Parsing config file and scheduling jobs

.gitignore

@@ -6,6 +6,7 @@
 # Folders
 _obj
 _test
+vendor
 
 # Architecture specific extensions/prefixes
 *.[568vq]

README.md

@@ -1 +1,3 @@
-# cronr
+# cronr
+
+cronr is a daemon utility intended to be an alternative to classic cron. The crontab is replaced by a custom config file, containing the jobs list. When cronr is started, each job is scheduled according to the config.

config.go

@@ -0,0 +1,15 @@
+package main
+
+// ConfigFile represents a YAML config file
+type ConfigFile struct {
+	Jobs []Job
+}
+
+// Job represents a unit to schedule
+type Job struct {
+	Cron    string   `yaml:"cron"`
+	Command []string `yaml:"command"`
+	// User       uint32   `yaml:"user"`
+	// Group      uint32   `yaml:"group"`
+	WorkingDir string `yaml:"working_dir"`
+}

cron.go

@@ -0,0 +1,105 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"os/signal"
+
+	"github.com/robfig/cron"
+	yaml "gopkg.in/yaml.v2"
+)
+
+type command struct {
+	name string
+	args []string
+}
+
+// CronAction parses and schedules jobs, waiting for SIGINT signal to stop
+func CronAction(configFilepath string, verbose bool) error {
+
+	// get config file content
+	fileContent, err := ioutil.ReadFile(configFilepath)
+	if err != nil {
+		return err
+	}
+
+	// parse config file
+	config := ConfigFile{}
+	err = yaml.Unmarshal(fileContent, &config)
+	if err != nil {
+		return err
+	}
+
+	// prepare cron
+	c := cron.New()
+
+	// creating jobs
+	for i := range config.Jobs {
+		job := config.Jobs[i]
+
+		c.AddFunc(job.Cron, func() {
+
+			if verbose {
+				log.Println(job)
+			}
+
+			cmdArgs := newCommand(job.Command)
+			cmd := exec.Command(cmdArgs.name, cmdArgs.args...)
+
+			if job.WorkingDir != "" {
+				cmd.Dir = job.WorkingDir
+			}
+
+			// if job.User != 0 && job.Group != 0 {
+			// 	fmt.Println(job.User, ":", job.Group)
+			// 	cmd.SysProcAttr = &syscall.SysProcAttr{}
+			// 	cmd.SysProcAttr.Credential = &syscall.Credential{Uid: job.User, Gid: job.Group}
+			// }
+
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+
+			err := cmd.Run()
+			if err != nil {
+				log.Printf("[ERROR] cmd: %v: %v\n", job.Command, err)
+			}
+
+		})
+	}
+
+	log.Printf("%v job(s) scheduled\n", len(c.Entries()))
+
+	// start cron
+	c.Start()
+
+	// prepare chan for catching signals
+	done := make(chan os.Signal, 1)
+	signal.Notify(done, os.Interrupt, os.Kill)
+
+	// waiting for signal to stop
+	<-done
+
+	c.Stop()
+
+	return nil
+}
+
+func newCommand(rawCommand []string) command {
+
+	var (
+		name string
+		args []string
+	)
+
+	if len(rawCommand) > 1 {
+		name = rawCommand[0]
+		args = rawCommand[1:]
+	} else {
+		name = rawCommand[0]
+		args = []string{}
+	}
+
+	return command{name: name, args: args}
+}

cronr.example.yml

@@ -0,0 +1,12 @@
+
+jobs:
+  - cron: "0/5 * * * * *"       # e.g:   0 30 * * * *    WARNING: first one is seconds (instead of minutes for classic cron, https://godoc.org/github.com/robfig/cron) 
+    command: 
+      - sh
+      - -c 
+      - /bin/echo foo >> output_1
+    working_dir: tests        # optional, cronr working dir by default
+  - cron: "0/2 * * * * *" 
+    command: 
+      - /bin/echo
+      - bar

glide.yaml

@@ -0,0 +1,5 @@
+package: webup/cronr
+import:
+- package: github.com/robfig/cron
+- package: github.com/jawher/mow.cli
+- package: gopkg.in/yaml.v2

main.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	cli "github.com/jawher/mow.cli"
+)
+
+func main() {
+
+	app := cli.App("cronr", "Executes scheduled jobs defined in a config file")
+
+	// version
+	app.Version("v version", "cronr 1 (build 1)")
+
+	// options & args
+	app.Spec = "-c [--verbose]"
+	configFile := app.StringOpt("c config-file", "", "Path of the cronr config file")
+	verbose := app.BoolOpt("verbose", false, "Display more informations on scheduled jobs")
+
+	// action
+	app.Action = func() {
+		err := CronAction(*configFile, *verbose)
+		if err != nil {
+			fmt.Println(err)
+			cli.Exit(1)
+		}
+	}
+
+	app.Run(os.Args)
+}