Google App Engine Update 2012

Google App Engine …is an expression of how Google thinks about infrastructure. DevNexus App Engine Update Mar 21, 2012 David Chandler Developer Advocate drfibonacci@google.comFriday, March 23, 2012

Agenda App Engine intro ‣ 60 second demo Whatʼs new in App Engine? ‣ SLA, premier accounts, security audits ‣ Backends, pull queues ‣ HRD, query planner, XG transactions ‣ Cloud SQL, Files API Load testing recipe Minimize response time, cost Case study (Mike Lawrence) Wrap up / Questions?Friday, March 23, 2012

Cloud in a box Easy to build ‣ Local SDK - Java, Python, Go ‣ Lots of APIs Easy to maintain ‣ Admin Console ‣ Site Reliability Engineers ‣ No clunky knobs/dials Easy to scale ‣ Google scale infrastructure ‣ No limits to how much data your can put in the datastoreFriday, March 23, 2012

Two minute demo 4Friday, March 23, 2012

Out of labs... weʼre growing up! ✓ Supported product ✓ 99.95% uptime guarantee (SLA) ✓ Paid operational support ✓ Platform certiﬁcations ✓ Growing fast... 5Friday, March 23, 2012

3B+ Requests / day 300k+ Apps 100k+ Developers 2008 2009 2010 2011 High Memcache Task Replication Queues Datastore HTTPS Appstats Go Runtime Channel XMPP Namespaces API ISAE3402 Python Runtime Java Runtime Email API Type II Certification Backends Pull QueuesFriday, March 23, 2012

Common types of App Engine apps Mobile/Tablet ‣ App backends ‣ Cloud persistence Social/Mobile Games ‣ Speed, scale ‣ API integrations Consumer Web Apps ‣ Unpredictable trafﬁc ‣ Scale Business Web Apps ‣ Enterprise ‣ Java runtimeFriday, March 23, 2012

App Engine customers 8Friday, March 23, 2012

Social networking at scale >75M Installs 9Friday, March 23, 2012

Angry Birds = + + + + 10Friday, March 23, 2012

Khan Academy SALMAN KHAN www.youtube.com/watch?v=gM95HHI4gLk#t=0m15s 11Friday, March 23, 2012

The Royal Wedding - 32k req/second peak - 37m pageviews - 13m visitors 12Friday, March 23, 2012

Mobile/game backend .... PocketGems 13Friday, March 23, 2012

WebFilings 14Friday, March 23, 2012

Best Buy 15Friday, March 23, 2012

Chillingo Crystal Gaming meets Social 16 Zombie Dash Angry Birds LITE Underground Meltdown CogsMission Deep Sea Speed Forge Guerilla Bob Ravensword: Angry Birds Extreme The Fallen KingFriday, March 23, 2012

What’s New? 17Friday, March 23, 2012

Feature overview URL Fetch Frontends XMPP Compute Backends Network Channel API Task Queues Mail API Cron Datastore Images API Storage Memcache App Identity Services Namespaces Users API Blobstore MapReduce API Cloud SQL Pipeline API Static content Prospective Search API 18Friday, March 23, 2012

Frontends, Backends, Task Queue, Cron Compute Pull (Task) Queues App App Engine Push (Task) Queues / Cron Engine Client Frontend Client Frontend App App App App Engine App Client Engine Engine App Client Engine Frontend Engine Backend Frontend Engine Backend Backend Backend 19Friday, March 23, 2012

URL Fetch Network HTTP/1.1 ‣ GET, POST, PUT, HEAD, and DELETE Maximum request deadlines ‣ 60s (default 5s): user facing (online) requests ‣ 10 minutes (new): cron, task queue (ofﬂine) requests Execution options ‣ Synchronous ‣ AsyncFriday, March 23, 2012

Talking to the outside world Network XMPP / Jabber ‣ Send/receive messages ‣ Send chat invites ‣ Request presence, status ‣ Set status Channel API ‣ Server push Mail API ‣ Send and receive Use cases ‣ Chat bot ‣ Realtime notiﬁcations ‣ Chat user interfaceFriday, March 23, 2012

Images Services 22Friday, March 23, 2012

Prospective search Services Register your queries ‣ Deﬁne interesting search criteria Create your data ‣ Users and systems interact with your app Receive callbacks ‣ App Engine tells you about data which matches searchesFriday, March 23, 2012

Identity Services Users API ‣ Require users to login and identify - Email address - Unique, stable id ‣ Servlet ﬁlter for dynamic requests App Identity ‣ Who am I? appIdentityService.getServiceAccountName() ‣ Assert your identity to applications - GAE handles key security, key rotation for you - Other Google APIs appIdentityService.getAccessToken() - On other systems appIdentityService.signForApp()Friday, March 23, 2012

MapReduce & Pipeline API Services code.google.com/p/appengine-pipeline/ 25Friday, March 23, 2012

