Outputs enhancement to require Description and SampleConfig functions

Closes #142

outputs/datadog/datadog.go

@@ -21,6 +21,14 @@ type Datadog struct {
 	client *http.Client
 }
 
+var sampleConfig = `
+	# Datadog API key
+	apikey = "my-secret-key" # required.
+
+	# Connection timeout.
+	# timeout = "5s"
+`
+
 type TimeSeries struct {
 	Series []*Metric `json:"series"`
 }
@@ -91,6 +99,14 @@ func (d *Datadog) Write(bp client.BatchPoints) error {
 	return nil
 }
 
+func (d *Datadog) SampleConfig() string {
+	return sampleConfig
+}
+
+func (d *Datadog) Description() string {
+	return "Configuration for DataDog API to send metrics to."
+}
+
 func (d *Datadog) authenticatedUrl() string {
 	q := url.Values{
 		"api_key": []string{d.Apikey},

outputs/influxdb/influxdb.go

@@ -22,6 +22,25 @@ type InfluxDB struct {
 	conn *client.Client
 }
 
+var sampleConfig = `
+	# The full HTTP endpoint URL for your InfluxDB instance
+	url = "http://localhost:8086" # required.
+
+	# The target database for metrics. This database must already exist
+	database = "telegraf" # required.
+
+	# Connection timeout (for the connection with InfluxDB), formatted as a string.
+	# Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+	# If not provided, will default to 0 (no timeout)
+	# timeout = "5s"
+
+	# username = "telegraf"
+	# password = "metricsmetricsmetricsmetrics"
+
+	# Set the user agent for the POSTs (can be useful for log differentiation)
+	# user_agent = "telegraf"
+`
+
 func (i *InfluxDB) Connect() error {
 	u, err := url.Parse(i.URL)
 	if err != nil {
@@ -57,6 +76,14 @@ func (i *InfluxDB) Close() error {
 	return nil
 }
 
+func (i *InfluxDB) SampleConfig() string {
+	return sampleConfig
+}
+
+func (i *InfluxDB) Description() string {
+	return "Configuration for influxdb server to send metrics to"
+}
+
 func (i *InfluxDB) Write(bp client.BatchPoints) error {
 	bp.Database = i.Database
 	if _, err := i.conn.Write(bp); err != nil {

outputs/registry.go

@@ -7,6 +7,8 @@ import (
 type Output interface {
 	Connect() error
 	Close() error
+	Description() string
+	SampleConfig() string
 	Write(client.BatchPoints) error
 }