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Making Plone easy again (and Sauna Sprint topics)

Posted on June 8, 2011

This blog post is about making Plone CMS to accessible for more developers. This is a major topic on which we are working on in Sauna Sprint 2011 (see the previous blog post about Sauna Sprint and motivation to come to Finland).

Preface

Please do not take this post too seriously if I am ranting tongue-in-cheek. This thinking does not reflect the official opinion of Sauna Sprint team any way, it is just my personal rambling.

Background

Plone is having popularity issues. This can be deducted by:

  • PHP CMS are more popular (Google trends and so on)
  • Plone lacks love
  • By discussing with Python programmers outside Plone community: they see Plone as monster

Plone is a superior CMS product (feature wise, polish wise, tech wise, and so on). So how did this happen?

My theory, you are free to disagree, is that the community has been driving “wrong” ideologies

  • Plone’s “buyers” are not users, but developers
  • There has been no driving community factor to make Plone accessible for more developers. Plone community has been working to make Plone work for the existing community members, not new members. The consulting companies have been too busy to extract money from their existing big clients. It might even be that it’s the best interest of these companies to keep the barrier of entry high, as this way they protect the Plone business for themselves. Note that this strategy will fail in the point there is no longer Plone business.

The big boys are telling that customers are abandoning Plone, because there are no developers. I know a lot of Plone developers, looking for more Plone work.  I’ll translate this that there are not enough affordable Plone developers entering the market.

I am also not buying arguments like

  • “don’t compare apples to oranges (Django vs. Plone)”
  • “its history and evolved that way”
  • “big tool must be complex”

The result

Plone is easy to use, but hard to develop. If you need to use code generators and boiler-plate in Python code, you are doing it wrong.

Plone is a soup of different, non-mainstream, technologies. To be a Plonista you need master: Python (ok docs), Plone user mode (good docs), Zope component architecture (some docs), ZCML (no useful docs), GenericSetup (no docs), TAL (some docs), Archetypes (basically no docs), buildout (aaaaaarghs) … You have too much to learn from material which does not exist. Today the material effectively does not exist if it’s not your first Google hit – I am against book.

New developers are not getting in. It is easier to duplicate basic Plone functionality in a hacky in-house Django CMS than customize Plone for your use case. Plone does not give any more added value to the new developers. There is no business motivation to adapt Plone as a technology platform in new ventures.

The quest

Let’s fix it, as I see the developer acceptance the most crucial challenge Plone community is facing if the community wants to survive.

What we can do here is

  • Make Plone easier for developers
  • Make more, better, learning material available
  • Eliminate and protect against factors in Plone which hinder the goals of two above bullets (do not include new technologies or modules to core if they make developers sad)

To accomplish this we can

  1. Promote “easy” technologies inside and outside Plone community (Dexterity over Archetypes, Grok over ZCML)
  2. Making a standard workflow available for them (Django style tutorial that do 1, 2, 3 and you are a certified Plone developer)
  3. Kill technologies which make the stack unnecessary complex and are not necessarily needed in newbie use cases (buildout, I am looking at you)
  4. Replace old, badly documented and difficult solutions with easier ones (could we actually replace TAL with something more popular?)

Operational plan

Here are some concrete tasks what we could tackle in Sauna Sprint.

Make it easy department

  • Plone auto-restart team: provide working and fast auto-restart á la Django or Tornado (hint: plone.reload doesn’t cut it – you need real restarts process-wise)
  • Default custom product team: ship Plone with a file-system based custom product skeleton, so that when you need to include your first custom Python module you don’t need to learn about buildout and paster first . You actually can copy-paste in Python code and it just works.
  • Through-the-web is happy again team: Make it possible to code and execute Python through-the-web so that it actually works.: a working replacement for RestrictedPython

Fix user-wise broken things department

  • Buildout team: make buildout more user friendly: spit out error messages which are actually useful, have newbie buildout tutorial from the developer perspective. Nothing bad should happen when buildout is run. Make buildout to confirm version updates, etc.
  • Anti-buildout team: how to install eggs without buildout. Why did we need the buildout in the first place?

