feat: convert cobra commands from Run to RunE (#111)

* feat: convert cobra commands from Run to RunE

---------

Co-authored-by: Radosław Skałbania <[email protected]>

cmd/apply.go

@@ -18,12 +18,13 @@ package cmd
 import (
 	"fmt"
 	"os"
-	"sync"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/sync/errgroup"
 
 	c "github.com/alegrey91/fwdctl/internal/constants"
 	"github.com/alegrey91/fwdctl/internal/rules"
 	iptables "github.com/alegrey91/fwdctl/pkg/iptables"
-	"github.com/spf13/cobra"
 )
 
 // applyCmd represents the apply command
@@ -32,61 +33,47 @@ var applyCmd = &cobra.Command{
 	Short:   "apply rules from file",
 	Long:    `apply rules described in a configuration file`,
 	Example: c.ProgramName + " apply --file rule.yml",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		rulesContent, err := os.Open(c.RulesFile)
 		if err != nil {
-			fmt.Printf("error opening file: %v", err)
-			os.Exit(1)
+			return fmt.Errorf("opening file: %v", err)
 		}
 		ruleSet, err := rules.NewRuleSetFromFile(rulesContent)
 		if err != nil {
-			fmt.Printf("unable to open rules file: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to open rules file: %v", err)
 		}
 		ipt, err := iptables.NewIPTablesInstance()
 		if err != nil {
-			fmt.Printf("unable to get iptables instance: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to get iptables instance: %v", err)
 		}
 
-		var wg sync.WaitGroup
-		chErr := make(chan error, len(ruleSet.Rules))
-		chLimit := make(chan int, 10)
+		g := new(errgroup.Group)
 		rulesFileIsValid := true
 
+		g.SetLimit(10)
 		for _, rule := range ruleSet.Rules {
-			wg.Add(1)
-			// add slot to buffered channel
-			chLimit <- 1
-			go func(rule iptables.Rule, wg *sync.WaitGroup, chErr chan error, chLimit chan int) {
-				err := ipt.ValidateForward(&rule)
-				wg.Done()
-				chErr <- err
-				// free slot from buffered channel
-				<-chLimit
-			}(rule, &wg, chErr, chLimit)
+			r := &rule
+			g.Go(func() error {
+				err := ipt.ValidateForward(r)
+				if err != nil {
+					rulesFileIsValid = false
+				}
+				return err
+			})
 		}
-		go func() {
-			wg.Wait()
-			close(chErr)
-		}()
 
-		for err := range chErr {
-			if err != nil {
-				fmt.Printf("error validating rule: %v\n", err)
-				os.Exit(1)
-			}
+		if err := g.Wait(); err != nil {
+			return fmt.Errorf("validating rule: %v", err)
 		}
 
 		if rulesFileIsValid {
 			for ruleId, rule := range ruleSet.Rules {
-				err = ipt.CreateForward(&rule)
-				if err != nil {
-					fmt.Printf("error applying rule (%s): %v\n", ruleId, err)
-					os.Exit(1)
+				if err := ipt.CreateForward(&rule); err != nil {
+					return fmt.Errorf("applying rule (%s): %v", ruleId, err)
 				}
 			}
 		}
+		return nil
 	},
 }
 

cmd/create.go

@@ -17,7 +17,6 @@ package cmd
 
 import (
 	"fmt"
-	"os"
 
 	c "github.com/alegrey91/fwdctl/internal/constants"
 	iptables "github.com/alegrey91/fwdctl/pkg/iptables"
@@ -53,18 +52,16 @@ your hypervisor, to external.
    +----------------------------+
 `,
 	Example: c.ProgramName + " create -d 3000 -s 192.168.199.105 -p 80",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		ipt, err := iptables.NewIPTablesInstance()
 		if err != nil {
-			fmt.Printf("unable to get iptables instance: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to get iptables instance: %v", err)
 		}
 		rule := iptables.NewRule(iface, proto, dport, saddr, sport)
-		err = ipt.CreateForward(rule)
-		if err != nil {
-			fmt.Println(err)
-			return
+		if err := ipt.CreateForward(rule); err != nil{
+			return fmt.Errorf("creating new rule: %v", err)
 		}
+		return nil
 	},
 }
 

cmd/daemon_start.go

@@ -30,20 +30,19 @@ var daemonStartCmd = &cobra.Command{
 	Use:   "start",
 	Short: "Start fwdctl daemon",
 	Long:  ``,
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error{
 		ipt, err := iptables.NewIPTablesInstance()
 		if err != nil {
-			fmt.Printf("unable to get iptables instance: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to get iptables instance: %v", err)
 		}
 		rulesFile, err := cmd.Flags().GetString("file")
 		if err != nil {
-			fmt.Printf("unable to read from flag: %v", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to read from flag: %v", err)
 		}
 		if res := daemon.Start(ipt, rulesFile); res != 0 {
 			os.Exit(1)
 		}
+		return nil
 	},
 }
 

cmd/delete.go

@@ -40,46 +40,38 @@ var deleteCmd = &cobra.Command{
 	Long: `Delete forward by passing a rule file or rule id.
 `,
 	Example: c.ProgramName + " delete -n 2",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		ipt, err := iptables.NewIPTablesInstance()
 		if err != nil {
-			fmt.Printf("unable to get iptables instance: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("unable to get iptables instance: %v", err)
 		}
 		// Delete rule number
 		if cmd.Flags().Lookup("id").Changed {
-			err := ipt.DeleteForwardById(ruleId)
-			if err != nil {
-				fmt.Printf("%v\n", err)
-				os.Exit(1)
+			if err := ipt.DeleteForwardById(ruleId); err != nil {
+				return fmt.Errorf("delete forward by ID: %v", err)
 			}
-			return
+			return nil
 		}
 
