Improve timeout in input plugins

plugins/inputs/mysql/mysql.go

@@ -2,8 +2,10 @@ package mysql
 
 import (
 	"database/sql"
+	"net/url"
 	"strconv"
 	"strings"
+	"time"
 
 	_ "github.com/go-sql-driver/mysql"
 	"github.com/influxdata/telegraf"
@@ -26,6 +28,8 @@ var sampleConfig = `
   servers = ["tcp(127.0.0.1:3306)/"]
 `
 
+var defaultTimeout = time.Second * time.Duration(5)
+
 func (m *Mysql) SampleConfig() string {
 	return sampleConfig
 }
@@ -122,6 +126,10 @@ func (m *Mysql) gatherServer(serv string, acc telegraf.Accumulator) error {
 		serv = ""
 	}
 
+	serv, err := dsnAddTimeout(serv)
+	if err != nil {
+		return err
+	}
 	db, err := sql.Open("mysql", serv)
 	if err != nil {
 		return err
@@ -207,6 +215,21 @@ func (m *Mysql) gatherServer(serv string, acc telegraf.Accumulator) error {
 	return nil
 }
 
+func dsnAddTimeout(dsn string) (string, error) {
+	u, err := url.Parse(dsn)
+	if err != nil {
+		return "", err
+	}
+	v := u.Query()
+
+	// Only override timeout if not already defined
+	if _, ok := v["timeout"]; ok == false {
+		v.Add("timeout", defaultTimeout.String())
+		u.RawQuery = v.Encode()
+	}
+	return u.String(), nil
+}
+
 func init() {
 	inputs.Add("mysql", func() telegraf.Input {
 		return &Mysql{}

plugins/inputs/mysql/mysql_test.go

@@ -84,3 +84,38 @@ func TestMysqlParseDSN(t *testing.T) {
 		}
 	}
 }
+
+func TestMysqlDNSAddTimeout(t *testing.T) {
+	tests := []struct {
+		input  string
+		output string
+	}{
+		{
+			"",
+			"?timeout=5s",
+		},
+		{
+			"127.0.0.1",
+			"127.0.0.1?timeout=5s",
+		},
+		{
+			"tcp(192.168.1.1:3306)/",
+			"tcp(192.168.1.1:3306)/?timeout=5s",
+		},
+		{
+			"root:passwd@tcp(192.168.1.1:3306)/?tls=false",
+			"root:passwd@tcp(192.168.1.1:3306)/?timeout=5s&tls=false",
+		},
+		{
+			"root:passwd@tcp(192.168.1.1:3306)/?tls=false&timeout=10s",
+			"root:passwd@tcp(192.168.1.1:3306)/?tls=false&timeout=10s",
+		},
+	}
+
+	for _, test := range tests {
+		output, _ := parseDSN(test.input)
+		if output != test.output {
+			t.Errorf("Expected %s, got %s\n", test.output, output)
+		}
+	}
+}