Deployment

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Revision as of 20:23, 14 December 2012 by Jimbo (talk | contribs)
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This page could use a lot of work. For now, a few smaller deployment tips!

See also: http://docs.mediagoblin.org/deploying.html (some of which may belong here)

FCGI script

This works great with the apache config example below :) 

#!/path/to/mediagoblin/bin/python

# Written in 2011 by Christopher Allan Webber
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty.
# 
# You should have received a copy of the CC0 Public Domain Dedication along
# with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.

from paste.deploy import loadapp
from flup.server.fcgi import WSGIServer

CONFIG_PATH = '/path/to/mediagoblin/paste.ini'

## Uncomment this to run celery in "always eager" mode... ie, you don't have
## to run a separate process, but submissions wait till processing finishes
# import os
# os.environ['CELERY_ALWAYS_EAGER'] = 'true'

def launch_fcgi():
    ccengine_wsgi_app = loadapp('config:' + CONFIG_PATH)
    WSGIServer(ccengine_wsgi_app).run()


if __name__ == '__main__':
    launch_fcgi()

Apache 2 Config with fcgid

Note that the libapache2-mod-fcgi in Debian is in the nonfree section, and MediaGoblin users will want to avoid that. Instead, libapache2-mod-fcgid can be used, but requires a slightly different configuration. 

 <VirtualHost *:80>
   Options +ExecCGI
 
   # Accept up to 16MB requests
   FcgidMaxRequestLen 16777216
 
   ServerName mediagoblin.example.org
 
   Alias /mgoblin_static/ /path/to/mediagoblin/mediagoblin/static/
   Alias /mgoblin_media/ /path/to/mediagoblin/user_dev/media/public/
 
   ScriptAlias / /path/to/mediagoblin/mg.fcgi/
 </VirtualHost>

Apache Config Example

This configuration example uses mod_fastcgi.

To install and enable mod_fastcgi on a Debian/Ubuntu based system: 

# apt-get install libapache2-mod-suexec libapache2-mod-fastcgi
# a2enmod suexec
# a2enmod fastcgi

Sample configuration: 

<VirtualHost *:80>
ServerName mediagoblin.yourdomain.tld
ServerAdmin webmaster@yourdoimain.tld
DocumentRoot /var/www/
# Custom log files
CustomLog /var/log/apache2/mediagobling_access.log combined
ErrorLog /var/log/apache2/mediagoblin_error.log

# Serve static and media files via alias
Alias /mgoblin_static/ /path/to/mediagoblin/mediagoblin/static/
Alias /mgoblin_media/ /path/to/mediagoblin/user_dev/media/public/

# Rewrite all URLs to fcgi, except for static and media urls
RewriteEngine On
RewriteRule ^(mgoblin_static|mgoblin_media)($|/) - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^/(.*)$ /mg.fcgi/$1 [QSA,L]

# Allow access to static and media directories
<Directory /path/to/mediagoblin/mediagoblin/static>
  Order allow,deny
  Allow from all
</Directory>
<Directory /path/to/mediagoblin/mediagoblin/user_dev/media/public>
  Order allow,deny
  Allow from all
</Directory>

# Connect to fcgi server
FastCGIExternalServer /var/www/mg.fcgi -host 127.0.0.1:26543
</VirtualHost>

Then, you need to make sure mediagoblin is running in fcgi mode: 

cd /path/to/mediagoblin
./lazyserver.sh --server-name=fcgi fcgi_host=127.0.0.1 fcgi_port=26543

Note: there may be several ways to improve this configuration

Juju

There is a juju charm available for deploying mediagoblin into EC2 or on your local box. juju is available in Ubuntu 11.10 and later, though it is recommended that you pull it from the juju PPA, which includes backported packages going back to Ubuntu 11.10. To use the juju charm, install juju and configure either the local provider or one of the cloud API providers, currently the EC2 provider is the best supported and works not only with Amazon Web Services but also OpenStack clouds. There is also a newer native OpenStack API provider which is known to support HP Cloud. 

