Running Google MusicManager for two profiles

I’ve previously made mention of my addiction to Google Play Music… but I was called out recently, and asked about the script I used at the time. I’m sorry to say that I have had some issues with it, and instead, have resorted to using X forwarding. Here’s how I do it.

I create a user account for that other person (note, GMM will only let you upload to 3 accounts using this method. For any more, you’ll need a virtual machine!).

I then create an SSH public/private key with no passphrase.

ssh-keygen -b 2048 -N “” -C “$(whoami)@localhost” -f ~/.ssh/gmm.id_rsa

I write the public key into that new user’s .ssh/authorized_keys, by running:

ssh-copy-id -i ~/.ssh/gmm.id_rsa bloggsf@localhost

I will be prompted for the password of that account.

Finally, I create this script:

This is then added to the startup tasks of my headless-but-running-a-desktop machine.

Today I learned… Cloud-init doesn’t like you repeating the same things

Because of templates I was building in my post “Today I learned… Ansible Include Templates”, I thought you could repeat the same sections over again. Here’s a snippet of something like what I’d built (after combining lots of templates together):

Note this is a non-working code sample!

- iperf
- git

- content: {% include 'files/public_key.j2' %}
  path: /root/.ssh/authorized_keys
  owner: root:root
  permission: '0600'
- content: {% include 'files/private_key.j2' %}
  path: /root/.ssh/id_rsa
  owner: root:root
  permission: '0600'

- byobu

- content: |
    git clone {{ test_scripts }} /root/iperf_scripts
    bash /root/iperf_scripts/
  path: /root/run_test
  owner: root:root
  permission: '0700'

- /root/run_test

I’d get *bits* of it to run – basically, the last file, the last package and the last runcmd… but not all of it.

Turns out, cloud-init doesn’t like having to rebuild all the fragments together. Instead, you need to put them all together, so the write_files items, and the packages items all live in the same area.

Which, when you think about what it’s doing, which is that the parent lines are defining a variable called… well, whatever that line is, and if you replace it, it’s only going to keep the last one, then it all makes sense really!

Today I learned… that you can look at the “cloud-init” files on your target server…

Today I have been debugging why my Cloud-init scripts weren’t triggering on my Openstack environment.

I realised that something was wrong when I tried to use the noVNC console[1] with a password I’d set… no luck. So, next I ran a command to review the console logs[2], and saw a message (now, sadly, long gone – so I can’t even include it here!) suggesting there was an issue parsing my YAML file. Uh oh!

I’m using Ansible’s os_server module, and using templates to complete the userdata field, which in turn gets populated as cloud-init scripts…. and so clearly I had two ways to debug this – prefix my ansible playbook with a few debug commands, but then that can get messy… OR SSH into the box, and look through the logs. I knew I could SSH in, so the cloud-init had partially fired, but it just wasn’t parsing what I’d submitted. I had a quick look around, and found a post which mentioned debugging cloud-init. This mentioned that there’s a path (/var/lib/cloud/instances/$UUID/) you can mess around in, to remove some files to “fool” cloud-init into thinking it’s not been run… but, I reasoned, why not just see what’s there.

And in there, was the motherlode – user-data.txt…. bingo.

In the jinja2 template I was using to populate the userdata, I’d referenced another file, again using a template. It looks like that template needs an extra line at the end, otherwise, it all runs together.


This does concern me a little, as I had previously been using this stanza to “simply” change the default user password to something a little less complicated:

ssh_pwauth: True
  list: |
    ubuntu:{{ default_password }}
  expire: False

But now that I look at the documentation, I realise you can also specify that as a pre-hashed value (in which case, you would suffix that default_password item above with |password_hash('sha512')) which makes it all better again!

[1] If you run openstack --os-cloud cloud_a console url show servername gives you a URL to visit that has an HTML5 based VNC-ish client. Note the “cloud_a” and “servername” should be replaced by your clouds.yml reference and the server name or server ID you want to connect to.
[2] Like before, openstack --os-cloud cloud_a console log show servername gives you the output of the boot sequence (e.g. dmesg plus the normal startup commands, and finally, cloud-init). It can be useful. Equally, it’s logs… which means there’s a lot to wade through!

Using as a bridge to Freenode

Over the last few months, I’ve been using (the client for as my primary IRC client, and access to other end-to-end-encrypted chats.

A few weeks ago I decided I wanted to use my “normal” IRC nickname on Freenode, so looked into how to do it. It’s surprisingly easy, but there are a few gotchas.

