Friday, December 20, 2013

Rubymotion: Controlling Info.plist generation with environment variables

I've been doing a fair amount of Rubymotion development these days and one trick that I'm using in my local development is to control the generation of the Info.plist via environment variables and some Ruby coding in the Rakefile. I can't stop raving about the excellent tools and development cadence that Rubymotion affords the iOS developer. I really like that I'm working out of Rubymine and not Xcode and using standard Ruby tools like rake and Bundler.

Like I said, using rake, you have the opportunity to change your Info.plist because it's generated through the rake process. I have a login view that needs a username and password entered into the text fields. I've rigged it up that these are prepopulated when working in dev, using environment variables and adding some logic to my Rakefile and the view controller. First up are the environment variables:

export DEV_MODE="true"
export DEV_USERNAME="chris.bartling@mycompany.net"
export DEV_PASSWORD="fahj2734hfjg86776dg$48df676"

Nothing earth shattering here. Normal environment variable assignments. Next up is the Rakefile changes:

Motion::Project::App.setup do |app|
    
	...    

    if ENV['DEV_MODE']
        puts '==========================================='
        puts '===> Using DEV_MODE Info.plist values <===='
        puts '==========================================='

        app.info_plist['DEV_USERNAME'] = ENV['DEV_USERNAME']
        app.info_plist['DEV_PASSWORD'] = ENV['DEV_PASSWORD']
    end

    app.pods do
        ....
    end
end

Again, pretty simple Ruby stuff here. If the DEV_HOME environment variable is set, add the username and password to the Info.plist during generation. Now, in your app, you can reference these values in your viewDidLoad method of your view controller, prepopulating the UI elements in your views:

dev_username = NSBundle.mainBundle.objectForInfoDictionaryKey('DEV_USERNAME')
dev_password = NSBundle.mainBundle.objectForInfoDictionaryKey('DEV_PASSWORD')
@email_field.text = dev_username || ''
@password_field.text = dev_password || ''

I probably sound like a broken record, but if you haven't used Rubymotion, definitely give it a try. Much different developer experience using Rubymotion tools vs. Apple's Xcode tooling.

Retrieving logs from your deployed Google App Engine Java application

If you need to see your application logs from your deployed Google App Engine (GAE) Java application, you can use the GAE appcfg.sh tool to do so. Issue the following command from your GAE app directory:

appcfg.sh --num_days=0 --severity=0 request_logs ./web ./logs/gae.log

where:

--num_days=0 will retrieve all of the logs available,
--severity=0 will retrieve DEBUG and above log levels,
./web is where the ./WEB-INF/appengine-web.xml descriptor file can be found, and
./logs/gae.log is the local log file to write records to.

There are other options available for this command. Execute appcfg.sh help request_logs to see more information on the options available for request logs command. This will dump all of your logs and they will not be truncated like they are in the Logs view of the GAE administration application.

Thursday, December 19, 2013

CoffeeScript Application Development by Ian Young

I had the opportunity to read CoffeeScript Application Development by Ian Young recently and thought I would put together a book review.

The author does a nice job describing why parentheses are required for executing CoffeeScript no-argument functions. This is an idiom that I have seen many developers trip over when first coming to CoffeeScript. CoffeeScript preserves JavaScript’s view of functions as first-class citizens. Parentheses are optional except when necessary to avoid ambiguity.

The author gives some nice examples of loop comprehensions, one of the snazzier features of CoffeeScript. Loop comprehensions come from Python and they make for a more readable way to iterate a list and selectively act on list elements which meet a certain criteria. I’m always looking for more examples of loop comprehensions in CoffeeScript and this book has some nice examples.

The CoffeeScript switch statement is explained thoroughly. This is a handy flow-control statement that works really well in its incarnation in CoffeeScript. There are numerous examples in the book where different usage scenarios are demonstrated. Very handy and welcomed.

I found the author’s treatment of classes and inheritance in CoffeeScript to be a nice, gentle introduction. The examples that are given in the book work well and the explanations that accompany the examples are clear and concise. It would have been nice to get an explanation of the boilerplate code that CoffeeScript generates for you when defining a class, but I guess that’s considered part of the magic of CoffeeScript. It isn’t until the discussion on inheritance that the author starts to poke his head under the hood to investigate the generated JavaScript. The inheritance discussion is extremely valuable and a big plus for this book. If you get this book for anything, it’s for this discussion. CoffeeScript is doing a whole bunch of interesting stuff when creating classes and implementing inheritance, and this is one of the first times that I have seen the generated JavaScript described line by line.

