GSE Nordic 2015 CICS Connectivity in DevOps The business driver behind adopting a DevOps approach to developing software, is the need to deliver applications to the market faster, with lower costs and higher quality. With CICS Transaction Server providing the core services on which many of these applications rely, the importance of being able to connect to CICS and reuse these core services continues to increase. When CICS introduced native Web services about a decade ago, SOA became a reality for CICS customers. Today, many customers are doing tens of millions of SOAP based CICS Web services per day. Some are doing much more. But SOAP based CICS Web services are only a part of the CICS connectivity story. Support for the REST architectural style in CICS is an increasingly popular alternative to SOAP. And JSON is a popular alternative to XML for many application use cases. In this session, we will explore the different CICS connectivity options, suggest use-cases in which they can be of most value, and most importantly, learn which is the right tool for the job.

1. CICS Connectivity in DevOps
Dan Millwood
CICS - S111

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configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve
results similar to those stated here.
Please note…

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Agenda
• What is DevOps?
• Improving the services CICS provides
• Communication
• Interface Design
• Extending SOAP / JSON interfaces
• How to create an interface
• The power of JAX-RS
• Connectivity choice factors
• Comparison of connectivity options
• Recommendations
•

4. © 2015 IBM Corporation
What is DevOps?
Development Operations
“The operations team take
an age to do anything. It
really impacts our ability to
deliver”
“I dont trust the developers.
I must protect the production
systems from their poor
code”

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See the bigger picture
Development Operations
“We are all driving towards a common goal”
“To deliver the software and services needed to meet the
business objectives for our company”

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Or the even bigger picture
Mobile Team Middleware
Team
CICS Team Service
Provider
CICS provides
services
CICS consumes
services

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How can we improve our services to help consumers?
• How can we deliver services faster?
• How can we deliver better quality services?
• How can we ensure the services we deliver meet the needs of
our consumers?
• How can we ensure that we can update the service to meet the
continued needs of our consumers?
• Good communication between the service consumers and the
service provider
• Good interface design
• Good choice of connectivity protocol and data format
•
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Good communication
• What we do in CICS
– Design Partnerships with customers help us to
●
Understand our customers needs better
●
Design a solution that meets those needs
– We try to “Fail Fast”
●
Every few weeks we playback to the customers on what we are doing
●
If we get it wrong, we can change it before the design is finalised
●
• How does this relate to designing service interfaces?
– Talk to the service consumers regularly to understand their needs
– Design the high level interface interactions on paper first and review it with
consumers, reworking as needed
– Design the data layout and field names for the various interface calls
●
Can the consumer correctly guess the meaning of fields unaided?
– Then think about implementing a first pass at the interface so the consumer
can try it out
– 8

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Good Interface Design
• A well thought out interface is:
– Easy to understand
●
Can I correctly guess meanings of fields?
– Easy to consume
●
Is the interface using a protocol I can work with?
– Easy to extend
●
Can an update be rolled out without breaking clients?
Take the time to design your interface.
It is the key to your service being useful!
•
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Wsbind based web services development
10
Bottom up – Start with a language
structure and convert it into a form
usable as a CICS web service
Top down – Start with a WSDL or
JSON schema document and convert
it into a form usable as a CICS web
service.
CICS
Bottom
up
Top
down
WSDL or JSON
schema
Language
Structures
e.g. COPYBOOK

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Wsbind based web services development
11
Bottom up – Start with a language
structure and convert it into a form
usable as a CICS web service
Top down – Start with a WSDL or
JSON schema document and convert
it into a form usable as a CICS web
service.
CICS
Bottom
up
Top
down
WSDL or JSON
schema
Language
Structures
e.g. COPYBOOK
A generated interface is
unlikely to be as easy to
use as one you designed