Making Matrix know your password

First of all you need to message the IRC bridge bot and tell it your nickserv password: !storepass MyComplexPassword

Next, you need to chat with NickServ directly and authenticate with it: identify MyNormalNick MyComplexPassword

Lastly, you go back to your chat with the bridge bot, and tell it your nickname: !nick MyNormalNick

If, in the process of doing this, you find you can’t log in as yourself, message NickServ and tell it to release your account from being protected: release MyNormalNick MyComplexPassword

Setting topics

While the bridge bot will let you set a topic (!cmd TOPIC #channel Something) this didn’t really work for me, so instead, I use ChanServ to do it for me: topic #channel My New Topic

Just remember that you must have ops granted to you for that channel through ChanServ to be able to make such changes.

You can also set modes for people, or the channel, ban people, voice or op them through ChanServ, just send the command help in the chat to ChanServ for more guidance!

And, if you’re stuck, feel free to come ask for help! I’m (predictably) JonTheNiceGuy!

Dependency Hell – and it’s not my package manager to blame

I’m writing a web service for conferences. I’ve been writing it, on and off for 3 years, and I think it would be fair to say the coding reflects my learning over those three years. The script is written in PHP. It has a MySQL backend. It has undergone a lot of changes.

In the beginning, was a concept. The concept was to have a digital timetable. One where you could register your interest in a talk, and the busiest talks got the biggest rooms. It should use any tech the user had to use the system including SMS. It would not expect you to have a user name and password combo (heaven forbid!), but would use OpenID.

The concept was implemented and demo’d at an event 2 years ago, and a friend [1] asked where the API was. “API?” I replied, feeling somewhat foolish, “It doesn’t have an API“.

[1] Lorna Jane Bowman (neé Mitchell aka @lornajane)

I realised the foolishness of my coding when discussing this issue [2]. “It’s dead simple, just create another view which returns just JSON” said someone. “View? I don’t know what you mean“… “Model, View, Controller? MVC – it’s a pretty common pattern”. “Oh no” I replied, “my project has inline PHP. It just seemed simpler that way.” “Well, how about you add a toString() function to your classes, and use that to render the output?” “Classes. Another thing my project doesn’t have. Sorry. Can’t do that either.

[2] With Lorna again, and adding Katherine Reeve (aka @BinaryKitten)

Did you ever get that slightly sinking feeling that maybe you’re making a fool of yourself?

“Well, there are lots of benefits to Classes in PHP, not least of which that you can use PHP CodeSniffer to enforce your coding standards” I start to laugh a little at this point “and you can use PHP Documenter to create all your developer documentation” which shut me right back up again “you can use PDO to create your objects from your database results” wow… mind blown – I’ve jumped on this little trick of a pony… “and of course, you can’t really do unit testing without classes”. Uh oh. “What’s unit testing?” “It’s a set of automated tests you can run against your code every time you commit to your version control software” whew! I’m using that at least! “to make sure that the code you’re committing hasn’t broken anything”.

Fast forward to this week, and I asked on Facebook whether anyone could teach me how to do Unit Testing. See, I’ve managed to cobble together my own MVC – I have classes called “Object_” which are the Models, the controller is my routing script – otherwise known as index.php, and then the Views are templates in Smarty, or just a json_encode((array) $object) [3] for my API. I have my own set of tests – not unit tests, it’s a script called “” which runs PHP against the file (to make sure that the pages don’t have brackets missing or similar), then runs PHP Code Sniffer against it, and finally, if all the files are OK, it then runs PHPDoc against the whole mass of it.

[3] As the Apple iPhone/iPad adverts say – some sequences shortened

So, one of the books suggested to me, again by the lovely Lorna Jane, was The Grumpy Programmer’s Guide To Building Testable PHP Applications which mentioned that it’s much easier to do unit testing if you set up dependency injection. Note, I’m still not yet doing Unit testing here.

Woah. What the hell is Dependency Injection? Well, fortunately, there were code examples in that book. Oh boy, were there code examples. So let’s look through this idea. Instead of writing

$stuff = new MyStuff();

class MyStuff()
    function construct()
        $this->db = mysql_connect('localhost', 'username', 'password');
        mysql_use_database('production', $this->db);

You could instead write this:

$db = mysql_connect('localhost', 'username', 'password');
mysql_use_database('production', $this->db);
$stuff = new MyStuff($db);

class MyStuff()
    function construct($db = null)
        $this->db = $db;

So, this now means that in your testing framework, you could pass it a non-production database, or a testing database, or, well, anything that relies on something outside your script.

