Categories: , ,
Posted by: bjb

If you are using pip install somepackage, and it is not going into your virtualenv, perhaps you are tripping over the same thing I did.

I had activated the virtualenv with /usr/local/pythonenv/DJANGO-1-1/bin/activate, and (DJANGO-1-1) was appearing in the shell prompt. which pip showed /usr/local/pythonenv/DJANGO-1-1/bin/pip. python followed by

import sys
for p in sys.path:
    print p

showed that the system site-packages directories were not being included. So why was the python package being installed to /usr/local/python2.6/site-packages???

Well, the pythonenvs had been installed as root. I was actually running sudo pip install somepackage and that meant I was losing the virtualenv environment (which sets some environment variables that don’t survive the sudo to root transition).

So the solution was to run [UPDATED 2011/01/04]

sudo /usr/local/pythonenv/DJANGO-1-1/bin/pip install -E /usr/local/pythonenv/DJANGO-1-1/ somepackage

and indeed I threw in the --download-cache option to cut down on the download time (although I subscribe to DSL, my download times are closer to dial-up speeds) for subsequent installs into the DJANGO-1-0 and DJANGO-1-2 virtual envs.

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Posted by: bjb

I really like django, but one thing it lacks is db schema migration. I’m trying out a django package called “south” that does that. (Debian package python-django-south).

South keeps track of migrations applied by adding a table to your database called south_migrationhistory. Of course, this table has to be added before south will work … you add it using syncdb. Fortunately, south keeps track of what it does and what syncdb does.

So you start using south by installing south, and then running ./ syncdb. Now you have some new ./ commands, called startmigration and migrate (also datamigration, schemamigration and graphmigrations, maybe I’ll look at those another time). To snapshot your initial db state or to detect changes to your schema, you use the startmigration command. To apply migrations to your database, you use the migrate command.

To snapshot your initial db state, use startmigration --initial. To detect changes to your schema, use startmigration --auto. The startmigration command will, in addition to other things, dump out the current db schema into the migration file. Every generated migration file contains a schema declaration towards the end. It also contains a migrate forwards and a migrate backwards command, for applying the migration and unapplying it automatically. The schema changes are detected by comparing the model data declarations with the migration schema dumps.

Some examples, for a db named clientportal and an app named portal:

# create migration named portal/migrations/
./ startmigration portal initial --initial

The initial migration is already in your database, so you don’t have to apply it yourself. Then you edit the portal/ file, and add a field. Then you can have south detect this and create a migration that applies the change to the database.

./ startmigration portal add_field --auto  

You can use the newly created migration to change the database:

# will find all migrations named 0002_add_field
# and apply them (in alpha order of app name)
./ migrate 0002_add_field 

I’m not sure how to better control the migrating naming and order of application. For instance, it seems that migrations are numbered sequentially within applications, but you don’t specify the number. So if you have more than one app (app a and app b), and you create a migrations in this order:


then you run ./ migrate, the migrations will be applied in this order:


And I’m afraid that if I made a new migration (add_another_field) for app a, it would be called 0002_add_another_field and would be applied with all the other migrations (on ./ migrate on a new db):


A little annoying when the migrations should have been applied in this order:


Hopefully there is a way to handle it, even if I don’t yet know what it is. Just being able to specify the 000n numbers would do it.

To list out the available migrations, you can ./ migrate --list. The migrations that have been installed have a * next to them.

UPDATE 2011/Jan/12: to revert to an old version: ./ migrate appname 0006_shortname_not_null

brings you to the state just after 0006_shortname_not_null has been applied.

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Posted by: bjb

I want to put rounded borders on a stretchy box — expandable vertically and horizontally. I searched the web for solutions to this using pure CSS and found … none.

All the solutions I found had some kind of drawback. They all require you to either have a non-stretchy box in at least one dimension, or they require that your corner graphics be non-transparent. I’m not interested in the solutions that require javascript. The javascript just adds HTML elements or changes the CSS, anyway. And it’s slower than pure HTML and CSS, and sometimes people turn off javascript. Heaven forbid that they should miss out on the rounded corners.

The non-stretchy solutions involve having a single graphic to cover two or more corners — making stretching in the dimension between the two corners impossible.

