Providing Database Handle for Interchange Testing
By Chris Kershaw
October 14, 2010
I’ve recently begun using the test driven development approach to my projects using Perl’s Test::More module. Most of my projects lately have been with Interchange which has some hurdles to get around as far as test driven development is concerned. Primarily this is because Interchange runs as a daemon and provides some readily available utilites like the database handle. This method is not available to our tests, so they need to be made available as discussed below.
I develop Usertags, GlobalSubs and ActionMaps where applicable as it helps keep the separation of business logic and views clear. I generally organize these to call a function within a Perl module so they can be tested properly. Most of these tags involve some sort of connection with the database to present information to the user in which I uses the Interchange ::database_exists_ref method.
When it comes to testing I want to ensure that the test script invokes the same method. Otherwise, your script will not be testing the code as its used in production.
Let’s say you are building a Perl module that looks something like this:
package YourMagic;
use strict;
sub do_something {
my ($opt) = @_;
# some code …interchange perl testing
Red Hat SELinux policy for mod_wsgi
By Adam Vollrath
October 13, 2010
Using SELinux, you can safely grant a process only the permissions it needs to perform its function, and no more. Linux distributions provide policies to enforce these limits on most software they package, but many aren’t covered. We’ve made allowances for mod_wsgi on RHEL and CentOS 5 by extending Apache httpd’s SELinux policy.
It seems the SELinux policy for Apache httpd is twice as large as any other package’s. The folks at Red Hat have put a lot of work into making sure that attackers who manage to exploit httpd can’t break out to the rest of your system, while still allowing the flexibility to serve most applications. Consult the httpd_selinux man page if messages in audit.log coincide with your error.
File Contexts
If you’ve created files and/or directories in /etc/httpd, make sure they have the proper file contexts so the daemon can read them:
# restorecon -vR /etc/httpdhttpd can only serve files with an explicitly allowed file context. Configure the context of files and directories within your production code base using the semanage command:
# semanage fcontext --add --ftype -- --type httpd_sys_content_t "/home/projectname/live(/.*)?"
# semanage fcontext …django hosting python redhat security selinux
Keep Your Tools Sharp To Avoid Personal Technical Debt
By Brian Gadoury
October 12, 2010
One of the things that really struck me when I started working here at End Point was how all of my co-workers possessed surprisingly deep knowledge of just about every tool they used in their work. Now, I’ve been developing web applications on Linux for years and I’ve certainly read my fair share of man pages. But, I’ve always tended to learn just enough about a specific tool or tool set to get my job done. That is, until I started working here.
I’ve always thought that a thirst for knowledge and an inquisitive nature are both prerequisites for becoming a good developer. Did you take apart your toys when you were a child because you wanted to see how they worked? Were you even able to put some of them back together such that they still worked?
I did, too. I wanted to know how everything worked. But, somewhere along the line I seem to have decided that there “wasn’t time to learn about that” (where “that” was git rebase or mock objects in unit testing, or NoSQL databases like Cassandra) because I live and work in the real world. I have projects with milestones and deadlines. I have meetings and code to review. I have a life outside the office. These are common constraints, and I had …
tips
Spree Sample Data: Orders and Checkout
By Steph Skardal
October 11, 2010
A couple of months ago, I wrote about setting up Spree sample data in your Spree project with fixtures to encourage consistent feature development and efficient testing. I discussed how to create sample product data and provided examples of creating products, option types, variants, taxonomies, and adding product images. In this article, I’ll review the sample order structure more and give an example of data required for a sample order.
The first step for understanding how to set up Spree order sample data might require you to revisit a simplified data model to examine the elements that relate to a single order. See below for the interaction between the tables orders, checkouts, addresses, users, line items, variants, and products. Note that the data model shown here applies to Spree version 0.11 and there are significant changes with Spree 0.30.
Basic diagram for Spree order data model.
