Deploying a Pylons app
to Google App Engine
Boston Python meetup - 6/18/08
Nate Aune
www.jazkarta.com
www.nateaune.com
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Disclaimer #1
\"I just started using Pylons last week.\"
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Disclaimer #2
\"I just started using Google App Engine last week.\"
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App: Gigblastr
• Goal: make it easier to promote an event
• Fill out a form with event details
• Blast event to dozens of event listing sites
• Similar to TubeMogul but for events instead
of videos.
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Tubemogul.com
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Musician
Add event
Title Poludaktulos Orchestra
Description The Poludaktulos Orchestra (the \"Many-
Fingered Orchestra\") employs unique
instrumentation in its lively performances of
northern Greek brass band music.
URL http://myspace.com/poludaktulosorchestra
Venue Johnny D's
Date 11/8/08
Start Time 9:00pm End 11:00pm
Blast it!
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Brief history
Implemented using content rules for Plone
• version 0.1 @ DevHouseBoston3 2007
• posting to Twitter and Eventful
• version 0.2 @ Home
• posting to Upcoming.org
• version 0.3 @ DevHouseBoston4 2008
• rewrite as Pylons app deployed to GAE
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Bootstrap with the
appenginemonkey
$ svn co http://appengine-monkey.googlecode.com/svn/trunk ape-monkey
$ cd ape-monkey
$ python2.5 appengine-boot.py --paste-deploy ~/gae/gigblastr
$ cd ~/gae/gigblastr
$ source bin/activate
(gigblastr)$ easy_install Mako==dev Pylons==dev Paste
...
(gigblastr)$ cd src
(gigblastr)$ paster create --template=pylons GigBlastr
(gigblastr)$ cd GigBlastr
(gigblastr)$ python setup.py develop
(gigblastr)$ python -m pth_relpath_fixup
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Configure your
environment
• Edit development.ini
[app:the-app]
use = config:src/GigBlastr/development.ini
• Launch the application
$ /usr/bin/python2.5 /usr/local/google_appengine/dev_appserver.py \\
~/gae/gigblastr/
• Visit http://localhost:8080/
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Edit the routes
• In GigBlastr/config/routing.py
map.connect('', controller='hello', action='index')
• Create a 'hello' controller
$ paster controller hello
• Restart and visit
http://localhost:8080/hello/index
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Hello World
import logging
from pylons import request, response, session
from pylons import tmpl_context as c
from pylons.controllers.util import abort, redirect_to
from gigblaster.lib.base import BaseController, render
#import gigblaster.model as model
log = logging.getLogger(__name__)
class HelloController(BaseController):
def index(self):
# Return a rendered template
# return render('/template.mako')
# or, Return a response
return 'Hello World'
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Twitter
(gigblastr)$ easy_install python_twitter
• In GigBlastr/controller/hello.py
import twitter
def tweet(self):
api = twitter.Api(username='natea',
password='xxxxxxx')
status = api.PostUpdate('testing tweets from GAE')
return status.text
• Restart and visit
http://localhost:8080/hello/tweet/index
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Eventful
(gigblastr)$ easy_install eventful
• In GigBlastr/controller/hello.py
import eventful
def evtful(self):
api = eventful.API('xxxxxxxxxxxxx')
events = api.call('/events/search', q='music', l='Cambridge, MA')
for event in events['events']['event']:
print \"%s at %s\" % (event['title'], event['venue_name'])
• Restart and visit
http://localhost:8080/hello/evtful/index
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Upload app to GAE
$ cd gigblastr
$ /usr/bin/python2.5 /usr/local/google_appengine/appcfg.py update .
• 973 files - whew!
• If your app has more than 1000 files, you'll
have to remove some unused eggs.
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Remove _speedups
import simplejson
File \"/base/data/home/apps/gigblastr/1.8/lib/python2.5/site-packages/simplejson-1.8.1-py2.5-macosx-10.5-i386.egg/
simplejson/__init__.py\", line 113, in <module>
from encoder import JSONEncoder
File \"/base/data/home/apps/gigblastr/1.8/lib/python2.5/site-packages/simplejson-1.8.1-py2.5-macosx-10.5-i386.egg/
simplejson/encoder.py\", line 6, in <module>
from simplejson import _speedups
File \"/base/data/home/apps/gigblastr/1.8/lib/python2.5/site-packages/simplejson-1.8.1-py2.5-macosx-10.5-i386.egg/
simplejson/_speedups.py\", line 7, in <module>
__bootstrap__()
File \"/base/data/home/apps/gigblastr/1.8/lib/python2.5/site-packages/simplejson-1.8.1-py2.5-macosx-10.5-i386.egg/
simplejson/_speedups.py\", line 5, in __bootstrap__
del __bootstrap__, __loader__
NameError: global name '__loader__' is not defined
• Remove _speedups.py and _speedups.so
from simplejson
• They are trying to cache on the file
system, which is a no-no on GAE.
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Guido, the creator of
Python speaks!
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ianbicking to the
rescue! Ian responds one
week later
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Use httplib on GAE
• In paste-deploy.py:
## If you want to use httplib but get socket errors,
## you should uncomment this line:
appengine_monkey.install_httplib()
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No Twitter from GAE
:(
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More info
• Google App Engine
http://code.google.com/appengine/
• Pylons
http://pylonshq.com
• Instructions for Pylons on GAE
http://code.google.com/p/appengine-monkey/wiki/Pylons
• DevHouseBoston
http://devhouseboston.org
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Thanks!
• To Ian Bicking for making appengine-
monkey, making the instructions, and
helping on IRC.
• The kind folks in #pylons who helped me
get my head around Pylons syntax
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