In typical fashion, the author introduces the fat arrow syntax in a gentle manner, clearly explaining the reasoning for such a feature. The author then gives a very good explanation why you should not overuse the fat arrow syntax in your CoffeeScript (hint, it’s due to memory usage). He also includes a very succinct definition and example around memoization in CoffeeScript. This is a feature that I have not had much exposure to, so it was great to see it described and used in an example.

IcedCoffeeScript is introduced in the chapter on Going Asynchronous. I have not used IcedCoffeeScript, so that was an interesting exploration into an extension to CoffeeScript for managing asynchronous invocations. Looks interesting.

The topic of debugging CoffeeScript is broached. This is an interesting subject, as I have seen a few developers really get frustrated with the mapping of generated JavaScript back to the original CoffeeScript. Luckily the author introduces source maps, which does this work for us. The author shows us how to set this feature up in Firefox and Chrome developer tools. Your mileage will vary on this feature, but it is an interesting tool for easing the inertia of moving to CoffeeScript. This discussion comes with a lot of screenshots that help you understand how the source maps feature can be used in the developer tools.

Overall I really liked this book and it’s a worthy addition to my other documentation on CoffeeScript. Link to the book

Tuesday, November 12, 2013

Debugging Before and After hooks in Cucumber

Had a heck of time trying to figure out why all my Cucumber steps were completing successfully, but my Cucumber scenario would fail. Seems that I had an issue with the web app that I was testing which would hit a REST endpoint asynchronously during the Cucumber scenario, causing an error. Cucumber seems to eat this normally, but running with the command line option of --format pretty dumps the backtrace of the exception. Blogging about this so I don't forget about it. Reference: https://groups.google.com/forum/#!topic/cukes/WTJDVWGQkTM

Monday, November 04, 2013

Python Imaging Library (PIL) on OS X Mavericks

Upgraded to Mavericks (10.9) over the weekend, not taking into account my current Python/Google App Engine development work. Thus, this Monday morning, I'm spending some quality time getting my Python environment back up and running. One of the things that I needed to re-install in this new environment is PIL or the Python Imaging Library. Unfortunately, doing a naïve pip install results in an error when looking for an X11 header file. This StackOverflow comment solved my problem, so I'm sharing with others who might get hung up on PIL on Mavericks. The pre-built PIL stuff doesn't seem to install on Mavericks, so the pip install seems to be the way to go for 10.9/Mavericks.

Monday, August 19, 2013

MySQL useCursorFetch property and Grails 2.2.4

Just hit a problem with using the useCursorFetch property in Grails 2.2.4. It may be present in earlier versions of Grails 2, but this was working up through Grails 1.3.9. I'm upgrading a Grails 1.3.9 application to Grails 2.2.4 and hit the following runtime exception when the JDBC URL has the useCursorFetch property set to true.


| Error 2013-08-19 09:05:50,365 [localhost-startStop-1] ERROR context.GrailsContextLoader  - Error initializing the application: java.lang.LinkageError: Illegal class file encountered. Try running with -Xverify:all in method executeBatchSerially
Message: java.lang.LinkageError: Illegal class file encountered. Try running with -Xverify:all in method executeBatchSerially
   Line | Method
->> 308 | evaluateEnvironmentSpecificBlock in grails.util.Environment
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|   301 | executeForEnvironment            in     ''
|   277 | executeForCurrentEnvironment . . in     ''
|   303 | innerRun                         in java.util.concurrent.FutureTask$Sync
|   138 | run . . . . . . . . . . . . . .  in java.util.concurrent.FutureTask
|   895 | runTask                          in java.util.concurrent.ThreadPoolExecutor$Worker
|   918 | run . . . . . . . . . . . . . .  in     ''
^   680 | run                              in java.lang.Thread