# if you have not bootstrapped
juju bootstrap
mkdir ~/charms
bzr init-repo ~/charms/precise
bzr branch lp:~clint-fewbar/charms/precise/mediagoblin/trunk ~/charms/precise/mediagoblin
juju deploy --repository ~/charms local:mediagoblin
juju expose mediagoblin

Currently the charm is volatile, deploying from trunk, and deploys a single-server version of MediaGoblin only. It will eventually relate to the existing juju charms for other supported data stores to allow one to scale out their MediaGoblin instance.

Init scripts

Debian init scripts

Joar has some scripts for running celery and mediagoblin separately that are designed for Debian.

https://github.com/joar/mediagoblin-init-scripts

Arch Linux init scripts

Jeremy Pope has written a nice blogpost on how to add init scripts to deploy MediaGoblin with both the python paste http server and the celery deployments separated.

If you want a simpler setup and don't want to deploy celery separately, consider either turning CELERY_ALWAYS_EAGER to true in the paste init script described above, or check out Chimo's guide.


Generic, simple init script

This is a super stupidly simple init script that was used for mediagoblin.com... note that this has Celery running in always eager mode.

You will need to adjust the paths appropriately. This could probably be better written! 

 #! /bin/sh
 
 ## Stupidly simple mediagoblin init script.
 # 
 # Written in 2012 by Christopher Allan Webber
 #
 # To the extent possible under law, the author(s) have dedicated all
 # copyright and related and neighboring rights to this software to the
 # public domain worldwide. This software is distributed without any
 # warranty.
 # 
 # You should have received a copy of the CC0 Public Domain Dedication along
 # with this software. If not, see
 # <http://creativecommons.org/publicdomain/zero/1.0/>.
 
 PASTER=/srv/mediagoblin.com/bin/paster
 PASTE_CONFIG=/srv/mediagoblin.com/paste.ini
 OPTIONS="--pid-file=/tmp/mediagoblin.pid \
  --log-file=/srv/mediagoblin.com/paster.log \
  --server-name=fcgi fcgi_host=127.0.0.1 fcgi_port=26543"
 
 CELERY_ALWAYS_EAGER=true su -pc "$PASTER serve $PASTE_CONFIG $1 $OPTIONS" webadmin

Running on Dreamhost.com

Set up your python virtualenv

dreamhost.com servers come with python 2.4 and 2.5 installed which is too old for mediagoblin. This means you need to compile and install a newer python (don't worry this is really not difficult on dreamhost servers). In order to be able to install python packages for a local user without touching system files, we need to setup a python virtualenv. Fortunately, this is not too tricky either. If your server has python 2.6 or 2.7 installed already, you can skip the python installation stuff and you'll only need to install virtualenv.

Install a local python

  1. Download the latest python: http://python.org/ftp/python/XXX/Python-XXX.tar.bz2
  2. Unpack with 
    tar xvjf Python-XXX.tar.bz2
  3. cd into the directory and compile and install python locally:
./configure --prefix=$HOME/local
make
make install
This will install python (I used 2.7.3) into /home/<USERNAME>/local/bin/python. You might get warnings about some modules not being able to compile. :It was tcl/tk and bzip2 mainly, but things still worked out overall.
You should now be able to invoke ~/local/bin/python and fall into a shell of your new python (exit with ctrl-d). Congrats, you have now a new python 2.7 that you can use. However, you will need to be able to install additional packages as a user and this is what virtualenv allows.

Setup virtualenv to install local python packages

  1. Download the latest virtualenv: http://pypi.python.org/packages/source/v/virtualenv/XXX
  2. Install the virtualenv: 
    ~/local/bin/python ~/virtualenv-1.8/virtualenv.py  $HOME/local/virtenv
You will now have: ~/local/virtenv/bin/python
  1. In ~/.bash_profile add: 
    PATH=~/local/virtenv/bin:~/local/bin:${PATH}
so that your local python will be preferred.
Log out, log in again and test python" to see which version will be invoked. It should be the new python. Check "which easy_install" to see if the one in local/virtenv would be executed.
You have now 1) a local python installation that you can use, and 2) easy_install will also work with your local user installation. From now on you can e.g. locally install the nose testing framework (easy_install nose) and use it (python -c "import nose").