The data model shown above represents the data required to build a single sample order. An order must have a corresponding checkout and user. The checkout must have a billing and shipping address. To be valid, an order must also have line items that have variants and products. Here’s an example of …
ecommerce rails spree
Upgrading old versions of Postgres
By Greg Sabino Mullane
October 11, 2010
Old elephant courtesy of Photos8.com
The recent release of Postgres 9.0.0 at the start of October 2010 was not the only big news from the project. Also released were versions 7.4.30 and 8.0.26, which, as I noted in my usual PGP checksum report, are going to be the last publicly released revisions in the 7.4 and 8.0 branches. In addition, the 8.1 branch will no longer be supported by the end of 2010. If you are still using one of those branches (or something older!), this should be the incentive you need upgrade as soon as possible. To be clear, this means that anyone running Postgres 8.1 or older is not going to get any official updates, including security and bug fixes.
A brief recap: Postgres uses major versions, containing two numbers, to indicate a major change in features and functionality. These are released about every two years. Each of these major versions has many revisions, which are released as often as needed. These revisions are designed to be completely binary compatible with the previous revision, meaning you can upgrade revisions very easily, with no dump and restore of the data needed.
Below are the options available for those running older versions of Postgres, …
database open-source postgres bucardo replication
Seeking a Ruby, Rails, Spree developer
By Jon Jensen
October 9, 2010
This position has been filled. See our active job listings here.
Today I realized that we never posted our job announcement on our own blog even though we’d posted it to several job boards. So here it is:
We are looking for a developer who can consult with our clients and develop Ruby web applications. Most of our needs center around Rails, Spree, and SQL, but Sinatra, DataMapper, and NoSQL are lately coming into play too.
End Point is a 15-year-old web consulting company based in New York City, with 20 full-time staff developers working remotely from around the United States. We prefer open source technology and do collaborative development with Git, GNU Screen, IRC, and voice.
Experience with mobile and location-based technologies is a plus.
Please email jobs@endpoint.com to apply.
(This job has been filled.)
jobs-closed ruby rails spree
Surge 2010 wrap-up
By Jon Jensen
October 5, 2010
Following up on my earlier post about day 1 of the conference, here is an unsorted collection of what I felt were noteworthy observations made in talks at Surge 2010:
Web engineering as a separate discipline from computer science or software development started around 1999. It is interdisciplinary, involving human factors engineering, systems engineering, operations research, fault-tolerant design, and control systems engineering. (John Allspaw)
A real-time system is one in which the correctness of a system is tied to its timeliness. Eventual consistency is an oxymoron if timeliness is part of the data itself. Caching by CDNs can’t solve our problems here. (Bryan Cantrill)
Pre-fab metrics are worth less (and maybe worthless) when not tied to something in your business. Message queues enable lots of new uses because of the ability to have multiple observers. See Esper (Java, GPL) for live ongoing SQL-like queries of messages from AMQP sources, etc. (Theo Schlossnagle)
On scaling up vs. out: If your numbers show “up” is enough, be happy you can keep your system simpler. (Theo Schlossnagle)
Anyone can only ever know the past in a distributed system. There’s no such thing as global …
conference scalability
Two Cool Things about Liquid Galaxy
By Benjamin Goldstein
October 4, 2010
I. It uses COTS Hardware.
Liquid Galaxy is suitable for using with COTS (Commodity Off The Shelf) hardware. Yes, Google Earth itself is rather resource intensive, so it helps performance to use feisty computers (including ones with SSDs) but it’s still COTS hardware. Of course the very cool thing about using COTS hardware is that the price is right and gets better all the time.
II. A simple, elegant and powerful master/slave configuration and communication approach
Liquid Galaxy works by configuring its “slave” systems to have offsets from the point of view of the master system that the system’s user navigates on. The slave systems “know” their locations relative to the master system. The master system broadcasts its location to the slaves via UDP packets. It’s then up to the slave systems to figure out what portion of a Google Earth globe they need to retrieve themselves relative to the coordinates broadcast from the master system.
With this approach it’s easy to scale to a large number of slave systems. An interesting extension to this configuration and communication approach that the Google engineering team for the project provided for is the ability to configure one or more …
visionport hardware