[wip] cmd/rescached: add telemetry using questdbdev-telemetry

The telemetry collect the Go runtime/metrics and forward it to questdb
instance in localhost.

1 files changed, 92 insertions, 0 deletions

diff --git a/cmd/rescached/main.go b/cmd/rescached/main.go
index e94be5e..1958974 100644
--- a/cmd/rescached/main.go
+++ b/cmd/rescached/main.go
@@ -13,8 +13,10 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"net/url"
 	"os"
 	"os/signal"
+	"regexp"
 	"strings"
 	"syscall"
 	"time"
@@ -22,6 +24,7 @@ import (
 	"git.sr.ht/~shulhan/ciigo"
 	"github.com/shuLhan/share/lib/debug"
 	"github.com/shuLhan/share/lib/memfs"
+	"github.com/shuLhan/share/lib/telemetry"
 
 	"github.com/shuLhan/rescached-go/v4"
 )
@@ -85,6 +88,12 @@ func main() {
 		go debugRuntime()
 	}
 
+	var telemetryAgent *telemetry.Agent
+	telemetryAgent, err = createTelemetryAgent(env.Telemetry)
+	if err != nil {
+		log.Print(err)
+	}
+
 	qsignal = make(chan os.Signal, 1)
 	signal.Notify(qsignal, syscall.SIGQUIT, syscall.SIGSEGV, syscall.SIGTERM, syscall.SIGINT)
 	<-qsignal
@@ -92,6 +101,9 @@ func main() {
 		running <- false
 		<-running
 	}
+	if telemetryAgent != nil {
+		telemetryAgent.Stop()
+	}
 	rcd.Stop()
 	os.Exit(0)
 }
@@ -111,6 +123,86 @@ func debugRuntime() {
 	}
 }
 
+func createTelemetryAgent(telemetryOpt string) (agent *telemetry.Agent, err error) {
+	if len(telemetryOpt) == 0 {
+		return nil, nil
+	}
+
+	var (
+		logp   = `createTelemetryAgent`
+		ilpFmt = telemetry.NewIlpFormatter(`rescached`)
+
+		forwarders []telemetry.Forwarder
+		telUrl     *url.URL
+	)
+
+	telUrl, err = url.Parse(telemetryOpt)
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	var schemes = strings.SplitN(telUrl.Scheme, `+`, 2)
+
+	switch schemes[0] {
+	case `questdb`:
+		telUrl.Scheme = schemes[1]
+
+		var (
+			qdbOpts = telemetry.QuestdbOptions{
+				Fmt:       ilpFmt,
+				ServerUrl: telUrl.String(),
+			}
+
+			qdbFwd *telemetry.QuestdbForwarder
+		)
+
+		qdbFwd, err = telemetry.NewQuestdbForwarder(qdbOpts)
+		if err != nil {
+			return nil, fmt.Errorf(`%s: %w`, logp, err)
+		}
+
+		log.Printf(`Starting telemetry using questdb: %s`, qdbOpts.ServerUrl)
+
+		forwarders = append(forwarders, qdbFwd)
+
+	default:
+		return nil, fmt.Errorf(`%s: unknown forwarder %s`, logp, schemes[0])
+	}
+
+	// Create metadata.
+	var md = telemetry.NewMetadata()
+	md.Set(`version`, rescached.Version)
+
+	var metricsCol telemetry.Collector
+	metricsCol, err = createMetricsCollector()
+	if err != nil {
+		return nil, fmt.Errorf(`%s: %w`, logp, err)
+	}
+
+	// Create the Agent.
+	var agentOpts = telemetry.AgentOptions{
+		Metadata:   md,
+		Forwarders: forwarders,
+		Collectors: []telemetry.Collector{
+			metricsCol,
+		},
+		Interval: 10 * time.Second,
+	}
+
+	agent = telemetry.NewAgent(agentOpts)
+	return agent, nil
+}
+
+func createMetricsCollector() (col *telemetry.GoMetricsCollector, err error) {
+	var metricsFilter *regexp.Regexp
+	metricsFilter, err = regexp.Compile(`^go_(cpu|gc|memory|sched)_.*$`)
+	if err != nil {
+		return nil, err
+	}
+	col = telemetry.NewGoMetricsCollector(metricsFilter)
+	return col, nil
+}
+
 // watchWww watch any changes to files inside _www directory and regenerate
 // the embed file "memfs_generate.go".
 func watchWww(env *rescached.Environment, running chan bool) {