libcontainerd/supervisor: consolidate platform-specific defaults

Commit a000934 updated the default
MaxRecvMsgSize and MaxSendMsgSize for Linux, but did not modify the
defaults for Windows. Those options should not be platform-specific,
which means that the only difference between the Linux and Windows
config are the addresses for GRPC and Debug (Windows defaulting
to a named pipe, whereas Linux sockets within exec-root).

This patch

- implements functions to return the default addresses for each platform
- moves the defaults into `supervisor.Start()`
- removes the now redundant `remote.setDefaults()` method

It's worth noting that prior to this path, `remove.setDefaults()` would
be applied _after_ any (custom) `DaemonOpt` was applied. However, none of
the existing `DaemonOpt` options currently mutates these options. `remote`
is also a non-exported type, so no external implementations can currently
be created. It is therefore safe to set these defaults before options are
applied.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

libcontainerd/supervisor/remote_daemon.go

@@ -48,8 +48,6 @@ type remote struct {
 	daemonStartCh chan error
 	daemonStopCh  chan struct{}
 
-	stateDir string
-
 	// logLevel overrides the containerd logging-level through the --log-level
 	// command-line option.
 	logLevel string
@@ -67,11 +65,18 @@ type DaemonOpt func(c *remote) error
 // Start starts a containerd daemon and monitors it
 func Start(ctx context.Context, rootDir, stateDir string, opts ...DaemonOpt) (Daemon, error) {
 	r := &remote{
-		stateDir: stateDir,
 		Config: config.Config{
 			Version: 2,
 			Root:    filepath.Join(rootDir, "daemon"),
 			State:   filepath.Join(stateDir, "daemon"),
+			GRPC: config.GRPCConfig{
+				Address:        defaultGRPCAddress(stateDir),
+				MaxRecvMsgSize: defaults.DefaultMaxRecvMsgSize,
+				MaxSendMsgSize: defaults.DefaultMaxSendMsgSize,
+			},
+			Debug: config.Debug{
+				Address: defaultDebugAddress(stateDir),
+			},
 		},
 		configFile:    filepath.Join(stateDir, configFile),
 		daemonPid:     -1,
@@ -86,7 +91,6 @@ func Start(ctx context.Context, rootDir, stateDir string, opts ...DaemonOpt) (Da
 			return nil, err
 		}
 	}
-	r.setDefaults()
 
 	if err := system.MkdirAll(stateDir, 0o700); err != nil {
 		return nil, err

libcontainerd/supervisor/remote_daemon_linux.go

@@ -6,7 +6,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/containerd/containerd/defaults"
 	"github.com/docker/docker/pkg/process"
 )
 
@@ -15,19 +14,12 @@ const (
 	debugSockFile = "containerd-debug.sock"
 )
 
-func (r *remote) setDefaults() {
-	if r.GRPC.Address == "" {
-		r.GRPC.Address = filepath.Join(r.stateDir, sockFile)
-	}
-	if r.GRPC.MaxRecvMsgSize == 0 {
-		r.GRPC.MaxRecvMsgSize = defaults.DefaultMaxRecvMsgSize
-	}
-	if r.GRPC.MaxSendMsgSize == 0 {
-		r.GRPC.MaxSendMsgSize = defaults.DefaultMaxSendMsgSize
-	}
-	if r.Debug.Address == "" {
-		r.Debug.Address = filepath.Join(r.stateDir, debugSockFile)
-	}
+func defaultGRPCAddress(stateDir string) string {
+	return filepath.Join(stateDir, sockFile)
+}
+
+func defaultDebugAddress(stateDir string) string {
+	return filepath.Join(stateDir, debugSockFile)
 }
 
 func (r *remote) stopDaemon() {

libcontainerd/supervisor/remote_daemon_windows.go

@@ -11,13 +11,12 @@ const (
 	debugPipeName = `\\.\pipe\containerd-debug`
 )
 
-func (r *remote) setDefaults() {
-	if r.GRPC.Address == "" {
-		r.GRPC.Address = grpcPipeName
-	}
-	if r.Debug.Address == "" {
-		r.Debug.Address = debugPipeName
-	}
+func defaultGRPCAddress(stateDir string) string {
+	return grpcPipeName
+}
+
+func defaultDebugAddress(stateDir string) string {
+	return debugPipeName
 }
 
 func (r *remote) stopDaemon() {