Initial Commit

README.md

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+# heartbeet - Health Check utility for hosts
+
+This utility is mainly for sending "is up" notification to Graphite server.
+
+## Environment Variables
+
+* PROJECT_NAME: Name of project which is included in metric name
+* RUN_MODE: This is usually the environment which it ran in, usually prod/stage/test/dev
+* GRAPHITE_KEY: This key is used as prefix if needed.
+* GRAPHITE_ADDRESS: Address of graphite carbon, e.g. `127.0.0.1:2003`
+
+
+## Run
+
+Just run with required environment variables
+
+```bash
+$ GRAPHITE_ADDRESS=graphitehost.local:2003 RUN_MODE=stage PROJECT_NAME=nginx ./heartbeet
+```

main.go

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+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"strings"
+	"time"
+)
+
+var (
+	client = &net.Dialer{
+		Timeout:   time.Second * 10,
+		DualStack: false,
+		KeepAlive: time.Second * 60,
+	}
+	// conn       net.Conn
+	ticker       *time.Ticker
+	quit         chan struct{}
+	project      = &projecttype{}
+	graphiteAddr string
+	graphiteKey  string
+	periodString string
+	period       periodValue
+)
+
+type projecttype struct {
+	name string
+	mode string
+}
+
+type metrictype struct {
+	prefix    string
+	metric    string
+	value     float64
+	timestamp time.Time
+	hostname  string
+	network   string
+}
+
+type periodValue struct {
+	time.Duration
+}
+
+func (p *periodValue) Set(value string) error {
+	duration, err := time.ParseDuration(value)
+	p.Duration = duration
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *periodValue) String() string {
+	return p.Duration.String()
+}
+
+func init() {
+	flag.Var(&period, "period", "Period ticker runs")
+	// flag.StringVar(&periodString, "period", "30s", "Duration to send metrics")
+
+	quit = make(chan struct{})
+	project.name = os.Getenv("PROJECT_NAME")
+	if project.mode = os.Getenv("RUN_MODE"); project.mode == "" {
+		project.mode = "dev"
+	}
+	graphiteKey = os.Getenv("GRAPHITE_KEY")
+	if graphiteAddr = os.Getenv("GRAPHITE_ADDRESS"); graphiteAddr == "" {
+		graphiteAddr = "127.0.0.1:2003"
+	}
+	flag.Parse()
+
+	if period.Duration > 0 {
+		ticker = time.NewTicker(period.Duration)
+	} else {
+		ticker = time.NewTicker(30 * time.Second)
+	}
+}
+
+func main() {
+	startTicker()
+	// go func(value float64) {
+	// }(value)
+}
+
+func startTicker() {
+	for {
+		select {
+		case <-ticker.C:
+			sendMetric()
+		case <-quit:
+			ticker.Stop()
+			return
+			// break loop
+		}
+	}
+
+}
+
+func sendMetric() {
+	m := newMetric("heartbeat", 1)
+	// m.prefix = modePrefixMap[project.mode]
+	err := m.send(graphiteAddr)
+	if err != nil {
+		log.Println(err)
+		m.network = "udp"
+		err = m.send(graphiteAddr)
+		if err != nil {
+			log.Println(err)
+		}
+	}
+}
+
+func (m *metrictype) init() {
+	if m.timestamp.IsZero() {
+		m.timestamp = time.Now()
+	}
+	if m.network == "" {
+		m.network = "tcp"
+	}
+	hostname, err := os.Hostname()
+	if err == nil {
+		m.hostname = hostname
+	}
+}
+
+func (m *metrictype) send(addr string) error {
+	conn, err := client.Dial(m.network, addr)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+	_, err = fmt.Fprintf(conn, "%s %0.2f %d\n", m.metricString(), m.value, m.timestamp.Unix())
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func newMetric(metric string, value float64) *metrictype {
+	prefixes := []string{}
+	if project.mode != "" {
+		prefixes = append(prefixes, project.mode)
+	}
+	if project.name != "" {
+		prefixes = append(prefixes, project.name)
+	}
+	prefix := strings.Join(prefixes, ".")
+
+	return newMetricWithPrefix(prefix, metric, value)
+}
+
+func newMetricWithPrefix(prefix string, metric string, value float64) *metrictype {
+	m := &metrictype{
+		prefix: prefix,
+		metric: metric,
+		value:  value,
+	}
+	m.init()
+	return m
+}
+
+func (m *metrictype) metricString() string {
+	metricslice := []string{m.metric}
+	if m.hostname != "" {
+		metricslice = append(metricslice, m.hostname)
+	}
+	if m.prefix != "" {
+		metricslice = append(metricslice, m.prefix)
+	}
+	if graphiteKey != "" {
+		metricslice = append(metricslice, graphiteKey)
+	}
+	// reverse slice
+	for left, right := 0, len(metricslice)-1; left < right; left, right = left+1, right-1 {
+		metricslice[left], metricslice[right] = metricslice[right], metricslice[left]
+	}
+	return strings.Join(metricslice, ".")
+}