Caused by LinkageError: Illegal class file encountered. Try running with -Xverify:all in method executeBatchSerially
->> 4566 | prepareStatement                 in com.mysql.jdbc.ConnectionImpl
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|   4479 | prepareStatement                 in     ''
|   281 | prepareStatement . . . . . . . . in org.apache.commons.dbcp.DelegatingConnection
|   313 | prepareStatement                 in org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper
|   111 | methodMissing . . . . . . . . .  in org.grails.datastore.gorm.GormStaticApi
|    56 | loadUsersAndRoles                in com.vocabra.eventlogging.services.DefaultDataLoaderService
|    22 | load . . . . . . . . . . . . . . in     ''
|   165 | doCall                           in GrailsMelodyGrailsPlugin$_closure4_closure15_closure16
|    18 | doCall . . . . . . . . . . . . . in BootStrap$_closure1
|   308 | evaluateEnvironmentSpecificBlock in grails.util.Environment
|   301 | executeForEnvironment . . . . .  in     ''
|   277 | executeForCurrentEnvironment     in     ''
|   303 | innerRun . . . . . . . . . . . . in java.util.concurrent.FutureTask$Sync
|   138 | run                              in java.util.concurrent.FutureTask
|   895 | runTask . . . . . . . . . . . .  in java.util.concurrent.ThreadPoolExecutor$Worker
|   918 | run                              in     ''
^   680 | run . . . . . . . . . . . . . .  in java.lang.Thread

Removing the property from the JDBC URL resolves the issue. Need to do more research into why this is happening.

Wednesday, July 31, 2013

When is a user story done?

I am beginning to hate the word "done". It means so many different things in software development and causes so much confusion that I am trying not to use the term, instead opting for statements which convey much more information and provide more transparency into our product development efforts.

In the past, I have been asked to figure out why two development groups under a common work area have radically different velocities and thus are being viewed much differently by management. The first group is chewing up stories, the other, not so much. Looking at the user stories of each group, differences between the two groups definitely exist. The "higher performing" group have simple stories with a few acceptance criteria. The acceptance criteria seem very high level; my gut feeling is that the acceptance criteria would be difficult to turn into actual acceptance tests. The "lower performing" group has more acceptance criteria which are more concrete--I can visualize actual acceptance tests with these criteria. Digging into the groups a bit more, it becomes apparent that the "higher performing" group's quality assurance effort is behind the development group in completion, but the group is considering stories "done" when the developers reach code complete. The "lower performing" group does not claim a story completed until it has been verified by quality assurance and the customer has signed off on the functionality (usually through some demonstration of the functionality).

So which group is really the high performer here? Saying a story is done when code complete is a misnomer and is likely building a false reality of where the group really is at. This "higher performing" group is setting themselves up for a big fall--there is no sense of quality assurance complete or customer complete.

Some in the agile community call this "done, done, done". I guess that's OK, but I think we need to be really careful with our terminology as we communicate within our development groups and outside of the development group to shareholders. I feel we should use specific terminology to describe where a story currently resides in the "done" spectrum. Daniel Gullo has a good article about this. He enumerates criteria for completion:

  • “Code complete”: Development completed, including accompanying unit tests (assumption here is that everyone is operating under test-driven development).
  • “Unit tested”: Unit tests completed. I don't really care for this designation, especially since my groups engage in test-driven development. I would call this Acceptance tested or something like that. Basically, demonstrate that we have satisfied the conditions for completion (aka acceptance criteria). Hopefully most of these acceptance tests are automated and have been written concurrently during the iteration by QA with the cooperation of the developers.
  • “Peer reviewed”: Developer code reviews completed. I like this concept when paired with feature branching and pull requests.
  • “QA complete”: QA testing, automated and exploratory, completed. I like having this as a separate stage-gate, allowing for exploratory testing by QA.
  • “Documented”: As needed. There's probably another blog post here around documentation and the agile process, but I will leave that alone for a while.

Now there is little ambiguity as to where a story stands when using this terminology. I may throw another level in there, customer complete, when the customer signs off on the newly developed feature. Thoughts? How do you communicate when a story is complete?

