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Checkout page

In the checkout page, a new quote is created indirectly after the priceOrder mutation is triggered in the front. Through a series of asynchronous steps, the on-apply lambda is triggered after the order is priced, and then the deliveryServiceApplyQuote lambda updates the delivery in the RBI order. The full processes is are described in the sequence diagram below.

Sequence diagram

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Decision

Include an optional unavailabilityReason field in the following interfaces:

Consequences

Little impact on platform existing quote logic and validations

Scales well with new reasons for restaurant unavailability

Doesn’t require the creation of new queries in front end

Includes a new field for delivery that will only be used for partners orders

Modifies more interfaces than some of the alternatives

Disregarded alternatives

Disregarded solution 1

Add new values to DeliveryStatus enum to represent possible unavailability reasons. This would require the inclusion of the following values in DeliveryStatus enum definition:

export enum DeliveryStatus {
  // Current values 
  DRIVER_ASSIGNED = 'DRIVER_ASSIGNED',
  DRIVER_AT_CUSTOMER = 'DRIVER_AT_CUSTOMER',
  DRIVER_AT_STORE = 'DRIVER_AT_STORE',
  DRIVER_STARTING = 'DRIVER_STARTING',
  DRIVER_UNASSIGNED = 'DRIVER_UNASSIGNED',
  ORDER_ABANDONED = 'ORDER_ABANDONED',
  ORDER_CANCELLED = 'ORDER_CANCELLED',
  ORDER_CREATED = 'ORDER_CREATED',
  ORDER_DROPPED_OFF = 'ORDER_DROPPED_OFF',
  ORDER_ERROR = 'ORDER_ERROR',
  ORDER_PICKED_UP = 'ORDER_PICKED_UP',
  ORDER_TIMEOUT = 'ORDER_TIMEOUT',
  QUOTE_ERROR = 'QUOTE_ERROR',
  QUOTE_NOT_REQUIRED = 'QUOTE_NOT_REQUIRED',
  QUOTE_REQUESTED = 'QUOTE_REQUESTED',
  QUOTE_SUCCESSFUL = 'QUOTE_SUCCESSFUL',
  QUOTE_UNAVAILABLE = 'QUOTE_UNAVAILABLE'

 // New values
 QUOTE_UNAVAILABLE_RESTAURANT_CLOSED
 QUOTE_UNAVAILABLE_NUMBER_OF_ORDERS
 QUOTE_UNAVAILABLE_TECHNICAL_ISSUES
 QUOTE_UNAVAILABLE_RESTAURANT_NEAR_TO_CLOSE
 QUOTE_UNAVAILABLE_WEATHER
 QUOTE_UNAVAILABLE_NO_DRIVERS_AVAILABLE
 QUOTE_UNAVAILABLE_REDUCED_CAPACITY
} 

Consequences

Doesn’t require changes in multiple interfaces, only a single enum

Bad semantics, since the new values are quote error reasons and not really a delivery status

Will impact the quote validation logic in many areas of the platform (e.g. isPriceOrderRequestComplete in fulfillment)

Doesn’t scale with new quote errors

Disregarded solution 2

This solution proposes the same as the chosen solution for the store-locator page, but for the checkout page, instead of saving the unavailability reason in the order it will save it in the quote dynamo table and poll for it in WL App. This would require the inclusion of the unavailabilityReason field in the following interfaces:

Currently, if any of the quote validations in the create quote fail and throw an error, the quote is not saved in the delivery table. This solution would require the create quote logic to also save quotes with errors. With this information stored, WL App can pool for it using the getQuote endpoint.

Consequences

Scales well with new reasons for restaurant unavailability

Doesn’t modify RBI Order interface

Adds a new pooling in the checkout, which is a critical page that already has poor performance

Saves failed quotes in dynamo, which increase storage cost in AWS