pyramid_appengine 0.8.5

Description:

pyramid appengine 0.8.5

A scaffold to help you get started writing a pyramid aplication that
will run on Google App Engine.

Looking for a new maintainer
I don’t do python anymore, or appengine for that matter. If anyone is interested in taking this scaffold over I will be happy to transfer it.


Installation
pyramid_appengine can be installed via pip or easy_install
$ pip install pyramid_appengine
Once installation has completed, an appengine_starter template will be
made avaialable to use to create projects.
$ pcreate --l
Available templates:
appengine_starter: Pyramid scaffold for appengine
...


Getting Started
The project generated from the scaffold utilizes buildout 2 which no
longer attempts to provide full or partial isolation from system
python installations. As a result it is a good idea to use a
virtualenv to provide that isolation.
This can be accomplished by simply creating a new virtualenv and using
it’s interpreter to run bootstrap.py. Using virtualenv is out of scope
but there is plenty of information on the internet on how to do it.
To get started, first create your project skeleton.
$ pcreate -t appengine_starter mynewproject
A buildout environment for your project will be created. once
complete, run the buildout as usual
$ cd meynewproject
$ virtualenv -p /usr/bin/python2.7 .env
$ .env/bin/python2.7 bootstrap.py
$ ./bin/buildout
The buildout will take care of downloading and installing the App
Engine SDK (currently 1.6.3). it will be located in
“./parts/google_appengine” all utils for deploying and running the
development server will be located in “./bin”
Your source code for your project will be located at
“./src/mynewproject”, a bundle of your source and it’s dependencies
will be located at “./parts/mynewproject”


Running your project for development
$ ./bin/supervisord
your pyramid site will be running on port 8000 so point your browser
at
http://localhost:8000
The app engine admin console for your app is on port 8010
You will find the supervisor service on port 9999 at
http://localhost:9999
From there you can check to see if the service is running, and you can
start/stop/restart and tail the log.


Deploying your application to App Engine
Assuming you have created an application id “mynewproject” on app engine, the
application can be deployed like so.
$ ./bin/appcfg update parts/mynewproject -A mynewproject -V dev
Then your application will be running at…
http://dev.mynewproject.appspot.com


What It Does And Why
Most pyramid scaffolds create a project directory structure that is an
installable through the pip/easy_install . However, App Engine
applications do not support that format. Instead App Engine assumes
that everything is contained in one directory including all of the
projects dependencies not provided by the App Engine run time.
So a directory structure for an application deployable to App Engine
looks like this…
/myproject/
/myproject/app.yaml
/myproject/index.yaml
/myproject/queue.yaml
/myproject/pyramid
/myproject/verlruse
/myproject/jinja2
/myproject/newfangledlib
Because of this directory structure, which is vastly different from
what is expected by other tools, we need a way to develop in your
typical python egg format, but deploy in an App Engine format.

Enter Buildout
Buildout is a tool that can be used to support the kind of setup where
you develop your application as an egg but deploy what App Engine
expects. If you aren’t familiar with buildout you may want to read up
on it. It has some of the same goals as virtualenv, but has more
features via recipes to help with deployment.
For running the buildout you typically do …
$ /path/to/python bootstrap.py
$ ./bin/buildout
The buildout.cfg file distributed with python_appengine does the
following.


creates a buildout environment where the source for your project
is located at ./src/nameofproject


When buildout is run …


all the dependencies for your project are downloaded and setup in
the buildout environment
the appengine sdk is downloaded and installed in the buildout
environment under ./parts/google_appengine .
tools such as devappserver, appcfg which are tools distributed
with the app engine sdk are put in the buildouts bin directory
a supervisor script to run the dev_appserver.py is generated




Buildout and Virtualenv
In order for Google App Engine’s Dev Server and upload script to
function correctly all files which are being used by the project must
be collected together into a flat hierarchy, as described above.
By default, however, buildout will not create directories for any
packages already present in the system’s site-packages directory.
Since buildout 2.0 has been released, the suggested way to provide
package isolation is to create a virtualenv and then use that
interpreter to bootstrap your buildout.