12. © 2015 IBM Corporation
Catalog Manager Sample
* Catalogue COMMAREA structure
03 CA-REQUEST-ID PIC X(6).
03 CA-RETURN-CODE PIC 9(2) DISPLAY.
03 CA-RESPONSE-MESSAGE PIC X(79).
* Fields used in Inquire Catalog
03 CA-INQUIRE-REQUEST.
05 CA-LIST-START-REF PIC 9(4) DISPLAY.
05 CA-LAST-ITEM-REF PIC 9(4) DISPLAY.
05 CA-ITEM-COUNT PIC 9(3) DISPLAY.
05 CA-CAT-ITEM OCCURS 15.
07 CA-ITEM-REF PIC 9(4) DISPLAY.
07 CA-DESCRIPTION PIC X(40).
07 CA-DEPARTMENT PIC 9(3) DISPLAY.
07 CA-COST PIC X(6).
07 IN-STOCK PIC 9(4) DISPLAY.
07 ON-ORDER PIC 9(3) DISPLAY.
Bottom up will create
A web service that expects all the fields as input and returns all the
fields as output
Variable names that are hard to understand
What does CA-LIST-START-REF mean?

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Use a meet-in-the-middle approach to expose
existing applications as Web services
Design the interface
to the service
New CICS
program
Existing
business application
(COBOL, C, C++, PLI)
Meet in the middle
Map
and
Generate
1) Design the new interface
2) Top-down generation of
language structures for the new
interface
3) Write new program to map
between existing business
applications interface and the
newly generated interface.

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Use a top-down approach to expose new
applications as Web services
1) Design the new interface
2) Top-down generation of
language structures for the new
interface
3) Write new business
application that uses the generated
language structures for its input
and output
New business
application
(COBOL, C, C++,
PLI, Java)
Design the interface
to the service
Top-down
Generate

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How to create an interface
• SOAP Web services using WSBind files
– Design the layout of the SOAP data, variable names etc
– Create a WSDL file using a WSDL Editor
• JSON Web services using WSBind files
– Design the layout of the JSON data, variable names etc
– Create a JSON schema
• JSON Web services using JAX-RS in Liberty
– Design the layout of the JSON data, variable names etc
– Implement using annotations on variables in a Java class
– Optionally create a JSON schema for consumers of service to use
• SOAP Web services using JAX-WS in Liberty
– Design the layout of the SOAP data, variable names etc
– Create a WSDL file
– Use WSImport tool to create Web service interface then create class that implements the
interface
• Commarea / Channel exposed to client
– Design and create data structure(s) representing the data
•

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The power of JAX-RS (and JAXB)
• Restful services from Liberty in CICS
• Both JSON and XML supported
• Built from annotations in Java source code
@XmlRootElement
@XmlAccessorType(XmlAccessType.FIELD)
public class Customer {
private String name;
private String company;
private int age;
public void setName(String s) {
name = s;
}
public void setCompany(String s) {
company = s;
}
public void setAge(int i) {
age = i;
}
}
XML
<?xml version="1.0" encoding="UTF-8"?>
<customer>
<name>John Smith</name>
<company>General Insurance</company>
<age>40</age>
</customer>
JSON
{
“name”:”John Smith”,
“company”:”General Insurance”,
“age”:40
}

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The power of JAX-RS (and JAXB)
@ApplicationPath("/CustomerApp")
@Path("/query")
public class CustomerApplication extends Application {
@GET
@Path("/customer")
@Produces({"application/xml","application/json"})
public Customer getCustomer() {
Customer customer = new Customer();
customer.setName("John Smith");
customer.setCompany("General Insurance");
customer.setAge(40);
return customer;
}
}
A http GET request to .../CustomerApp/query/customer returns the XML variant
A http GET request to .../CustomerApp/query/customer with http header
Accept: application/json returns the JSON variant
You could map a COMMAREA to Java using J2C or JZOS, then expose a new JSON
service using JAX-RS and JAXB.

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Designing an extensible SOAP interface
• SOAP messages must conform to a schema
– Adding a new field to a SOAP message will break its conformity to the
schema
– You can plan ahead by use of the xsd:any tag
<xsd:element name="Customer">
<xsd:complexType>
<xsd:sequence>
<xsd:element name="Title" type="xsd:string"/>
<xsd:element name="FirstName" type="xsd:string"/>
<xsd:element name="Surname" type="xsd:string"/>
<xsd:any minOccurs="0" maxOccurs=”unbounded”/>
</xsd:sequence>
</xsd:complexType>
</xsd:element>
– In this instance, any data elements following Surname will be accepted so a
future update to the Customer element could be made without breaking
existing clients
– Most useful for enabling the service consumer to ignore additional data
added by the provider

