[25.0 backport] Add tests for CLI/plugin communication

cli-plugins/socket/socket_test.go

@@ -0,0 +1,133 @@
+package socket
+
+import (
+	"io/fs"
+	"net"
+	"os"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+
+	"gotest.tools/v3/assert"
+	"gotest.tools/v3/poll"
+)
+
+func TestSetupConn(t *testing.T) {
+	t.Run("updates conn when connected", func(t *testing.T) {
+		var conn *net.UnixConn
+		listener, err := SetupConn(&conn)
+		assert.NilError(t, err)
+		assert.Check(t, listener != nil, "returned nil listener but no error")
+		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")
+
+		pollConnNotNil(t, &conn)
+	})
+
+	t.Run("allows reconnects", func(t *testing.T) {
+		var conn *net.UnixConn
+		listener, err := SetupConn(&conn)
+		assert.NilError(t, err)
+		assert.Check(t, listener != nil, "returned nil listener but no error")
+		addr, err := net.ResolveUnixAddr("unix", listener.Addr().String())
+		assert.NilError(t, err, "failed to resolve listener address")
+
+		otherConn, err := net.DialUnix("unix", nil, addr)
+		assert.NilError(t, err, "failed to dial returned listener")
+
+		otherConn.Close()
+
+		_, err = net.DialUnix("unix", nil, addr)
+		assert.NilError(t, err, "failed to redial listener")
+	})
+
+	t.Run("does not leak sockets to local directory", func(t *testing.T) {
+		var conn *net.UnixConn
+		listener, err := SetupConn(&conn)
+		assert.NilError(t, err)
+		assert.Check(t, listener != nil, "returned nil listener but no error")
+		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")
+		checkDirNoPluginSocket(t)
+	})
+}
+
+func checkDirNoPluginSocket(t *testing.T) {
+	t.Helper()
+
+	files, err := os.ReadDir(".")
+	assert.NilError(t, err, "failed to list files in dir to check for leaked sockets")
+
+	for _, f := range files {
+		info, err := f.Info()
+		assert.NilError(t, err, "failed to check file info")
+		// 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")
+		}
+	}
+}
+
+func TestConnectAndWait(t *testing.T) {
+	t.Run("calls cancel func on EOF", func(t *testing.T) {
+		var conn *net.UnixConn
+		listener, err := SetupConn(&conn)
+		assert.NilError(t, err, "failed to setup listener")
+
+		done := make(chan struct{})
+		t.Setenv(EnvKey, listener.Addr().String())
+		cancelFunc := func() {
+			done <- struct{}{}
+		}
+		ConnectAndWait(cancelFunc)
+		pollConnNotNil(t, &conn)
+		conn.Close()
+
+		select {
+		case <-done:
+		case <-time.After(10 * time.Millisecond):
+			t.Fatal("cancel function not closed after 10ms")
+		}
+	})
+
+	// 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)
+		assert.NilError(t, err, "failed to setup listener")
+		t.Setenv(EnvKey, listener.Addr().String())
+		numGoroutines := runtime.NumGoroutine()
+
+		ConnectAndWait(func() {})
+		assert.Equal(t, runtime.NumGoroutine(), numGoroutines+1)
+
+		pollConnNotNil(t, &conn)
+		conn.Close()
+		poll.WaitOn(t, func(t poll.LogT) poll.Result {
+			if runtime.NumGoroutine() > numGoroutines+1 {
+				return poll.Continue("waiting for connect goroutine to exit")
+			}
+			return poll.Success()
+		}, poll.WithDelay(1*time.Millisecond), poll.WithTimeout(10*time.Millisecond))
+	})
+}
+
+func pollConnNotNil(t *testing.T, conn **net.UnixConn) {
+	t.Helper()
+
+	poll.WaitOn(t, func(t poll.LogT) poll.Result {
+		if *conn == nil {
+			return poll.Continue("waiting for conn to not be nil")
+		}
+		return poll.Success()
+	}, poll.WithDelay(1*time.Millisecond), poll.WithTimeout(10*time.Millisecond))
+}

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
+}