Stream performance metrics (#1785)

* WIP playback metrics

* Playback metrics collecting + APIs. Closes #793

* Cleanup console messages

* Update test

* Increase browser test timeout

* Update browser tests to not fail

controllers/playbackMetrics.go

@@ -0,0 +1,40 @@
+package controllers
+
+import (
+	"encoding/json"
+	"net/http"
+
+	"github.com/owncast/owncast/metrics"
+	log "github.com/sirupsen/logrus"
+)
+
+// ReportPlaybackMetrics will accept playback metrics from a client and save
+// them for future video health reporting.
+func ReportPlaybackMetrics(w http.ResponseWriter, r *http.Request) {
+	if r.Method != POST {
+		WriteSimpleResponse(w, false, r.Method+" not supported")
+		return
+	}
+
+	type reportPlaybackMetricsRequest struct {
+		Bandwidth             float64 `json:"bandwidth"`
+		Latency               float64 `json:"latency"`
+		Errors                float64 `json:"errors"`
+		DownloadDuration      float64 `json:"downloadDuration"`
+		QualityVariantChanges float64 `json:"qualityVariantChanges"`
+	}
+
+	decoder := json.NewDecoder(r.Body)
+	var request reportPlaybackMetricsRequest
+	if err := decoder.Decode(&request); err != nil {
+		log.Errorln("error decoding playback metrics payload:", err)
+		WriteSimpleResponse(w, false, err.Error())
+		return
+	}
+
+	metrics.RegisterPlaybackErrorCount(request.Errors)
+	metrics.RegisterPlayerBandwidth(request.Bandwidth)
+	metrics.RegisterPlayerLatency(request.Latency)
+	metrics.RegisterPlayerSegmentDownloadDuration(request.DownloadDuration)
+	metrics.RegisterQualityVariantChangesCount(request.QualityVariantChanges)
+}