This is how you do it department

  • Tutorial team: Make “gapless” hand-holding tutorial for creating your first view, form and content-type. Make it so that you do not need to look outside the tutorial or learn anything unnecessary (don’t make me think)
  • Picture team: draw big pictures of Plone architecture, how different parts are connected, so that new developers get hang on things easily
  • Document generator team: Integrate collective.developermanual with Sphinx tool that generate the reference  documentation from the source code: views, viewlets, templates, CSS classes, portlets, etc.

Hasta la vista babe department

  • Kill it with fire team: Hunt down all bad learning material and make it redirect to new learning material (no ExternalMethods, no Install.py, no plone_skins, etc.)
  • Nuke it from orbit team: I am not sure what this team could do, but I like the feeling of the name

We hope that novice  developers attend the sprint. This way we can use you as guinea pigs and document the pain points on a road to become Plone developer. Don’t worry – we’ll inject you with proper medicine to numb the pain and forget bad memories.

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Reducing MySQL memory usage on Ubuntu / Debian Linux

Posted on March 31, 2011

If you are running your services on a low end virtual hosting every byte of memory you can save is important. The memory is often the limiting factor of how many applications you can run on VPS: CPUs are shared, memory not, on the same physical host.

  • Low-end VPS come with 512 MB memory or less
  • Front front-end server Apache / Nginx / Varnish takes > 100 MB +  min. 20 MB for each child process
  • Memecached takes its toll
  • MySQL takes 200 – 400 MB
  • Each Python / PHP process takes at least 15 MB and you need parallel processes for paraller HTTP requests (FCGI, pre-fork, others… )
  • Operating system processes need some memory (SSH, cron, sendmail)

As you can see it gets very crowded in 512 MB.

It’s especially troublesome since the memory is allocated lazily and the memory usage builds up slowly. In some point caches are no longer caches, but swapped to a disk – virtual memory usage grows beyond available RAM. To keep the server response, everything time critical should fit to RAM once and if the processes themselves don’t know how to release memory in this situation you need to tune a memory cap for them.

MySQL memory consumption

MySQL can be a greedy bastard what comes to memory consumption. Here on this server MySQL seems to take 417M virtual memory which seems to be little excessive for just running two WordPress instances and one Django / Python application:

1310 mysql     20   0  417M 21100  2776 S  0.0  1.2  0:00.00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/v

After some tuning I was able to bring it down a bit

3354 mysql     20   0  276m  19m 2848 S    0  1.2   3:41.19 mysqld

A reduction of 130 MB, or 1/4 of the server total memory. Not bad.

Use mtop to monitor running MySQL, its querieries, etc. so you know what’s going on. As you can see this MySQL has very good cache rate meaning that basically it is keeping everything in memory. If the content of the sites is less than 10 MBytes total, 400 MB contains plenty of space to cache the content:

load average: 0.05, 0.08, 0.16 mysqld 5.0.51a-3ubuntu5.8-log up 1 day(s), 19:47 hrs                                                             
2 threads: 1 running, 6 cached. Queries/slow: 187.1K/0 Cache Hit: 99.39%

What eats memory

I am not an expert on MySQL, so I hope someone with more insight could post comments regarding how to tune MySQL for low memory situations and how it is expected to behave.

Some ideas I run through my head

  • MySQL default cache settings are not too tight on Ubuntu/Debian, making it suitable for moderate loads, not low loads. If you don’t have much content, everything is just kept in memory (even if not needed)
  • MySQL uses round robin for connections and if there is 100 max connections it will allocate a thread stack for each connection (someone please confirm this – I found contracting infos).

Configuring MySQL

Here are listed some methods how to reduce the memory usage. This is what I done on this little box

MySQL is mostly configured in /etc/mysql/my.cnf on Ubuntu / Debian.

The final adjustments

key_buffer              = 8M
max_connections         = 30
query_cache_size        = 8M
query_cache_limit       = 512K
thread_stack            = 128K

More info

Send in more tips please! Is 32-bit better than 64-bit for low end VPS, how much this affects MySQL?

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Copy/move phpBB3 forum from a server to another computer (Ubuntu/Linux)

Posted on March 30, 2011

Here are short instructions what you need to do in order to move / copy phpBB3 forum.

