rclone/vfs/vfstest/submount.go

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package vfstest
import (
"bufio"
"context"
"encoding/json"
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
"runtime"
"strings"
"time"
"github.com/rclone/rclone/cmd/mountlib"
"github.com/rclone/rclone/fs"
"github.com/rclone/rclone/fs/cache"
"github.com/rclone/rclone/fstest"
"github.com/rclone/rclone/lib/file"
"github.com/rclone/rclone/vfs"
"github.com/rclone/rclone/vfs/vfscommon"
)
// Functions to run and control the mount subprocess
var (
runMount = flag.String("run-mount", "", "If set, run the mount subprocess with the options (internal use only)")
)
// Options for the mount sub processes passed with the -run-mount flag
type runMountOpt struct {
MountPoint string
MountOpt mountlib.Options
VFSOpt vfscommon.Options
Remote string
}
// Start the mount subprocess and wait for it to start
func (r *Run) startMountSubProcess() {
// If testing the VFS we don't start a subprocess, we just use
// the VFS directly
if r.useVFS {
vfs := vfs.New(r.fremote, r.vfsOpt)
r.os = vfsOs{vfs}
return
}
r.os = realOs{}
r.mountPath = findMountPath()
log.Printf("startMountSubProcess %q (%q) %q", r.fremote, r.fremoteName, r.mountPath)
opt := runMountOpt{
MountPoint: r.mountPath,
MountOpt: mountlib.Opt,
VFSOpt: *r.vfsOpt,
Remote: r.fremoteName,
}
opts, err := json.Marshal(&opt)
if err != nil {
log.Fatal(err)
}
// Re-run this executable with a new option -run-mount
args := append(os.Args, "-run-mount", string(opts))
r.cmd = exec.Command(args[0], args[1:]...)
r.cmd.Stderr = os.Stderr
r.out, err = r.cmd.StdinPipe()
if err != nil {
log.Fatal(err)
}
r.in, err = r.cmd.StdoutPipe()
if err != nil {
log.Fatal(err)
}
err = r.cmd.Start()
if err != nil {
log.Fatal("startMountSubProcess failed", err)
}
r.scanner = bufio.NewScanner(r.in)
// Wait it for startup
log.Print("Waiting for mount to start")
for r.scanner.Scan() {
rx := strings.TrimSpace(r.scanner.Text())
if rx == "STARTED" {
break
}
log.Printf("..Mount said: %s", rx)
}
if r.scanner.Err() != nil {
log.Printf("scanner err %v", r.scanner.Err())
}
log.Printf("startMountSubProcess: end")
}
// Find a free path to run the mount on
func findMountPath() string {
if runtime.GOOS != "windows" {
mountPath, err := os.MkdirTemp("", "rclonefs-mount")
if err != nil {
log.Fatalf("Failed to create mount dir: %v", err)
}
return mountPath
}
// Find a free drive letter
letter := file.FindUnusedDriveLetter()
drive := ""
if letter == 0 {
log.Fatalf("Couldn't find free drive letter for test")
} else {
drive = string(letter) + ":"
}
return drive
}
// Return true if we are running as a subprocess to run the mount
func isSubProcess() bool {
return *runMount != ""
}
// Run the mount - this is running in a subprocesses and the config
// is passed JSON encoded as the -run-mount parameter
//
// It reads commands from standard input and writes results to
// standard output.
