Merge pull request #3 from odise/commandline_args

Commandline args, HTTP port

README.md

@@ -1,8 +1,42 @@
 go-cron
 =========
 
-Simple golang wrapper over `github.com/robfig/cron` and `os/exec` as a cron replacement
+Simple golang wrapper over `github.com/robfig/cron` and `os/exec` as a cron replacement. 
+Additionally the application opens a HTTP port that can be used as a healthcheck.
 
 ## usage
 
-`go-cron "* * * * * *" /bin/bash -c "echo 1"`
+`go-cron -s "* * * * * *" -p 8080 -- /bin/bash -c "echo 1"`
+
+Check the healthcheck:
+
+```
+$ curl -v localhost:18080
+* Rebuilt URL to: localhost:18080/
+* Hostname was NOT found in DNS cache
+*   Trying ::1...
+* Connected to localhost (::1) port 18080 (#0)
+> GET / HTTP/1.1
+> User-Agent: curl/7.37.1
+> Host: localhost:18080
+> Accept: */*
+>
+< HTTP/1.1 200 OK
+< Content-Type: application/json
+< Date: Wed, 11 Mar 2015 12:59:07 GMT
+< Content-Length: 237
+<
+{
+  "Running": {},
+  "Last": {
+    "Exit_status": 0,
+    "Stdout": "1\n",
+    "Stderr": "",
+    "ExitTime": "2015-03-11T13:59:05+01:00",
+    "Pid": 14420,
+    "StartingTime": "2015-03-11T13:59:05+01:00"
+  },
+  "Schedule": "*/5 * * * *"
+* Connection #0 to host localhost left intact
+}
+```

bin/go-cron.go

@@ -1,7 +1,7 @@
 package main
 
 import (
-	//"fmt"
+	"flag"
 	gocron "github.com/odise/go-cron"
 	"log"
 	"os"
@@ -12,19 +12,59 @@ import (
 var build string
 
 func main() {
-	log.Println("Running version:", build)
+	flagArgs, execArgs := splitArgs()
+	os.Args = flagArgs
+
+	var (
+		help     = flag.Bool("h", false, "display usage")
+		port     = flag.String("p", "18080", "bind healthcheck to a specific port, set to 0 to not open HTTP port at all")
+		schedule = flag.String("s", "* * * * *", "schedule the task the cron style")
+	)
+
+	flag.Parse()
 
-	if len(os.Args) < 3 {
-		log.Fatalf("run: go-cron <schedule> <command>")
+	if *help {
+		println("Usage of", os.Args[0], "(build", build, ")")
+		println(os.Args[0], " [ OPTIONS ] -- [ COMMAND ]")
+		flag.PrintDefaults()
+		os.Exit(1)
 	}
+	log.Println("Running version:", build)
 
-	c, wg := gocron.Create()
+	c, wg := gocron.Create(*schedule, execArgs[0], execArgs[1:len(execArgs)])
 
 	go gocron.Start(c)
-	go gocron.Http_server()
+	if *port != "0" {
+		go gocron.Http_server(*port)
+	}
 
 	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
 	println(<-ch)
 	gocron.Stop(c, wg)
 }
+
+func splitArgs() (flagArgs []string, execArgs []string) {
+
+	split := len(os.Args)
+
+	for idx, e := range os.Args {
+
+		if e == "--" {
+			split = idx
+			break
+		}
+
+	}
+
+	flagArgs = os.Args[0:split]
+
+	if split < len(os.Args) {
+		execArgs = os.Args[split+1 : len(os.Args)]
+	} else {
+		execArgs = []string{}
+	}
+
+	return flagArgs, execArgs
+
+}

go-cron.go

@@ -93,10 +93,7 @@ func execute(command string, args []string) {
 	Current_state.Last = run
 }
 
-func Create() (cr *cron.Cron, wgr *sync.WaitGroup) {
-	var schedule string = os.Args[1]
-	var command string = os.Args[2]
-	var args []string = os.Args[3:len(os.Args)]
+func Create(schedule string, command string, args []string) (cr *cron.Cron, wgr *sync.WaitGroup) {
 
 	wg := &sync.WaitGroup{}
 

httpserver.go

@@ -22,9 +22,10 @@ func handler(w http.ResponseWriter, r *http.Request) {
 	w.Write(js)
 }
 
-func Http_server() {
+func Http_server(port string) {
+	log.Println("Opening port", port, "for health checking")
 	http.HandleFunc("/", handler)
-	err := http.ListenAndServe(":18080", nil)
+	err := http.ListenAndServe(":"+port, nil)
 	if err != nil {
 		log.Fatal("ListenAndServe: ", err)
 	}