Prerequisites

What you need in order to benefit from these instructions

  • Basic UNIX command-line knowledge
  • SSH access to the server
  • MySQL access to the database
  • LAMP stack ready on the new server

These instructions have been tested on Ubuntu/Debian/Linux but they should work in other environments too.

Write down database access information

Get password from config.php file on the old server:

cd /var/www/phpBB3
cat config.php

Write down database name, username and password.

Copy files

Use rsync to remotely copy forum files to a new computer. On new computer, in /var/www folder

rsync -av --compress-level=9 user@oldserver.com:/var/www/phpBB3 .

Dump and copy database

Execute the following command on the new server. It takes SSH connection to the old server and dumps phpBB3 database to the new server over the SSH connection.

ssh user@oldserver.com -C -o CompressionLevel=9 mysqldump -u databaseuser --password=databasepassword --skip-lock-tables --add-drop-table databasename > phpbb3.sql

Create a new database

Use the old access information from config.php to create a database with identical access information on the new server. You need a MySQL root access to create new databases.

mysql -uroot -p

Create database and grant access to phpBB3 user for it.

mysql> create database databasename;
mysql> GRANT ALL ON databasename.* TO 'databaseuser'@'localhost' identified by 'databasepassword';

Load the database on the new server from the dump file:

mysql> connect databasename;
mysql> source phpbb3.sql

Configure Apache virtualhost for the new server

The last step is to set-up Apache virtual host on the new server, so you can access the phpBB3 using a domain name. Note that this doesn’t need to be a real domain name, but you can spoof the domain name using /etc/hosts file on your local workstation.

Add file /etc/apache2/sites-enabled/phpbb3.conf (or pick a filename based on forum name if you host multiple forums)

<VirtualHost *>
 ServerName yourdomainname.com

 DocumentRoot /var/www/phpBB3
 <Directory />
   Options FollowSymLinks
   AllowOverride None
 </Directory>

</VirtualHost>

Note that <virtualhost *> may change depending on how Apache has been set up to listen IP addresses and ports. Also if you are using a shared hosting package or VPS you might need to use the server control panel (cPanel) to do this step.

Then check if your new config file is ok and restart Apache:

apache2ctl configtest
apache2ctl graceful

Hosts spoofing trick

If you are not having a DNS server of your own which you can use for the copy you can always use /etc/hosts file trick to spoof domain names. This way you can make Apache to serve the forum from the server even if the forum is not connected to any real domain name yet.

 

 

 

 

 

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When Python sucks: how you call a function and document it

Posted on March 29, 2011

Though maybe written tongue-in-cheek, this Python Makes Me Nervous article has some excellent points.

  • Because of duck-typing, you should rigorously document how methods should be called (try epytext and its fields).
  • Most open source Python projects do the exact opposite
  • Even Python standard library is poorly documented and sets a very bad example (missing manual ???)
  • Thus, programming in Python becomes nightmare of grepping through source code (the implementation) or stepping into it in pdb just to figure out how APIs should work (Plone/Zope, anyone?)

Should Python community stop in some point to focus on delivering better documentation instead of focusing on new features and goodies (like the syntax moratorium which was recently lifted)?

From my personal experience

  • The best, and the only, person to document the code adequately is the person how originally wrote it
  • Because the author already knows how to use the code he doesn’t need to care about the fact how to enable the code for other users.  Many libraries and projects are driven by “scratching your own need” mentality, not by “let’s make this a happy community” mentality. The exception is something like Facebook or Google whose sole purpose is to attract new users their platform bringing in new €€€.
  • If you are developing a framework or community project make the documentation a requirement for deliverable and stick with it. If you let one person to skip one hour of writing documentation you are making 10 persons spending one hour figuring out how to use the damn thing.
  • Doctests are not documentation. They are tests. They are extremely unreadable way to say “how I should use this thing”, because doctests are often executed in the context of test stubs which do not reflect connections to the other parts of the framework or real contexts.
  • “Buy a book – it tells you everything” business model is not feasible in long run. Books get old. Books are not searchable. People don’t buy books.

The good documentation is a way to differentiate, and win, in the situation where there are competing frameworks. I believe the success of Django was mostly driven by its good documentation.

This points could be applied to other duck-typed, open source driven programming languages (PHP anyone?). With good documentation we can reduce the need of Valium recipes for everyone of us.

 

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