Merge pull request #9 from FMotalleb/command-credential

Command-credential

abstraction/validatable.go

@@ -1,8 +1,9 @@
 package abstraction
 
+import "github.com/sirupsen/logrus"
+
 type (
-	ValidatableStr string
-	Validatable    interface {
-		Validate() error
+	Validatable interface {
+		Validate(log *logrus.Entry) error
 	}
 )

cmd/root.go

@@ -6,6 +6,7 @@ import (
 	"runtime"
 
 	"github.com/joho/godotenv"
+	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 
@@ -139,7 +140,7 @@ func initConfig() {
 		"Cannot unmarshal the config file: %s",
 	)
 	panicOnErr(
-		CFG.Validate(),
+		CFG.Validate(logrus.WithField("section", "config.validation")),
 		"Failed to initialize config file: %s",
 	)
 }

config.example.yaml

@@ -11,7 +11,7 @@ jobs:
     # disabled: true
     tasks:
       # This line specifies the actual command to be executed.
-      - command: echo 15
+      - command: echo $(whoami)
         # This setting determines the number of times the task will be retried if it fails
         # A failure is defined by either a non-zero exit code for commands or a status code of 400 or higher for HTTP requests.
         retries: 3
@@ -20,12 +20,13 @@ jobs:
         # This sets a maximum time limit for the task to complete.
         # If the task exceeds 15 seconds, it will be considered failed and stopped (command) or canceled (http requests)
         timeout: 15s
-        # This defines the working directory for the command.
-        working-dir: C://
+        user: root
+        # # This defines the working directory for the command.
+        # working-dir: C://
         # This section allows you to set environment variables that will be available to the command during execution.
         # `SHELL` and `SHELL_ARGS` can be used to change this commands shell environment
-        env:
-          DB_HOST: 10.0.0.5
+        # env:
+        #   DB_HOST: 10.0.0.5
 
       # # A simple get request
       # - get: https://example.com/get

config/config.go

@@ -50,6 +50,9 @@ type (
 		Headers          map[string]string `mapstructure:"headers" json:"headers,omitempty"`
 		Data             any               `mapstructure:"data" json:"data,omitempty"`
 
+		UserName  string `mapstructure:"user" json:"user,omitempty"`
+		GroupName string `mapstructure:"group" json:"group,omitempty"`
+
 		Retries    uint          `mapstructure:"retries" json:"retries,omitempty"`
 		RetryDelay time.Duration `mapstructure:"retry-delay" json:"retry_delay,omitempty"`
 		Timeout    time.Duration `mapstructure:"timeout" json:"timeout,omitempty"`

config/validators.go

@@ -4,53 +4,56 @@ import (
 	"encoding/json"
 	"fmt"
 
+	"github.com/sirupsen/logrus"
+
+	credential "github.com/FMotalleb/crontab-go/core/os_credential"
 	"github.com/FMotalleb/crontab-go/core/schedule"
 )
 
-func (cfg *Config) Validate() error {
+func (cfg *Config) Validate(log *logrus.Entry) error {
 	if err := cfg.LogFormat.Validate(); err != nil {
 		return err
 	}
 	if err := cfg.LogLevel.Validate(); err != nil {
 		return err
 	}
 	for _, job := range cfg.Jobs {
-		if err := job.Validate(); err != nil {
+		if err := job.Validate(log); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func (c *JobConfig) Validate() error {
+func (c *JobConfig) Validate(log *logrus.Entry) error {
 	if c.Disabled == true {
 		return nil
 	}
 
 	for _, s := range c.Schedulers {
-		if err := s.Validate(); err != nil {
+		if err := s.Validate(log); err != nil {
 			return err
 		}
 	}
 	for _, t := range c.Tasks {
-		if err := t.Validate(); err != nil {
+		if err := t.Validate(log); err != nil {
 			return err
 		}
 	}
 	for _, t := range c.Hooks.Done {
-		if err := t.Validate(); err != nil {
+		if err := t.Validate(log); err != nil {
 			return err
 		}
 	}
 	for _, t := range c.Hooks.Failed {
-		if err := t.Validate(); err != nil {
+		if err := t.Validate(log); err != nil {
 			return err
 		}
 	}
 	return nil
 }
 
-func (t *Task) Validate() error {
+func (t *Task) Validate(log *logrus.Entry) error {
 	actions := []bool{
 		t.Get != "",
 		t.Command != "",
@@ -70,7 +73,9 @@ func (t *Task) Validate() error {
 			t.Post,
 		)
 	}
-
+	if err := credential.Validate(log, t.UserName, t.GroupName); err != nil {
+		return err
+	}
 	if t.Command != "" && (t.Data != nil || t.Headers != nil) {
 		return fmt.Errorf("command cannot have data or headers field, violating command: `%s`", t.Command)
 	}
@@ -101,7 +106,7 @@ func (t *Task) Validate() error {
 	return nil
 }
 
