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

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

7 files changed, 124 insertions, 13 deletions

diff --git a/_test/etc/rescached/rescached.cfg b/_test/etc/rescached/rescached.cfg
index fd11806..9c406d6 100644
--- a/_test/etc/rescached/rescached.cfg
+++ b/_test/etc/rescached/rescached.cfg
@@ -11,6 +11,7 @@
 file.resolvconf=
 debug=1
 wui.listen = 127.0.0.1:5381
+telemetry = questdb+tcp://127.0.0.1:9009
 
 [block.d "a.block"]
 name = a.block
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) {
diff --git a/environment.go b/environment.go
index 1068ea9..85e584a 100644
--- a/environment.go
+++ b/environment.go
@@ -73,6 +73,12 @@ type Environment struct {
 	FileResolvConf string `ini:"rescached::file.resolvconf"`
 	WUIListen      string `ini:"rescached::wui.listen"`
 
+	// Telemetry define the URI for sending telemetry.
+	// Format: "<forwarder>+<url>".
+	// For example, collecting telemetry to store in questdb at localhost,
+	// "questdb+tcp://127.0.0.1:9009"
+	Telemetry string `ini:"rescached::telemetry"`
+
 	HostBlockd     map[string]*Blockd `ini:"block.d"`
 	hostBlockdFile map[string]*dns.HostsFile
 	hostsd         map[string]*dns.HostsFile
diff --git a/environment_test.go b/environment_test.go
index 467bd5b..0f1ffdc 100644
--- a/environment_test.go
+++ b/environment_test.go
@@ -73,6 +73,7 @@ func TestLoadEnvironment(t *testing.T) {
 			fileConfig: filepath.Join(testDirBase, "/etc/rescached/rescached.cfg"),
 
 			WUIListen: "127.0.0.1:5381",
+			Telemetry: `questdb+tcp://127.0.0.1:9009`,
 			HostBlockd: map[string]*Blockd{
 				"a.block": &Blockd{
 					Name: "a.block",
diff --git a/go.mod b/go.mod
index 11a5865..82bbc84 100644
--- a/go.mod
+++ b/go.mod
@@ -6,14 +6,17 @@ module github.com/shuLhan/rescached-go/v4
 go 1.19
 
 require (
-	git.sr.ht/~shulhan/ciigo v0.9.3
-	github.com/shuLhan/share v0.45.0
+	git.sr.ht/~shulhan/ciigo v0.10.0
+	github.com/shuLhan/share v0.46.0
 )
 
 require (
 	git.sr.ht/~shulhan/asciidoctor-go v0.4.1 // indirect
-	golang.org/x/net v0.7.0 // indirect
-	golang.org/x/sys v0.5.0 // indirect
+	github.com/yuin/goldmark v1.5.4 // indirect
+	github.com/yuin/goldmark-meta v1.1.0 // indirect
+	golang.org/x/net v0.12.0 // indirect
+	golang.org/x/sys v0.10.0 // indirect
+	gopkg.in/yaml.v2 v2.3.0 // indirect
 )
 
-//replace github.com/shuLhan/share => ../share
+replace github.com/shuLhan/share => ../share
diff --git a/go.sum b/go.sum
index 809c93e..9fc748c 100644
--- a/go.sum
+++ b/go.sum
@@ -1,10 +1,16 @@
 git.sr.ht/~shulhan/asciidoctor-go v0.4.1 h1:Zev0L5HyMjH43sPaoJal8E/Hmbel/akoGOxNykhN4Dw=
 git.sr.ht/~shulhan/asciidoctor-go v0.4.1/go.mod h1:vRHDUl3o3UzDkvVR9dEFYQ0JDqOh0TKpOZWvOh/CGZU=
-git.sr.ht/~shulhan/ciigo v0.9.3 h1:q6EqGVvIU8ymkPqBS4HEyHIhbfVhJn6urwvGDg83TAY=
-git.sr.ht/~shulhan/ciigo v0.9.3/go.mod h1:SsRnbqnBo+9jWDDZD/uc9IkdgGpBfp39vV0JPXNro9c=
-github.com/shuLhan/share v0.45.0 h1:3uCGNtgWy9mta6re61ayMVp7WICNMtBUvHwtUBVTgZw=
-github.com/shuLhan/share v0.45.0/go.mod h1:BhnIWJxq84BTOs3Z2gLFAN8ih9mBfhZbRIjqGupGJag=
-golang.org/x/net v0.7.0 h1:rJrUqqhjsgNp7KqAIc25s9pZnjU7TUcSY7HcVZjdn1g=
-golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
-golang.org/x/sys v0.5.0 h1:MUK/U/4lj1t1oPg0HfuXDN/Z1wv31ZJ/YcPiGccS4DU=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+git.sr.ht/~shulhan/ciigo v0.10.0 h1:s1SJ3/NzBcbOLmEZ4z1Cx9Vf7ZdDIvm45b7KMCZKzEY=
+git.sr.ht/~shulhan/ciigo v0.10.0/go.mod h1:cG6av+ywJZZp96F43kmLB2QWjm2hYiahbsbeTX/vlgk=
+github.com/yuin/goldmark v1.5.4 h1:2uY/xC0roWy8IBEGLgB1ywIoEJFGmRrX21YQcvGZzjU=
+github.com/yuin/goldmark v1.5.4/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+github.com/yuin/goldmark-meta v1.1.0 h1:pWw+JLHGZe8Rk0EGsMVssiNb/AaPMHfSRszZeUeiOUc=
+github.com/yuin/goldmark-meta v1.1.0/go.mod h1:U4spWENafuA7Zyg+Lj5RqK/MF+ovMYtBvXi1lBb2VP0=
+golang.org/x/net v0.12.0 h1:cfawfvKITfUsFCeJIHJrbSxpeu/E81khclypR0GVT50=
+golang.org/x/net v0.12.0/go.mod h1:zEVYFnQC7m/vmpQFELhcD1EWkZlX69l4oqgmer6hfKA=
+golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
+golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=
+gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
diff --git a/testdata/rescached.cfg.test.out b/testdata/rescached.cfg.test.out
index 8f36010..a31a1d6 100644
--- a/testdata/rescached.cfg.test.out
+++ b/testdata/rescached.cfg.test.out
@@ -1,6 +1,7 @@
 [rescached]
 file.resolvconf =
 wui.listen = 127.0.0.1:5381
+telemetry = questdb+tcp://127.0.0.1:9009
 debug = 1
 
 [block.d "a.block"]
@@ -27,6 +28,7 @@ parent = udp://10.8.0.1
 http.idle_timeout = 0s
 cache.prune_delay = 0s
 cache.prune_threshold = 0s
+debug = 0
 http.port = 0
 tls.port = 0
 tls.allow_insecure = true