add openvpn_connected_clients

+ dockerfile + minor go review

Dockerfile

@@ -0,0 +1,42 @@
+# BUILD:
+# docker build --force-rm=true -t openvpn_exporter .
+
+# RUN:
+# docker run -it -p 9176:9176 -v /path/to/openvpn_server.status:/etc/openvpn_exporter/server.status openvpn_exporter
+
+FROM golang as builder
+
+RUN mkdir /app
+RUN mkdir /go/src/app
+ADD . /go/src/app
+WORKDIR /go/src/app
+
+# Go dep
+RUN go get -d ./...
+
+# Build a standalone binary
+RUN set -ex && \
+  CGO_ENABLED=0 go build \
+        -tags netgo \
+        -o /app/openvpn_exporter \
+        -v -a \
+        -ldflags '-extldflags "-static"' && \
+  ls
+
+# Create the second stage with a basic image.
+# this will drop any previous
+# stages (defined as `FROM <some_image> as <some_name>`)
+# allowing us to start with a fat build image and end up with
+# a very small runtime image.
+
+FROM busybox
+
+# add compiled binary
+COPY --from=builder /app/openvpn_exporter /openvpn_exporter
+
+# add a default file to be processed
+ADD examples/server2.status /etc/openvpn_exporter/server.status
+
+# run
+EXPOSE 9176
+CMD ["/openvpn_exporter", "-openvpn.status_paths", "/etc/openvpn_exporter/server.status"]

README.md

@@ -18,7 +18,9 @@ exported over TCP port 9176.
 Please refer to this utility's `main()` function for a full list of
 supported command line flags.
 
-## Client statistics
+## Exposed metrics example
+
+### Client statistics
 
 For clients status files, the exporter generates metrics that may look
 like this:
@@ -37,7 +39,7 @@ openvpn_status_update_time_seconds{status_path="..."} 1.490092749e+09
 openvpn_up{status_path="..."} 1
 ```
 
-## Server statistics
+### Server statistics
 
 For server status files (both version 2 and 3), the exporter generates
 metrics that may look like this:
@@ -48,4 +50,49 @@ openvpn_server_client_sent_bytes_total{common_name="...",connection_time="...",r
 openvpn_server_route_last_reference_time_seconds{common_name="...",real_address="...",status_path="...",virtual_address="..."} 1.493018841e+09
 openvpn_status_update_time_seconds{status_path="..."} 1.490089154e+09
 openvpn_up{status_path="..."} 1
+openvpn_server_connected_clients 1
+```
+
+## Usage
+
+Usage of openvpn_exporter:
+```
+  -openvpn.status_paths string
+    	Paths at which OpenVPN places its status files. (default "examples/client.status,examples/server2.status,examples/server3.status")
+  -web.listen-address string
+    	Address to listen on for web interface and telemetry. (default ":9176")
+  -web.telemetry-path string
+    	Path under which to expose metrics. (default "/metrics")
+```
+
+E.g:
+```
+openvpn_exporter -openvpn.status_paths /etc/openvpn/openvpn-status.log
+```
+
+## Docker
+
+Build the image:
+```
+docker build --force-rm=true -t openvpn_exporter .
+```
+
+The final image is around 8MB. A temporary image has been downloaded(Golang) to make the final one. Once built, this temporary image become orphan, you can delete it:
+```
+docker rmi -f $(docker images | grep "<none>" | awk "{print \$3}")
+```
+
+To use with docker you must mount your status file to `/etc/openvpn_exporter/server.status`.
+```
+docker run -it -p 9176:9176 -v /path/to/openvpn_server.status:/etc/openvpn_exporter/server.status openvpn_exporter
+```
+
+Metrics should be available on your host IP: http://<host_ip>:9176/metrics. E.g: http://10.39.9.94:9176/metrics
+
+
+## Get a standalone executable binary
+
+Use the docker image to copy the built binary into a mounted volume
+```bash
+docker run -it -v /local/empty/folder:/volume openvpn_exporter cp openvpn_exporter /volume
 ```

openvpn_exporter.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 type OpenvpnServerHeader struct {
@@ -52,8 +53,12 @@ var (
 		[]string{"status_path"}, nil)
 
