Add prometheus serializer and use it in prometheus output

docs/DATA_FORMATS_OUTPUT.md

@@ -5,10 +5,11 @@ standard data formats that may be selected from when configuring many output
 plugins.
 
 1. [InfluxDB Line Protocol](/plugins/serializers/influx)
-1. [JSON](/plugins/serializers/json)
+1. [Carbon2](/plugins/serializers/carbon2)
 1. [Graphite](/plugins/serializers/graphite)
+1. [JSON](/plugins/serializers/json)
+1. [Prometheus](/plugins/serializers/prometheus)
 1. [SplunkMetric](/plugins/serializers/splunkmetric)
-1. [Carbon2](/plugins/serializers/carbon2)
 1. [Wavefront](/plugins/serializers/wavefront)
 
 You will be able to identify the plugins with support by the presence of a

internal/http.go

@@ -2,6 +2,7 @@ package internal
 
 import (
 	"crypto/subtle"
+	"net"
 	"net/http"
 )
 
@@ -43,3 +44,49 @@ func (h *basicAuthHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request)
 
 	h.next.ServeHTTP(rw, req)
 }
+
+// IPRangeHandler returns a http handler that requires the remote address to be
+// in the specified network.
+func IPRangeHandler(network []*net.IPNet, onError ErrorFunc) func(h http.Handler) http.Handler {
+	return func(h http.Handler) http.Handler {
+		return &ipRangeHandler{
+			network: network,
+			onError: onError,
+			next:    h,
+		}
+	}
+}
+
+type ipRangeHandler struct {
+	network []*net.IPNet
+	onError ErrorFunc
+	next    http.Handler
+}
+
+func (h *ipRangeHandler) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
+	if len(h.network) == 0 {
+		h.next.ServeHTTP(rw, req)
+		return
+	}
+
+	remoteIPString, _, err := net.SplitHostPort(req.RemoteAddr)
+	if err != nil {
+		h.onError(rw, http.StatusForbidden)
+		return
+	}
+
+	remoteIP := net.ParseIP(remoteIPString)
+	if remoteIP == nil {
+		h.onError(rw, http.StatusForbidden)
+		return
+	}
+
+	for _, net := range h.network {
+		if net.Contains(remoteIP) {
+			h.next.ServeHTTP(rw, req)
+			return
+		}
+	}
+
+	h.onError(rw, http.StatusForbidden)
+}

plugins/inputs/file/file.go

@@ -33,8 +33,8 @@ const sampleConfig = `
   ## more about them here:
   ## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
   data_format = "influx"
-  
-  ## Name a tag containing the name of the file the data was parsed from.  Leave empty 
+
+  ## Name a tag containing the name of the file the data was parsed from.  Leave empty
   ## to disable.
   # file_tag = ""
 `

plugins/inputs/prometheus/README.md

@@ -11,8 +11,14 @@ in Prometheus format.
   ## An array of urls to scrape metrics from.
   urls = ["http://localhost:9100/metrics"]
 
-  ## Metric version (optional, default=1, supported values are 1 and 2)
-  # metric_version = 2
+  ## Metric version controls the mapping from Prometheus metrics into
+  ## Telegraf metrics.  When using the prometheus_client output, use the same
+  ## value in both plugins to ensure metrics are round-tripped without
+  ## modification.
+  ##
+  ##   example: metric_version = 1; deprecated in 1.13
+  ##            metric_version = 2; recommended version
+  # metric_version = 1
 
   ## An array of Kubernetes services to scrape metrics from.
   # kubernetes_services = ["http://my-service-dns.my-namespace:9100/metrics"]

plugins/inputs/prometheus/prometheus.go

@@ -62,8 +62,14 @@ var sampleConfig = `
   ## An array of urls to scrape metrics from.
   urls = ["http://localhost:9100/metrics"]
 
-  ## Metric version (optional, default=1, supported values are 1 and 2)
-  # metric_version = 2
+  ## Metric version controls the mapping from Prometheus metrics into
+  ## Telegraf metrics.  When using the prometheus_client output, use the same
+  ## value in both plugins to ensure metrics are round-tripped without
+  ## modification.
+  ##
+  ##   example: metric_version = 1; deprecated in 1.13
+  ##            metric_version = 2; recommended version
+  # metric_version = 1
 
   ## Url tag name (tag containing scrapped url. optional, default is "url")
   # url_tag = "scrapeUrl"
@@ -95,7 +101,7 @@ var sampleConfig = `
   # username = ""
   # password = ""
 
-	## Specify timeout duration for slower prometheus clients (default is 3s)
+  ## Specify timeout duration for slower prometheus clients (default is 3s)
   # response_timeout = "3s"
 
   ## Optional TLS Config
@@ -114,6 +120,13 @@ func (p *Prometheus) Description() string {
 	return "Read metrics from one or many prometheus clients"
 }
 
