The installer for Postgresql on Lion is supposedly “unsupported”, which means that they haven’t got it working yet. Looking at it quickly is seems to be the way that the postgres user is being created using dscl.
To get it to work, manually create a postgres user from under System Preferences:
Then run the installer as per normal. I used the Postgres 9 installer.
I also upgraded python to 2.7.2 and installed psycopg2 pointing to pg_config under /Library/PostgreSQL/9.0/bin/pg_config.
Looking back over the last posts I realize that I haven’t been talking much about the software and and code that I have been using every day and some of it is really quite interesting.
Python. I use python a lot, it’s my preferred go to language to solve a lot of problems. It has great libraries, an awesome community and the language itself is compact and non verbose. We are using Django heavily in our solutions and its really enjoyable to work with, and I never feel that coding is a chore. Coupled with the fact that we can target Java servers with Jython, .Net with IronPython and have an amazing solution in PyPy for python running on Python I can see the love affair continue.
Eventlet, Gevent and Meinheld. Python networking libraries (actually Meinheld is a WSGI server) that work in an event’d manner, all are really easy to work with, all are really fast. With these libraries its really easy to build highly performant services that scale well on standard architecture. For instance to write a websocket / comet server, I wouldn’t hesitate to use Eventlet or Gevent. Tornado looks like another nice Python alternative but I have never been happy with its lib curl dependancy.
Celery. Asynchronous task queue/job queue written in Python for python that can use message servers such as RabbitMQ. Really easy to build strong reliable services spanning multiple machines.
Hudson. Continuous integration server that is just seamless, I use it for building packages (python and Debian), running test frameworks and automatically building documentation which gets uploaded to Dropbox. Can’t recommend it strongly enough.
Linux KVM and Proxmox. Virtualisation has obviously been a part of most deployment and development cycles for some time now , but innovation is still being made. Having used VMWare, VMWare ESX, VirtualBox, Microsoft’s Hyper-V and others I have found what I believe to be the sweet point in Linux KVM – simple extensions to the Linux kernel which allows for running virtual machines on top of a normal Linux platform. I have moved my personal servers, and our work servers to KVM as much as possible and an easy integrated way of doing this is to run ProxMox.
Memcached. Memory caching server that I use with my goto web services stack – Nginx – Supervisord – Meinheld – Django – Memcached – Postgres. Simply just works.
Selenium. Automated browser testing, this is a product that no matter how much I use it, I feel that I can use it more than I do. Have been using the RC version to do browser testing against firefox and IE on Windows.
PostgreSQL. NoSQL is all very well and good, but for most serious projects I tend to turn to Postgres for its fully featured SQL compliance, its rock solid hosting of data and its well proven ability to scale.
RabbitMQ. RabbitMQ is a message queue that I tend to deploy with Python Celery to help perform offline processing of tasks.
Supervisord. Currently used for daemonising a setup.
Git. Distributed version control. I have tried most of the others, and before that been a long time user of SVN but Git installs on everything, has awesome support in GitHub, and I am really enjoying the extending merging and branching.
Redmine. For task tracking and bug fixing, this is the best tool that I have used. Migrated everything from trac to it with no problems, and have also migrated from Redmine backed by MySQL to PostgreSQL with no problems.
Glassfish. My goto Java Application Server. I hope to have more exposure to JBoss in the coming few months, but Glassfish has been good so far.
nginx. Can’t say enough good things about Nginx. Its fast, easy to configure, flexible, lightweight and hosts all our software at Cantemo with little problem.
HAProxy. When I need to load balance nginx or other services (including straight TCP/IP which nginx can’t load balance) I turn to HAProxy.
backbone.js. Almost all the Javascript that I am now creating is built upon underscore.js and backbone.js. There are many tutorials but this deserves another space all of its own.
In fact there are many things that I have left out that I am using everyday but these are some of the technologies, software and libraries that have been making my life easier and the systems that I have built more interesting for the past 18 months or so. I really ought to do a write up on each of them.
As a followup to my last post, and also because Portal needs to support audio as well as video, I have implemented the same kind of detection and serving of files for audio. We transcode audio files into MP3 slightly low bitrate (depends on the clients wishes, but its not a great codec for streaming lots of audio over a network), and we can also do an OGG version. Here is the current support list:
| Browser | MP3 | Ogg | WAV | Notes |
|---|---|---|---|---|
| Safari | 5.0+ | - | 5.0+ | |
| firefox | Use flash | 3.6+ | 3.6+ | |
| Chrome | 6.0+ | 6.0+ | - | |
| Opera | Use flash | 10.5+ | 10.5+ | |
| IE | 9.0+ | - | 9.0+* | IE8 and before only support using flash fallback |
Of course this doesn’t actually talk about the problems, such as MP3 always having silence at the beginning and the end of the file, and that Chrome’s support has been surprisingly bad over time. Its a pity that there are so many inconstancies and the specification doesn’t really seem to have been thought out (where is the buffering support?)
There is an even more in-depth view here:
http://www.phoboslab.org/log/2011/03/the-state-of-html5-audio
At Cantemo for our Portal product we are working a lot with HTML5 video, its starting to get really nicely supported by all the major vendors and we have some nice technology to support frame accurate playback, frameforward and frameback on a lot of browsers (Chrome, firefox, Safari etc).
This puts us in a much better position than we have had in the past with h.264 playing back through the Flash player (though this is a fallback mechanism still).
Trouble is we have to implement support for different codecs, for the different browsers. Our software supports this out of the box, but it means that we have to do some interesting detection of browsers, formats that we have, and offer a plugin solution. Today we can transcode to OGG, WebM and h.264 with no problems, and then match this to browsers:
Here is a table of what browsers support which video formats:
| Browser | Ogg | h.264 (mp4 extension) | WebM | Notes |
|---|---|---|---|---|
| Safari | * | 3.0+ | * | *Safari will play what Quicktime supports |
| firefox | 3.5+ | Use flash. | 4.0+ | |
| Chrome | 5.0+ | 5.0+ | 6.0+ | h.264 will drop soon, still works as of 12 |
| Opera | 10.5+ | Use flash | 10.6+ | |
| IE | - | 9.0+ | 9.0+* | *Only works with optional plugin |
This table assumes that h.264 is in an MP4 wrapper, with an AAC codec for sound. OGG is encoded using Theora, with a Vorbis audio codec.