add rtsp_proxies metrics (#61)

README.md

@@ -216,6 +216,8 @@ There are multiple ways to monitor the server usage over time:
   * `rtsp_clients{state="idle"}` is the count of clients that are neither publishing nor reading
   * `rtsp_clients{state="publishing"}` is the count of clients that are publishing
   * `rtsp_clients{state="reading"}` is the count of clients that are reading
+  * `rtsp_proxies{state="idle"}` is the count of proxy sources that are not running
+  * `rtsp_proxies{state="running"}` is the count of proxy sources that are running
 
 * A performance monitor, compatible with pprof, can be enabled with the option `pprof: yes`; then the server can be queried for metrics with pprof-compatible tools, like:
   ```

conf.go

@@ -216,7 +216,7 @@ func loadConf(fpath string, stdin io.Reader) (*conf, error) {
 
 		if pconf.Source != "record" {
 			if pconf.regexp != nil {
-				return nil, fmt.Errorf("a path with a regular expression cannot have a RTSP source; use another path")
+				return nil, fmt.Errorf("a path with a regular expression (or path 'all') cannot have a RTSP source; use another path")
 			}
 
 			pconf.sourceUrl, err = url.Parse(pconf.Source)

main.go

@@ -34,6 +34,8 @@ type program struct {
 	countClients        int64
 	countPublishers     int64
 	countReaders        int64
+	countProxies        int64
+	countProxiesRunning int64
 
 	clientNew       chan net.Conn
 	clientClose     chan *client

metrics.go

@@ -60,6 +60,8 @@ func (m *metrics) onMetrics(w http.ResponseWriter, req *http.Request) {
 	countClients := atomic.LoadInt64(&m.p.countClients)
 	countPublishers := atomic.LoadInt64(&m.p.countPublishers)
 	countReaders := atomic.LoadInt64(&m.p.countReaders)
+	countProxies := atomic.LoadInt64(&m.p.countProxies)
+	countProxiesRunning := atomic.LoadInt64(&m.p.countProxiesRunning)
 
 	out := ""
 	out += fmt.Sprintf("rtsp_clients{state=\"idle\"} %d %v\n",
@@ -68,6 +70,10 @@ func (m *metrics) onMetrics(w http.ResponseWriter, req *http.Request) {
 		countPublishers, now)
 	out += fmt.Sprintf("rtsp_clients{state=\"reading\"} %d %v\n",
 		countReaders, now)
+	out += fmt.Sprintf("rtsp_proxies{state=\"idle\"} %d %v\n",
+		countProxies, now)
+	out += fmt.Sprintf("rtsp_proxies{state=\"running\"} %d %v\n",
+		countProxiesRunning, now)
 
 	w.WriteHeader(http.StatusOK)
 	io.WriteString(w, out)

path.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"sync/atomic"
 	"time"
 )
 
@@ -147,7 +148,8 @@ func (pa *path) onCheck() {
 		pa.source.state == sourceStateRunning &&
 		!pa.hasClients() &&
 		time.Since(pa.lastDescribeReq) >= sourceStopAfterDescribeSecs {
-		pa.log("stopping on demand source since (not requested anymore)")
+		pa.log("stopping on demand source (not requested anymore)")
+		atomic.AddInt64(&pa.p.countProxiesRunning, -1)
 		pa.source.state = sourceStateStopped
 		pa.source.setState <- pa.source.state
 	}
@@ -241,6 +243,7 @@ func (pa *path) onDescribe(client *client) {
 		if pa.source != nil && pa.source.state == sourceStateStopped { // start if needed
 			pa.log("starting on demand source")
 			pa.lastDescribeActivation = time.Now()
+			atomic.AddInt64(&pa.p.countProxiesRunning, +1)
 			pa.source.state = sourceStateRunning
 			pa.source.setState <- pa.source.state
 		}

source.go

@@ -3,6 +3,7 @@ package main
 import (
 	"math/rand"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/aler9/gortsplib"
@@ -46,10 +47,13 @@ func newSource(p *program, path *path, pathConf *pathConf) *source {
 		done:      make(chan struct{}),
 	}
 
+	atomic.AddInt64(&p.countProxies, +1)
+
 	if pathConf.SourceOnDemand {
 		s.state = sourceStateStopped
 	} else {
 		s.state = sourceStateRunning
+		atomic.AddInt64(&p.countProxiesRunning, +1)
 	}
 
 	return s