How to save in vim a remote file asynchronously?

Question

Edit a remote file with

 vim scp://remote/file

Saving the file with :w blocks the editor till the file changes are saved to the remote.

I was trying to use :Dispatch :write to avoid being blocked but that does not work (using tmux or iterm strategy). :Dispatch is provided by the plugin vim-dispatch.

Relevant internet search results suggest:

• Ssh to remote and work there (if you have a slow connection, check this question or consider ssh-alternative mosh)
• eshion/vim-sync offers the possibility to autosync changes of a local file to the remote
• Git hook auto-push: after each commit push changes to the remote
• satiani/async-scp-vim (see for details blog) launch SCP calls whenever the BufWritePost event is triggered
• Ssh tunnel faster write due to open ssh connection (see also Speeding up Vim's Netrw plugin over ssh/scp and autossh).
• sshfs/osxfuse-sshfs set directory=~/.vim/swaps//; set backupdir=~/.vim/backups
• Neovim no release yet and nightly build does not do it out of the box. Any answer here appreciated. It has been reported as an issue #1464
• Backchannel Vi

The solutions are helpful but require setup of vcs, config files, etc.

I'd prefer

• to work locally
• no configuration for each file (configuring the editor once and for all is ok)
• Not every write should be a commit.

Keeping an ssh tunnel open didn't improve it either.

Update I'd like to know whether there is a solution to run the save process asynchronously. The save process means here, as netrw is showing in the commandline, a scp call to copy the temp file to the remote which can take some time. I'd like to return to my editing in the meanwhile and don't be blocked. I hope this makes my question clearer.

Alternatives to tpope/dispatch are: Shougo/vimproc, idbrii/AsyncCommand, which I haven't tried yet.

Answer 1

It was an old question, yet I encountered the same problem of how to work with remote files efficiently.

My solution is to use unison to sync files on the fly. A command is defined to call the sync function within vim.

function! s:Sync()
  call system("unison -batch /home/user ssh://user@server//home/user")
endfunction

command! Sync :call <SID>Sync()

The speed of sync files using unison is so fast that I don't have much motivation to make it run asynchronously.

Answer 2

Plugin AsyncRun for vim8/neovim

describes on following wiki page how to get netrw using this plugin when saving to remote:

https://github.com/skywind3000/asyncrun.vim/wiki/Get-netrw-using-asyncrun-to-save-remote-files

Copy of the patch:

Following diff to $VIMRUNTIME/autoload/netrw.vim (version 156) saves asynchronously with AsyncRun when you put into your vimrc let g:netrw_write_AsyncRun = 1:

❯ git diff netrw-156.vim netrw.vim
diff --git a/netrw-156.vim b/netrw.vim
index 76485c2..183fc96 100644
--- a/netrw-156.vim
+++ b/netrw.vim
@@ -510,6 +510,7 @@ call s:NetrwInit("g:NetrwTopLvlMenu","Netrw.")
 call s:NetrwInit("g:netrw_win95ftp",1)
 call s:NetrwInit("g:netrw_winsize",50)
 call s:NetrwInit("g:netrw_wiw",1)
+call s:NetrwInit("g:netrw_write_AsyncRun",0)
 if g:netrw_winsize > 100|let g:netrw_winsize= 100|endif
 " ---------------------------------------------------------------------
 " Default values for netrw's script variables: {{{2
@@ -2377,6 +2378,14 @@ fun! netrw#NetWrite(...) range
 "    call Decho("(netrw) Processing your write request...",'~'.expand("<slnum>"))
    endif
+   " NetWrite: Perform AsyncRun Write {{{3
+   " ============================
+   if exists("g:netrw_write_AsyncRun") && g:netrw_write_AsyncRun == 1
+       let bang_cmd = 'AsyncRun -post=call\ delete('.s:ShellEscape(tmpfile,1).')\ |\ echo\ "(netrw)\ Your\ write\ request\ has\ finished." '
+    else
+        let bang_cmd ="!"
+   endif
+
    ".........................................
    " NetWrite: (rcp) NetWrite Method #1 {{{3
    if  b:netrw_method == 1
@@ -2515,7 +2524,7 @@ fun! netrw#NetWrite(...) range
     else
      let useport= ""
     endif
-    call s:NetrwExe(s:netrw_silentxfer."!".g:netrw_scp_cmd.useport." ".s:ShellEscape(tmpfile,1)." ".s:ShellEscape(g:netrw_machine.":".b:netrw_fname,1))
+    call s:NetrwExe(s:netrw_silentxfer.bang_cmd.g:netrw_scp_cmd.useport." ".s:ShellEscape(tmpfile,1)." ".s:ShellEscape(g:netrw_machine.":".b:netrw_fname,1))
     let b:netrw_lastfile = choice

    ".........................................
@@ -2612,9 +2621,11 @@ fun! netrw#NetWrite(...) range

   " NetWrite: Cleanup: {{{3
 "  call Decho("cleanup",'~'.expand("<slnum>"))
-  if s:FileReadable(tmpfile)
-"   call Decho("tmpfile<".tmpfile."> readable, will now delete it",'~'.expand("<slnum>"))
-   call s:NetrwDelete(tmpfile)
+  if !exists("g:netrw_write_AsyncRun") || g:netrw_write_AsyncRun == 0
+    if s:FileReadable(tmpfile)
+"     call Decho("tmpfile<".tmpfile."> readable, will now delete it",'~'.expand("<slnum>"))
+      call s:NetrwDelete(tmpfile)
+    endif
   endif
   call s:NetrwOptionRestore("w:")

Answer 3

SSHFS: My Problem with sshfs was the vim plugin lightline.vim using fugitive.vim function.

The statusline is updated quite often when you scroll (line number changes) and therefore the fugitive function to show the current branch was evaluated all the time.

This slowed the scrolling significantly down. Removing fugitive status from statusline alleviated the slow down.

There is another plugin https://github.com/seletskiy/vim-refugi which reports that

git through sshfs is slow as hell.

I also installed this plugin for fugitive and applied their tip

Because this script uses ssh multiplexing, it is good to configure your ssh to automatically open master connections.

E.g. you need this in your ~/.ssh/config:

host *
    controlmaster auto
    controlpath   ~/.ssh/connections/%r_%h_%p