 	// Metrics specific to OpenVPN servers.
+	openvpnConnectedClientsDesc = prometheus.NewDesc(
+		prometheus.BuildFQName("openvpn", "", "openvpn_server_connected_clients"),
+		"Number Of Connected Clients", nil, nil)
+
 	openvpnServerHeaders = map[string]OpenvpnServerHeader{
-		"CLIENT_LIST": OpenvpnServerHeader{
+		"CLIENT_LIST": {
 			LabelColumns: []string{
 				"Common Name",
 				"Connected Since (time_t)",
@@ -62,15 +67,15 @@ var (
 				"Username",
 			},
 			Metrics: []OpenvpnServerHeaderField{
-				OpenvpnServerHeaderField{
+				{
 					Column: "Bytes Received",
 					Desc: prometheus.NewDesc(
 						prometheus.BuildFQName("openvpn", "server", "client_received_bytes_total"),
 						"Amount of data received over a connection on the VPN server, in bytes.",
 						[]string{"status_path", "common_name", "connection_time", "real_address", "virtual_address", "username"}, nil),
 					ValueType: prometheus.CounterValue,
 				},
-				OpenvpnServerHeaderField{
+				{
 					Column: "Bytes Sent",
 					Desc: prometheus.NewDesc(
 						prometheus.BuildFQName("openvpn", "server", "client_sent_bytes_total"),
@@ -80,14 +85,14 @@ var (
 				},
 			},
 		},
-		"ROUTING_TABLE": OpenvpnServerHeader{
+		"ROUTING_TABLE": {
 			LabelColumns: []string{
 				"Common Name",
 				"Real Address",
 				"Virtual Address",
 			},
 			Metrics: []OpenvpnServerHeaderField{
-				OpenvpnServerHeaderField{
+				{
 					Column: "Last Ref (time_t)",
 					Desc: prometheus.NewDesc(
 						prometheus.BuildFQName("openvpn", "server", "route_last_reference_time_seconds"),
@@ -159,7 +164,7 @@ func CollectStatusFromReader(statusPath string, file io.Reader, ch chan<- promet
 		// Client statistics.
 		return CollectClientStatusFromReader(statusPath, reader, ch)
 	} else {
-		return fmt.Errorf("Unexpected file contents: %q", buf)
+		return fmt.Errorf("unexpected file contents: %q", buf)
 	}
 }
 
@@ -168,6 +173,9 @@ func CollectServerStatusFromReader(statusPath string, file io.Reader, ch chan<-
 	scanner := bufio.NewScanner(file)
 	scanner.Split(bufio.ScanLines)
 	headersFound := map[string][]string{}
+	// counter of connected client
+	numberConnectedClient := 0
+
 	for scanner.Scan() {
 		fields := strings.Split(scanner.Text(), separator)
 		if fields[0] == "END" && len(fields) == 1 {
@@ -179,17 +187,19 @@ func CollectServerStatusFromReader(statusPath string, file io.Reader, ch chan<-
 			headersFound[fields[1]] = fields[2:]
 		} else if fields[0] == "TIME" && len(fields) == 3 {
 			// Time at which the statistics were updated.
-			time, err := strconv.ParseFloat(fields[2], 64)
+			timeStartStats, err := strconv.ParseFloat(fields[2], 64)
 			if err != nil {
 				return err
 			}
 			ch <- prometheus.MustNewConstMetric(
 				openvpnStatusUpdateTimeDesc,
 				prometheus.GaugeValue,
-				time,
+				timeStartStats,
 				statusPath)
 		} else if fields[0] == "TITLE" && len(fields) == 2 {
 			// OpenVPN version number.
+		} else if fields[0] == "CLIENT_LIST"{
+			numberConnectedClient ++
 		} else if header, ok := openvpnServerHeaders[fields[0]]; ok {
 			// Entry that depends on a preceding HEADERS directive.
 			columnNames, ok := headersFound[fields[0]]
@@ -230,9 +240,14 @@ func CollectServerStatusFromReader(statusPath string, file io.Reader, ch chan<-
 				}
 			}
 		} else {
-			return fmt.Errorf("Unsupported key: %q", fields[0])
+			return fmt.Errorf("unsupported key: %q", fields[0])
 		}
 	}
+	// add the number of connected client
+	ch <- prometheus.MustNewConstMetric(
+		openvpnConnectedClientsDesc,
+		prometheus.GaugeValue,
+		float64(numberConnectedClient))
 	return scanner.Err()
 }
 
@@ -249,14 +264,14 @@ func CollectClientStatusFromReader(statusPath string, file io.Reader, ch chan<-
 		} else if fields[0] == "Updated" && len(fields) == 2 {
 			// Time at which the statistics were updated.
 			location, _ := time.LoadLocation("Local")
-			time, err := time.ParseInLocation("Mon Jan 2 15:04:05 2006", fields[1], location)
+			timeParser, err := time.ParseInLocation("Mon Jan 2 15:04:05 2006", fields[1], location)
 			if err != nil {
 				return err
 			}
 			ch <- prometheus.MustNewConstMetric(
 				openvpnStatusUpdateTimeDesc,
 				prometheus.GaugeValue,
-				float64(time.Unix()),
+				float64(timeParser.Unix()),
 				statusPath)
 		} else if desc, ok := openvpnClientDescs[fields[0]]; ok && len(fields) == 2 {
 			// Traffic counters.
@@ -270,7 +285,7 @@ func CollectClientStatusFromReader(statusPath string, file io.Reader, ch chan<-
 				value,
 				statusPath)
 		} else {
-			return fmt.Errorf("Unsupported key: %q", fields[0])
+			return fmt.Errorf("unsupported key: %q", fields[0])
 		}
 	}
 	return scanner.Err()
@@ -327,13 +342,18 @@ func main() {
 	)
 	flag.Parse()
 
+	log.Printf("Starting OpenVPN Exporter\n")
+	log.Printf("Listen address: %v\n", *listenAddress)
+	log.Printf("Metrics path: %v\n", *metricsPath)
+	log.Printf("openvpn.status_path: %v\n", *openvpnStatusPaths)
+
 	exporter, err := NewOpenVPNExporter(strings.Split(*openvpnStatusPaths, ","))
 	if err != nil {
 		panic(err)
 	}
 	prometheus.MustRegister(exporter)
 
-	http.Handle(*metricsPath, prometheus.Handler())
+	http.Handle(*metricsPath, promhttp.Handler())
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		w.Write([]byte(`
 			<html>