-func (s *JobScheduler) Validate() error {
+func (s *JobScheduler) Validate(log *logrus.Entry) error {
 	if s.Interval < 0 {
 		return fmt.Errorf("received a negative time in interval: `%v`", s.Interval)
 	} else if _, err := schedule.CronParser.Parse(s.Cron); s.Cron != "" && err != nil {

core/jobs/runner.go

@@ -31,7 +31,7 @@ func InitializeJobs(log *logrus.Entry, cronInstance *cron.Cron) {
 
 		logger := initLogger(c, log, job)
 		logger = logger.WithField("concurrency", job.Concurrency)
-		if err := job.Validate(); err != nil {
+		if err := job.Validate(log); err != nil {
 			log.Panicf("failed to validate job (%s): %v", job.Name, err)
 		}
 

core/os_credential/unix_credential.go

@@ -0,0 +1,95 @@
+//go:build !windows
+// +build !windows
+
+package credential
+
+import (
+	"errors"
+	"fmt"
+	"os/exec"
+	osUser "os/user"
+	"strconv"
+	"syscall"
+
+	"github.com/sirupsen/logrus"
+)
+
+func Validate(log *logrus.Entry, usr string, grp string) error {
+	cu, err := osUser.Current()
+	if err != nil {
+		return fmt.Errorf("cannot get current user error: %s", err)
+	}
+	if usr != "" && cu.Uid != "0" {
+		return errors.New("cannot switch user of tasks without root privilege, if you need to use user in tasks run crontab-go as user root")
+	}
+	_, _, err = lookupUIDAndGID(usr, log)
+	if err != nil {
+		return fmt.Errorf("cannot get uid and gid of user `%s` error: %s", usr, err)
+	}
+	_, err = lookupGID(grp, log)
+	if err != nil {
+		return fmt.Errorf("cannot get gid of group `%s` error: %s", grp, err)
+	}
+
+	return nil
+}
+
+func SetUser(log *logrus.Entry, proc *exec.Cmd, usr string, grp string) {
+	if usr == "" {
+		log.Trace("no username given, running as current user")
+		return
+	}
+
+	uid, gid, err := lookupUIDAndGID(usr, log)
+	if err != nil {
+		log.Panicf("cannot get uid and gid of user %s, error: %s", usr, err)
+	}
+	if grp != "" {
+		gid, _ = lookupGID(grp, log)
+	}
+
+	setUID(log, proc, uid, gid)
+}
+
+func lookupGID(grp string, log *logrus.Entry) (gid uint32, err error) {
+	g, err := osUser.LookupGroup(grp)
+	if err != nil {
+		log.Panicf("cannot find group with name %s in the os: %s, you've changed os users during application runtime", grp, err)
+	}
+	gidU, err := strconv.ParseUint(g.Gid, 10, 32)
+	if err != nil {
+		return 0, err
+	}
+	return uint32(gidU), nil
+}
+
+func lookupUIDAndGID(usr string, log *logrus.Entry) (uid uint32, gid uint32, err error) {
+	u, err := osUser.Lookup(usr)
+	if err != nil {
+		log.Panicf("cannot find user with name %s in the os: %s, you've changed os users during application runtime", usr, err)
+	}
+	uidU, err := strconv.ParseUint(u.Uid, 10, 32)
+	if err != nil {
+		return 0, 0, err
+	}
+	gidU, err := strconv.ParseUint(u.Gid, 10, 32)
+	if err != nil {
+		return 0, 0, err
+	}
+	return uint32(uidU), uint32(gidU), nil
+}
+
+func setUID(
+	log *logrus.Entry,
+	proc *exec.Cmd,
+	uid uint32,
+	gid uint32,
+) {
+	log.Tracef("Setting: uid(%d) and gid(%d)", uid, gid)
+	attrib := &syscall.SysProcAttr{}
+	proc.SysProcAttr = attrib
+	proc.SysProcAttr.Credential = &syscall.Credential{
+		Uid: uid,
+		Gid: gid,
+	}
+}

