Target then source

I’m surprised it took me this long to figure this out. But there’s a very big problem with a command like this:

rsync var/data/ target:/var/data/

The problem is that in order to type that command, you first have to type the first part of the command, which includes this command:

rsync var/data/ target:/

That first part of the command is in fact a valid command, and if you pressed ENTER accidentally before you had finished typing the whole command, then rsync would begin to replace your entire root file system with the contents of var. That’s the sort of thing that will ruin your day.

So from now on, when I write command-line tools, I will nominate the target *before* the source, and if both the target and source are not specified then I will return an error.

p.s. Yes, the reverse problem exists, that when you nominate the target first you can still fuck up with the source, but given that you are operating on the target from the source, if you get the source wrong, you can just fix your command and run it again and it will be fixed up.

Salt file.recurse source file not found (file encoding issue)

So I was running this:

    - clean: True
    - user: root
    - group: root
    - dir_mode: 755
    - file_mode: 644
    - source: salt://inst/mediawiki-1.29
    - require:
      - pkg: apache2

And getting an error like this:

          ID: /var/www/
    Function: file.recurse
      Result: False
     Comment: #### /var/www/ ####
              Source file 'salt://inst/mediawiki-1.29/vendor/james-heinrich/getid3/getid3/' not found

              #### /var/www/ ####
              Source file 'salt://inst/mediawiki-1.29/vendor/james-heinrich/getid3/getid3/' not found
     Started: 14:27:18.352264
    Duration: 134735.945 ms

The issue was that the source files mentioned weren’t in UTF-8 format. To convert the files I ran, e.g.:

$ iconv -f WINDOWS-1252 -t UTF-8//TRANSLIT < >

(Actually I couldn’t get the ‘iconv’ command to work so I edited manually in Vim)

Debugging JINJA in Salt Stack

So I was trying to figure out how to report the template source file within the template itself and I found myself wanting to know what was available in the JINJA globals for a Salt Stack JINJA template.

Turns out you use the show_full_context() function, like this:

Context is: {{ show_full_context() }}

You can parse the output to see what top-level items are available. In my case I found the ‘source’ setting for the JINJA template in use.

Hot tip: if you’re using Vim to inspect the show_full_context() output, try using ‘%’ or ‘]}’ to move between matching braces.

Bonus: while I was learning about reporting the JINJA context I discovered that you can call Salt functions from JINJA templates, like this:

# The following two function calls are equivalent.
{{ salt['']('whoami') }}
{{'whoami') }}

Installing Subversion on Mac OS X with WebDAV support (serf library)

cd ~/Development/svn-install
tar xzf scons-2.3.4.tar.gz
tar xzf apr-1.5.1.tar.gz 
tar xzf apr-util-1.5.4.tar.gz
tar xzf subversion-1.8.10.tar.gz
cd scons-2.3.4
sudo python install
cd ../apr-1.5.1
./configure --prefix=/usr/local
sudo make install
cd ../apr-util-1.5.4
./configure --with-apr=/usr/local --prefix=/usr/local
sudo make install
cd ../subversion-1.8.10
sh serf
cd serf
scons APR=/usr/local APU=/usr/local OPENSSL=/usr/local PREFIX=/usr/local
sudo scons PREFIX=/usr/local install
cd ..
./configure --with-openssl --with-serf=/usr/local --prefix=/usr/local
sudo make install

Nuff said!

Oh, wait… there’s a problem with misconfigured CA certificates…

cd ~/Development/svn-install

Run the MackPorts*.pkg…

xcode-select --install


sudo /opt/local/bin/port install curl-ca-bundle


sudo -s
cd /System/Library/OpenSSL/certs/
ln -s /opt/local/etc/openssl/cert.pem cert.pem
cd /usr/local/etc/openssl/certs
ln -s /opt/local/etc/openssl/cert.pem cert.pem


openssl s_client -connect -CApath /opt/local/etc/openssl/

Using MacPorts OpenSSL:

sudo port install openssl
cd ~/Development/svn-install/subversion-1.8.10/serf/
scons APR=/usr/local APU=/usr/local OPENSSL=/opt/local PREFIX=/usr/local
sudo scons PREFIX=/usr/local install


Changing parent’s directory from a subshell

I was trying to figure out how to have a child process change the current directory of a parent process. Turns out you can’t quite do that. One thing I guess you could do is export a global variable and then have the parent check that when the child returns, but I decided on another approach. What I do is write a file to ~/bin/errdir that contains a single line in the format:

  pushd "/path/to/directory"

I can then source this as a command file after my script has run to change directory into the directory where the last erroneous file was encountered with the command:

  $ . errdir

When I’m finished I can just type ‘popd’ to return myself to wherever I was before I changed into the error directory.