Minor usability fixes to config

plugins/mysql/mysql.go

@@ -9,12 +9,8 @@ import (
 	"github.com/influxdb/tivan/plugins"
 )
 
-type Server struct {
-	Address string
-}
-
 type Mysql struct {
-	Servers []*Server
+	Servers []string
 }
 
 var sampleConfig = `
@@ -32,7 +28,7 @@ func (m *Mysql) Description() string {
 	return "Read metrics from one or many mysql servers"
 }
 
-var localhost = &Server{}
+var localhost = ""
 
 func (m *Mysql) Gather(acc plugins.Accumulator) error {
 	if len(m.Servers) == 0 {
@@ -80,8 +76,8 @@ var mappings = []*mapping{
 	},
 }
 
-func (m *Mysql) gatherServer(serv *Server, acc plugins.Accumulator) error {
-	db, err := sql.Open("mysql", serv.Address)
+func (m *Mysql) gatherServer(serv string, acc plugins.Accumulator) error {
+	db, err := sql.Open("mysql", serv)
 	if err != nil {
 		return err
 	}

plugins/postgresql/postgresql.go

@@ -31,7 +31,7 @@ var sampleConfig = `
 # to sslmode=disable as well.
 # 
 
-address = "localhost"
+address = "sslmode=disable"
 
 # A list of databases to pull metrics about. If not specified, metrics for all
 # databases are gathered.
@@ -69,6 +69,10 @@ func (p *Postgresql) Gather(acc plugins.Accumulator) error {
 }
 
 func (p *Postgresql) gatherServer(serv *Server, acc plugins.Accumulator) error {
+	if serv.Address == "" {
+		serv = localhost
+	}
+
 	db, err := sql.Open("postgres", serv.Address)
 	if err != nil {
 		return err

plugins/redis/redis.go

@@ -94,11 +94,19 @@ func (g *Redis) Gather(acc plugins.Accumulator) error {
 	return outerr
 }
 
+const defaultPort = "6379"
+
 func (g *Redis) gatherServer(addr string, acc plugins.Accumulator) error {
 	if g.c == nil {
+
+		_, _, err := net.SplitHostPort(addr)
+		if err != nil {
+			addr = addr + ":" + defaultPort
+		}
+
 		c, err := net.Dial("tcp", addr)
 		if err != nil {
-			return err
+			return fmt.Errorf("Unable to connect to redis server '%s': %s", addr, err)
 		}
 
 		g.c = c