cp-remote
v1.0.2
Published
Remote child_process runner with message support
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cp-remote
Node.js child_process
done remotely, IPC channel intact!
Example:
var cp_remote = require('cp-remote');
var assert = require('assert');
var remote = cp_remote.run('host', '/path/on/host/to/sub.js', 'foo', { answer: 42 });
remote.on('message', function (msg)
{
assert.deepEqual(msg, { foo: 'bar' });
});
remote.send({ hello: 'world' });
You might implement the remote script, sub.js
, like this:
var assert = require('assert');
assert.equal(process.argv[2], 'foo')
assert.deepEqual(process.argv[3], { answer: 42 });
process.on('message', function (msg)
{
assert.deepEqual(msg, { hello: 'world' });
process.disconnect();
});
process.send({ foo: 'bar' });
The API is described here.
Pre-requisites
Client:
- SSH client (e.g. OpenSSH), configured for password-less logon to the remote host (e.g. using a private key).
- Node.js (of course)
- Bash
- socat
Remote host:
- SSH server (e.g. OpenSSH)
- Node.js (
node
command should be in the remotePATH
of SSH sessions) - Python (it provides access to
socketpair
, Node does not) - socat
Installation
npm install cp-remote
Limitation
You can't pass handles to a remote child process like you can with local child processes.
How it works
cp-remote
callschild_process.spawn
to run a Bash script,cp-remote.sh
. The IPC channel will be on$NODE_CHANNEL_FD
.cp-remote.sh
runssocat
, telling it to relay data between$NODE_CHANNEL_FD
and an SSH connection to the remote host.- The SSH connection is told to start
cp-remote.py
on the remote host. cp-remote.py
callssocket.socketpair
to create a pair of connected file descriptors (Unix domain sockets).cp-remote.py
startssocat
, telling it to relay data between standard input (i.e. the SSH connection) and one of the connected file descriptors.cp-remote.py
setsNODE_CHANNEL_FD
to the other connected file descriptor and startsnode
, telling it to run the module you specified.
Licence
Test
To test creating and communicating with remote child processes:
grunt test --remote=<host1> --remote=<host2> ...
You can specify as many remote hosts as you like. The test will try to create a remote child process on each host and then communicate with each one.
It assumes the cp-remote
module is installed at the same path on each host.
Lint
grunt lint
Code Coverage
grunt coverage --remote=<host1> --remote=<host2> ...
c8 results are available here.
Coveralls page is here.
API
Source: index.js
run(host, module_path)
Run a Node.js module on a remote host and return a
child_process.ChildProcess
object for communication with it.
Parameters:
{String} host
The name (or IP address) of the remote host to run the module on.{String} module_path
The path to the module on the remote host. Any arguments followingmodule_path
will be made available to the module in itsprocess.argv
(starting at the third element).
Return:
{child_process.ChildProcess}
The ChildProcess
object for the remote process. You can do the same things with this object as a local ChildProcess
, except send it handles (i.e. the optional sendHandle
parameter to child.send
isn't supported).
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