Vado and vamount

Vado intro

Hamish Mackenzie and I have been working on vado - a quick way to run commands on a remote ssh server. Just mount the directory you want to run the command in using sshfs, in that directory (or its subdirectory) run vado like this:

vado ls -l

vado will run 'mount' to identify the user account, server name and the remote directory to run the command in. It will then run ssh to connect to the server and run the command.

You can also pass ssh options like this:

vado -t htop

This tells vado to pass -t to ssh (forces pseudo-tty allocation and makes programs like vim and htop work nicely).

I will explain below how to set up vado for multiple remote servers/sshfs mount points and how to develop Haskell projects on a remote server/VM nicely using Emacs and ghc-mod.

.vadosettings

Vado is not tied to vagrant, but can be used with it and is faster than vagrant ssh. If the user and host detected in mount are specified in the ~/.vadosettings file, then the specified key and port will be used.

The contents of the ~/.vadosettings file is basically a Haskell list of MountSettings datastructures and we use standard Read and Show type-classes for serialization.

The MountSettings data type is defined as follows:

-- | Mount point settings
data MountSettings = MountSettings {
    sshfsUser :: Text
  , sshfsHost :: Text
  , sshfsPort :: Int
  , idFile :: FilePath
  } deriving (Show, Read)

If the file is not present or incorrectly formatted then the default settings for vagrant will be used:

• User: vagrant

• Host: 127.0.0.1

• Port: 2222

• Key file: ~/.vagrant.d/insecure_private_key

Example .vadosettings file

An example settings file might look like this:

[
  MountSettings {
    sshfsUser = "vagrant"
  , sshfsHost = "localhost"
  , sshfsPort = 2222
  , idFile = "/Users/dan/.vagrant.d/insecure_private_key"
  }, 
  MountSettings {
    sshfsUser = "admin"
  , sshfsHost = "server.local"
  , sshfsPort = 2233
  , idFile = "/Users/dan/keys/local_server_key"
  }
]

Vamount

Of course, using vado requires mounting the sshfs beforehand. But it gets tedious typing out

sshfs vagrant@localhost:/home/vagrant ../vm/ -p2222
-reconnect,defer_permissions,negative_vncache,volname=ghcjs,IdentityFile=~/.vagrant.d/insecure_private_key

every time. A tool called vamount which is bundled together with vado can be used for mounting remote filesystems based on ~/.vadosettings file.

You can use it like this:

vamount [ssh options] remote_path [profile #]

The remote_path from the remote server specified in the ~/.vadosettings file under number [profile #] will be mounted in the current directory using sshfs.

The profile number count starts from 1. If the [profile #] is absent or is 0 then the default (vagrant) configuration will be used.