Add ability to generate config from available plugins

cmd/tivan/tivan.go

@@ -16,6 +16,7 @@ var fDebug = flag.Bool("debug", false, "show metrics as they're generated to std
 var fTest = flag.Bool("test", false, "gather metrics, print them out, and exit")
 var fConfig = flag.String("config", "", "configuration file to load")
 var fVersion = flag.Bool("version", false, "display the version")
+var fSampleConfig = flag.Bool("sample-config", false, "print out full sample configuration")
 
 var Version = "unreleased"
 
@@ -27,6 +28,11 @@ func main() {
 		return
 	}
 
+	if *fSampleConfig {
+		tivan.PrintSampleConfig()
+		return
+	}
+
 	var (
 		config *tivan.Config
 		err    error

config.go

@@ -8,6 +8,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/influxdb/tivan/plugins"
 	"github.com/naoina/toml"
 	"github.com/naoina/toml/ast"
 )
@@ -113,3 +114,74 @@ func (c *Config) ListTags() string {
 
 	return strings.Join(tags, " ")
 }
+
+type hasConfig interface {
+	BasicConfig() string
+}
+
+type hasDescr interface {
+	Description() string
+}
+
+var header = `# Tivan configuration
+
+# Tivan is entirely plugin driven. All metrics are gathered from the
+# declared plugins.
+
+# Even if a plugin has no configuration, it must be declared in here
+# to be active. Declaring a plugin means just specifying the name
+# as a section with no variables.
+
+# Configuration for influxdb server to send metrics to
+# [influxdb]
+# url = "http://10.20.2.4"
+# username = "tivan"
+# password = "metricsmetricsmetricsmetrics"
+# database = "tivan"
+# user_agent = "tivan"
+# tags = { "dc": "us-east-1" }
+
+# Tags can also be specified via a normal map, but only one form at a time:
+
+# [influxdb.tags]
+# dc = "us-east-1"
+
+# PLUGINS
+
+`
+
+func PrintSampleConfig() {
+	fmt.Printf(header)
+
+	var names []string
+
+	for name, _ := range plugins.Plugins {
+		names = append(names, name)
+	}
+
+	sort.Strings(names)
+
+	for _, name := range names {
+		creator := plugins.Plugins[name]
+
+		plugin := creator()
+
+		fmt.Printf("# %s\n[%s]\n", plugin.Description(), name)
+
+		var config string
+
+		config = strings.TrimSpace(plugin.SampleConfig())
+
+		if config == "" {
+			fmt.Printf("  # no configuration\n\n")
+		} else {
+			fmt.Printf("\n")
+			lines := strings.Split(config, "\n")
+			for _, line := range lines {
+				fmt.Printf("%s\n", line)
+			}
+
+			fmt.Printf("\n")
+		}
+	}
+}

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
+	Servers []string
-	Address  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 {
+	if len(g.Servers) == 0 {
-		return nil
-	}
-
-	var servers []string
-
-	if g.Address != "" {
-		servers = append(servers, g.Address)
-	}
-
-	servers = append(servers, g.Servers...)
-
-	if len(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 {