Add ability to generate config from available plugins

plugins/mysql/mysql.go

@@ -14,17 +14,27 @@ type Server struct {
 }
 
 type Mysql struct {
-	Disabled bool
-	Servers  []*Server
+	Servers []*Server
+}
+
+var sampleConfig = `
+# specify servers via a url matching:
+#  [username[:password]@][protocol[(address)]]/[?tls=[true|false|skip-verify]]
+#
+# If no servers are specified, then localhost is used as the host.
+servers = ["localhost"]`
+
+func (m *Mysql) SampleConfig() string {
+	return sampleConfig
+}
+
+func (m *Mysql) Description() string {
+	return "Read metrics from one or many mysql servers"
 }
 
 var localhost = &Server{}
 
 func (m *Mysql) Gather(acc plugins.Accumulator) error {
-	if m.Disabled {
-		return nil
-	}
-
 	if len(m.Servers) == 0 {
 		// if we can't get stats in this case, thats fine, don't report
 		// an error.

plugins/postgresql/postgresql.go

@@ -17,6 +17,39 @@ type Postgresql struct {
 	Servers []*Server
 }
 
+var sampleConfig = `
+# specify servers via an array of tables
+[[postgresql.servers]]
+
+# specify address via a url matching:
+#   postgres://[pqgotest[:password]]@localhost?sslmode=[disable|verify-ca|verify-full]
+# or a simple string:
+#   host=localhost user=pqotest password=... sslmode=...
+# 
+# All connection parameters are optional. By default, the host is localhost
+# and the user is the currently running user. For localhost, we default
+# to sslmode=disable as well.
+# 
+
+address = "localhost"
+
+# A list of databases to pull metrics about. If not specified, metrics for all
+# databases are gathered.
+
+# databases = ["app_production", "blah_testing"]
+
+# [[postgresql.servers]]
+# address = "influx@remoteserver"
+`
+
+func (p *Postgresql) SampleConfig() string {
+	return sampleConfig
+}
+
+func (p *Postgresql) Description() string {
+	return "Read metrics from one or many postgresql servers"
+}
+
 var localhost = &Server{Address: "sslmode=disable"}
 
 func (p *Postgresql) Gather(acc plugins.Accumulator) error {

plugins/redis/redis.go

@@ -13,14 +13,27 @@ import (
 )
 
 type Redis struct {
-	Disabled bool
-	Address  string
-	Servers  []string
+	Servers []string
 
 	c   net.Conn
 	buf []byte
 }
 
+var sampleConfig = `
+# An array of address to gather stats about. Specify an ip on hostname
+# with optional port. ie localhost, 10.10.3.33:18832, etc.
+#
+# If no servers are specified, then localhost is used as the host.
+servers = ["localhost"]`
+
+func (r *Redis) SampleConfig() string {
+	return sampleConfig
+}
+
+func (r *Redis) Description() string {
+	return "Read metrics from one or many redis servers"
+}
+
 var Tracking = map[string]string{
 	"uptime_in_seconds":           "uptime",
 	"connected_clients":           "clients",
@@ -59,19 +72,7 @@ var ErrProtocolError = errors.New("redis protocol error")
 // Reads stats from all configured servers accumulates stats.
 // Returns one of the errors encountered while gather stats (if any).
 func (g *Redis) Gather(acc plugins.Accumulator) error {
-	if g.Disabled {
-		return nil
-	}
-
-	var servers []string
-
-	if g.Address != "" {
-		servers = append(servers, g.Address)
-	}
-
-	servers = append(servers, g.Servers...)
-
-	if len(servers) == 0 {
+	if len(g.Servers) == 0 {
 		g.gatherServer(":6379", acc)
 		return nil
 	}
@@ -80,7 +81,7 @@ func (g *Redis) Gather(acc plugins.Accumulator) error {
 
 	var outerr error
 
-	for _, serv := range servers {
+	for _, serv := range g.Servers {
 		wg.Add(1)
 		go func(serv string) {
 			defer wg.Done()

plugins/registry.go

@@ -5,6 +5,8 @@ type Accumulator interface {
 }
 
 type Plugin interface {
+	SampleConfig() string
+	Description() string
 	Gather(Accumulator) error
 }
 

plugins/system/system.go

@@ -46,6 +46,12 @@ type CPUStats struct {
 	ps PS
 }
 
+func (_ *CPUStats) Description() string {
+	return "Read metrics about cpu usage"
+}
+
+func (_ *CPUStats) SampleConfig() string { return "" }
+
 func (s *CPUStats) Gather(acc plugins.Accumulator) error {
 	times, err := s.ps.CPUTimes()
 	if err != nil {
@@ -77,6 +83,12 @@ type DiskStats struct {
 	ps PS
 }
 
+func (_ *DiskStats) Description() string {
+	return "Read metrics about disk usage by mount point"
+}
+
+func (_ *DiskStats) SampleConfig() string { return "" }
+
 func (s *DiskStats) Gather(acc plugins.Accumulator) error {
 	disks, err := s.ps.DiskUsage()
 	if err != nil {
@@ -103,6 +115,12 @@ type DiskIOStats struct {
 	ps PS
 }
 
+func (_ *DiskIOStats) Description() string {
+	return "Read metrics about disk IO by device"
+}
+
+func (_ *DiskIOStats) SampleConfig() string { return "" }
+
 func (s *DiskIOStats) Gather(acc plugins.Accumulator) error {
 	diskio, err := s.ps.DiskIO()
 	if err != nil {
@@ -131,6 +149,12 @@ type NetIOStats struct {
 	ps PS
 }
 
+func (_ *NetIOStats) Description() string {
+	return "Read metrics about network interface usage"
+}
+
+func (_ *NetIOStats) SampleConfig() string { return "" }
+
 func (s *NetIOStats) Gather(acc plugins.Accumulator) error {
 	netio, err := s.ps.NetIO()
 	if err != nil {
@@ -159,6 +183,12 @@ type MemStats struct {
 	ps PS
 }
 
+func (_ *MemStats) Description() string {
+	return "Read metrics about memory usage"
+}
+
+func (_ *MemStats) SampleConfig() string { return "" }
+
 func (s *MemStats) Gather(acc plugins.Accumulator) error {
 	vm, err := s.ps.VMStat()
 	if err != nil {
@@ -186,6 +216,12 @@ type SwapStats struct {
 	ps PS
 }
 
+func (_ *SwapStats) Description() string {
+	return "Read metrics about swap memory usage"
+}
+
+func (_ *SwapStats) SampleConfig() string { return "" }
+
 func (s *SwapStats) Gather(acc plugins.Accumulator) error {
 	swap, err := s.ps.SwapStat()
 	if err != nil {
@@ -208,6 +244,12 @@ type DockerStats struct {
 	ps PS
 }
 
+func (_ *DockerStats) Description() string {
+	return "Read metrics about docker containers"
+}
+
+func (_ *DockerStats) SampleConfig() string { return "" }
+
 func (s *DockerStats) Gather(acc plugins.Accumulator) error {
 	containers, err := s.ps.DockerStat()
 	if err != nil {
@@ -271,6 +313,12 @@ type SystemStats struct {
 	ps PS
 }
 
+func (_ *SystemStats) Description() string {
+	return "Read metrics about system load"
+}
+
+func (_ *SystemStats) SampleConfig() string { return "" }
+
 func (s *SystemStats) add(acc plugins.Accumulator,
 	name string, val float64, tags map[string]string) {
 	if val >= 0 {