pkg/shell: Add cancellable versions of Run and RunWithExitCode

A subsequent commit will use this to ensure that the user can still
interact with the image download prompt while 'skopeo inspect' fetches
the image size from the remote registry.  Initially, the prompt will be
shown without the image size.  If the user responds before the size is
fetched, then the pending 'skopeo inspect' will be cancelled.

containers#752
containers#1263

src/pkg/shell/shell.go

@@ -1,5 +1,5 @@
 /*
- * Copyright © 2019 – 2022 Red Hat Inc.
+ * Copyright © 2019 – 2023 Red Hat Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,6 +17,7 @@
 package shell
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -27,7 +28,13 @@ import (
 )
 
 func Run(name string, stdin io.Reader, stdout, stderr io.Writer, arg ...string) error {
-	exitCode, err := RunWithExitCode(name, stdin, stdout, stderr, arg...)
+	ctx := context.Background()
+	err := RunContext(ctx, name, stdin, stdout, stderr, arg...)
+	return err
+}
+
+func RunContext(ctx context.Context, name string, stdin io.Reader, stdout, stderr io.Writer, arg ...string) error {
+	exitCode, err := RunContextWithExitCode(ctx, name, stdin, stdout, stderr, arg...)
 	if err != nil {
 		return err
 	}
@@ -37,13 +44,18 @@ func Run(name string, stdin io.Reader, stdout, stderr io.Writer, arg ...string)
 	return nil
 }
 
-func RunWithExitCode(name string, stdin io.Reader, stdout, stderr io.Writer, arg ...string) (int, error) {
+func RunContextWithExitCode(ctx context.Context,
+	name string,
+	stdin io.Reader,
+	stdout, stderr io.Writer,
+	arg ...string) (int, error) {
+
 	logLevel := logrus.GetLevel()
 	if stderr == nil && logLevel >= logrus.DebugLevel {
 		stderr = os.Stderr
 	}
 
-	cmd := exec.Command(name, arg...)
+	cmd := exec.CommandContext(ctx, name, arg...)
 	cmd.Stdin = stdin
 	cmd.Stdout = stdout
 	cmd.Stderr = stderr
@@ -53,6 +65,10 @@ func RunWithExitCode(name string, stdin io.Reader, stdout, stderr io.Writer, arg
 			return 1, fmt.Errorf("%s(1) not found", name)
 		}
 
+		if ctxErr := ctx.Err(); ctxErr != nil {
+			return 1, ctxErr
+		}
+
 		var exitErr *exec.ExitError
 		if errors.As(err, &exitErr) {
 			exitCode := exitErr.ExitCode()
@@ -64,3 +80,9 @@ func RunWithExitCode(name string, stdin io.Reader, stdout, stderr io.Writer, arg
 
 	return 0, nil
 }
+
+func RunWithExitCode(name string, stdin io.Reader, stdout, stderr io.Writer, arg ...string) (int, error) {
+	ctx := context.Background()
+	exitCode, err := RunContextWithExitCode(ctx, name, stdin, stdout, stderr, arg...)
+	return exitCode, err
+}

src/pkg/shell/shell_test.go

@@ -1,10 +1,29 @@
+/*
+ * Copyright © 2023 Red Hat Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 package shell_test
 
 import (
+	"context"
 	"errors"
 	"io"
 	"os"
+	"strings"
 	"testing"
+	"time"
 
 	"github.com/containers/toolbox/pkg/shell"
 	"github.com/sirupsen/logrus"
@@ -100,6 +119,126 @@ func TestShellRun(t *testing.T) {
 	}
 }
 
+func TestRunContextWithExitCode(t *testing.T) {
+	testCases := []struct {
+		cancel   bool
+		command  []string
+		err      error
+		errMsg   string
+		exitCode int
+		stdout   []byte
+		stderr   []byte
+		timeout  time.Duration
+	}{
+		{
+			command: []string{"true"},
+		},
+		{
+			command:  []string{"false"},
+			exitCode: 1,
+		},
+		{
+			command: []string{"echo"},
+			stdout:  []byte("\n"),
+		},
+		{
+			command:  []string{"echo", "hello, world"},
+			err:      nil,
+			exitCode: 0,
+			stdout:   []byte("hello, world\n"),
+		},
+		{
+			command:  []string{"command-does-not-exist"},
+			errMsg:   "command-does-not-exist(1) not found",
+			exitCode: 1,
+		},
+		{
+			command:  []string{"cat", "/file/does/not/exist"},
+			exitCode: 1,
+			stderr:   []byte("cat: /file/does/not/exist: No such file or directory\n"),
+		},
+		{
+			cancel:   true,
+			command:  []string{"sleep", "+Inf"},
+			err:      context.Canceled,
+			exitCode: 1,
+		},
+		{
+			command:  []string{"sleep", "+Inf"},
+			err:      context.DeadlineExceeded,
+			exitCode: 1,
+			timeout:  1 * time.Second,
+		},
+	}
+
+	for _, tc := range testCases {
+		name := strings.Join(tc.command, " ")
+		if tc.cancel {
+			name += " (cancel)"
+		}
+		if tc.timeout != 0 {
+			name += " (timeout)"
+		}
+
+		t.Run(name, func(t *testing.T) {
+			var cancel context.CancelFunc
+			ctx := context.Background()
+			if tc.cancel {
+				ctx, cancel = context.WithCancel(ctx)
+				defer cancel()
+			}
+			if tc.timeout != 0 {
+				ctx, cancel = context.WithTimeout(ctx, tc.timeout)
+				defer cancel()
+			}
+
+			if tc.cancel {
+				cancel()
+			}
+
+			var stdout outputMock
+			var stderr outputMock
+
+			exitCode, err := shell.RunContextWithExitCode(ctx,
+				tc.command[0],
+				os.Stdin,
+				&stdout,
+				&stderr,
+				tc.command[1:]...)
+
+			if tc.err == nil && tc.errMsg == "" {
+				assert.NoError(t, err)
+			}
+
+			if tc.err != nil {
+				assert.Error(t, err)
+				assert.ErrorIs(t, err, tc.err)
+			}
+
+			if tc.errMsg != "" {
+				assert.Error(t, err)
+				assert.EqualError(t, err, tc.errMsg)
+			}
+
+			assert.Equal(t, tc.exitCode, exitCode)
+
+			if tc.stdout == nil {
+				assert.Empty(t, stdout.written)
+			} else {
+				assert.NotEmpty(t, stdout.written)
+				assert.Equal(t, tc.stdout, stdout.written)
+			}
+
+			if tc.stderr == nil {
+				assert.Empty(t, stderr.written)
+			} else {
+				assert.NotEmpty(t, stderr.written)
+				assert.Equal(t, tc.stderr, stderr.written)
+			}
+		})
+	}
+}
+
 func TestShellRunWithExitCode(t *testing.T) {
 	type input struct {
 		commandName string