Building an E-Commerce Marketplace Middleware in Clojure

Have you ever wondered how we can build a real-world, production-ready, end-to-end application using the functional programming principles? Immutability, Pure Functions and all other functional programming things sound good on paper but How can we build something useful by applying it?

At Ajira, We recently built an e-commerce marketplace middleware in Clojure for a leading retail chain to sell their products on multiple e-commerce sites seamlessly. In this case study, we are going to build a minimal version of this project using which I will be sharing how we implemented it.

Transcript

1. 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
2. OMS Back office Cromā
3. Back office Cromā
4. Cromā
5. Marketplace Middleware Cromā
6. The System Requirement OMS Back office
7. The System Requirement OMS … IBMMQ Back office
8. The System Requirement OMS … IBMMQ Marketplace Middleware Back office
9. The System Requirement OMS … IBMMQ Marketplace Middleware HTTP Back office
10. The System Requirement OMS … IBMMQ Marketplace Middleware HTTP Back office
11. The System Requirement OMS … IBMMQ Marketplace Middleware HTTP Back office PostgreSQL Back office
12. OMS … IBMMQ Marketplace Middleware HTTP Back office
13. OMS … IBMMQ Marketplace Middleware HTTP Back office Twelve Different Types Of Messages Ranging, Deranging, Pricing, Confirming Order, etc.,
14. OMS … IBMMQ Marketplace Middleware HTTP Back office Twelve Different Types Of Messages Ranging, Deranging, Pricing, Confirming Order, etc., Three Different Target Systems Tata-CliQ, Flipkart, Amazon
15. OMS … IBMMQ 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
16. OMS … IBMMQ 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.,
17. How to implement Marketplace Middleware ?
18. Lifecycle of an OMS Message
19. Reading messages from IBMMQ and dispatching them to handler Parsing the message Processing the message Logging the events OMS … IBMMQ Marketplace Middleware HTTPS Back office Handling the message
20. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Logging the events PostgreSQL, Slack) OMS … IBMMQ Marketplace Middleware HTTPS Back office Handling the message
21. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Handling the message Logging the events PostgreSQL, Slack) Separate Application Boundaries
22. Parsing The Message
23. A Sample Ranging Message <EXTNChannelList> <EXTNChannelItemList> <EXTNChannelItem ChannelID="UA" EAN="EAN_1" ItemID="SKU1" RangeFlag="Y"AB <EXTNChannelItem ChannelID="UA" EAN="EAN_2" ItemID=“SKU2" RangeFlag="Y"AB AEEXTNChannelItemList> <EXTNChannelItemList> <EXTNChannelItem ChannelID="UB" EAN="EAN_3" ItemID="SKU3" RangeFlag="Y"AB AEEXTNChannelItemList> AEEXTNChannelList>
24. Parsed Ranging Message
25. A Sample Pricing Message <EXTNChannelList> <EXTNChannelItemList ChannelID="UA"> <EXTNChannelItem ItemID="194521"> <VKP0PriceLine VKP0Price="999.1292"AB <OfferPriceLine OfferPrice="999"AB <ZMRPPriceLine ZMRPPrice="1000"AB AEEXTNChannelItem> <EXTNChannelItem ItemID="185027"> <VKP0PriceLine VKP0Price="650"AB <OfferPriceLine OfferPrice="650"AB <ZMRPPriceLine ZMRPPrice="700"AB AEEXTNChannelItem> AEEXTNChannelItemList> AEEXTNChannelList>
26. Parsed Pricing Message
27. Parsing The Message
37. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Handling the message Logging the events PostgreSQL, Slack) Progress …
38. Processing The Message
39. Ranging on Tata-CliQ Channel
40. Pricing on Tata-CliQ Channel
41. Ranging on Flipkart Channel
42. Pricing on Flipkart Channel
43. Processing The Message
48. Reading messages from IBMMQ 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
49. Getting Channel Configuration
50. Getting Channel Configuration
51. Getting Channel Configuration
52. Reading messages from IBMMQ 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
53. Processing Ranging on Channels
63. Ranging on Tata-CliQ Channel
64. Transforming Ranging Items
65. Transforming Ranging Items
66. Transforming Ranging Items
67. Tata-CliQ API Client
68. Tata-CliQ API Client
69. Tata-CliQ API Client
72. Ranging on Flipkart Channel
73. Reading messages from IBMMQ 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
74. Processing the Ranging Message
75. Reading messages from IBMMQ 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
76. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Handling the message Logging the events PostgreSQL, Slack) Progress …
77. Handling the OMS Message
78. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Handling the message Logging the events PostgreSQL, Slack) Progress …
79. Message Handling 10,000 ft View
80. Integration Operation Segregation Principle (IOSP) A module should either contain business logic or integrate other modules but not both.
82. Polymorphic) Polymorphic) Processing the message Getting the channel config Transforming the message Performing the action Reading messages from IBMMQ and dispatching them to handler Parsing the message Handling the message Polymorphic) Logging the event PostgreSQL, Slack) Progress … Getting the channel config
83. Reading Messages from IBM-MQ
84. Reading Messages from IBM-MQ
85. Reading messages from IBMMQ and dispatching them to handler Parsing the message Polymorphic) Processing the message Polymorphic) Handling the message Logging the events PostgreSQL, Slack) Progress …
86. … IBMMQ Logging The Events OMS Marketplace Middleware HTTP Back office
87. … IBMMQ Logging The Events OMS Marketplace Middleware HTTP Back office PostgreSQL Back office
88. 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.
89. 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.
90. Marketplace Middleware PostgreSQL Back office
91. Don’t Do! Express!!
93. Log Appenders
94. Imperative Shell
95. Functional Core
96. Imperative Shell
97. Imperative Shell
98. Imperative Shell
99. Imperative Shell
100. Imperative Shell
102. Error Handling
103. Don’t Do! Express!!
104. Don’t Do! Express!!
105. Don’t Do! Express!!
106. handling with care :)
107. Error Handling
108. processing with care :)
109. Error Handling
110. Inspired By