There are a few non-transparent solutions that allow you to have a stretchy box. The solutions are various ways of stretching the sides of the box out to the corners, and then putting corner graphics on top of the sides. Thus the requirement to have opaque corners. One method is the sliding doors, another the Russian doll divs, and there are more as well.

One solution uses the pseudo-elements :before and :after, which is not supported in MSIE. Unfortunately, some people who read my blog (there are one or two people) use MSIE and complain when my blog looks funny. And they won’t switch browsers (or OSs, too bad).

Some solutions to the rounded-corners problem require you to have a certain set of elements in your html structure on which to place the corner and side graphics, and then claim that the solution does not require extraneous html elements. But if you don’t want a header element or a definition list in your box, you’re out of luck for that solution.

But I want stretchy sides and transparent-background corners around arbitrary contents.

Given that in order to implement this, I’m going to have to introduce extra HTML elements anyway, I think it is worth mentioning that a table can do what I want. A three by three table, with narrow fixed-width first and third columns and rows will allow the middle cell to stretch to accomodate its content. The first and third column and row cells can each have a different background image and each image displays in its own space with no overlap, allowing for transparent backgrounds in the graphics. Or, if you don’t want to have to maintain the table column and row widths and heights in sync with the graphics, you can put the graphics into those cells as HTML elements. Hey, one method is as evil as the other.

So, sometimes I’m going to use tables in my HTML. It is the best possible solution for this problem at this time. I sure hope HTML 5 has some sensible help for layout.

Posted by: bjb

The first beam:

Image IMG_3547-med.JPG Image IMG_3548-med.JPG Image IMG_3549-med.JPG

Preparing for the second beam, at right angles to the first:

Image IMG_3551-med.JPG Image IMG_3552-med.JPG Image IMG_3553-med.JPG

The second beam is up, they are adjusting its position with a sledgehammer:

Image IMG_3557-med.JPG

Connect the two beams:

Image IMG_3559-med.JPG Image IMG_3560-med.JPG

Take out a temporary wall:

Image IMG_3656-med.JPG Image IMG_3657-med.JPG

The view without the temporary wall:

Image IMG_3658-med.JPG Image IMG_3727-med.JPG Image IMG_3730-med.JPG

Posted by: bjb

Here’s the replacement for the load-bearing walls (see the nice red beams up near the ceiling). John put wood 2x6 along the bottom of the beam in order to have something to attach to while doing the rest of the finishing.


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Posted by: bjb

I apt-get upgraded, and then apt-get using apt-cacher didn’t work any more. It seems if you have a perl IPv6 library installed (IO::Socket::INET6), apt-cacher will assume you have deployed IPv6 and it will make an IPv6 only connection for listening.

To make all your services obtain IPv4 address along with IPv6 ones, as root “echo 0 > /proc/sys/net/ipv6/bindv6only” and edit /etc/sysctl.d/bindv6only.conf to contain 0 rather than 1. Then restart your service(s).

Or if you do have IPv6 running locally, you can change your apt sources.list file (/etc/apt/sources.list) to refer to ipv6-localhost instead of localhost:

deb     http://ip6-localhost:3142/ unstable main contrib non-free
deb-src http://ip6-localhost:3142/ unstable main contrib non-free

(other distro’s might use another name like localhost6. Look in your /etc/hosts file for the right name.)

Another gotcha: If you install apt-cacher-ng, and you already have apt-cacher running, then apt-cacher-ng will attach to the remaining free interface (the IPv4 one) and apt-cacher will still be running on IPv6. The two packages don’t conflict. Yeargh. I can’t wait to see the cache corruption … Ah, no cache corruption. It starts its own cache — from scratch. Well better that than corruption I guess. But, even better to be running only one of them on all listening ports.

And another gotcha: Installing apt-cacher-ng might end up adding a proxy config to your apt config like so:

/etc/apt/apt.conf:  Acquire::http::Proxy "";

so then if you use urls as above, you would have specified the proxy twice: once in the url and once in the apt.conf file. Apt then complains with:

Failed to fetch  403  URL seems to be made for proxy but contains apt-cacher-ng port. Inconsistent apt configuration?

The fix is to remove the proxy either from apt.conf or from the sources.list entries. Note that the proxy might have been put in /etc/apt/apt.conf.d/01proxy or something like that instead.

Well that was a lot more exciting than I’d hoped for.

