Add timeout option for kubernetes (#3211)

plugins/inputs/kubernetes/kubernetes.go

@@ -30,6 +30,9 @@ type Kubernetes struct {
 	// Use SSL but skip chain & host verification
 	InsecureSkipVerify bool
 
+	// HTTP Timeout specified as a string - 3s, 1m, 1h
+	ResponseTimeout internal.Duration
+
 	RoundTripper http.RoundTripper
 }
 
@@ -40,6 +43,9 @@ var sampleConfig = `
   ## Use bearer token for authorization
   # bearer_token = /path/to/bearer/token
 
+  ## Set response_timeout (default 5 seconds)
+  # response_timeout = "5s"
+
   ## Optional SSL Config
   # ssl_ca = /path/to/cafile
   # ssl_cert = /path/to/certfile
@@ -101,10 +107,17 @@ func (k *Kubernetes) gatherSummary(baseURL string, acc telegraf.Accumulator) err
 	}
 
 	if k.RoundTripper == nil {
+		// Set default values
+		if k.ResponseTimeout.Duration < time.Second {
+			k.ResponseTimeout.Duration = time.Second * 5
+		}
+		if err != nil {
+			return err
+		}
 		k.RoundTripper = &http.Transport{
 			TLSHandshakeTimeout:   5 * time.Second,
 			TLSClientConfig:       tlsCfg,
-			ResponseHeaderTimeout: time.Duration(3 * time.Second),
+			ResponseHeaderTimeout: k.ResponseTimeout.Duration,
 		}
 	}