Interesting Things

• An EngineYard-hosted project had an issue with monit attempting to restart
  mongrel too often. It turned out that the mongrel processes were not
  dropping pid files soon enough. The EngineYard-suggested fix:

  • Upgrade mongrel to 1.1.5.1 (patched to drop the pid file faster)
  • Upgrade to monit 5.0 beta 6
  • Update to the latest ey-monit-scripts
• FiveRuns dash is a cool, customizable metrics
  service. Pat created a plug-in
  for sending continuous integration stats there: dash-ci.

• Using Cucumber to test Capistrano deployment:

  cap --dry-run will run Capistrano without completing the actual task
  (e.g., deployment). Cucumber can then be used to write some nice,
  story-like deployment expectations that search the Capistrano output to
  document your project’s deployment process and ensure the documentation
  remains valid. Something like:

  Feature: Deployment
    In order to deploy the application
    As an administrator
    I should run Capistrano commands
  
  
    Scenario: Deploying
      Given I am working from the RAILS_ROOT directory
        And the parent directory is a Git repository
      When  I run a deployment task
      Then  'scm_user' for the deployment should be derived from the Git config for the remote origin
  
  
    Scenario: Deploying to demo
      Given I am working from the RAILS_ROOT directory
      When  I run 'cap demo deploy'
      Then  the deploy should succeed
        And the deployed code matches the latest 'web/stable' tag
        And the deployed code should be marked with a new 'web/demo' tag
  

  More on this to come.

• Using Selenium to ensure unique IDs in your DOM:

  # ----------------------------------------------------------------------
  # The examples below illustrate the technique with the Prototype and
  # jQuery libraries, respectively.  Both use Pat Nakajima's selenium
  # helper for executing javascript in the tested browser window.
  #
  # For more on that helper, see:
  # http://pivotallabs.com/users/patn/blog/articles/717-run-javascript-in-selenium-tests-easily-
  # ----------------------------------------------------------------------
  
  
  # ----------------------------------------------------------------------
  # with prototype
  # note the exception catching... prototype chokes on invalid IDs
  # e.g., "invalid_id[][]"
  # ----------------------------------------------------------------------
  def assert_unique_ids
    audit_json = run_javascript <<-JS
      audit_ids = function() {
        var results = {};
        $A($$('*[id]')).each(function(element) {
          if(element.id.replace(' ', '').length > 0) {
            try {
              if($$('#' + element.id ).length > 1) {
                if( ! results.duplicates) {
                  results.duplicates = {};
                }
                var count = results.duplicates[element.id] || 0;
                count ++;
                results.duplicates[element.id] = count;
              }
            }
            catch(err) {
              // uncomment to capture invalid IDs
              // var invalid = results.invalid || [];
              // invalid.push(element.id);
              // results.invalid = invalid;
            }
          }
        });
        return ($H(results).toJSON());
      }
      audit_ids();
    JS
    assert_equal({}, JSON.parse(audit_json)), 'Expected no duplicate IDs')
  end
  
  
  # ----------------------------------------------------------------------
  # with jQuery
  # additionally depends on the jquery-json plugin:
  # http://code.google.com/p/jquery-json/
  # ----------------------------------------------------------------------
  def assert_unique_ids
    audit_json = run_javascript <<-JS
      audit_ids = function() {
        var results = {};
        $('*[id]').each(function() {
          if(this.id.replace(' ', '').length > 0) {
            if($('*[id=' + this.id + ']').length > 1) {
              if( ! results.duplicates) {
                results.duplicates = {};
              }
              var count = results.duplicates[this.id] || 0;
              count ++;
              results.duplicates[this.id] = count;
            }
          }
        });
        return $.toJSON(results);
      }
      audit_ids();
    JS
    assert_equal({}, JSON.parse(audit_json)), 'Expected no duplicate IDs')
  end
  

Help Wanted

• One project recently moved from Rimu to EngineYard, only to find their Mongrel processes double in memory consumption. Any thoughts on why?