Categories: , , ,
Posted by: bjb

The exim4 config file is a bit annoying because it is hard to know what statements are assignments and what statements are conditions. Below, the debug_print, driver, and data statements (in the hub_user route) are assignments, while the domains and check_local_user statements are conditions. Note how the config file designer helpfully mixed them together.

  debug_print = "R: hub_user for $local_part@$domain"
  driver = redirect
  domains = +local_domains
  data = ${local_part}@DCreadhost

  debug_print = "R: hub_user_smarthost for $local_part@$domain"
  driver = manualroute
  domains = DCreadhost
  transport = remote_smtp_smarthost
  route_list = * DCsmarthost byname
  host_find_failed = defer
  same_domain_copy_routing = yes

Anyway, to help with debugging exim4 routers, you can use the -bt option to exim4:

blueeyes:~# exim4 -bt bjb bjb@localhost bjb@blueeyes
R: system_aliases for
R: userforward for
R: procmail for
  router = procmail, transport = procmail_pipe
R: system_aliases for bjb@localhost
R: userforward for bjb@localhost
R: procmail for bjb@localhost
  router = procmail, transport = procmail_pipe
R: system_aliases for bjb@blueeyes
R: userforward for bjb@blueeyes
R: procmail for bjb@blueeyes
  router = procmail, transport = procmail_pipe

Note to self: “satellite” mail type is for machines whose mail is forwarded to another machine. Use “smarthost” for machines on which I actually read mail.

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Posted by: bjb

Handy quick conversion for timestamps in Nagios or unix logs: time.localtime (time.time);


bjb@bjb-pc:~/work/redmine/redmine-abitibi/app/views/mailer$ python
Python 2.5.2 (r252:60911, Jan 24 2010, 17:44:40)
[GCC 4.3.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import time
>>> time.time
<built-in function time>
>>> time.time ()
>>> time.localtime (1284523200)
(2010, 9, 15, 0, 0, 0, 2, 258, 1)
>>> time.localtime (1284520137)
(2010, 9, 14, 23, 8, 57, 1, 257, 1)
Categories: ,
Posted by: bjb

Both before and after upgrading byteflow to use django 1.2, one thing that wasn’t working is postimage. The most recent problem was the link to post an image (in the admin page for creating or editing a blog post) was completely missing (whereas before it was present but malfunctioned).

The reason it was missing was that the javascript to create that link, in static/js/postimage.js, failed on line 42, in the showLinkFor function. It failed on


I fixed it by inserting the link before the blog text instead of after the previous node’s contents:

    //  showLinkFor: function(elem) {
    //      elem.previousSibling.appendChild(document.createElement('br'));
    //      elem.previousSibling.appendChild(this.getLink(;
    //  },

    showLinkFor: function(elem) {
        var parent = elem.parentNode;
        var mybr = document.createElement('br');
        var myid = this.getLink(;
        parent.insertBefore (myid, elem);
        parent.insertBefore (mybr, elem);

I have a non-standard URL_PREFIX of bjb/ and postimage didn’t play nice with that. I hard-coded my URL_PREFIX into the postimage.js file:

    getLink: function(id) {
        var link = document.createElement('a');
        link.setAttribute('href', '/bjb/admin/postimage/attach/?for=' + id);

Not elegant, but it got me past that problem. The next problem was that the list of files was empty. I set the POSTIMAGE_ROOT to point to a directory on the server machine with pictures in it, and then the list was not empty.

But it wasn’t full of all the pictures in that hierarchy either … that was just a file permission problem (web server couldn’t read some of them).

So now I can use postimage. It doesn’t do quite what I expected. What it does is allow you to choose among pictures on your server for inclusion into your blog. It doesn’t let you preview them. All it does is give you a list of files, and then put a link to the most recently chosen file in your blog text. You can call it over and over and it will add more image links. It looks like it can take the render method into account — there is a choice of markdown, html, rst. But, that choice was in the source code … not sure if it will detect your render method automatically.

I expected to be able to upload pictures to the blog … oh well. I guess the way postimage works is safer. It doesn’t put files up there for you — it assumes you have put them up already — into a “POSTIMAGE_ROOT” directory — and just accesses what is already there.

Posted by: bjb



During (1):


During (2):


During (3):


During (4):


During (5):


Look Ma! No load-bearing walls! … now how do you put this thing back together again ???