core/os_credential/windows_credential.go

@@ -0,0 +1,19 @@
+//go:build windows
+// +build windows
+
+package credential
+
+import (
+	"os/exec"
+
+	"github.com/sirupsen/logrus"
+)
+
+func Validate(log *logrus.Entry, usr string, grp string) error {
+	log.Warn("windows os does not have capability to set user dus validation will pass but will not work")
+	return nil
+}
+
+func SetUser(log *logrus.Entry, _ *exec.Cmd, _ string, _ string) {
+	log.Warn("cannot set user in windows platform")
+}

core/task/command.go

@@ -14,6 +14,7 @@ import (
 	"github.com/FMotalleb/crontab-go/abstraction"
 	"github.com/FMotalleb/crontab-go/cmd"
 	"github.com/FMotalleb/crontab-go/config"
+	credential "github.com/FMotalleb/crontab-go/core/os_credential"
 )
 
 type Command struct {
@@ -23,6 +24,9 @@ type Command struct {
 	log              *logrus.Entry
 	cancel           context.CancelFunc
 
+	user  string
+	group string
+
 	shell     string
 	shellArgs []string
 
@@ -32,42 +36,43 @@ type Command struct {
 }
 
 // Cancel implements abstraction.Executable.
-func (g *Command) Cancel() {
-	if g.cancel != nil {
-		g.log.Debugln("canceling executable")
-		g.cancel()
+func (c *Command) Cancel() {
+	if c.cancel != nil {
+		c.log.Debugln("canceling executable")
+		c.cancel()
 	}
 }
 
 // Execute implements abstraction.Executable.
-func (cmmnd *Command) Execute(ctx context.Context) (e error) {
+func (c *Command) Execute(ctx context.Context) (e error) {
 	r := getRetry(ctx)
-	log := cmmnd.log.WithField("retry", r)
-	if getRetry(ctx) > cmmnd.retries {
+	log := c.log.WithField("retry", r)
+	if getRetry(ctx) > c.retries {
 		log.Warn("maximum retry reached")
 		return fmt.Errorf("maximum retries reached")
 	}
 	if r != 0 {
-		log.Debugln("waiting", cmmnd.retryDelay, "before executing the next iteration after last fail")
-		time.Sleep(cmmnd.retryDelay)
+		log.Debugln("waiting", c.retryDelay, "before executing the next iteration after last fail")
+		time.Sleep(c.retryDelay)
 	}
 	ctx = increaseRetry(ctx)
 	var procCtx context.Context
 	var cancel context.CancelFunc
-	if cmmnd.timeout != 0 {
-		procCtx, cancel = context.WithTimeout(ctx, cmmnd.timeout)
+	if c.timeout != 0 {
+		procCtx, cancel = context.WithTimeout(ctx, c.timeout)
 	} else {
 		procCtx, cancel = context.WithCancel(ctx)
 	}
-	cmmnd.cancel = cancel
+	c.cancel = cancel
 
 	proc := exec.CommandContext(
 		procCtx,
-		cmmnd.shell,
-		append(cmmnd.shellArgs, *&cmmnd.exe)...,
+		c.shell,
+		append(c.shellArgs, *&c.exe)...,
 	)
-	proc.Env = *cmmnd.envVars
-	proc.Dir = cmmnd.workingDirectory
+	credential.SetUser(log, proc, c.user, c.group)
+	proc.Env = *c.envVars
+	proc.Dir = c.workingDirectory
 	var res bytes.Buffer
 	proc.Stdout = &res
 	proc.Stderr = &res
@@ -76,7 +81,7 @@ func (cmmnd *Command) Execute(ctx context.Context) (e error) {
 	log.Infof("command finished with answer: `%s`", strings.TrimSpace(string(res.Bytes())))
 	if e != nil {
 		log.Warn("failed to execute the command ", e)
-		return cmmnd.Execute(ctx)
+		return c.Execute(ctx)
 	}
 	return
 }
@@ -119,5 +124,7 @@ func NewCommand(
 		retries:    task.Retries,
 		retryDelay: task.RetryDelay,
 		timeout:    task.Timeout,
+		user:       task.UserName,
+		group:      task.GroupName,
 	}
 }

helpers/err_handlers.go

@@ -0,0 +1,23 @@
+package helpers
+
+import (
+	"github.com/sirupsen/logrus"
+)
+
+func PanicOnErr(log *logrus.Entry, err error, message string) {
+	if err != nil {
+		log.Panicf(message, err)
+	}
+}
+
+func FatalOnErr(log *logrus.Entry, err error, message string) {
+	if err != nil {
+		log.Fatalf(message, err)
+	}
+}
+
+func WarnOnErr(log *logrus.Entry, err error, message string) {
+	if err != nil {
+		log.Warnf(message, err)
+	}
+}