add command timeout support for skopeo

* add global command-timeout option for skopeo

cmd/skopeo/copy.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"os"
@@ -88,7 +87,10 @@ func copyHandler(c *cli.Context) error {
 		}
 	}
 
-	_, err = copy.Image(context.Background(), policyContext, destRef, srcRef, &copy.Options{
+	ctx, cancel := commandTimeoutContextFromGlobalOptions(c)
+	defer cancel()
+
+	_, err = copy.Image(ctx, policyContext, destRef, srcRef, &copy.Options{
 		RemoveSignatures:      removeSignatures,
 		SignBy:                signBy,
 		ReportWriter:          os.Stdout,

cmd/skopeo/delete.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"errors"
 	"fmt"
 	"strings"
@@ -25,7 +24,10 @@ func deleteHandler(c *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	return ref.DeleteImage(context.Background(), sys)
+
+	ctx, cancel := commandTimeoutContextFromGlobalOptions(c)
+	defer cancel()
+	return ref.DeleteImage(ctx, sys)
 }
 
 var deleteCmd = cli.Command{

cmd/skopeo/inspect.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"encoding/json"
 	"fmt"
 	"strings"
@@ -67,7 +66,8 @@ var inspectCmd = cli.Command{
 		},
 	},
 	Action: func(c *cli.Context) (retErr error) {
-		ctx := context.Background()
+		ctx, cancel := commandTimeoutContextFromGlobalOptions(c)
+		defer cancel()
 
 		img, err := parseImage(ctx, c)
 		if err != nil {

cmd/skopeo/layers.go

@@ -1,7 +1,6 @@
 package main
 
 import (
-	"context"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -26,7 +25,8 @@ var layersCmd = cli.Command{
 			return errors.New("Usage: layers imageReference [layer...]")
 		}
 
-		ctx := context.Background()
+		ctx, cancel := commandTimeoutContextFromGlobalOptions(c)
+		defer cancel()
 
 		sys, err := contextFromGlobalOptions(c, "")
 		if err != nil {

cmd/skopeo/main.go

@@ -60,6 +60,10 @@ func createApp() *cli.App {
 			Value: "",
 			Usage: "use `OS` instead of the running OS for choosing images",
 		},
+		cli.DurationFlag{
+			Name:  "command-timeout",
+			Usage: "timeout for the command execution",
+		},
 	}
 	app.Before = func(c *cli.Context) error {
 		if c.GlobalBool("debug") {

cmd/skopeo/utils.go

@@ -40,6 +40,15 @@ func contextFromGlobalOptions(c *cli.Context, flagPrefix string) (*types.SystemC
 	return ctx, nil
 }
 
+func commandTimeoutContextFromGlobalOptions(c *cli.Context) (context.Context, context.CancelFunc) {
+	ctx := context.Background()
+	var cancel context.CancelFunc = func() {}
+	if c.GlobalDuration("command-timeout") > 0 {
+		ctx, cancel = context.WithTimeout(ctx, c.GlobalDuration("command-timeout"))
+	}
+	return ctx, cancel
+}
+
 func parseCreds(creds string) (string, string, error) {
 	if creds == "" {
 		return "", "", errors.New("credentials can't be empty")

completions/bash/skopeo

@@ -110,6 +110,7 @@ _skopeo_skopeo() {
 	   --registries.d
        --override-arch
        --override-os
+       --command-timeout
      "
      local boolean_options="
 	   --insecure-policy

docs/skopeo.1.md

@@ -59,6 +59,8 @@ Most commands refer to container images, using a _transport_`:`_details_ format.
 
   **--override-os** _OS_ Use _OS_ instead of the running OS for choosing images.
 
+  **--command-timeout** _duration_ Timeout for the command execution.
+
   **--help**|**-h** Show help
 
   **--version**|**-v** print the version number