mri-bp2015
Description
Keynote presentation for
Workshop on Methodologies for Robustness Injectioninto Business Processes, May 2015
Transcript
Keith D Swenson
May 2015
@swensonkeith
Robustness in Process
http:// www.slideshare.net / kswenson / mribp2015
1. Coding Effect on Robustness
2.Process and Transactions
3.Transactions and Messages
4. Distributed Scenarios
5. Etiquette
APPLICATION
DISK SPACE ….
The Day the Application Stood Still
Application built and deployed
Works fine with some number of people, say 50
CPU is around 2%
Memory and disk IO is reasonable
Above that number of people
CPU spikes to ~90%
Users complain of frozen screens
Disk IO and memory usage spike
Becomes impossible to do the simplest tasks
What is going on?
The Beast
…
try {
InitialContext cxt = new InitialContext();
String dataSourceJndi = mapComponentSettings.get(“AssocDataSource”);
DataSource ds = (DataSource) cxt.lookup(dataSourceJndi);
privateAssociations.setDataSource(ds);
}
catch (Exception e) {
log.error(“Unable to load JNDI data source from context.”);
}
…
Don’t Swallow
Exceptions
…
try {
InitialContext cxt = new InitialContext();
String dataSourceJndi = mapComponentSettings.get(“AssocDataSource”);
DataSource ds = (DataSource) cxt.lookup(dataSourceJndi);
privateAssociations.setDataSource(ds);
}
catch (Exception e) {
log.error(“Unable to load JNDI data source: ” + e.toString());
return null;
}
…
Don’t Swallow
ExceptionsYou Don’t Know
what the
Exception
will be!
ADD the
Current
Context
& RETHROW
Don’t Log
IT!
Callers
Don’t test
For NULL
Normal
Situation
Error
Situation
Error
Situation
Error
Situation
condition
condition
condition
Started at Netscape in 1990’s
Input to Java team
Informed by projects from iFlow
and Interstage BPM in 2000’s
While the purpose of error
reporting is to assist in solving
the problem.
There is a problem
The system can’t handle it
The more completely the problem is
described, the faster it is resolved,
the happier users will be.
Throwing an exception should never be used to return a “normal” value
back to the caller.
Describe the current scope! Not what you think caused the exception.
Use a single monomorphic exception class.
• Every method (that throws) should declare throwing java.lang.Exception.
• Every catch block should catch java.lang.Exception
Do not assume that there is only one possible exception to be caught.
Always test for the exact exception class and the exact message key
before handling the exception in any other way than wrap and re-throw.
Don’t worry about making catch blocks efficient. Instead, design them to
be easy to maintain and easy to verify that the exception correctly
handled.
Act as if LOG files are not accessible
https://agiletribe.wordpress.com/
TRANSACTIONS
3GL Code
Data Sources
Resting state Transaction
Occurs
Resting state
A transition is a transaction
Transaction
Data Sources
Transaction Rollback … User View
Transaction
Rollback
Data Sources
Fail
Data Sources
Error State
Resting state
(error mode)
Transaction 1 Fail
Rollback
Transaction
2
Subprocess Scenario
Parent Process
Child Process
Subprocess Scenario
Parent Process
Child Process
Subprocess Scenario
Parent Process
Child Process
Subprocess Scenario
Parent Process
Child Process
Subprocess Scenario
Parent Process
Child Process
Subprocess Scenario
Parent Process
Child Process
Retries are Evil
Retries!
Data Sources
BPMN Transactional Notation
Transaction 1
Transaction 2
A Single
Transaction
Any failure in
either node,
you roll back to
where you started,
and put the process
in error mode.
What does this mean?
A BPMN transaction boundary
Something like
this might make
more sense …
but not really.
Front
1
2
3
Unit 1 Unit 2
Unit 3
4
5
6
Message
Bus
Front
Unit 1 Unit 2
Unit 3
Unit 5
Unit 4
Message
Bus
Fire and Forget
Front
Unit 1 Unit 2
Unit 3
Unit 5
Unit 4
Fail
Message
Bus
HOWEVER…
Distributed Systems
One transactionally
consistent enclave
Another transactionally
consistent enclave
You have to deal with the fact that you can not have
transactional consistency everywhere
Business Process != System Architecture
Business Process != System Architecture
Required configuration in 6 different environments to be
consistent.
If one got our of sync, it broke the processes.
Messages were assumed to be reliable, but between reliable
system, they can NOT be reliable.
Your protocol MUST assume that messages are reliable, and
must deal with that.
Gringo
Symposium Process
Reserve
Room
Invite
Speaker
Order
Drinks
Gringo
Symposium Process
Order
Drinks
Order Fulfillment
A
B
Infinite Liquors
A reliable message
Transport with
“exactly once”
delivery
“Six cases of
Sierra Nevada
Pale Ale for
delivery.”
2:07 PM 2:07 PM
Gringo
Symposium Process
Order
Drinks
Order Fulfillment
A
B
Infinite Liquors
Disk
Crash
2:10 PM
Gringo
Symposium Process
Order
Drinks
Order Fulfillment
A
B
Infinite Liquors
2:30 PM
1:00 PM
Backup
2:30 PM
Reliable
System
#1
Reliable
System
#2
Always
Consistent
Always
Consistent
Reliable
System
#1a
Reliable
System
#1c
Always
Consistent?
#1b
Consistency Seeking
Gringo
Symposium
Order
Drinks
Order Fulfillment
A
B
Infinite Liquors
Orders
FOR
Infinite
Liquors
Orders
FROM
Gringo
Compare.
Are these
Consistent?
Take action
To make
Consistent.
Hourly
Poll.
Ship Bridge
to Engine Room
telegraph
use the same
principle
BPM
Roles, and Etiquette
Purchasing Agent Product Development
Business Etiquette Modeling
For each role in an organization, determine:
each of the services that role might perform
what must be provided
what will be produced
what conditions will decide whether the task is accepted or not
what contexts all this is valid in
Use simulation across many roles in the organization to see if
the process is ‘optimal’
tweak the etiquette rules as necessary
Record history and track KPIs like normal
Respond if necessary by tweaking the etiquette rules
Cross Company Emergent Processes
Manufacturing Company
Consulting Firm
1. Coding Effect on Robustness
2.Process and Transactions
3.Transactions and Messages
4. Distributed Scenarios
5. Etiquette
Workflow Management Coalition
• Standards
• Books
• Awards
• Information
Four years running. Four books
Real-life use cases.
Experience with ACM.
http://AdaptiveCaseManagement.org/
Workflow Management Coalition
2014:
Thriving on
Adaptability:
Best
practices
for knowledge
workers
NEW!
When Thinking Matters in
the Workplace: How
Executives and Leaders of
Knowledge Work Teams can
Innovate with Case
Management.
http:// ThinkingMattersBook.com
Q & A
http:// www.slideshare.net / kswenson / mribp2015
Antifragility
http:// www.slideshare.net / kswenson / bpm201446:00
We know what
fragility is.
But what is
the opposite?
Fragile
?
Fragile Robust
Fragile Robust Antifragile
Definition of BPM
Business Process Management (BPM) is a
discipline involving any combination of
modeling, automation, execution,
control, measurement and optimization
of business activity flows,
in support of enterprise goals,
spanning systems, employees, customers and partners
within and beyond the enterprise boundaries.
“The System”
Your
Organization
IT
System
&
People
Offices
Agreements
Skills
Expertise
Relationships
Hardware
Software
Data
Desire to
optimize
the entire
system
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