Empowering Magnolia for Enterprise Use Cases - Experience Report

Empowering Magnolia for Enterprise Use Cases Magnolia Conference, Technical Track | Basel, 16. September 2010

About us Sebastian Frick Jörg von Frantzius Technical Project Manager System Architect

Some facts about Aperto  Internet agency in Berlin  Offering Conception, Design, Development, Online Marketing  Building projects with Magnolia since 2006 for clients like Siemens, Bertelsmann, EADS, INSM, Frankfurt School and others  Contributed frontend and concept for Standard Templating Kit

What we are talking about today Part 1: workflow specific enhancements Part 2: approach on dealing with user generated content

Part 1: workflow specific enhancements  Workflows - out of box features  Typical business requirements  Customization examples  Best practises / recommendations

Workflows - out of box features  Standard 4-eyes-workflow for publishing process  Sending of E-mail notifications  Management of multiple workflows  Time-based de-/activation  Commenting  Inbox for editors for managing workflow items

Standard 4 Eyes-Workflow Group „Editors“ Group „Publishers“ activates content approves content published rejects content

Mapping Configuration in AdminCentral  Workflows depending on paths in CMS  Different repositories can share one workflow or run their own one

OpenWFE – XML definition XML contains  Process-definitions  Participants (e.g. group, role, user)  Fields (variables)  Conditional expressions (if, while, loop)  Many more expressions or patterns (OpenWFE manual)

There do exist some tools, but...  OpenWFE IDE  DroFlo – visual editor Not mature or Magnolia specific enough – for modelling a workflow it usually takes good text editor with syntax highlighting and a developer.

Typical business requirements > workflow process  Enhanced number of steps or states (e.g. 8-eyes-workflow)  Automatic or manual selection of next receiver  Non-linear pattern (e.g. one item assigned to different groups at the same time)  Workflow engine for different scenarios than publishing (e.g. internal processes)

Manual selection of receiver

Manual selection of receiver  activation dialog is extendible like any usual Magnolia dialog  setted variables can be retrieved via OpenWFE-elements

Automatic selection of receiver Possible scenarios  by language of content  by section in site tree  by role

Dynamic selection of receiver  Make use of commands or custom functions for „outsourcing“ business logic to custom Java classes or external services 1 2 method added in OpenWFE‘s function-map.xml

Typical business requirements – workflow usability  Display of current number of workflow items  Display of current process status & participiant  Better traceability: workflow history

For editors: lack of workflow information in standard view

Custom column providing additional workflow information

Custom column providing additional workflow information  Sitetree-Implementation can be exchanged by configuration  Adding additional columns is quite easy (via Java)  Meta-information can be retrieved from WorkflowItem-Object

Current number of items in inbox  Example for dynamic display of current workflow items via AJAX based polling  AdminCentral frontend is extendible, but we‘re looking forward to new MagnoliaUI

Inbox view: enhancing workflow item dialog

Enhancing workflow-dialog by history tab  History info of an workflow item can be build from attributes available in WorkflowItem-Object

Enhancing workflow-dialog by references tab  Since content on one page can be located in several repositories, showing up references may be helpful  relations (UUID) and activation state can be retrieved via Magnolia standard functions

Best practises / recommendations

Best practises / recommendations #1 Specification via state diagram

Best practises / recommendations #2  Identify patterns and conditions  Proof of OpenWFE-Support vs. custom implementation

www.workflowpatterns.org for evaluation and comparison

flash based animations and descriptions of patterns

Best practises / recommendations #3  Avoid redundancies in workflow definitions whenever possible  Make use of Java-based commands (easier to maintain)

Best practises / recommendations #4  If groups will be used for determining workflow participants – don‘t add ACLs to workflow groups  use seperate groups insteads  define a proper naming convention

Best practises / recommendations #5  Don‘t underestimate testing efforts  Set up at testing plan  Have already an idea on how to monitor single workitems before development phase  Iterative development and testing  Regulary acceptance testing, adjustments will be usually necessary

Links  Evaluation matrix of workflow engines  Magnolia Workflow introduction  Home of OpenWFE

Part 2: approach on dealing with user generated content 1) 2.1. UGC: what‘s the problem? 2) 2.2. General solution + 2 implementation approaches 3) 2.3. GWT in the admin central

Client‘s UGC requirements (UGC = User Generated Comments, e.g. page comments) Client‘s website has page-commenting feature At peak load times, thousands of users want to post their page comments within a couple of minutes Client‘s requirement: Sustained content delivery during UGC peak loads! Basel | 10.09.2009 | Magnolia Conference | Technical Track 34

