E-commerce under the hood

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E-commerce: under the hood Sean Sullivan February 21, 2017 Portland Java User Group

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• software engineer • 20 years Java • 6 years at Gilt • back ofﬁce systems @ Gilt About me

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www.gilt.com

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No content

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Case studies • order processing • logistics invoicing • payment processing • checkout

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Case studies • order processing • logistics invoicing • payment processing • checkout

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2008 order processing

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2017 discount service payment service ship calculator service order processing

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Gilt order

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Order items

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ORDERS ORDER_ITEMS Domain tables

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ORDERS orders_audit_trigger AFTER INSERT OR DELETE OR UPDATE ON orders FOR EACH ROW EXECUTE PROCEDURE orders_audit_function() ORDER_ITEMS order_items_audit_trigger AFTER INSERT OR DELETE OR UPDATE ON order_items FOR EACH ROW EXECUTE PROCEDURE order_items_audit_function() Triggers

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ORDERS_AUDIT_LOG ORDER_ITEMS_AUDIT_LOG Audit tables

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select id,status,submitted_at,shipped_at from orders where id = 85352432; -[ RECORD 1 ]+--------------------------- id | 85352432 status | x submitted_at | 2017-02-13 20:57:25+00 shipped_at | 2017-02-15 05:30:16.376+00

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select count(*) from orders_audit_log where order_id = 85352432; -[ RECORD 1 ] count | 12

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select order_id,change_type,changed_at, old_shipped_at,new_shipped_at from orders_audit_log where order_id = 85352432 and old_shipped_at is null and new_shipped_at is not null; -[ RECORD 1 ]--+------------------------------ order_id | 85352432 change_type | u changed_at | 2017-02-15 14:12:26.668751+00 old_shipped_at | new_shipped_at | 2017-02-15 05:30:16.376+00

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More information https://wiki.postgresql.org/wiki/Audit_trigger https://wiki.postgresql.org/wiki/Audit_trigger_91plus https://github.com/2ndQuadrant/audit-trigger https://github.com/pgaudit/pgaudit

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Case studies • order processing • logistics invoicing • payment processing • checkout

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http://www.recode.net/2014/2/4/11623056/gilts-new-business-running-logistics-for-other-e-commerce-sites February 2014

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February 2014

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warehouse cloud WMS invoicing service messaging service

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invoicing service • Scala • Akka • Squeryl • Postgres • db-journaling

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db-journaling https://github.com/gilt/db-journaling

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Case studies • order processing • logistics invoicing • payment processing • checkout

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Checkout service Order processing Payment service

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OPM (for MongoDB) https://github.com/gilt/opm

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“OPM is a Scala library for managing the value of an object over time as a timeline of changes” https://github.com/gilt/opm

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Demo! payment history endpoint

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Case studies • order processing • logistics invoicing • payment processing • checkout

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Web Checkout Android Checkout iPhone Checkout Checkout service

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https://martinfowler.com/eaaDev/EventSourcing.html

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https://martinfowler.com/eaaDev/EventSourcing.html “Capture all changes to an application state as a sequence of events”

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https://martinfowler.com/eaaDev/EventSourcing.html “Event Sourcing ensures that all changes to application state are stored as a sequence of events”

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https://martinfowler.com/eaaDev/EventSourcing.html “The key to Event Sourcing is that we guarantee that all changes to the domain objects are initiated by the event objects"

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http://blogs.atlassian.com/2014/08/replayable-transactions-event-sourcing-dynamodb/

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http://blogs.atlassian.com/2014/08/replayable-transactions-event-sourcing-dynamodb/ "event sourcing involves storing the sequence of events that produce the current view of the entity"

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http://blogs.atlassian.com/2014/08/replayable-transactions-event-sourcing-dynamodb/ "an event represents an operation or transformation from one view of the entity to another"

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http://blogs.atlassian.com/2014/08/replayable-transactions-event-sourcing-dynamodb/ “events are therefore tied to a starting view or snapshot, thus making any transformation idempotent”

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https://github.com/gilt/lib-event-sourcing/

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import com.gilt.eventsourcing.Transform  import com.gilt.eventsourcing.Transform.{Delete, Insert, Update}  import com.gilt.eventsourcing.dynamodb.DynamoDbMappingEventSource import com.gilt.eventsourcing.dynamodb.DynamoMappings.Mappings  import com.gilt.eventsourcing.dynamodb.client.{AttributeDefinition, _}  import com.gilt.eventsourcing.dynamodb.util.TableHelper  lib-event-sourcing

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object DemoDynamoDBEventSource extends DynamoDbMappingEventSource[JsValue] class DemoDynamoCommits(client: AmazonDynamoDBClient) extends DynamoCommits(client) class DemoMappingAPI(val store: Storage[Task]) extends EventSourceAPI[Task] lib-event-sourcing

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val key = LogicalKey(uid) eventSourceApi.save( key, Some(ContentKey(Json.toJson(thing)))).run val result = eventSourceApi.get(key) lib-event-sourcing

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def put(order: Order): Task[Try[Unit]] = { val checkoutGuid: CheckoutSessionGuid = order.sessionGuid eventSourceApi.save( LogicalKey(checkoutGuid.toString()), Some(ContentKey(Json.toJson(order)))). map(_ => Success(())). handle { case e: Exception => Failure(e) } } Gilt checkout service