Sunday, June 09, 2013

Connecting DbVisualizer to Heroku PostgreSQL database

Just a quick note on how to connect DbVisualizer to a Heroku PostgreSQL database. The trick is to get the SSL stuff to work, as DbVisualizer needs to be told to use a SSL factory (via the sslfactory driver property). I used the 'org.postgresql.ssl.NonValidatingFactory' SSL factory. I set this property and the ssl property (to true) in the Properties tab of the connection information. The rest of the connection information you need to get from Heroku, in particular the Heroku database configuration. Go to your Heroku dashboard, drill into your app of interest and click on the Heroku Postgres link (mine was labelled "Heroku Postgres Dev"). This will take you to the herokupostgres setting for your application. Click on the bi-directional arrows icon (Connection Settings) and you can find your connection setting there. I used the JDBC properties and filled out the Server Info settings format. This format seems to work better in DbVisualizer. Also allows you to ping the database server.

Tuesday, April 23, 2013

Jasmine spying on jQuery selectors

Quick blog post about how to spy for jQuery selectors. Say I want to write something like the following:
var $element = $('div.my-element');
How would you write a Jasmine specification to drive this line of code in a Backbone.View function? Here it is:
it("find the element using a jQuery selector", function() {
   var spy = spyOn(jQuery.fn, 'find');
   this.view.doSomething();
   expect(spy).toHaveBeenCalledWith('div.my-element');
});
The reason you can do this is that $(selector, context) becomes $(context).find(selector). By default, selectors perform their searches within the DOM starting at the document root. However, an alternate context can be given for the search by using the optional second parameter to the $() function (from http://api.jquery.com/jQuery/#jQuery1). Had to write this down in a blog so I remember it again some day. Cheers!

Wednesday, February 20, 2013

Disabling hashListening in jQuery Mobile 1.2

Just a quick note. Spending a little time today integrating Backbone.js with jQuery Mobile. Both frameworks have routing solutions which do not work together. However, there is some simple configuration that you can use to turn off the jQuery Mobile routing in favor of Backbone.js routing:
$(document).bind("mobileinit", function () {
    $.mobile.ajaxEnabled = false;
    $.mobile.linkBindingEnabled = false;
    $.mobile.hashListeningEnabled = false;
    $.mobile.pushStateEnabled = false;
});
The trick to getting this to work is loading this bit of code before you load jQuery Mobile. More information at http://jquerymobile.com/demos/1.2.0/docs/api/globalconfig.html.

Friday, February 08, 2013

Disappearing USB ports on Mac Pro (Early 2009)

Just a quick note before bed. Recently I've been having issues with my Mac Pro not recognizing my HiFiMan headphone amp through a USB connection. I thought it might be the amp, but I tried it on my MacBook Pro and it recognized it immediately. Tonight, I noticed that my iPod would not connect iTunes on my Mac Pro. Searching around, I found an easy solution:

  1. Shut down your computer.
  2. Unplug the computer from power and wait about 15 seconds or so.
  3. Plug the computer power cord back into a power outlet.
  4. Restart your computer.


Voila! I have my USB ports back and my system is recognizing both the HiFiMan amp and my iPod.

Thursday, February 07, 2013

Effective use of the Rails has_and_belongs_to_many association

Just a note to myself and others using the Rails has_and_belongs_to_many association:
  • The naming of the association table is by alphabetical convention. For example, a many-to-many relationship between Assemblies and Parts models would result in an association table named assemblies_parts. The migration will look like:
    class CreateAssembliesPartsAssociationTable < ActiveRecord::Migration
    
        def self.up
            create_table :assemblies_parts, :id => false do |t|
                t.integer :assembly_id, :null => false
                t.integer :part_id, :null => false
            end
    
            add_foreign_key(:assemblies_parts, :assemblies)
            add_foreign_key(:assemblies_parts, :parts)
        end
    
        def self.down
            drop_table :assemblies_parts
        end
    
    end
    		
    Note that I am using the foreigner gem to implement foreign keys in my migrations.
  • Use this association type when you want a direct many-to-many mapping of models without any intervening association model.
  • The model mapping looks like the following:
    class Assembly < ActiveRecord::Base
    
        has_and_belongs_to_many :parts
    end
    
    and
    class Part < ActiveRecord::Base
    
        has_and_belongs_to_many :assemblies
    end
    
I just got caught by the alphabetically ordering of the association table name. Thought I would write something up about it.