func startMount(mountFn mountlib.MountFn, useVFS bool, opts string) {
log.Print("startMount")
ctx := context.Background()
var opt runMountOpt
err := json.Unmarshal([]byte(opts), &opt)
if err != nil {
log.Fatalf("Unmarshal failed: %v", err)
}
fstest.Initialise()
f, err := cache.Get(ctx, opt.Remote)
if err != nil {
log.Fatalf("Failed to open remote %q: %v", opt.Remote, err)
}
err = f.Mkdir(ctx, "")
if err != nil {
log.Fatalf("Failed to mkdir %q: %v", opt.Remote, err)
}
log.Printf("startMount: Mounting %q on %q with %q", opt.Remote, opt.MountPoint, opt.VFSOpt.CacheMode)
mnt := mountlib.NewMountPoint(mountFn, opt.MountPoint, f, &opt.MountOpt, &opt.VFSOpt)
_, err = mnt.Mount()
if err != nil {
log.Fatalf("mount FAILED %q: %v", opt.Remote, err)
}
defer umount(mnt)
log.Printf("startMount: mount OK")
fmt.Println("STARTED") // signal to parent all is good
// Read commands from stdin
scanner := bufio.NewScanner(os.Stdin)
exit := false
for !exit && scanner.Scan() {
rx := strings.Trim(scanner.Text(), "\r\n")
var tx string
tx, exit = doMountCommand(mnt.VFS, rx)
fmt.Println(tx)
}
err = scanner.Err()
if err != nil {
log.Fatalf("scanner failed %q: %v", opt.Remote, err)
}
}
// Do a mount command which is a line read from stdin and return a
// line to send to stdout with an exit flag.
//
// The format of the lines is
//
// command \t parameter (optional)
//
// The response should be
//
// OK|ERR \t result (optional)
func doMountCommand(vfs *vfs.VFS, rx string) (tx string, exit bool) {
command := strings.Split(rx, "\t")
// log.Printf("doMountCommand: %q received", command)
var out = []string{"OK", ""}
switch command[0] {
case "waitForWriters":
vfs.WaitForWriters(waitForWritersDelay)
case "forget":
root, err := vfs.Root()
if err != nil {
out = []string{"ERR", err.Error()}
} else {
root.ForgetPath(command[1], fs.EntryDirectory)
}
case "exit":
exit = true
default:
out = []string{"ERR", "command not found"}
}
return strings.Join(out, "\t"), exit
}
// Send a command to the mount subprocess and await a response
func (r *Run) sendMountCommand(args ...string) {
r.cmdMu.Lock()
defer r.cmdMu.Unlock()
tx := strings.Join(args, "\t")
// log.Printf("Send mount command: %q", tx)
var rx string
if r.useVFS {
// if using VFS do the VFS command directly
rx, _ = doMountCommand(r.os.(vfsOs).VFS, tx)
} else {
_, err := io.WriteString(r.out, tx+"\n")
if err != nil {
log.Fatalf("WriteString err %v", err)
}
if !r.scanner.Scan() {
log.Fatalf("Mount has gone away")
}
rx = strings.Trim(r.scanner.Text(), "\r\n")
}
in := strings.Split(rx, "\t")
// log.Printf("Answer is %q", in)
if in[0] != "OK" {
log.Fatalf("Error from mount: %q", in[1:])
}
}
// wait for any files being written to be released by fuse
func (r *Run) waitForWriters() {
r.sendMountCommand("waitForWriters")
}
// forget the directory passed in
func (r *Run) forget(dir string) {
r.sendMountCommand("forget", dir)
}
// Unmount the mount
func umount(mnt *mountlib.MountPoint) {
/*
log.Printf("Calling fusermount -u %q", mountPath)
err := exec.Command("fusermount", "-u", mountPath).Run()
if err != nil {
log.Printf("fusermount failed: %v", err)
}
*/
log.Printf("Unmounting %q", mnt.MountPoint)
err := mnt.Unmount()
if err != nil {
log.Printf("signal to umount failed - retrying: %v", err)
time.Sleep(3 * time.Second)
err = mnt.Unmount()
}
if err != nil {
log.Fatalf("signal to umount failed: %v", err)
}
log.Printf("Waiting for umount")
err = <-mnt.ErrChan
if err != nil {
log.Fatalf("umount failed: %v", err)
}
// Cleanup the VFS cache - umount has called Shutdown
err = mnt.VFS.CleanUp()
if err != nil {
log.Printf("Failed to cleanup the VFS cache: %v", err)
}
}