Software engineering notes

Posts Tagged ‘node

Getting started with Watchr (and trying again to install Node.js on Mac 10.6.4)

I recently started exploring testing options for Node.js. Yesterday, I wrote about my experiences with nodeunit. Today, I found Christian Johansen’s blog post Unit testing node.js apps. (Thanks for the write-up, Christian!) Although I was looking for unit testing options, what really got me excited was his mention of Watchr.

Watchr provides a way to run tests automatically in response to system events, e.g., when a file is saved, much like Autotest. I had fallen in love with Autotest’s functionality after learning about it in Micheal Hartl’s nice Ruby on Rails tutorial. According to Watchr’s docs, Autotest leaves something to be desired, but in any case I very much would like my tests to run without my having to think about it.

Git-ting (ha!) Watchr was easy enough, but to run Node tests on my Mac, which for some reason is an idea I’m hung up on, I need Node, and to date I haven’t been able to build Node on my Mac (10.6.4) successfully, so this is my challenge. After searching here and there, I found an archived thread from the Node mailing list that seemed promising. It mentions that MacPorts can break if I upgrade to Snow Leopard without upgrading MacPorts, which I had, and that this can prevent Node from compiling. After clicking through to the MacPorts migration docs, I followed the steps outlined there and I was able to build Node like this:

  1. I had tried and failed to build Node multiple times, so I blew away the build directory: rm -rf build
  2. ./configure
  3. Clean things up to be thorough: make clean
  4. make
  5. Run tests just in case: make test
  6. sudo make install

Ok, on to the testing. Here’s my folder structure:

project/
    – autotest.watchr
    – lib/
      – example.js
    – test/
       – test_example.js

My autotest.watchr file is a blend of the one on Christian’s blog, and Watchr’s tests.watchr prepackaged script. It contains

watch( 'test/test_.*\.js' )  {|md| system("node #{md[0]}") }
watch( 'lib/(.*)\.js' )      {|md| system("node test/test_#{md[1]}.js") }

# --------------------------------------------------
# Signal Handling
# --------------------------------------------------
# Ctrl-\
Signal.trap('QUIT') do
  puts " --- Running all tests ---\n\n"
  run_all_tests
end

# Ctrl-C
Signal.trap('INT') { abort("\n") }

example.js contains

exports.foo = 'bar';

test_example.js contains

var assert = require("assert");
var example = require('../lib/example');

assert.strictEqual(example.foo, 'bar', 'var foo should be "bar"');

I fire up watchr like this: watchr autotest.watchr

Watchr then captures the terminal until I enter Ctrl+C. Saving either example.js or test_example.js causes test_example.js to run. At this point the tests are crude, so my output is nothing if the test passes, or an assertion error, e.g., “AssertionError: var foo should be “bar””, if the test fails.

I think this is a good start. Time to listen to some Bonobo and call it a day.

Written by Erik

December 9, 2010 at 1:17 am

getting started with Node.js

I found what appears to be a nice tutorial for installing Node on Ubuntu 10.4, so I’ll start with that.

To keep things simple, I’m going to skip the dependencies, grab the tgz file, and just try running it. Why not? Thing’s could’ve changed w/ Node and/or Ubuntu since that post was written, and I love it when packages are designed well enough to provide irrational users with informative feedback, so let’s see.

  1. wget http://nodejs.org/dist/node-v0.2.3.tar.gz
  2. tar -xf node-v0.2.3.tar.gz
  3. cd node
  4. ./configure
  5. make
  6. sudo make install
/home/erik/node-v0.2.3/wscript:132: error: could not configure a cxx compiler!

Nice! I need g++:
sudo apt-get install g++

/home/erik/node-v0.2.3/wscript:188: error: Could not autodetect OpenSSL support. Make sure OpenSSL development packages are installed. Use configure --without-ssl to disable this message.

Looks like I need ssl too:
sudo apt-get install libssl-dev

Configuration now passes, but I see this in the output:

...
Checking for openssl                     : not found
Checking for function SSL_library_init   : yes
Checking for header openssl/crypto.h     : yes
Checking for library rt                  : yes
--- libeio ---
Checking for library pthread             : yes
Checking for function pthread_create     : yes
Checking for function pthread_atfork     : yes
Checking for futimes(2)                  : yes
Checking for readahead(2)                : yes
Checking for fdatasync(2)                : yes
Checking for pread(2) and pwrite(2)      : yes
Checking for sendfile(2)                 : yes
Checking for sync_file_range(2)          : yes
--- libev ---
Checking for header sys/inotify.h        : yes
Checking for function inotify_init       : yes
Checking for header sys/epoll.h          : yes
Checking for function epoll_ctl          : yes
Checking for header port.h               : not found
Checking for header poll.h               : yes
Checking for function poll               : yes
Checking for header sys/event.h          : not found
Checking for header sys/queue.h          : yes
Checking for function kqueue             : not found
...

Rather than run into mysterious errors later, I’ll go ahead and install all the dependencies mentioned in the post:
sudo apt-get install g++ curl libssl-dev apache2-utils

But it doesn’t correct the problem. Doh! Oh, well. I’ll deal with any errors later.

Continuing on, I run make (it’s been a while since I watched C compile), and then sudo make install:

'install' finished successfully (0.239s)

🙂

Rather than starting with the tutorial’s translation example, I opt for the hello world example on the Node site:

var http = require('http');
http.createServer(function (req, res) {
  res.writeHead(200, {'Content-Type': 'text/plain'});
  res.end('Hello World\n');
}).listen(8124, "127.0.0.1");
console.log('Server running at http://127.0.0.1:8124/');

I tried loading this, but no response. However, I grappled with my vm’s firewall recently enough to remember that I hadn’t opened port 8124, so I update the code to use port 80, and re-launch, but still get no response. Undaunted, I tell ufw to take a break:
sudo ufw disable && sudo shutdown -r now

Upon trying again, I noticed that I had the address wrong earlier – pilot error – but before enabling ufw, let’s see if we can get a response.

Curling http://127.0.0.1:8124/ returns “hello world”, but I’m not able to see this server from my laptop, i.e., curl http://172.16.83.133:8124/ doesn’t work.

Update (11/22/10): check out Padraig’s comment below about binding to 0.0.0.0.

It’s getting late, so this is a race against mental mutiny. Desparate, I stumble across another node.js + Ubuntu tutorial, and blindly install everything. I launch socket.io as per the instructions, bounce over to the browser, and … it works. Awesome. To the author of that post, nice job.

Ok. That’s enough for tonight. I’ll revisit this again later and try to understand what just happened.

In parting: Cats! In 3D! Don’t think. Just stare.

Cats Anaglyph 3D اناگلیف

Photo credit: Shahrokh Dabiri

Written by Erik

October 21, 2010 at 12:27 am

Posted in notes

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