I had a few problems when displaying my slide deck at the
conference. When I'm speaking at an event, I usually like to use whatever
equipment is provided. To be assured of compatibility between my MacBook Pro
and the projector, I would need to bring like [what seems like] 23 different
video adapters. It's easier to just bring my slide deck on a thumb drive.
The email from the conference organizers told us there would
be "Dell laptops" in the room. I remember thinking how boneheaded it was of
them to be running Windows at the Open Source convention, but I complied and
brought my slides as a PowerPoint file.
And then I got there and discovered that I was the one being
a bonehead for assuming that "Dell laptop" == "Windows + Office". Actually, those
Dell laptops were running Linux with OpenOffice.org. Anyway, OO.org imported
my .pptx file, but it botched the formatting in some rather unexpected and
entertaining ways.
Since OSCON ended three weeks ago, folks on our team have
been taking their summer vacations, but we've still made some good progress:
After things settle down just a
bit more, we'll be ready to start publishing nightly tarballs.
Several folks have asked for a copy of the slides from my
talk at OSCON last week, so here they are (PDF, 2
MB). They might be a little hard to follow without the narrative that goes
with them. A videotape of the talk will be posted in a week or so.
Thanks to all who attended my presentation. The turnout was
great, and folks seemed quite enthusiastic about Veracity.
I was especially appreciative of the attendance and
expressions of support from several members of the original Subversion
development team. Subversion is one of the most successful version control
tools ever, and I watched its early development closely enough to develop an
admiration for the folks who built it. So it was a very pleasant surprise to
find a few "celebrities" in attendance at my session. :-)
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Tools and
technologies we've been using to build Veracity
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C
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The core library and the command-line app are written
entirely in C. Some folks won't like our coding conventions. I'll probably
do a whole blog entry sometime to ((apologize for) && (defend)) the
liberties we've taken with the C preprocessor.
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JavaScript
jQuery
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On the browser side of things, Veracity is a web app
written in JavaScript using jQuery.
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SVG
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Burn down charts and other web graphics are done using
SVG.
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JSON
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Veracity uses JSON all over the place. All serialized
structures in the repo are JSON. Database records and templates are JSON.
We have a bunch of C code for parsing JSON, writing JSON, and dealing with JSON-like
data in memory.
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SQLite
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We use SQLite in several places as a more scalable disk
format, and also as an index.
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Mongoose
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The Veracity command-line app has an embedded web server
for personal use. It's based on Mongoose.
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Curl
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The client side of push/pull is done by calling libcurl.
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UTF-8
ICU
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Early on in the Veracity project, we did a lot of work to
make sure that stuff was done right with respect to Unicode. Our preferred
encoding is UTF-8. The ICU library from IBM has been helpful in a number of
places.
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REST
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The Veracity web API is very RESTy. And of course,
everything serialized over the network is in JSON.
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CMake
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Our build system is CMake, with which we have a love/hate
relationship. We love it because it generates makefiles, Xcode projects or
Visual Studio solutions. We hate it because its language makes Forth look
sane.
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CTest
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We have a huge suite of automated tests. CMake's
integrated test stuff actually works pretty well. Just run 'ctest' at the
top level directory.
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SpiderMonkey
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A lot of our tests are written in Javascript. We have a
command-line executable called 'vscript' which is basically the Spidermonkey
Javascript engine glued to the main Veracity library.
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Continuous Integration
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Our CI system system rebuilds from scratch and runs the
main tests after every checkin, on Mac, Linux and Windows. Results are
published to an internal web page and sent to the team by email.
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Scrum
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The more we use Scrum, the more I like it. We're patient
with ourselves. We just try to get a little better in our Scrum practices
each iteration.
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gcov
lcov
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Nightly builds run the entire test suite with code
coverage done by gcov. Our current coverage level is 81%.
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vcdiff
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For binary deltas, Veracity uses the algorithm described
in RFC 3284. (Actually, the use of binary deltas is currently turned off by
default, so if you notice that repositories seem big, that's why. All the
plumbing is done. We're just not using it yet.) Anyway, we've got our own
implementation of vcdiff. We may consider switching to Google's open-vcdiff
at some point if its performance is better.
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zlib
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For simple non-deltified compression in repo
implementations, Veracity uses zlib.
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Valgrind
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When coding in C, valgrind is indispensable.
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Shark
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I do most of my coding on the Mac, so I use the Shark
profiler. Very cool.
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emacs
vim
Eclipse
Visual Studio
bash
gdb
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Every developer on our team chooses their own tools. We
have a good representation of most of the major religions.
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Firefox
Safari
Chrome
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Similarly, every developer chooses their own web browser.
I'm not sure what feelings to have upon noticing that nobody is using
Internet Explorer. It seems so wrong. And yet, so right.
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A few notable
things we'll probably be using later
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.NET
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Even though Veracity was not built fundamentally on the
.NET platform, we are committed to providing excellent support for Windows
developers. Visual Studio integration is a high priority.
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Java
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Similarly, we didn't use Java to build the core libraries
for Veracity, but we plan to deliver excellent integration into the Java
world, including an Eclipse plugin.
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IIS
Apache
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The embedded web server is fine for personal use on the
desktop, but large teams will want to run a real web server for their central
repository. We designed for this case early, but have not yet implemented
something like an IIS plugin.
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A few notable
things we are NOT using (and maybe never will)
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C++
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Here's another blog article I need to write. Basically,
we only considered two choices: C, and the C-like subset of C++. We chose
plain C. I just wish the Microsoft C compiler supported C99.
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Flash
Silverlight
GWT
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We seriously considered other ways of building our web
apps. We ended up choosing basic HTML/CSS/jQuery/Ajax. No regrets, but I
sometimes wonder how things are going for people using GWT.
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NSPR
APR
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Sorry folks, in an apparent fit of NIH syndrome, we wrote
our own portability layer. And I am completely unrepentant.
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XML
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JSON won. What can I say? I just like curly braces a lot
more than angle brackets.
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