Install mediagoblin as a site package

  1. Check out mediagoblin from git to e.g. ~/mediagoblin
  2. Install MediaGoblin and all dependencies for MediaGoblin with easy_install.
  • In the mediagoblin directory issue:
python setup.py
  • You will also need to: easy_install lxml
  • Python-image was trickier to install: 
    easy_install --find-links http://www.pythonware.com/products/pil/ Imaging
Test by leaving the mediagoblin directory and see if you can import it: 
python -c "import mediagoblin"
looking for error messages.

Set up an WSGI environment on Dreamhost

  1. Enable the mod_passenger setting for ruby/python in the domains web panel
  2. cd into the domain directory (e.g. ~/media.sspaeth.de for me)
  3. Copy mediagoblin.ini and paste.ini from the ~/mediagoblin directory here
  4. Create passenger_wsgi.py in your domain directory (e.g. ~/media.sspaeth.de for me):
import sys, os
INTERP = "/home/<username>/local/virtenv/bin/python"
#INTERP is present twice so that the new python interpreter knows the actual executable path
if sys.executable != INTERP: os.execl(INTERP, INTERP, *sys.argv)

from paste.deploy import loadapp
application = loadapp('config:/home/mediagoblin/media.sspaeth.de/paste.ini')

#If in case of errors, all you get are mysterious error 500, you can set debug=true in paste.ini to see stack traces
# Otherwise, add this:
#from paste.exceptions.errormiddleware import ErrorMiddleware
#application = ErrorMiddleware(application, debug=True)
  1. Set up the database by issueing: 
    gmg dbupdate
  2. (optional but recommended) Serve the static files directly from the webserver.
In paste.ini in this section: [composite:routing] comment out the static files:
  #/mgoblin_static/ = mediagoblin_static
  #/theme_static/ = theme_static
and symlink the mediagobin/mediagoblin/static directoy to public/mgoblin_static
and mediagoblin/mediagoblin/themes to public/theme_static
so it is displayed directly. This step might be different depending on your web server configuration. There is no reason that static
files need to go through all the python indirection when they can be served directly by nginx/apache/...
In case you want to delete your git checkout after the installation (you don't need it, since you installed the mediagoblin package to ~/local/virtenv/lib/python2.7/mediagoblin... you should do the symlinking from there.

Open Issues

Please fill in the blanks if you find them out:

  • How to enable logging to a file or standard html logs? Console output just disappears.
  • How to set up things not using sqlite. What's wrong with mySQL?

Troubleshooting

  • First of all: invoke 
    python passenger_wsgi.py
    directly from the shell. This will tell you if there are import errors etc. If this command exits without any output on the console, you have already achieved a lot.
  • In paste.ini set debug=true. This will show you python backtraces directly in the web page
  • You will need to configure an smtp user/passwd/server in mediagoblin.ini, so you actually get the account creation token mailed out. Hint, the relevant settings are: 
    email_debug_mode = false

email_sender_address = postmaster@sspaeth.de email_smtp_host = SMTP.DOMAIN.TLD email_smtp_user = USERNAME email_smtp_pass = WEIRDPASSWORD

  • In case you can upload media, but it does not appear. You don't have the celery server running. Add 
    CELERY_ALWAYS_EAGER = true
    to the [celery] section in mediagoblin.ini

Miscellaneous Hacks

Force translation

There might some conditions under which you would prefer that MediaGoblin always return the same translation. If you are deploying with nginx and fastcgi, you can force MediaGoblin to return a spefcific translation regardless of browser preferences by passing a specific HTTP_ACCEPT_LANGUAGE fastcgi parameter in your location block. Example last line in location block: 

    fastcgi_param HTTP_ACCEPT_LANGUAGE es; #force spanish translation
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