 		// Loop over file content and delete rule one-by-one.
 		if cmd.Flags().Lookup("file").Changed {
-			err := deleteFromFile(ipt, file)
-			if err != nil {
-				fmt.Printf("%v\n", err)
-				os.Exit(1)
+			if err := deleteFromFile(ipt, file); err != nil {
+				return fmt.Errorf("delete from file: %v", err)
 			}
-			return
+			return nil
 		}
 
 		if cmd.Flags().Lookup("all").Changed {
-			err := ipt.DeleteAllForwards()
-			if err != nil {
-				fmt.Println(err)
-				os.Exit(1)
+			if err := ipt.DeleteAllForwards();err != nil {
+				return fmt.Errorf("delete all forwards: %v", err)
 			}
-			return
+			return nil
 		}
 
-		err = deleteFromFile(ipt, file)
-		if err != nil {
-			fmt.Printf("%v\n", err)
-			os.Exit(1)
+		if err = deleteFromFile(ipt, file);err != nil {
+			return fmt.Errorf("delete from file: %v", err)
 		}
+		return nil
 	},
 }
 

cmd/generate_rules.go

@@ -17,11 +17,11 @@ package cmd
 
 import (
 	"fmt"
-	"os"
+
+	"github.com/spf13/cobra"
 
 	"github.com/alegrey91/fwdctl/internal/template"
 	rt "github.com/alegrey91/fwdctl/internal/template/rules_template"
-	"github.com/spf13/cobra"
 )
 
 // generateRulesCmd represents the generateRules command
@@ -30,13 +30,12 @@ var generateRulesCmd = &cobra.Command{
 	Short: "generates empty rules file",
 	Long: `generates empty rules file
 `,
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		rules := rt.NewRules()
-		err := template.GenerateTemplate(rules, outputFile)
-		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
+		if err := template.GenerateTemplate(rules, outputFile); err != nil {
+			return fmt.Errorf("generating template: %w", err)
 		}
+		return nil
 	},
 }
 

cmd/generate_systemd.go

@@ -17,7 +17,6 @@ package cmd
 
 import (
 	"fmt"
-	"os"
 
 	c "github.com/alegrey91/fwdctl/internal/constants"
 	"github.com/alegrey91/fwdctl/internal/template"
@@ -34,17 +33,16 @@ var generateSystemdCmd = &cobra.Command{
 	Short: "generates systemd service file",
 	Long: `generates systemd service file to run fwdctl at boot
 `,
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		systemd, err := st.NewSystemdService(serviceType, installationPath, c.RulesFile)
 		if err != nil {
-			fmt.Println(err)
-			os.Exit(1)
+			return fmt.Errorf("cannot create systemd service: %v", err)
 		}
-		err = template.GenerateTemplate(systemd, outputFile)
-		if err != nil {
-			fmt.Printf("error generating templated file: %v\n", err)
-			os.Exit(1)
+
+		if err = template.GenerateTemplate(systemd, outputFile);err != nil {
+			return fmt.Errorf("generating templated file: %v", err)
 		}
+		return nil
 	},
 }
 

cmd/list.go

@@ -17,7 +17,6 @@ package cmd
 
 import (
 	"fmt"
-	"os"
 
 	c "github.com/alegrey91/fwdctl/internal/constants"
 	"github.com/alegrey91/fwdctl/internal/printer"
@@ -36,24 +35,21 @@ var listCmd = &cobra.Command{
 	Short:   "list forwards",
 	Long:    `list forwards made with iptables`,
 	Example: c.ProgramName + "list -o table",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error{
 		ipt, err := iptables.NewIPTablesInstance()
 		if err != nil {
-			fmt.Printf("unable to get iptables instance: %v\n", err)
-			os.Exit(1)
+			return fmt.Errorf("getting iptables instance: %v", err)
 		}
 		ruleList, err := ipt.ListForward(format)
 		if err != nil {
-			fmt.Println(err)
-			return
+			return fmt.Errorf("listing rules: %v", err)
 		}
 
 		p := printer.NewPrinter(format)
-		err = p.PrintResult(ruleList)
-		if err != nil {
-			fmt.Printf("failed printing results: %v", err)
-			return
+		if err = p.PrintResult(ruleList);err != nil {
+			return fmt.Errorf("printing result: %v", err)
 		}
+		return nil
 	},
 }
 

go.mod

@@ -19,6 +19,7 @@ require (
 	github.com/spf13/cast v1.5.0 // indirect
 	github.com/spf13/jwalterweatherman v1.1.0 // indirect
 	github.com/subosito/gotenv v1.4.2 // indirect
+	golang.org/x/sync v0.8.0 // indirect
 	golang.org/x/sys v0.4.0 // indirect
 	golang.org/x/text v0.5.0 // indirect
 	golang.org/x/tools v0.1.12 // indirect

go.sum

@@ -281,6 +281,8 @@ golang.org/x/sync v0.0.0-20200317015054-43a5402ce75a/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sync v0.0.0-20200625203802-6e8e738ad208/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20201207232520-09787c993a3a/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=