nfs: implement Guest mountpoint

Author: djdv

internal/filesystem/nfs/client.go

@@ -62,10 +62,7 @@ type (
 	ClientOption func(*clientSettings) error
 )
 
-const (
-	errStale               = generic.ConstError("handle became stale")
-	GuestID  filesystem.ID = "NFS"
-)
+const errStale = generic.ConstError("handle became stale")
 
 func NewNFSGuest(maddr multiaddr.Multiaddr, options ...ClientOption) (*goFS, error) {
 	var (

internal/filesystem/nfs/mountpoint.go

@@ -24,9 +24,23 @@ type (
 	Host struct {
 		Maddr multiaddr.Multiaddr `json:"maddr,omitempty"`
 	}
+	// Guest holds metadata required to establish
+	// a client connection to an NFS server.
+	Guest struct {
+		Maddr         multiaddr.Multiaddr `json:"maddr,omitempty"`
+		Hostname      string              `json:"hostname,omitempty"`
+		Dirpath       string              `json:"dirpath,omitempty"`
+		LinkSeparator string              `json:"linkSeparator,omitempty"`
+		LinkLimit     uint                `json:"linkLimit,omitempty"`
+		UID           uint32              `json:"uid,omitempty"`
+		GID           uint32              `json:"gid,omitempty"`
+	}
 )
 
-const HostID filesystem.Host = "NFS"
+const (
+	HostID  filesystem.Host = "NFS"
+	GuestID filesystem.ID   = "NFS"
+)
 
 func (*Host) HostID() filesystem.Host { return HostID }
 
@@ -76,3 +90,41 @@ func (nh *Host) Mount(fsys fs.FS) (io.Closer, error) {
 	go func() { errsCh <- nfs.Serve(goListener, cachedHandler) }()
 	return closerFn, nil
 }
+
+func (*Guest) GuestID() filesystem.ID { return GuestID }
+func (gn *Guest) UnmarshalJSON(b []byte) error {
+	// multiformats/go-multiaddr issue #100
+	var maddrWorkaround struct {
+		Maddr maddrc.Multiaddr `json:"maddr,omitempty"`
+	}
+	if err := json.Unmarshal(b, &maddrWorkaround); err != nil {
+		return err
+	}
+	gn.Maddr = maddrWorkaround.Maddr.Multiaddr
+	return json.Unmarshal(b, &struct {
+		Hostname      *string `json:"hostname,omitempty"`
+		Dirpath       *string `json:"dirpath,omitempty"`
+		LinkSeparator *string `json:"linkSeparator,omitempty"`
+		LinkLimit     *uint   `json:"linkLimit,omitempty"`
+		UID           *uint32 `json:"uid,omitempty"`
+		GID           *uint32 `json:"gid,omitempty"`
+	}{
+		Hostname:      &gn.Hostname,
+		Dirpath:       &gn.Dirpath,
+		LinkSeparator: &gn.LinkSeparator,
+		LinkLimit:     &gn.LinkLimit,
+		UID:           &gn.UID,
+		GID:           &gn.GID,
+	})
+}
+
+func (gn *Guest) MakeFS() (fs.FS, error) {
+	return NewNFSGuest(gn.Maddr,
+		WithHostname(gn.Hostname),
+		WithDirpath(gn.Dirpath),
+		WithLinkSeparator(gn.LinkSeparator),
+		WithLinkLimit(gn.LinkLimit),
+		WithUID(gn.UID),
+		WithGID(gn.GID),
+	)
+}