feat: add alert feature

README.md

@@ -5,14 +5,15 @@ Easiest status page to check something service is dead:skull: or alive:heavy_che
 
 ## Features
 
-- status checking with
+- status checking with:
   * HTTP/HTTPS
   * ICMP echo (ping)
   * TCP connect
   * DNS resolve
   * execute external command (or script file)
 - view status page in browser.
 - view status page via cURL.
+- kick alert if target failure.
 
 ### Good at
 - Make status page for temprary usage. (You can start it via one command! And, stop via just Ctrl-C!)
@@ -21,4 +22,3 @@ Easiest status page to check something service is dead:skull: or alive:heavy_che
 ### Not good at
 - Complex customize, extension. (There is nothing options for customize.)
 - Investigate more detail. (This is just for check dead or alive.)
-- Alert sending. (This is just status page.)

alert.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"net/url"
+	"time"
+
+	"github.com/macrat/ayd/probe"
+	"github.com/macrat/ayd/store"
+)
+
+type Alert struct {
+	target *url.URL
+}
+
+func NewAlert(target string) (*Alert, error) {
+	p, err := probe.Get(target)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Alert{p.Target()}, nil
+}
+
+func (a *Alert) Target() *url.URL {
+	return &url.URL{
+		Scheme: "alert",
+		Opaque: a.target.String(),
+	}
+}
+
+func (a *Alert) Trigger(r store.Record) []store.Record {
+	qs := a.target.Query()
+	qs.Set("ayd_target", r.Target.String())
+	qs.Set("ayd_checked_at", r.CheckedAt.Format(time.RFC3339))
+	qs.Set("ayd_status", r.Status.String())
+
+	u := *a.target
+	u.RawQuery = qs.Encode()
+
+	p, err := probe.GetByURL(&u)
+	if err != nil {
+		return []store.Record{{
+			CheckedAt: time.Now(),
+			Target:    a.Target(),
+			Status:    store.STATUS_UNKNOWN,
+			Message:   err.Error(),
+		}}
+	}
+
+	result := p.Check()
+	for i := range result {
+		result[i].Target = a.Target()
+	}
+
+	return result
+}
+
+func (a *Alert) TriggerIfNeed(rs []store.Record) []store.Record {
+	if a == nil {
+		return nil
+	}
+
+	var result []store.Record
+	for _, r := range rs {
+		if r.Status != store.STATUS_HEALTHY {
+			result = append(result, a.Trigger(r)...)
+		}
+	}
+	return result
+}

main.go

@@ -18,6 +18,7 @@ var (
 	listenPort = flag.Int("p", 9000, "Listen port of status page.")
 	storePath  = flag.String("o", "./ayd.log", "Path to log file. Log file is also use for restore status history.")
 	oneshot    = flag.Bool("1", false, "Check status only once and exit. Exit with 0 if all check passed, otherwise exit with code 1.")
+	alertURI   = flag.String("a", "", "The alert URI that the same format as target URI.")
 )
 
 func Usage() {
@@ -155,7 +156,7 @@ func ParseArgs(args []string) ([]Task, []error) {
 	return result, errors
 }
 
-func RunOneshot(tasks []Task) {
+func RunOneshot(tasks []Task, alert *Alert) {
 	var failed atomic.Value
 
 	s, err := store.New(*storePath)
@@ -173,6 +174,7 @@ func RunOneshot(tasks []Task) {
 		go func() {
 			rs := f()
 			s.Append(rs...)
+			s.Append(alert.TriggerIfNeed(rs)...)
 			for _, r := range rs {
 				if r.Status == store.STATUS_FAILURE {
 					failed.Store(true)
@@ -188,7 +190,7 @@ func RunOneshot(tasks []Task) {
 	}
 }
 
-func RunServer(tasks []Task) {
+func RunServer(tasks []Task, alert *Alert) {
 	listen := fmt.Sprintf("0.0.0.0:%d", *listenPort)
 	fmt.Printf("starts Ayd on http://%s\n", listen)
 
@@ -212,7 +214,9 @@ func RunServer(tasks []Task) {
 
 		f := t.Probe.Check
 		job := func() {
-			s.Append(f()...)
+			rs := f()
+			s.Append(rs...)
+			s.Append(alert.TriggerIfNeed(rs)...)
 		}
 
 		if t.Schedule.NeedKickWhenStart() {
@@ -234,6 +238,16 @@ func main() {
 	flag.Usage = Usage
 	flag.Parse()
 
+	var alert *Alert
+	if *alertURI != "" {
+		var err error
+		alert, err = NewAlert(*alertURI)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "Invalid alert target:", err)
+			os.Exit(2)
+		}
+	}
+
 	tasks, errors := ParseArgs(flag.Args())
 	if errors != nil {
 		fmt.Fprintln(os.Stderr, "Invalid argument:")
@@ -249,8 +263,8 @@ func main() {
 	}
 
 	if *oneshot {
-		RunOneshot(tasks)
+		RunOneshot(tasks, alert)
 	} else {
-		RunServer(tasks)
+		RunServer(tasks, alert)
 	}
 }

store/store.go

@@ -125,9 +125,10 @@ func (s *Store) Append(rs ...Record) {
 		fmt.Println(str)
 		_, s.lastError = fmt.Fprintln(s.file, str)
 
-		s.ProbeHistory.append(r)
-
-		s.setIncidentIfNeed(r)
+		if r.Target.Scheme != "alert" {
+			s.ProbeHistory.append(r)
+			s.setIncidentIfNeed(r)
+		}
 	}
 }
 
@@ -151,9 +152,10 @@ func (s *Store) Restore() error {
 			continue
 		}
 
-		s.ProbeHistory.append(r)
-
-		s.setIncidentIfNeed(r)
+		if r.Target.Scheme != "alert" {
+			s.ProbeHistory.append(r)
+			s.setIncidentIfNeed(r)
+		}
 	}
 
 	return nil