intro to app engine and appscale
DESCRIPTION
These slides introduce new users to Google App Engine and AppScale, focusing on the APIs that App Engine offers and how AppScale implements them.TRANSCRIPT
introTo
Googleapp engine
&Appscale
build apps faster and easier
developer innovation
K
rapid releases
Zdeploy and
scale on any cloud
x
Chris [email protected]
(
b8
5
$
>
a common pattern
One of several recurring problems seen in the real world today.
• You have a cool idea
• To make it into an app, you need to:
• Setup hardware
• Configure, deploy app services
• And you have to do this for every app!
www.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected] PAGE
Why not Amazon?
3
• You don’t want to deploy and maintain:
• Servers
• Load balancers
• App Servers
• Databases
• And you don’t want to hire people to do it!
www.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected] PAGE
google app engine
4
• A web application hosting service
• Never log into a server
• Crystallizes web service best practices
• Share common services between apps
• Focus on writing your app
www.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected] PAGE
Supported Languages
5
Go
Python
Go
Java
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
Programming Model
(
Ñ
6
Everything is a web request
Stateless, scalable web server, meaning:
• No filesystem access
• Persistence via Datastore / memcache
• 60 second time limit on requests
• APIs from whitelist only
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
The DATAstore
7
• Not a relational database, but resembles an object database
• You define Kinds of data you want to store
• Each object stored is an Entity
• Entities can be arranged into Groups
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
Defining a kind
8
class Person(ndb.Model):
user = ndb.UserProperty()
balance = ndb.FloatProperty()
phone = ndb.StringProperty()
last_login = ndb.DateTimeProperty()
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
EXTENDING a kind
9
class Person(ndb.Model):
user = ndb.UserProperty()
balance = ndb.FloatProperty()
phone = ndb.StringProperty()
last_login = ndb.DateTimeProperty()
login_location = ndb.GeoPt()
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
Kind, entities
10
class Person(ndb.Model):
...
new_person = Person()
new_person.put()
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
transactions
11
• Updating an Entity happens in a Transaction
• Apps tell App Engine which Entities will be updated together by putting them into an Entity Group
• Transactions can only occur within an Entity Group*
def f():
person = db.get(key1)
person.balance = 100.00
person.put()
db.run_in_transaction(f)
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
memcache
12
data = memcache.get(‘key’)
if data:
return data
else:
data = db.get(‘key’)
memcache.set(‘key’, data, 300)
return data
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
users
13
user = users.get_current_user()
if user:
return user.nickname()
else:
return None
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
14
from = “Chris Bunch <[email protected]>”
to= “You <[email protected]>”
subject = “Try out AppScale!”
body = “http://download.appscale.com”
mail.send_mail(sender=from, to=to, subject=subject, body=body)
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
task queue
15
taskqueue.add(url=“/path/to/worker”)
cron:- description: sends friendly emails url: /path/to/worker schedule: every 24 hours
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
url fetch
16
r = urlfetch.fetch(“http://www.google.com/”)
if r.status_code == 200:
do_something_with_result(r.content)
else:
# retry later
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
xmpp
17
user = “[email protected]”
msg = “Hello there!”
status = xmpp.send_message(user, msg)
if status != xmpp.NO_ERROR:
# decide what to do with the failed msg
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
enter appscale
18
• But what if you need:
• To fail over to a private cloud?
• To run your App Engine app in-house?
• To use APIs App Engine doesn’t support?
• Then you need AppScale!
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
datastore
20
• Supports NoSQL datastores via a database agnostic API:
• get
• put
• range_query
• delete
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
load balancing + app servers
23
PAGEwww.appscale.comPhone: +1(805) 845 0010 | e-mail: [email protected]
the development cycle
25
• App Engine SDK for rapid development
• Limitations:
• Many APIs are stubbed out (XMPP, Mail)
• Not designed for production workloads
• Use AppScale!
Demo