tests: add plugin-socket-compatibility tests

Adds a new plugin to the e2e plugins that simulates an older
plugin binary and a test suite to ensure older plugin binaries
keep behaving the same with newer CLI versions.

Signed-off-by: Laura Brehm <[email protected]>
(cherry picked from commit cfa9fef)
Signed-off-by: Sebastiaan van Stijn <[email protected]>

cli-plugins/socket/socket_test.go

@@ -5,6 +5,7 @@ import (
 	"net"
 	"os"
 	"runtime"
+	"strings"
 	"testing"
 	"time"
 
@@ -49,17 +50,17 @@ func TestSetupConn(t *testing.T) {
 		listener, err := SetupConn(&conn)
 		assert.NilError(t, err)
 		assert.Check(t, listener != nil, "returned nil listener but no error")
-		checkDirClean(t)
+		checkDirNoPluginSocket(t)
 
 		addr, err := net.ResolveUnixAddr("unix", listener.Addr().String())
 		assert.NilError(t, err, "failed to resolve listener address")
 		_, err = net.DialUnix("unix", nil, addr)
 		assert.NilError(t, err, "failed to dial returned listener")
-		checkDirClean(t)
+		checkDirNoPluginSocket(t)
 	})
 }
 
-func checkDirClean(t *testing.T) {
+func checkDirNoPluginSocket(t *testing.T) {
 	t.Helper()
 
 	files, err := os.ReadDir(".")
@@ -68,7 +69,8 @@ func checkDirClean(t *testing.T) {
 	for _, f := range files {
 		info, err := f.Info()
 		assert.NilError(t, err, "failed to check file info")
-		if info.Mode().Type() == fs.ModeSocket {
+		// check for a socket with `docker_cli_` in the name (from `SetupConn()`)
+		if strings.Contains(f.Name(), "docker_cli_") && info.Mode().Type() == fs.ModeSocket {
 			t.Fatal("found socket in a local directory")
 		}
 	}
@@ -96,6 +98,8 @@ func TestConnectAndWait(t *testing.T) {
 		}
 	})
 
+	// TODO: this test cannot be executed with `t.Parallel()`, due to
+	// relying on goroutine numbers to ensure correct behaviour
 	t.Run("connect goroutine exits after EOF", func(t *testing.T) {
 		var conn *net.UnixConn
 		listener, err := SetupConn(&conn)

e2e/cli-plugins/plugins/presocket/main.go

@@ -0,0 +1,123 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/docker/cli/cli-plugins/manager"
+	"github.com/docker/cli/cli-plugins/plugin"
+	"github.com/docker/cli/cli/command"
+	"github.com/spf13/cobra"
+)
+
+func main() {
+	plugin.Run(RootCmd, manager.Metadata{
+		SchemaVersion: "0.1.0",
+		Vendor:        "Docker Inc.",
+		Version:       "test",
+	})
+}
+
+func RootCmd(dockerCli command.Cli) *cobra.Command {
+	cmd := cobra.Command{
+		Use:   "presocket",
+		Short: "testing plugin that does not connect to the socket",
+		// override PersistentPreRunE so that the plugin default
+		// PersistentPreRunE doesn't run, simulating a plugin built
+		// with a pre-socket-communication version of the CLI
+		PersistentPreRunE: func(cmd *cobra.Command, args []string) error {
+			return nil
+		},
+	}
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "test-no-socket",
+		Short: "test command that runs until it receives a SIGINT",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			go func() {
+				<-cmd.Context().Done()
+				fmt.Fprintln(dockerCli.Out(), "context cancelled")
+				os.Exit(2)
+			}()
+			signalCh := make(chan os.Signal, 10)
+			signal.Notify(signalCh, syscall.SIGINT, syscall.SIGTERM)
+			go func() {
+				for range signalCh {
+					fmt.Fprintln(dockerCli.Out(), "received SIGINT")
+				}
+			}()
+			<-time.After(3 * time.Second)
+			fmt.Fprintln(dockerCli.Err(), "exit after 3 seconds")
+			return nil
+		},
+	})
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "test-socket",
+		Short: "test command that runs until it receives a SIGINT",
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return plugin.PersistentPreRunE(cmd, args)
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			go func() {
+				<-cmd.Context().Done()
+				fmt.Fprintln(dockerCli.Out(), "context cancelled")
+				os.Exit(2)
+			}()
+			signalCh := make(chan os.Signal, 10)
+			signal.Notify(signalCh, syscall.SIGINT, syscall.SIGTERM)
+			go func() {
+				for range signalCh {
+					fmt.Fprintln(dockerCli.Out(), "received SIGINT")
+				}
+			}()
+			<-time.After(3 * time.Second)
+			fmt.Fprintln(dockerCli.Err(), "exit after 3 seconds")
+			return nil
+		},
+	})
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "test-socket-ignore-context",
+		Short: "test command that runs until it receives a SIGINT",
+		PreRunE: func(cmd *cobra.Command, args []string) error {
+			return plugin.PersistentPreRunE(cmd, args)
+		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			signalCh := make(chan os.Signal, 10)
+			signal.Notify(signalCh, syscall.SIGINT, syscall.SIGTERM)
+			go func() {
+				for range signalCh {
+					fmt.Fprintln(dockerCli.Out(), "received SIGINT")
+				}
+			}()
+			<-time.After(3 * time.Second)
+			fmt.Fprintln(dockerCli.Err(), "exit after 3 seconds")
+			return nil
+		},
+	})
+
+	cmd.AddCommand(&cobra.Command{
+		Use:   "tty",
+		Short: "test command that attempts to read from the TTY",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			done := make(chan struct{})
+			go func() {
+				b := make([]byte, 1)
+				_, _ = dockerCli.In().Read(b)
+				done <- struct{}{}
+			}()
+			select {
+			case <-done:
+			case <-time.After(2 * time.Second):
+				fmt.Fprint(dockerCli.Err(), "timeout after 2 seconds")
+			}
+			return nil
+		},
+	})
+
+	return &cmd
+}