May 2015 – Page 2 – Kev's Development Toolbox

May 24, 2015

Choosing an Issue Tracker for an Online Service

I’ve been working on an application that I’m getting close to publicly launching, and while the site is mostly functional with most of the development done (I’ve been working on it in my ‘spare time’ for almost a year), there’s some non-development tasks I need to complete before launching, including:

adding Google AdSense and Analytics
completing online documentation
setting up an online issue tracker

The options for an issue tracker has taken me by surprise as there are so many options, ranging from free to varying monthly fee options. I’m somewhat familiar with some of the older free development project focused options, like Bugzilla, Trac, Redmine, and commercial options like Atlassian’s Jira. Part of my app is open source on GitHub and so to use the GitHub issue tracker for that part is an easy choice. I’d also like to make sure whichever issue tracker I chose is easy to use from the point of view of my end users, the majority of which are unlikely to have existing GitHub accounts, or accounts on other online tracker sites, and I want to make sure it’s as easy as possible for them to log issues and enhancement requests.

(This article here has a good list of a number of issue trackers.)

Ranging from simplest to use, Trello is a stand-out from the crowd. Although it’s not a dedicated issue tracker, the approach of managing lists of items and moving items (cards) from one list (e.g. open items) to another (e.g.closed items) is trivial.

Categorized in interesting-but-with-high-technical-requirements is YouTrack from JetBrains, and free for upto 10 users … but requiring 1GB heap to run, this would cost me some monthly runtime costs for medium gear on OpenShift, so I’m not sure if this is worth the investment at this point.

Next up in the looks-interesting category is Asana – I’m not familiar with this service, it looks like it offers much more than I would need, but could be worth investigating.

I’ve some decisions to make here, and right now I’m thinking either using GitHub’s issue tracker or Trello. What would you recommend – leave me a comment!

May 21, 2015

Happy 20th Birthday Java! What’s your Java story?

I started learning Java in 1996, from the book ‘Learn Java in 21 Days’, published by SAMS. For some reason I even still have the same book:

At the time I was working for Royal Sun Alliance and we were doing OS/2 client/server development using Application Manager, against a CICS/COBOL backend. One of the guys I was working with, Mike, said I should take a look at this new language called Java because it can run on any platform. At that time developing on OS/2 and seeing demand slowing for OS/2 AM developers, the promise of a development language not tied to a specific platform seemed an attractive offer, and a potential ticket to move away from OS/2.

I started working through the exercises in the book, building my first Applets – I think one of the first applets I built was a lottery ticket number generator that I had on my webpage at the time. In 1996 it was pretty cool to have interactive content on your web site! Even though this turned out to not be Java’s strong point (most Java development is arguably server side now days), it was where it all got started.

Although I continued to play with Java in my own time, it wasn’t until I changed jobs in 1997 and moved to TSW/Indus, a software house developing Enterprise Asset Manager software, that I had the opportunity to start Java development ‘on the job’. At the time the company had a Powerbuilder/Oracle PL/SQL based client/server product, and while in that first year I cross trained to Powerbuilder, we started prototypes of building a web-based replacement for the Powerbuilder client, against a Java backend. At the time this was using a ‘Java Cartridge’ on Oracle Application Server (I think it was called), and the Java code was invoked CGI-BIN style using HTTP GET query string parameters that were passed into Java code on the server.

At some point pretty soon after these first prototypes the Servlet API came along, and then EJB1.x came along… looking back which was an absolute nightmare from a developer productivity point of view. Somewhere in there I also dabbled with some CORBA based backend running on a server that I think was called IONA (although those memories are long gone now).

I’ve seen a lot of incredible changes in the Java space, and 19 years later from where I started, I’m still coding Java and it’s still going strong!

May 20, 2015

Calling C printf from ARM ASM

A while back I started to learn some ARM assembly on the Raspberry Pi. In my previous snippets, I was using SWI to do a system call to write to stdout, but it appears syscall 4 to write to stdout only writes Strings – if you have a byte value, this approach doesn’t work (without converting to a String first?)

From this question here, it appears you can call C functions like printf, which seems like cheating a bit, but I guess it gets the job done.

Here’s a quick snippet to add two numbers, and then print the result using printf with a string containing %d to substitute the result into the String:

[code]
.global main
.extern printf
main:
push {ip, lr}
mov r3, #1 /* move 1 to r3 */
mov r4, #2 /* move 2 to r4 */
add r4, r3, r4 /* r4 = r3 + r4 */
_ouput:
ldr r0,=output /* load address of output string */
mov r1, r4 /* move r4 result to r1 to include as param in string */
bl printf /* call printf */
_exit:
MOV R1, #0
MOV R7, #1
SWI 0
.data
output:
.asciz "Result: %d\n"
[/code]

Where previously I was compiling and linking in two steps with as and ld, it seems this doesn’t work if you are referencing C functions too, so for this example, compile with: ‘gcc add.s -o add’

This snippet and a few others I’ve started to collect I’ve shared in a github repo here: https://github.com/kevinhooke/learning-arm-asm

May 20, 2015

Enjoy your additional ‘leap second’ on June 30th 2015

This year on June 30th at 23:59:59 UTC, rather than the 59th second ticking to 00, there is an additional second added so clocks will tick to 60 before going to 00.

If this sounds rather odd, check out a more detailed explanation here on Wikipedia.

So what does this mean for us as software developers? Well, for Java JVMs, you can use the provided tzupdater tool (updates described here, and usage described here), download the updated timezone file and apply the update. For other platforms and operating systems, check release notes and updates from your vendors (e.g. For RHEL, check here).

Should you be worried about the impact to your systems? Well that depends on how sensitive your system is to the date/time and synchronization with other systems that you integrate with. For example, the ICE futures exchange have announced they are taking their systems down for an hour overlapping with 23:59:59 on June 30th to avoid any unexpected issues. Whether you have to go that far depends on your system.