Written by Pete Corey on Feb 9, 2015.

Meteor Requires Node v0.10.33 or Later

The other day I added Velocity to a Meteor app (meteor add mike:mocha) and I was greeted with a strange error when the server restarted:

W20150130-22:24:55.285(-8)? (STDERR) [velocity-mirror] Meteor requires Node v0.10.33 or later.

Hmm. Doesn’t the current version of Meteor (1.0.3) use its own instance of Node v0.10.33? Let’s check…

% meteor shell
> process.argv[0]
‘/home/pcorey/.meteor/packages/meteor-tool/.1.0.40.moil5k++os.linux.x86_32+web.browser+web.cordova/meteor-tool-os.linux.x86_32/dev_bundle/bin/node’
% /home/pcorey/.meteor/packages/meteor-tool/.1.0.40.moil5k++os.linux.x86_32+web.browser+web.cordova/meteor-tool-os.linux.x86_32/dev_bundle/bin/node --version
v0.10.33

Just like I thought, Meteor is using Node v0.10.33. So where is this error coming from? Let’s do some monkey patching to find out!

Monkey Patching to the Rescue

I started by editing Meteor’s boot.js (/home/pcorey/.meteor/packages/meteor-tool/.1.0.40.moil5k++os.linux.x86_32+web.browser+web.cordova/meteor-tool-os.linux.x86_32/tools/server/boot.js). I overwrote console.error with my own custom function which prints the current call stack and then logs the error as usual:

oldConsoleError = console.error;
console.error = function() {
    var orig = Error.prepareStackTrace;
    Error.prepareStackTrace = function(_, stack){ return stack; };
    var err = new Error;
    Error.captureStackTrace(err, arguments.callee);
    var stack = err.stack;
    Error.prepareStackTrace = orig;

    oldConsoleError(stack.toString().replace(/,/g,'\n'));
    oldConsoleError.apply(this, arguments);
}

So now what happens when we start the Meteor server?

(STDERR) Socket.<anonymous> (/home/pcorey/velocity-test/.meteor/local/build/programs/server/packages/velocity_node-soft-mirror.js:493:17)
(STDERR) Socket.emit (events.js:95:17)
(STDERR) Socket.<anonymous> (_stream_readable.js:764:14)
(STDERR) Socket.emit (events.js:92:17)
(STDERR) emitReadable_ (_stream_readable.js:426:10)
(STDERR) emitReadable (_stream_readable.js:422:5)
(STDERR) readableAddChunk (_stream_readable.js:165:9)
(STDERR) Socket.Readable.push (_stream_readable.js:127:10)
(STDERR) Pipe.onread (net.js:528:21)
(STDERR) [velocity-mirror] Meteor requires Node v0.10.33 or later.

Interesting… It looks like we should take a look at velocity_node-soft-mirror.js:493:

mirrorChild.getChild().stderr.on('data', function (data) {
    console.error('[velocity-mirror]', data.toString());
}); 

So this is where the error is coming from. mirrorChild is a child node process spawned a few lines earlier:

mirrorChild.spawn({
    command: 'node',
    args: [mainJs],
    options: {
        silent: true,
        detached: true,
        cwd: process.env.PWD,
        env: _.defaults(environment, process.env)
    }
});

It looks like it’s simply running node, which will use the version of node on the system’s PATH, not Meteor’s bundled version of node. Let’s check what version of node lives on the PATH:

% node --version
v0.10.25

Mystery solved. Velocity is spawning a “mirror” instance of Meteor but it’s using whatever instance of node is installed on the machine, not the version bundled with Meteor.

Fixing the Problem

Interestingly, if we look through the node-soft-mirror package on Github, we can see that this problem exists in the tagged version 0.2.6 and below, but it was fixed in version 0.2.7. If we take a look at the meteor-mocha-web project on Github, we can see that it’s explicitly depending on version 0.2.4 of node-soft-mirror.

An easy way to fix this is to explicitly add version 0.2.7 or higher of node-soft-mirror to our project.

meteor add velocity:node-soft-mirror@0.3.1

After that, the Meteor server should start without issue and everything should work as expected.

Well, that was definitely an adventure. It was pretty obvious what was going on after I dug into the internals of the error and how Velocity uses its “mirror”, but hindsight is always 20/20. I’ve filed a bug on the meteor-mocha-web project to update their node-soft-mirror package.

TL;DR

The current version of mike:mocha uses the version installed on the system, not the version packaged with Meteor. Explicitly add velocity:node-soft-mirror v0.2.7 or above to fix the problem.