But … Magnolia does scale just great! So, what‘s the problem? Basel | 10.09.2009 | Magnolia Conference | Technical Track 35

The problem: UGC POST requests differ from content requests Content requests  can be satisfied from cache, i.e. fast response time per request  no bottleneck, i.e. performance scales linearly with number of servers  network bandwidth can be maxed out, given a  good caching hierarchy and  sufficient hardware sizing Not the case with UGC POST requests… Basel | 10.09.2009 | Magnolia Conference | Technical Track 36

The problem: UGC POST have much larger performance impact! UGC POST requests  cannot be satisfied from cache!  because require DB insert  requests take orders of magnitude longer, meanwhile blocking your HTTP worker threads  system can take fewer of these requests simultaneously before becoming unavailable  DB will become the bottleneck at some point  UGC load can exceed any hardware sizing Basel | 10.09.2009 | Magnolia Conference | Technical Track 37

Solution (system architecture) Website availability can only be ensured by Separating content delivery from UGC processing , through separate operating system processes UGC processing can run on dedicated hardware if necessary So it could also be shifted into the cloud Basel | 10.09.2009 | Magnolia Conference | Technical Track 38

Solution (system architecture): consequences Consequences of separation:  Even if UGC processes fail (all threads busy): Magnolia processes happily continue to serve content requests  Worst case only means: enduser will still see web page contents, with additional error message „page commenting currently unavailabe“ Basel | 10.09.2009 | Magnolia Conference | Technical Track 39

Magnolia approach for page comments  Commenting module (http://documentation.magnolia-cms.com/modules/commenting.html)  In order to separate processes: have dedicated Magnolia instances that serve only commenting repository  Must have multiple of these instances for scalability  UGC is not published from author to publish servers, but still all publish servers must see same content:  must set up shared JCR repository using Jackrabbit clustering (http://wiki.apache.org/jackrabbit/Clustering) Basel | 10.09.2009 | Magnolia Conference | Technical Track 40

Decision Magnolia approach vs. custom solution Problems that we saw for us:  Increased system complexity (setup Jackrabbit clustering, setup dedicated Magnolia instances with commenting repository)  Our lack of practical experience with clustered Jackrabbit:  How hard is it to setup?  How does it scale, in terms of lock contention?  How does it behave under high load?  What long-term consequences does journaling have (performance, maintenance)  For us: incurred complexity and risks outweigh advantages Basel | 10.09.2009 | Magnolia Conference | Technical Track 42

Custom architecture chosen for UGC processing  Page comments are rendered in browser by Javascript, using Google Web Toolkit (GWT)  UGC requests served by separate tomcats, containing only a single REST webservice  Comments data is stored in clustered RDBMS  Comment moderation implemented with GWT  Proven software stack on server-side, we know which screws to turn for optimization Basel | 10.09.2009 | Magnolia Conference | Technical Track 43

Basel | 10.09.2009 | Magnolia Conference | Technical Track 44

Comment moderation: UI requirements Comment moderation requires lots of tedious manual work, UI shouldn‘t make a hard job even worse So UI should have:  High useability  In particular: immediate responsiveness where possible (i.e. no noticeable delay between click and visual response) Basel | 10.09.2009 | Magnolia Conference | Technical Track 45

Comment moderation in admin interface with GWT Solution: Google Web Toolkit (GWT) (Java translated to Javascript + great tooling)  suitable for functional UIs (i.e. without pixel-grained styling)  server roundtrips can be minimized:  As much logic as wanted can be executed in browser (e.g. status message update upon selection change)  As much state as wanted can be held in browser (e.g. caching of previously shown rows in a paging table)  Economical implementation through development and debugging in Java Basel | 10.09.2009 | Magnolia Conference | Technical Track 46

Comment moderation demo Demo… For the technically interested: Use of GWT RPC, turned out to be fast and reliable, most of all: much easier to program than custom REST webservice JPA2 entities are serialized transparently through GWT RPC, by using net.sf.gilead Paging table based on org.gwtlib Following: the big picture… Basel | 10.09.2009 | Magnolia Conference | Technical Track 47

Basel | 10.09.2009 | Magnolia Conference | Technical Track 48

Thank you for your interest! Our contacts.. Sebastian.frick@aperto.de Joerg.Frantzius@aperto.de In the web...  http://www.aperto.de  http://blog.aperto.de  http://www.twitter.com/aperto

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Empowering Magnolia for Enterprise Use Cases - Experience Report

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Empowering Magnolia for Enterprise Use Cases - Experience Report Presentation Transcript