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Lead Consultant
www.ajira.tech
Tamizhvendan S
Passionate, Pragmatic and Polyglot Programmer
https://www.demystifyfp.com
tamizhvendan
Building an
E-Commerce Marketplace
Middleware in Clojure
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OMS
Back office
Cromā
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Back office
Cromā
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Cromā
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Marketplace
Middleware
Cromā
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The System Requirement
OMS
Back office
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The System Requirement
OMS …
IBMMQ
Back office
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The System Requirement
OMS …
IBMMQ Marketplace
Middleware
Back office
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The System Requirement
OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
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The System Requirement
OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
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The System Requirement
OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
PostgreSQL
Back office
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OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
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OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
Twelve Different Types Of Messages
Ranging, Deranging, Pricing, Confirming Order, etc.,
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OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
Twelve Different Types Of Messages
Ranging, Deranging, Pricing, Confirming Order, etc.,
Three Different Target Systems
Tata-CliQ, Flipkart, Amazon
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OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
Twelve Different Types Of Messages
Ranging, Deranging, Pricing, Confirming Order, etc.,
Three Different Target Systems
Tata-CliQ, Flipkart, Amazon
Four Different Data Representations
OMS, Tata-CliQ, Flipkart, Amazon
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OMS …
IBMMQ Marketplace
Middleware
HTTP
Back office
Twelve Different Types Of Messages
Ranging, Deranging, Pricing, Confirming Order, etc.,
Three Different Target Systems
Tata-CliQ, Flipkart, Amazon
Four Different Data Representations
OMS, Tata-CliQ, Flipkart, Amazon
Error Handling
Invalid Message, Invalid Channel Configuration, Processing Failure, etc.,
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How to implement
Marketplace Middleware ?
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Lifecycle of an OMS Message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message
Processing the message
Logging the events
OMS …
IBMMQ Marketplace
Middleware
HTTPS
Back office
Handling the message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Logging the events PostgreSQL, Slack)
OMS …
IBMMQ Marketplace
Middleware
HTTPS
Back office
Handling the message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Handling the message
Logging the events PostgreSQL, Slack)
Separate Application Boundaries
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Parsing The Message
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A Sample Ranging Message
AEEXTNChannelList>
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Parsed Ranging Message
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A Sample Pricing Message
AEEXTNChannelItemList>
AEEXTNChannelList>
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Parsed Pricing Message
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Parsing The Message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
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Processing The Message
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Ranging on Tata-CliQ Channel
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Pricing on Tata-CliQ Channel
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Ranging on Flipkart Channel
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Pricing on Flipkart Channel
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Processing The Message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message (ranging)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
Getting the channel config
Polymorphic)
Updating the channel
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Getting Channel Configuration
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Getting Channel Configuration
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Getting Channel Configuration
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message (ranging)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
Getting the channel config
Polymorphic)
Updating the channel
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Processing Ranging on Channels
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Ranging on Tata-CliQ Channel
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Transforming Ranging Items
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Transforming Ranging Items
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Transforming Ranging Items
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Tata-CliQ API Client
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Tata-CliQ API Client
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Tata-CliQ API Client
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Ranging on Flipkart Channel
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message (ranging)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
Getting the channel config
Polymorphic)
Updating the channel
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Processing the Ranging Message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message (pricing)
Handling the message
Logging the events PostgreSQL, Slack)
Pricing - Repeat Yourself
Getting the channel config
Polymorphic)
Updating the channel
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
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Handling the OMS Message
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
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Message Handling 10,000 ft View
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Integration Operation
Segregation Principle (IOSP)
A module should either
contain business logic or
integrate other modules but
not both.
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Polymorphic)
Polymorphic)
Processing the message
Getting the channel config
Transforming the message
Performing the action
Reading messages from IBMMQ and dispatching them to handler
Parsing the message
Handling the message
Polymorphic)
Logging the event PostgreSQL, Slack)
Progress …
Getting the channel config
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Reading Messages from IBM-MQ
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Reading Messages from IBM-MQ
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Reading messages from IBMMQ and dispatching them to handler
Parsing the message Polymorphic)
Processing the message Polymorphic)
Handling the message
Logging the events PostgreSQL, Slack)
Progress …
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…
IBMMQ
Logging The Events
OMS
Marketplace
Middleware
HTTP
Back office
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…
IBMMQ
Logging The Events
OMS
Marketplace
Middleware
HTTP
Back office
PostgreSQL
Back office
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https://www.youtube.com/watch?v=yTkzNHF6rMs
… functional core is surrounded by a shell of
imperative code: it manipulates stdin, stdout, the
database, and the network, all based on values
produced by the functional core.
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https://www.youtube.com/watch?v=yTkzNHF6rMs
… functional core is surrounded by a shell of
imperative code: it manipulates stdin, stdout, the
database, and the network, all based on values
produced by the functional core.
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Marketplace
Middleware
PostgreSQL
Back office
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Don’t Do! Express!!
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Log Appenders
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Imperative Shell
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Functional Core
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Imperative Shell
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Imperative Shell
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Imperative Shell
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Imperative Shell
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Imperative Shell
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Error Handling
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Don’t Do! Express!!
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Don’t Do! Express!!
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Don’t Do! Express!!
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handling with care :)
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Error Handling
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processing with care :)
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Error Handling
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Inspired By