds.Uid,

pkg/setting/setting.go

@@ -850,11 +850,15 @@ func (cfg *Cfg) Load(args *CommandLineArgs) error {
 	DataProxyTLSHandshakeTimeout = dataproxy.Key("tls_handshake_timeout_seconds").MustInt(10)
 	DataProxyExpectContinueTimeout = dataproxy.Key("expect_continue_timeout_seconds").MustInt(1)
 	DataProxyMaxConnsPerHost = dataproxy.Key("max_conns_per_host").MustInt(0)
-	DataProxyMaxIdleConns = dataproxy.Key("max_idle_connections").MustInt(100)
-	DataProxyMaxIdleConnsPerHost = dataproxy.Key("max_idle_connections_per_host").MustInt(2)
+	DataProxyMaxIdleConns = dataproxy.Key("max_idle_connections").MustInt()
 	DataProxyIdleConnTimeout = dataproxy.Key("idle_conn_timeout_seconds").MustInt(90)
 	cfg.SendUserHeader = dataproxy.Key("send_user_header").MustBool(false)
 
+	if val, err := dataproxy.Key("max_idle_connections_per_host").Int(); err == nil {
+		cfg.Logger.Warn("[Deprecated] the configuration setting 'max_idle_connections_per_host' is deprecated, please use 'max_idle_connections' instead")
+		DataProxyMaxIdleConns = val
+	}
+
 	if err := readSecuritySettings(iniFile, cfg); err != nil {
 		return err
 	}