gaetk is a small collection of tools that tries to make programming Google AppEngine faster, more comfortable and less error prone. It is pre-alpha quality software.
It comes bundled with gaesession and webapp2. Check the documentation of these projects for further information.
Create a appengine Project, then:
mkdir lib
git submodule add [email protected]:mdornseif/appengine-toolkit.git lib/gaetk
git submodule update --init lib/gaetk
cp lib/gaetk/examples/Makefile .
cp lib/gaetk/examples/config.py .
cp lib/gaetk/examples/appengine_config.py .
sed -i -e "s/%%PUT_RANDOM_VALUE_HERE%%/`(date;md5 /etc/* 2&>/dev/null)|md5`-5a17/" appengine_config.py
# If you want to use jinja2
git submodule add https://github.com/mitsuhiko/jinja2.git lib/jinja2
git submodule update --init lib/jinja2
You might also want to install https://github.com/hudora/huTools for some additional functionality.
Generation of sequential numbers ('autoincrement') on Google appengine is hard. See Stackoverflow for some discussion of the issues. gaetk implements a sequence number generation based on transactions. This will yield only a preformance of half a dozen or so requests per second but at least allows to alocate more than one number in a single request.
>>> from gaeth.sequences import *
>>> init_sequence('invoce_number', start=1, end=0xffffffff)
>>> get_numbers('invoce_number', 2)
[1, 2]
gaetk offers a hybrid Google Apps / Credential based authentication via session Cookies and HTTP Auth. This approach tries to accomodate command-line/API clients like curl and browser based clients. If a client does provide an Accept-Header containing text/html (all Browsers do) the client is redirected to /_ah/login_required where the user can Enter uid and secret (Session-Based Authentication) or login via OpenID/Google Apps. If there is no Accept: text/html the client is presented with a 401 status code, inviting the client to offer HTTP-Basic-Auth.
To use OpenID with Google Apps configure your Application to use "Federated Login":
Users are represented by gaetk.handler.Credential objects. For OpenID users a uid ("Username") and secret ("Password") are autogenerated. For Session or HTTP-Auth based ssers uid and secret should also be autogenerated. I strongly avaise against user settable passwords and suggest you might also consider avoiding user settable usernames. Use Credential.create() to create new Crdentials including auto-generated uid and secret. If you want to set the uid mannually , give the uid parameter.
gaetk.handler.Credential.create(text='API Auth for Schulze Server', email='[email protected]')
gaetk.handler.Credential.create(uid='user5711', text='...', email='[email protected]')
To use it add the following to app.yaml:
handlers:
- url: /_ah/login_required
script: lib/gaetk/gaetk/login.py
- url: /logout
script: lib/gaetk/gaetk/login.py
Now in your views/handlers you can easyly force authentication like this:
from gaetk.handler import BasicHandler
class HomepageHandler(BasicHandler):
def get(self):
user = self.login_required() # results in 401/403 if can't login
...
Unless you call login_required(deny_localhost=False) access from localhost is always considered authenticated.
Add the following to app.yaml:
- url: /gaetk/.*
script: lib/gaetk/gaetk/defaulthandlers.py
Now you can get some Application statistics at http://EXAMPLE.appspot.com/gaetk/stats.json:
{"datastore": {"count": 174789,
"kinds": 16,
"bytes": 102391232},
"memcache": {"hits": 1665726,
"items": 1171,
"bytes": 4588130,
"oldest_item_age": 2916,
"misses": 50674,
"byte_hits": 833839440}}
gaetk.handler.JsonResponseHandler helps to generate nice JSON and JSONP responses. A valid view will look like this:
class VersandauslastungHandler(gaetk.handler.JsonResponseHandler):
def get(self):
entity = BiStatistikZeile.get_by_key_name('versandauslastung_aktuell')
ret = dict(werte=hujson.loads(entity.jsonValue),
...)
return (ret, 200, 60)
This will generate a JSON reply with 60 Second caching and a 200 status code. The reply will support JSONP via an optional callback parameter in the URL.
Add the following lines to your app.yaml:
- url: /gaetk/.*
script: lib/gaetk/gaetk/defaulthandlers.py
This will allow you to get JSON encoded statistics at /gaetk/stats.json:
curl http://localhost:8080/gaetk/stats.json
{"datastore": {"count": 149608,
"kinds": 16,
"bytes": 95853319},
"memcache": {"hits": 0,
"items": 0,
"bytes": 0,
"oldest_item_age": 0,
"misses": 0,
"byte_hits": 0}}
You might want eo use Munin to graph these values.
In models.py you find a superclass LoggedModel for implementing audit logs for a model:
All create, update and delete operations are logged via the AuditLog model.
Example:
import gaetk.models
from google.appengine.ext import db
class MyModel(gaetk.models.LoggedModel):
name = db.StringProperty()
obj = MyModel(name=u'Alex')
print obj.logentries()
Please note: Changes in (subclasses of) UnindexedProperty (hence TextProperty and BlobProperty) are not logged.
Tools contians general helpers. It is independent of the rest of gaetk.
tools.split(s) "Splits a string at space characters while respecting quoting.
>>> split('''A "B and C" D 'E or F' G " "''')
['A',
'B and C',
'D',
'E or F',
'G',
'']
Infrastructure contians helpers for accessing the GAE infrastructure. It is independent of the rest of gaetk.
taskqueue_add_multi batch adds jobs to a Taskqueue:
tasks = []
for kdnnr in kunden.get_changed():
tasks.append(dict(kundennr=kdnnr))
taskqueue_add_multi('softmq', '/some/path', tasks)
In addition to the server side functionality gaetk also includes various javascript helper methods. They must be used in combination with ExtJS and provide methods for easy handling of often-used tasks. To use the javascript helpers you will have to link the web directory into the directory declared the static_dir directory in your app.yaml. Then include the gaetk-extjs-helpers.js and gaetk-extjs-helpers.css files into your HTML page template.
Currently the helpers include two methods:
Hudora.Helpers.spinnerMessageBox(message): display a non-closable messagebox with a spinner indicating progressHudora.Helpers.errorMessageBox(title, message): display a error message box without having to write five lines of code every time you need an error messagebox.
Axel Schlüter for suggestions on abstracting login and JsonResponseHandler.
Contains gaesession.py by David Underhill - http://github.com/dound/gae-sessions Updated 2010-10-02 (v1.05), Licensed under the Apache License Version 2.0.
Contains code from webapp2, Copyright 2010 Rodrigo Moraes. Licensed under the Apache License, Version 2.0
gaetk code is Copyright 2010 Hudora GmbH and dual licensed under GPLv3 and the Apache License Version 2.0.