High Replication Datastore (HRD) Storage Schemaless Object datastore ‣ Entities & Entity Groups Query engine ‣ Standard & custom indexes Atomic transactions Features ‣ Highly scalable - More distributed as more data is stored ‣ Highly reliable - Synchronous, multi-datacenter replication ‣ Managed www.google.com/events/io/2011/sessions/more-9s-please- under-the-covers-of-the-high-replication-datastore.htmlFriday, March 23, 2012

Advanced query planner New! Storage Datastore never requires an exploding index ‣ code.google.com/appengine/docs/python/datastore/ queries.html#Big_Entities_and_Exploding_Indexes dev_appserver ‣ Understands query planner changes Zigzag merge-join queries ‣ Will continue scanning for up to 30 sec ‣ No more "needs index" errors (although some may timeout) ‣ www.google.com/events/io/2009/sessions/ BuildingScalableComplexApps.htmlFriday, March 23, 2012

The “old” query planner Storage es Index(Photo, I owner_id,s -date)ndex Tag -rating) = 256 Index(Photo, owner_id, 2^6*4 12 Index(Photo, 1 owner_id, -comments) = 5 Index(Photo, 2 2^7*4 owner_id, -downloads) 1024 = Index(Photo, size, -date) 2^ 8*4 3 . Index(Photo, size, -rating) . Index(Photo, . size, -comments) . Index(Photo, size, -downloads) . . … Index(Photo, owner_id, size, -date) Index(Photo, owner_id, size, -rating) Index(Photo, owner_id, size, -comments) Index(Photo, owner_id, size, -downloads) … Index(Photo, aspect, coloration, license, owner_id, size, -date) Index(Photo, aspect, coloration, license, owner_id, size, -rating) Index(Photo, aspect, coloration, license, owner_id, size, -comments) Index(Photo, aspect, coloration, license, owner_id, size, -downloads) = 2^(no. of filters) * (no. of different orders) = 2 ^ 6 * 4 = 256 indexesFriday, March 23, 2012

The “improved” query planner Storage Index(Photo, owner_id, -date) Index(Photo, owner_id, -rating) Index(Photo, owner_id, -comments) Index(Photo, owner_id, -downloads) Index(Photo, size, -date) Index(Photo, size, -rating) Index(Photo, size, -comments) Index(Photo, size, -downloads) … Index(Photo, license, -date) Index(Photo, license, -rating) Index(Photo, license, -comments) Index(Photo, license, -downloads) … Index(Photo, tag, -date) Index(Photo, tag, -rating) Index(Photo, tag, -comments) Index(Photo, tag, -downloads) = (number of filters) * (number of orders) = 7 * 4 = 28 indexesFriday, March 23, 2012

Query planner performance - cost trade-offs Option #1 - Write to more indexes at write time ‣ Entity writes are expensive ‣ Possible queries must be known in advance - Others will fail with Needs Index error ‣ Predictable / fast query time [for supported queries] Option #2 - Scan multiple indexes at read time ‣ Entity writes much cheaper ‣ More queries possible with fewer indexes ‣ Ad hoc queries ‣ Query response time depends on shape of data - Speciﬁc cases can be optimized by providing addʼl indexesFriday, March 23, 2012

Using the new query planner Storage Upgrade to 1.5.4+ Turn off auto index generation ‣ Python: dev_appserver.py --require_indexes ‣ Java: <datastore-indexes autoGenerate="false"> Remove unnecessary custom index deﬁnitions ‣ Python: - index.yaml ‣ Java: - WEB-INF/datastore-indexes.xml - WEB-INF/appengine-generated/datastore-indexes-auto.xml Test your app Deploy to production ‣ Judiciously run: appcfg vacuum_indexesFriday, March 23, 2012

XG Transactions New! Storage In a single transaction… ‣ Access 1..5 entity groups - read and/or write ‣ Does not provide transactional ancestor-less query ‣ Does allow 1..5 separate ancestor queries within transaction Concurrency exceptions possible ‣ 1st access of each entity group ‣ For reads as well as writes Availability ‣ Only in HRD apps ‣ App Engine 1.5.5 release Non-ancestor (transaction-less) queries may see… ‣ Partially committed non-XG transaction (same as before) ‣ Partially committed XG transactions (more likely)Friday, March 23, 2012

XG Transactions - Java Storage import com.google.appengine.api.datastore.*; void transferFunds(long amt, String fromAccount, String toAccount) { DatastoreService datastore = DatastoreServiceFactory.getDatastoreService(); TransactionOptions options = TransactionOptions.Builder.withXG(true); Transaction txn = datastore.beginTransaction(options); Entity a = datastore.get(KeyFactory.createKey("Account", fromAccount)); Entity b = datastore.get(KeyFactory.createKey("Account", toAccount)); a.setProperty("balance", (Long) a.getProperty("balance") - amt); b.setProperty("balance", (Long) b.getProperty("balance") + amt); datastore.put(txn, a); datastore.put(txn, b); txn.commit(); }Friday, March 23, 2012

Cloud SQL (labs) Storage New! Cloud SQL support in Google Plugin for Eclipse 2.5 Client Client Client Client 34Friday, March 23, 2012

