Improve timeout in input plugins

plugins/inputs/redis/redis.go

@@ -9,6 +9,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/plugins/inputs"
@@ -30,6 +31,8 @@ var sampleConfig = `
   servers = ["tcp://localhost:6379"]
 `
 
+var defaultTimeout = 5 * time.Second
+
 func (r *Redis) SampleConfig() string {
 	return sampleConfig
 }
@@ -120,12 +123,15 @@ func (r *Redis) gatherServer(addr *url.URL, acc telegraf.Accumulator) error {
 		addr.Host = addr.Host + ":" + defaultPort
 	}
 
-	c, err := net.Dial("tcp", addr.Host)
+	c, err := net.DialTimeout("tcp", addr.Host, defaultTimeout)
 	if err != nil {
 		return fmt.Errorf("Unable to connect to redis server '%s': %s", addr.Host, err)
 	}
 	defer c.Close()
 
+	// Extend connection
+	c.SetDeadline(time.Now().Add(defaultTimeout))
+
 	if addr.User != nil {
 		pwd, set := addr.User.Password()
 		if set && pwd != "" {