Moved my blog

I’ve moved my blog to blog.repl.ca. It’s the same stuff, with a different name. I’ll leave the existing posts up here, for search engines and whatnot.

HOWTO Make a USB Y Cable for Host Mode

Many smartphones or tablets support USB host mode (or On The Go mode) with an adapter. Unfortunately, a lot of those devices don’t supply power to their client USB devices; you can’t just plug a host mode adapter into an HP TouchPad, for example, then plug a keyboard into the host mode adapter, and expect everything to work.

I put up a video on youtube explaining how to build and use a USB Y cable to inject power to the client devices. If you’d like, you can watch it here

An Access Logger for Netty and HTTP

We needed to do CLF style HTTP access logging for Thumbslug, which is implemented in Java + Netty. I couldn’t find any code to do this with a quick google search, so I wrote my own. If you need such a thing, try here or here (backup).

Measuring Network Speeds with Netcat and Dd

I’ve seen a few posts on the web about testing your network speeds with netcat, but they all seem to not work with recent versions of netcat.

On one machine, run:

nc -v -l 2222 > /dev/null


(Make sure you’re not blocking connections to 2222!)

On a second machine, run:

dd if=/dev/zero bs=1024K count=512 | nc -v $IP_OF_FIRST_MACHINE 2222


dd will give you your speed:

536870912 bytes (537 MB) copied, 4.87526 s, 117 MB/s


Yay, gigabit!

ymmv, test with /dev/zero at your own risk. Speak with your NOC before starting any network infrastructure changes.

Converting SVN Commits to Git Patches

In case you find yourself in need of a way to turn an svn revision into a git patch that can be applied with ‘git am’, keeping the commit message and authorship information, here’s a script I used recently:

#!/usr/bin/python
#
# svnrev2git.py - Convert an SVN revsion to a Git patch.
#
# Author: James Bowes <jbowes@repl.ca>
#
# Usage:
#   $> cd my-svn-repo
#   $> python svnrev2git.py [AUTHORS_FILE] [REV_RANGE | REVSION [REVISION..]]
#
#   AUTHORS_FILE - a CSV of  svn username, full name, email
#   REV_RANGE - an svn revision range, like 100-700
#   REVISION - a single svn revision
#
#   You may specify either a revision range, or a series of individual
#   svn revisions
#
# Output:
#   A series of git style patch files, one per svn revision, which can then be
#   applied with 'git am'
#
# Why use this instead of 'git svn'?
#   I had done a large repo conversion via git svn where we wanted no downtime
#   for the switchover. After removing the git svn specific info from our git
#   commits, I used this tool to bring in commits from svn, keeping svn and git
#   in sync, until we were ready to switch.

import sys
import commands

def svnlog_to_gitlog(authors, svnlog):

    lines = svnlog.split("\n")
    lines = lines[1:-1]

    metainfo = lines[0].split(" | ")
    subject = lines[2]
    description = lines[3:]

    author = metainfo[1]

    day = metainfo[2].split("(")[1][:-1]
    time = metainfo[2].split(" ")[1]
    offset = metainfo[2].split(" ")[2]

    gitlog = []
    gitlog += ["From: %s <%s>" % authors[author]]
    gitlog += ["Date: %s %s %s" % (day, time, offset)]
    gitlog += ["Subject: [PATCH] %s" % subject]
    gitlog += [""]
    gitlog += description
    gitlog += [""]

    return '\n'.join(gitlog)

def svndiff_to_gitdiff(svndiff):
    lines = svndiff.split("\n")

    gitdiff = []
    for line in lines:
        if line.startswith("--- "):
            gitdiff.append("--- a/" + line[4:])
        elif line.startswith("+++ "):
            gitdiff.append("+++ b/" + line[4:])
        else:
            gitdiff.append(line)

    return '\n'.join(gitdiff)

def make_patch(authors, rev):
    out = commands.getoutput("svn log -c %s ." % rev)

    if len(out.split("\n")) < 2:
        print "skipping r%s" % rev
        return

    patch = open(rev + ".patch", 'w')
    patch.write(svnlog_to_gitlog(authors, out))
    patch.write("---\n\n")

    out = commands.getoutput("svn diff -c %s ." % rev)
    patch.write(svndiff_to_gitdiff(out))

    patch.write("\n---\n")
    patch.write("svnrev2git.py\n")

    patch.close()
    print "wrote %s.patch" % rev

def main(args):
    author_file = open(args[0])
    authors = {}

    print "loading authors"
    for line in author_file.readlines():
        parts = line.strip().split(", ")
        authors[parts[0]] = (parts[1], parts[2])

    author_file.close()

    revs = args[1:]

    if len(revs) == 1 and '-' in revs[0]:
        start, end = revs[0].split('-')
        start = int(start)
        end = int(end)
        revs = [str(x) for x in range(start, end + 1)]

    for rev in revs:
        make_patch(authors, rev)

if __name__ == "__main__":
    main(sys.argv[1:])

DIY Velcro Cable Ties

Making your own velcro cable ties is a great idea. $2 in materials made as many cable ties as Wal-Mart was selling for $13. Thrifty!

I’d suggest sewing the velcro together vs stapling, especially if you have cats that are far too curious about staples.

Perceptions of Toronto

Growing up on the east coast of Canada, this is how I imagined Toronto to be, like, 24/7.

I’ve been here for nine months or so, and have yet to be invited to any trendy VICE parties. Just so you know, VICE, I am very willing to grow out some stubble and wear vintage clothing or an ironic t-shirt for the event.

Toronto is great though, even without the free Red Stripe.