Managing dependencies for deployment
As mentioned earlier, all dependencies must be contained in the
applications deployment directory under parts or provided by the app
engine runtime environment. As your application gets bigger and bigger
you will likely edit the buildout.cfg from time to time to add more
dependencies so that they are deployed with your application.
To update the dependencies for your application edit the packages
attribute under the stanza for your project in the buildout.cfg and
then run ./bin/buildout again to have the dependencies symlinked or
copied to parts/mynewproject


Testing
As a general rule, having a thorough unit test suite is good. But in
the authors opinion it is essential for app engine applications. The
main reason being that app engine requires you to specify the
datastore indexes you need to support the application at deployment
time via the index.yaml.
The app engine sdk will update your index.yaml for you when you are
running your application on the development server. But it requires
you use something that generates an HTTP request in order to trigger
the behavior. So in theory, you would have to make sure you hit every
page of your application before you deploy to insure any new index
needs caused by new or updated queries are recorded.
This method is error prone and time consuming. A better way is to have
your unit tests generate it.
The project generated by the scaffold includes everything you need to
do this. By using py.test and hooks specified in conftest.py, a couple
things are guaranteed.


a clean appengine environment is initialized before each test
any changes to index.yaml are written after each test


Tests can be run from the root of the project directory like so.
$ ../../bin/python setup.py test
or …
$ ../../bin/py.test

0.8.5
update buildout to new bootstrap file
undo setuptools pin
update for app engine sdk 1.9.17


0.8.4
update for app engine sdk 1.9.11
remove mako and chameleon dependencies since they are no longer required for pyramid as of version 1.5


0.8.3.1
somehow 0.8.3 got zipped with a README.rst instead of a readme.rst


0.8.3
upgrade sdk to 1.8.7
fix setuptools craziness with rod.recipe.appengine by pinning
setuptools in versions.cfg
add flag in supervisor config for devappserver to avoid checking for
sdk updates when it starts up so that the app either comes up or
errors out, not just hangs there waiting for user input that it will
never get.
Slight modification to docs to give an actual opinion on whether to
use virtualenv or not. As in yes, use a virtualenv for less python
packaging pain.


0.8.2-a2
rebuild with all the artifacts (reademe.rst, CHANGES.txt etc…..)


0.8.2-a1
added supervisord scripts to run dev_appserver
App Engine SDK version bumped to 1.8.0


0.8.1
include versions.cfg template for scaffold


0.8
bump sdk to 1.7.5
bump pyramid version to 1.4
upgrade to buildout 2.0
added versions.cfg to make managing versions of dependencies easier.


0.7
bump sdk version to 1.7.2
adding “unzip=true” to the buildout.cfg template to help out with eggs
that are distributed that way
pinning to pyramid version 1.3


0.6.1
bump SDK version to 1.6.6


0.6: 06-13-2012
changed buildout.cfg to ignore site-packages which should fix a lot of
issues with various namespaces packages that pyramid potentially
depends on.


0.5.4.1: 05-05-2012
doc corrections


0.5.4
upgrading buildout to appengine sdk 1.6.5 and pyramid 1.3
changed application template to not use an ini file because it doesn’t
really add any value on appengine, but handling the paste*
dependencies is troublesome for the recipe rod.recipe.appengine under
some circumstances.
This is just the default behavior of course, there’s nothing stopping
you from deploying with an ini file if you wish.


0.5.3: 03-27-2012
upgrading buildout to appengine sdk 1.6.4, the first SDK which works
with python2.7.


0.5.2: 03-23-2012
fixes to address github issue #6
usage of project vs package used incorrectly.
https://github.com/twillis/pyramid_appengine/issues/6


0.5.1: 03-21-2012
minor changes to readme.rst


0.5: 03-21-2012
initial release