Cloud SQL (labs) Storage Developer console ‣ Easy to use Fully managed ‣ Site Reliability Engineers (SREs) High availability ‣ Synchronous replication to multiple data centers Integrated with Google App Engine ‣ Java: JDBC, Python: DB-API ‣ Use with High Replication Datastore Migration ‣ MySQL Import / exportFriday, March 23, 2012

Google Cloud Storage / Files API Storage Google Cloud Storage ‣ Buckets in the cloud ‣ REST API ‣ Command line ‣ Web UI tool ‣ Enable in APIs console Use from App Engine ‣ Files API (new) ‣ No more OAuth hassle ‣ http://code.google.com/appengine/docs/java/googlestorage/ overview.htmlFriday, March 23, 2012

Minimize response time 37Friday, March 23, 2012

Appstats “I used to be blind, but now I can see :-)” --An early Appstats user 38Friday, March 23, 2012

Load testing - Guidelines Test trafﬁc must be representative of real user trafﬁc Ramp over a period of several minutes his! o ts ! s t d hi e i etter on’ T ic D N uc h b mFriday, March 23, 2012

Load testing - basic recipe Send steady 5 qps trafﬁc to your site ‣ Uncover basic problems, e.g. entity contention on global data Monitor for 15-20 minutes and expect to see: ‣ Stable request latency <1000ms (no longer an issue) ‣ Zero quota denials ‣ Low error rate ‣ Tasks queues are keeping up ‣ No elevated datastore contention Slowly ramp up; increase trafﬁc by 2x ‣ Uncover next application bottleneck, if any Repeat until serving desired qps ‣ Plan your next featureFriday, March 23, 2012

Memcache 2 ms App App Client Engine App Client Engine App Frontend Engine Frontend Engine Backend Backend 20m s 41Friday, March 23, 2012

Enable content caching Free lunch possibility ‣ And your users will be happier too Use memcache ‣ Only if you care about your users Static resource ﬁles ‣ Do not consume instance hours HTTP/1.1 caching Cache-Control: public, s-maxage=... ‣ Respected by browsers, ISPs and App Engine ‣ Saves bandwidth Replace dynamic content with ‣ Static content ‣ Blobstore (custom HTTP headers)Friday, March 23, 2012

Best practices in client-side code Clients all t his! Av oid checking in at a speciﬁc time of day Spread out load: - Randomize client checkin times Clients retr y failures after a t his! And ﬁxe d interval Avoi d a Denials-of-Ser vice (DoS) on yo ur app after a failure: - Use exponential back-off: 1s, 2s, 4s, 8s, 16s, … - Use a fuzz factor: randomize retr y times 43Friday, March 23, 2012

Best practices in server-side code Reduce instance hours ‣ Reduce request latency ‣ Use Memcache ‣ Datastore/Memcache batch get/put ‣ Async URL Fetch, Datastore, Memcache - Parallelize RPCs ‣ Enable HTTP session async writes Spin up fewer instances ‣ Task queue rate and max_concurrent_requests ‣ X-AppEngine-FailFast code.google.com/appengine/articles/managing-resources.htmlFriday, March 23, 2012

Best practices in server-side code Enable concurrent requests ‣ Java appengine-web.xml ‣ Python 2.7 Discounted reserved instance hours ‣ $0.08/hr → $0.05/hr Scheduler knobs ‣ Max Idle Instances ‣ Min Pending LatencyFriday, March 23, 2012

Manage storage costs Discard stuff you no longer need ‣ Entities ‣ Indexes ‣ Blobs ‣ Tasks Drop unwanted indexes ‣ Vacuum custom indexes ‣ New query planner Explicitly mark properties as unindexed ‣ To migrate existing entities, put() again with: Python: foo = db.StringProperty(indexed=False) Java: entity.setUnindexedProperty(“foo”, “bar”)Friday, March 23, 2012

Manage datastore ops costs Number of write ops in SDK Fewer indexes & indexed properties → fewer write ops Take advantage of query planner improvements Replace queries with ‣ keys-only queries (cheaper) ‣ fetch-by-key (optimal) ‣ datastore cursors (for pagination)Friday, March 23, 2012

Enable warming requests Request logs /_ah/warmup Default behavior ‣ Enabled for Java apps / Disabled for Python apps ‣ All jar files are indexed in memory ‣ Initializes your application and filters - Servlets marked in <load-on-startup> - ServletContextListener filters Custom warmup servlet ‣ Override built-in _ah_warmup servlet <servlet> <servlet-name>_ah_warmup</servlet-name> <servlet-class>foo.MyWarmupServlet</servlet-class> </servlet>Friday, March 23, 2012

Only upload what you need Python static_files, static_dir skip_files Java <static-files> <resource-files> Diagnostics appcfg.sh --retain_upload_dir update …Friday, March 23, 2012

Custom error pages Avoid Java <static-error-handlers> <handler file="default_error.html"/> <handler file="over_quota.html" error- code="over_quota"/> </static-error-handlers> Python error_handlers: - file: default_error.html - error_code: over_quota file: over_quota.htmlFriday, March 23, 2012

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Google App Engine Update 2012

by David Chandler

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