I did a bit of digging around to find some other examples of dependency injection code that might be a bit easier to use, which is to say, something so I don’t need to amend all my constructor functions.

I found this slideshare from a talk at PHP Barcelona about dependency injection which says you can do dependency injection like this:

$thing = new MyClass($dependency);


$thing = new MyClass();


$thing = new MyClass();
 $thing->dependency = $dependency;

but somewhat weirdly, it also says that you can create a container class which holds your dependencies, and refer to that later – and that this isn’t a singleton. Sadly, I didn’t understand all that code fully (and have gone on to file a bug for the PHP documentation for the functions I didn’t understand to help people who follow behind with it!), but (and I’ve copied this verbatim from the slideshare) essentially, it looks like this:

class Container { protected $values = array(); function __set($id,$value) {  $this->values[$id] = $value;  }  function __get($id) {  if (!isset($this->values[$id])) {  throw new InvalidArgumentException(sprintf('Value "%s" is not defined.', $id));  }  if (is_callable($this->values[$id])) {  return $this->values[$id]($this);  } else { return $this->values[$id];  }  }  function asShared ($callable) {  return function($c) use ($callable) {  static $object; if (is_null($object)) {  $object=$callable($c);  }  return $object; }; } } $container = new Container(); $container->session_name='SESSION_ID'; $container->storage_class='SessionStorage'; $container->user = $container->asShared( function($c) {  return new User($c->storage);  } ); $container->storage = $container->asShared(  function($c) {  return new $c->storage_class($c->session_name); } );

Now, I have to be honest, this confuses the hell out of me. How on earth do I use this in my code? I’ve been doing this in my code thus far:

class Object_User{
  protected $intUserID    = null; // Obtained by the getCurrentUser() function
  protected $strUsername  = null;
  protected $hashPassword = null; // More of these, depending on the SQL

  function getCurrentUser() { // Called as $user = Base_User::getCurrentUser();
 $objCache  = Base_Cache::getHandler(); // A singleton to "cache" any data we've pulled to save getting it repeatedly
    if (
          && $objCache->arrCache['Object_User']['current'] != false
        ) {
      return $objCache->arrCache['Object_User']['current'];
    $arrRequest  = Base_Request::getRequest(); // Returns array of parsed request data
    $objDatabase = Base_Database::getConnection(); // Returns a PDO object

    $sql = "SELECT * FROM users WHERE strUsername = ? and hashPassword = ?";
    $query = $db->prepare($sql);
    $query->execute(array($request['username'], $request['password'])); $result = $query->fetchObject('Object_User');
    if ($result != false) {
      $objCache->arrCache['Object_User']['id'][$result->getVal('intUserID')] = $result;
      $objCache->arrCache['Object_User']['current'] = $result;
    return $result;

  function getVal($key) { // Return protected variables
    if (!isset($this->$key)) {
      return false;
    return $this->$key;

I know that singleton methods are considered “Bad” because they’re (apparently) difficult to unit test, but I would have thought that it would have been pretty straightforward to create a singleton class which holds all the dependencies (see following)

class Base_Dependencies
  protected static $handler = null; protected $arrDependencies = array();   protected function GetHandler() {
    if (self::$handler == null) { self::$handler = new self(); }
    return self::$handler;

  function set($key, $dependency) {
    $handler = self::GetHandler();
    $handler->arrDependencies[$key] = $dependency;

  function get($key) {
    $handler = self::GetHandler();
    if (isset($handler->arrDependencies[$key])) {
      return $handler->arrDependencies[$key];
    } else {
      return false;

  function unset($key) { // Only used for Unit Testing, I would imagine
    $handler = self::GetHandler();
    if (isset($handler->arrDependencies[$key])) {

Doing it this way means I can, from, for example, my database class, which is currently a singleton, say instead:

function GetConnection() {
  $db = Base_Dependencies::get("Database");
  if ($db != false) {
    return $db;
  $config = Base_Config::getAllConfig();
  $db = new PDO($config['DSN'], $config['DB_User'], $config['DB_Pass']);
  Base_Dependencies::set("Database", $db);
  return $db;

Is this wrong? Is this just not best practice? Given the above, how can I fix my dependencies in such a way that the poor schmuck who wants to commit a patch can figure out what they’re sending? Or do I just need to fix how my head works with this stuff? If it’s the latter, can someone provide some samples of what I’m doing wrong?

Thanks for reading this mammoth post!