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  • Circular dependency detected while autoloading constant

    I recently ran into this frustrating and intermittent error in Ruby on Rails 4 (JRuby, actually): Circular dependency detected while autoloading constant Googling turned up several articles advising one to abide by the Rails conventions, but that was not the issue. The application I’m writing uses background threads. The problem shows up when trying to…

  • Adobe password breach as the world’s greatest crossword puzzle

    Adobe was recently breached and 150,000,000 user accounts were stolen. Adobe was following the one of the worst practices of password storage — reversible encryption (rather than hashing with a salt using a good, slow algorithm like bcrypt). A very, very old throwaway password of mine was among those leaked. XKCD has referred to this…

  • The specified bucket is not S3 v2 safe

    I ran into this error when running ec2-upload-bundle:The specified bucket is not S3 v2 safe (see S3 documentation for details)This was due to uppercase letters or underscores. Later I also ran into an issue with periods in bucket names which showed up as this error message:ERROR: Error talking to S3: Server.AccessDenied(403): Access DeniedHere is an…

  • CN Tower Climb for United Way

    On October 22, I’ll be climbing the CN Tower stairs for United Way. Any contribution is appreciated.

  • IBD-3475A Crunch Big Data in the Cloud with IBM BigInsights and Hadoop

    I’m teaching a hands-on lab at Information on Demand 2013. I will edit the post to include lab materials closer to the date. Session: IBD-3475A Crunch Big Data in the Cloud with IBM BigInsights and Hadoop Time: Thu, 7/Nov, 10:00 AM – 01:00 PM Location: Mandalay Bay South Convention Center – Shorelines B Lab [Room…

  • Machine learning with Mahout and Hadoop session

    Tonight I attended a session about machine learning with Mahout at BNotions. The session was organized through the Toronto Hadoop User Group. Quick Notes BNotions uses Hadoop and Mahout for their Vu mobile app. Vu is a smart news reader that recommends articles based on article similarity to things you like as well as user…

  • Have bash warn you about uninitialized variables with set -u

    By default, Bash treats uninitialized variables the same way as Perl — they are blank strings. If you want them treated more like Python, you can issue the following command in your bash script: set -u You will then start seeing warning messages like the following: ./my_script.sh: line 419: FOO_BAR: unbound variable Note that this…

  • Set PuTTY defaults, permanently

    PuTTY or one of its forks is a standard tool for administering Unix and Linux machines from Windows. It provides SSH connectivity for command line access, as well as keypair management for compatible programs like WinSCP. Unfortunately, PuTTY has some terrible defaults. For example, it limits itself to 200 lines of scrollback by default, which…

  • Hardening WordPress against the ongoing brute-force attack

    There’s an ongoing brute-force attack against WordPress and Joomla sites. The attack tries to brute-force the admin password. (Reddit) I had to harden my WordPress some time ago. Here are the guides I followed when hardening my installation: My WordPress Site Was Hacked Hardening WordPress Ultimate Security Checker plugin (guide) Additional steps I’ve taken today:…

  • Alternatives to Gmail?

    Now that I’ve moved from Google Reader to Fever, I’d like to reduce my reliance on other Google services. Switching from Google search to Bing is pretty easy, but I’m on much less sure ground when it comes to replacing Gmail. Requirements: Paid service (If you aren’t paying, you are the product, not the customer)…