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Node.js is Cancer
by Ted Dziuba on Saturday, October 01, 2011
If there's one thing web developers love, it's knowing better than
conventional wisdom, but conventional wisdom is conventional for a
reason: that shit works. Something's been bothering me for a while
about this node.js nonsense, but I never took the time to figure
it out until I read this butthurt post from Ryan Dahl, Node's
creator. I was going to shrug it off as just another jackass who
whines because Unix is hard. But, like a police officer who senses
that something isn't quite right about the family in a minivan he
just pulled over and discovers fifty kilos of black horse heroin
in the back, I thought that something wasn't quite right about this
guy's aw-shucks sob story, and that maybe, just maybe, he has no
idea what he is doing, and has been writing code unchecked for
years.
Since you're reading about it here, you probably know how my hunch
turned out.
Node.js is a tumor on the programming community, in that not only
is it completely braindead, but the people who use it go on to
infect other people who can't think for themselves, until eventually,
every asshole I run into wants to tell me the gospel of event loops.
Have you accepted epoll into your heart?
A Scalability Disaster Waiting to Happen
Let's start with the most horrifying lie: that node.js is scalable
because it "never blocks" (Radiation is good for you! We'll put it
in your toothpaste!). On the Node home page, they say this:
Almost no function in Node directly performs I/O, so the process
never blocks. Because nothing blocks, less-than-expert programmers
are able to develop fast systems.
This statement is enticing, encouraging, and completely fucking
wrong.
Let's start with a definition, because you Reddit know-it-alls keep
your specifics in the pedantry. A function call is said to block
when the current thread of execution's flow waits until that function
is finished before continuing. Typically, we think of I/O as
"blocking", for example, if you are calling socket.read(), the
program will wait for that call to finish before continuing, as you
need to do something with the return value.
Here's a fun fact: every function call that does CPU work also
blocks. This function, which calculates the n'th Fibonacci number,
will block the current thread of execution because it's using the
CPU.
function fibonacci(n) {
if (n < 2)
return 1;
else
return fibonacci(n-2) + fibonacci(n-1);
}
(Yes, I know there's a closed form solution. Shouldn't you be in
front of a mirror somewhere, figuring out how to introduce yourself
to her?.)
Let's see what happens to a node.js program that has this little
gem as its request handler:
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end(fibonacci(40));
}).listen(1337, "127.0.0.1");
On my older laptop, this is the result:
ted@lorenz:~$ time curl http://localhost:1337/ 165580141 real
0m5.676s user 0m0.010s sys 0m0.000s
5 second response time. Cool. So we all know JavaScript isn't a
terribly fast language, but why is this such an indictment? It's
because Node's evented model and brain damaged fanboys make you
think everything is OK. In really abusive pseudocode, this is how
an event loop works:
while(1) {
ready_file_descriptor = event_library->poll();
handle_request(ready_file_descriptor);
}
That's all well and good if you know what you're doing, but when
you apply this to a server problem, you've pluralized that shit.
If this loop is running in the same thread that handle_request is
in, any programmer with a pulse will notice that the request handler
can hold up the event loop, no matter how asynchronous your library
is.
So, given that, let's see how my little node server behaves under
the most modest load, 10 requests, 5 concurrent:
ted@lorenz:~$ ab -n 10 -c 5 http://localhost:1337/
...
Requests per second: 0.17 [#/sec] (mean)
...
0.17 queries per second. Diesel. Sure, Node allows you to fork child
processes, but at that point your threading/event model is so tightly
coupled that you've got bigger problems than scalability.
Considering Node's original selling point, I'm God Damned terrified
of any "fast systems" that "less-than-expert programmers" bring
into this world.
Node Punishes Developers Because it Disobeys the Unix Way
A long time ago, the original neckbeards decided that it was a good
idea to chain together small programs that each performed a specific
task, and that the universal interface between them should be text.
If you develop on a Unix platform and you abide by this principle,
the operating system will reward you with simplicity and prosperity.
As an example, when web applications first began, the web application
was just a program that printed text to standard output. The web
server was responsible for taking incoming requests, executing this
program, and returning the result to the requester. We called this
CGI, and it was a good way to do business until the micro-optimizers
sank their grubby meathooks into it.
Conceptually, this is how any web application architecture that's
not cancer still works today: you have a web server program that's
job is to accept incoming requests, parse them, and figure out the
appropriate action to take. That can be either serving a static
file, running a CGI script, proxying the connection somewhere else,
whatever. The point is that the HTTP server isn't the same entity
doing the application work. Developers who have been around the
block call this separation of responsibility, and it exists for a
reason: loosely coupled architectures are very easy to maintain.
And yet, Node seems oblivious to this. Node has (and don't laugh,
I am not making this shit up) its own HTTP server, and that's what
you're supposed use to serve production traffic. Yeah, that example
above when I called http.createServer(), that's the preferred setup.
If you search around for "node.js deployment", you find a bunch of
people putting Nginx in front of Node, and some people use a thing
called Fugue, which is another JavaScript HTTP server that forks a
bunch of processes to handle incoming requests, as if somebody maybe
thought that this "nonblocking" snake oil might have an issue with
CPU-bound performance.
If you're using Node, there's a 99% probability that you are both
the developer and the system administrator, because any system
administrator would have talked you out of using Node in the first
place. So you, the developer, must face the punishment of setting
up this HTTP proxying orgy if you want to put a real web server in
front of Node for things like serving statics, query rewriting,
rate limiting, load balancing, SSL, or any of the other futuristic
things that modern HTTP servers can do. That, and it's another layer
of health checks that your system will need.
Although, let's be honest with ourselves here, if you're a Node
developer, you are probably serving the application directly from
Node, running in a screen session under your account.
It's Fucking JavaScript
This is probably the worst thing any server-side framework can do:
be written in JavaScript.
if (typeof my_var !== "undefined" && my_var !== null) {
// you idiots put Rasmus Lerdorf to shame
}
What is this I don't even...
tl;dr
Node.js is an unpleasant software library and I will not use it.