commands: mount - add NFS guest support

Author: djdv

internal/commands/flag.go

@@ -14,6 +14,7 @@ import (
 	"unicode/utf8"
 	"unsafe"
 
+	"github.com/djdv/go-filesystem-utils/internal/filesystem"
 	"github.com/djdv/go-filesystem-utils/internal/generic"
 	"github.com/djdv/p9/p9"
 	"github.com/multiformats/go-multiaddr"
@@ -579,3 +580,7 @@ func parseMultiaddrList(parameter string) ([]multiaddr.Multiaddr, error) {
 	}
 	return maddrs, nil
 }
+
+func prefixIDFlag(system filesystem.ID) string {
+	return strings.ToLower(string(system)) + "-"
+}

internal/commands/mount.go

@@ -293,6 +293,7 @@ func makeGuestCommands[
 ](host filesystem.Host,
 ) []command.Command {
 	guests := makeIPFSCommands[HC, HM](host)
+	guests = append(guests, makeNFSGuestCommand[HC, HM](host))
 	sortCommands(guests)
 	return guests
 }

internal/commands/mountpoint.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/djdv/go-filesystem-utils/internal/filesystem"
 	p9fs "github.com/djdv/go-filesystem-utils/internal/filesystem/9p"
+	"github.com/djdv/go-filesystem-utils/internal/filesystem/nfs"
 	"github.com/djdv/go-filesystem-utils/internal/generic"
 	"github.com/djdv/p9/p9"
 )
@@ -143,6 +144,8 @@ func makeMountPointGuests[
 ) mountPointGuests {
 	guests := make(mountPointGuests)
 	makeIPFSGuests[HC](guests, path)
+	// TODO: [build constraints] this pulls in nfs; split out.
+	guests[nfs.GuestID] = newMountPointFunc[HC, nfs.Guest](path)
 	return guests
 }
 

internal/commands/mountpoint_ipfs.go

@@ -71,10 +71,6 @@ func guestOverlayText(overlay, overlaid filesystem.ID) string {
 	return string(overlay) + " is an " + string(overlaid) + " overlay"
 }
 
-func prefixIDFlag(system filesystem.ID) string {
-	return strings.ToLower(string(system)) + "-"
-}
-
 func (*ipfsOptions) usage(filesystem.Host) string {
 	return string(ipfs.IPFSID) + " provides an empty root directory." +
 		"\nChild paths are forwarded to the IPFS API."

internal/commands/mountpoint_nfs.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"errors"
 	"flag"
+	"fmt"
 
 	"github.com/djdv/go-filesystem-utils/internal/command"
 	"github.com/djdv/go-filesystem-utils/internal/filesystem"
@@ -16,11 +17,20 @@ import (
 )
 
 type (
-	nfsHostSettings nfs.Host
-	nfsHostOption   func(*nfsHostSettings) error
-	nfsHostOptions  []nfsHostOption
+	nfsHostSettings  nfs.Host
+	nfsHostOption    func(*nfsHostSettings) error
+	nfsHostOptions   []nfsHostOption
+	nfsGuestSettings nfs.Guest
+	nfsGuestOption   func(*nfsGuestSettings) error
+	nfsGuestOptions  []nfsGuestOption
 )
 
+const nfsServerFlagName = "server"
+
+func (ns nfsGuestSettings) marshal(string) ([]byte, error) {
+	return json.Marshal(ns)
+}
+
 func makeNFSCommand() command.Command {
 	return makeMountSubcommand(
 		nfs.HostID,
@@ -73,3 +83,47 @@ func unmarshalNFS() (filesystem.Host, decodeFunc) {
 		return "", errors.New("maddr not present in parsed JSON") // TODO: real error value
 	}
 }
+
+func makeNFSGuestCommand[
+	HC mountCmdHost[HT, HM],
+	HM marshaller,
+	HT any,
+](host filesystem.Host,
+) command.Command {
+	return makeMountCommand[HC, HM, nfsGuestOptions, nfsGuestSettings](host, nfs.GuestID)
+}
+
+func (*nfsGuestOptions) usage(filesystem.Host) string {
+	return string(nfs.GuestID) + " attaches to an NFS file server"
+}
+
+func (no *nfsGuestOptions) BindFlags(flagSet *flag.FlagSet) {
+	var (
+		flagPrefix = prefixIDFlag(nfs.GuestID)
+		srvUsage   = "NFS server `maddr`"
+		srvName    = flagPrefix + nfsServerFlagName
+	)
+	flagSetFunc(flagSet, srvName, srvUsage, no,
+		func(value multiaddr.Multiaddr, settings *nfsGuestSettings) error {
+			settings.Maddr = value
+			return nil
+		})
+}
+
+func (no nfsGuestOptions) make() (nfsGuestSettings, error) {
+	settings, err := makeWithOptions(no...)
+	if err != nil {
+		return nfsGuestSettings{}, err
+	}
+	if settings.Maddr == nil {
+		var (
+			flagPrefix = prefixIDFlag(nfs.GuestID)
+			srvName    = flagPrefix + nfsServerFlagName
+		)
+		return nfsGuestSettings{}, fmt.Errorf(
+			"flag `-%s` must be provided for NFS guests",
+			srvName,
+		)
+	}
+	return settings, nil
+}