+func (p *Prometheus) Init() error {
+	if p.MetricVersion != 2 {
+		p.Log.Warnf("Use of deprecated configuration: 'metric_version = 1'; please update to 'metric_version = 2'")
+	}
+	return nil
+}
+
 var ErrProtocolError = errors.New("prometheus protocol error")
 
 func (p *Prometheus) AddressToURL(u *url.URL, address string) *url.URL {
@@ -311,7 +324,9 @@ func (p *Prometheus) gatherURL(u URLAndAddress, acc telegraf.Accumulator) error
 		tags := metric.Tags()
 		// strip user and password from URL
 		u.OriginalURL.User = nil
-		tags[p.URLTag] = u.OriginalURL.String()
+		if p.URLTag != "" {
+			tags[p.URLTag] = u.OriginalURL.String()
+		}
 		if u.Address != "" {
 			tags["address"] = u.Address
 		}

plugins/outputs/file/README.md

@@ -9,6 +9,11 @@ This plugin writes telegraf metrics to files
   ## Files to write to, "stdout" is a specially handled file.
   files = ["stdout", "/tmp/metrics.out"]
 
+  ## Use batch serialization format instead of line based delimiting.  The
+  ## batch format allows for the production of non line based output formats and
+  ## may more effiently encode and write metrics.
+  # use_batch_format = false
+
   ## The file will be rotated after the time interval specified.  When set
   ## to 0 no time based rotation is performed.
   # rotation_interval = "0h"

plugins/outputs/file/file.go

@@ -3,7 +3,6 @@ package file
 import (
 	"fmt"
 	"io"
-	"log"
 	"os"
 
 	"github.com/influxdata/telegraf"
@@ -18,6 +17,8 @@ type File struct {
 	RotationInterval    internal.Duration `toml:"rotation_interval"`
 	RotationMaxSize     internal.Size     `toml:"rotation_max_size"`
 	RotationMaxArchives int               `toml:"rotation_max_archives"`
+	UseBatchFormat      bool              `toml:"use_batch_format"`
+	Log                 telegraf.Logger   `toml:"-"`
 
 	writer     io.Writer
 	closers    []io.Closer
@@ -28,6 +29,11 @@ var sampleConfig = `
   ## Files to write to, "stdout" is a specially handled file.
   files = ["stdout", "/tmp/metrics.out"]
 
+  ## Use batch serialization format instead of line based delimiting.  The
+  ## batch format allows for the production of non line based output formats and
+  ## may more effiently encode metric groups.
+  # use_batch_format = false
+
   ## The file will be rotated after the time interval specified.  When set
   ## to 0 no time based rotation is performed.
   # rotation_interval = "0d"
@@ -98,15 +104,27 @@ func (f *File) Description() string {
 func (f *File) Write(metrics []telegraf.Metric) error {
 	var writeErr error = nil
 
-	for _, metric := range metrics {
-		b, err := f.serializer.Serialize(metric)
+	if f.UseBatchFormat {
+		octets, err := f.serializer.SerializeBatch(metrics)
 		if err != nil {
-			log.Printf("D! [outputs.file] Could not serialize metric: %v", err)
+			f.Log.Errorf("Could not serialize metric: %v", err)
 		}
 
-		_, err = f.writer.Write(b)
+		_, err = f.writer.Write(octets)
 		if err != nil {
-			writeErr = fmt.Errorf("E! [outputs.file] failed to write message: %v", err)
+			f.Log.Errorf("Error writing to file: %v", err)
+		}
+	} else {
+		for _, metric := range metrics {
+			b, err := f.serializer.Serialize(metric)
+			if err != nil {
+				f.Log.Debugf("Could not serialize metric: %v", err)
+			}
+
+			_, err = f.writer.Write(b)
+			if err != nil {
+				writeErr = fmt.Errorf("E! [outputs.file] failed to write message: %v", err)
+			}
 		}
 	}
 

plugins/outputs/prometheus_client/README.md

@@ -1,6 +1,7 @@
-# Prometheus Client Service Output Plugin
+# Prometheus Output Plugin
 
-This plugin starts a [Prometheus](https://prometheus.io/) Client, it exposes all metrics on `/metrics` (default) to be polled by a Prometheus server.
+This plugin starts a [Prometheus](https://prometheus.io/) Client, it exposes
+all metrics on `/metrics` (default) to be polled by a Prometheus server.
 
 ## Configuration
 
@@ -10,6 +11,14 @@ This plugin starts a [Prometheus](https://prometheus.io/) Client, it exposes all
   ## Address to listen on.
   listen = ":9273"
 
+  ## Metric version controls the mapping from Telegraf metrics into
+  ## Prometheus format.  When using the prometheus input, use the same value in
+  ## both plugins to ensure metrics are round-tripped without modification.
+  ##
+  ##   example: metric_version = 1; deprecated in 1.13
+  ##            metric_version = 2; recommended version
+  # metric_version = 1
+
   ## Use HTTP Basic Authentication.
   # basic_username = "Foo"
   # basic_password = "Bar"