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Designing an extensible JSON interface
• JSON often used informally (without a schema)
• A lot of JSON consumers are based off of example messages and
documentation.
– They will typically just look for the fields they want, therefore sending
new properties in the response to them isn't a problem
• The top down WSBind tooling does require a JSON schema
– Whilst the schema allows for extensions, the WSBind tooling does
not.
– If CICS is the service provider, you will probably be able to extend
the response message without breaking consumers
– If CICS is a WSBind based requester and the service provider
extends the response data, the CICS requester will need updating

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Connectivity Choice Factors
• Client/server coupling
– Tightly or loosely coupled?
• Synchronous or asynchronous invocation
– Request/reply or event-based?
• Application development tools
– Depends on preference or what you already have
• Security
– Does choice support your security requirements?
• Transactional scope
– 2PC or not 2PC (that is not the only question!)
• High availability and scalability
– Who doesn’t want high availability and scalability?
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Connectivity Choice Factors
• Client needs
– What are the clients preferred connectivity options?
– What would tempt the clients to use this service?
– How quickly is the service required, and for how long?
• How easily can the service interface be extended?
– What are the impacts on the clients to extending the interface?
• What development skills are available?
– Is there time to train people in something new, or funding to bring in new
skills to the team?
• What is the required service response time?
– Response time can impact the decision as to where to host the service
• Anticipated load
– Can the load requirements be met?
•

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Comparison of connectivity options
SOAP/
HTTP or
WMQ
JSON/
HTTP
CTG HTTP WMQ WOLA Sockets
Security Message
+ TLS +
client auth
+ basic
auth +
asserted
id
TLS +
client auth
+ basic
auth
TLS +
client
auth +
basic
auth +
asserted
id
TLS +
client
auth +
basic
auth
Queue +
TLS +
AMS +
basic auth
+
asserted
id
(TLS not
required)
+
asserted
id
TLS +
client auth
Transactionality 2 PC /
Local
Local 2 PC /
1 PC /
Local
Local Queue 2 PC /
Local
Local
Binary data Yes Base64 Yes Yes Yes Yes Yes
Required
middleware
None None (or
zOS
Connect)
CTG +
JEE
server
None WMQ on
z/OS
WAS on
z/OS
None

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Comparison of connectivity options
SOAP/
HTTP or
WMQ
JSON/
HTTP
CTG HTTP WMQ WOLA Sockets
Inbound /
Outbound
Both with
CICS API
for
outbound
Both Inbound Both Both Both Both
Easy to
extend
Depends
on
interface
design
Probably
able to add
new fields
without
client
changes
Depends
on
interface
design
Depends
on
interface
design
Depends
on
interface
design
Depends
on
interface
design
Depends on
interface
design
Standard for
reporting
errors
SOAP
Fault
No defined
standard
No
defined
standard
Status
code
No defined
standard
No defined
standard
No defined
standard

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Recommendations
• Web services
– Should be first consideration for service enabling CICS applications,
particularly when you need to support multiple service requester types or
need bi-directional support
– SOAP
●
A mature set of standards with high QoS via WS-* specifications
●
Widely supported across the industry, with good tooling support
●
Strict, well defined data structures
●
Best for enterprise application to enterprise application communication
– JSON
●
Easy to integrate into JavaScript applications, making it a preferred data format
for many mobile application developers
●
A simpler way of representing data than SOAP, but with fewer qualities of service
and less tooling support
●
Use when providing services for mobile applications, web pages, or when the
market demands it

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Recommendations
• CTG
– Most appropriate solution when service requester is JEE component and when high
QoS required
• WOLA
– Particularly useful for JCA access to and from CICS, and for very high throughput and
performance requirements between WebSphere Application Server for z/OS and CICS
• HTTP
– Use with web services, RESTful services, and ATOM feeds, or when remote
client/server only supports HTTP.
• WebSphere MQ for z/OS
– Exploit MQ for basic messaging, asynchronous services and flowing web services.
• CICS Sockets
– Use when remote client/server only supports TCP/IP sockets communication
•

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Questions

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