Front-end
Say we have the following order:
With this improvements, we want to split the amount of the delivery fee into two fields:
delivery fee and management fee.
Similar to what we have in the current app (airtouch):
gastos de envio → delivery fee
otros gastos → management fee
FE tech discovery can be found here
Mapping of how delivery fee is set (BE):
PriceOrder
Calls partner to get price related info including fees.
Persists fees into the database
GetOrder
Retrieves order related info from the database, including fees
Backend discovery
priceOrder
intl-whitelabel-app →
priceOrder
intl-whitelabel-graphql →
priceOrder
intl-fullfilment-service →
priceOrder
updateDeliveryEntry
intl-delivery-service
getFeeAndDiscountByBrand
( using intl-packages delivery lib or intl-delivery-service?)
Delivery fees are managed by the fee service ( intl-delivery-service):
getFeeAndDiscountByBrand
getFeeChargeByTier
It get the values from launchdarkly based on the service mode.
If catering , it uses
tiered-catering-delivery-fees
Otherwise, it uses
tiered-delivery-fees
Searches the tier list from highest to lowest key, stopping when requestedAmountCents exceeds that tier.
Said that, we can to analyze the following "return” to propose the management fee. Apart from that, looks like Launchdarkly existing configuration (variations) were thought to enable "free delivery” and we can leverage this approach.
return { baseDeliveryFee: fee, --> LD fee deliverySurchargeFee, --> LD expandedFees (based on delivery quotation value) discount, --> LD discount fee: fee + geographicalFee + serviceFee + smallCartFee + deliverySurchargeFee, geographicalFee, --> LD geographicalFee serviceFee, --> Calculated with LD serviceFeePercent of the requested amount smallCartFee, --> LD smallCartFee };
Going further in priceOrder (fulfillment), it reaches the applyQuote service
await this.quotesApi.applyQuote(applyQuoteParameters);
/api/v1/quotes/apply
return this.service.enqueueApplyQuoteNotification(request);
→SQS_APPLY_QUOTE_QUEUE_URL
/SNS_QUOTE_TOPIC_ARN
Here, the services are decoupled. Therefore, there is a lambda function that listens to the apply quote queue and handles it.
intl-delivery-service
on-apply-quote Lambda
return quoteService.applyQuote(message);
async applyQuote(request: ApplyQuoteRequestDto): Promise<ApplyQuoteResponseDto> {
getFees
As result, zeroed fees are being set. See cloud watch logs from lambda function.
*The quotedFee comes from partners. In Iberia, it comes from DMP, aka: intl-partners-delivery. But it depends on the market. DMP also uses launchdarkly to calculate the fee. It doesn’t get the other fees.
Once we get these fees (including the zeroed one), intl-delivery-service sends the result to
SNS: dev-plk-delivery-quote-outcome
SQS: aws-rbi-dev-plk-apply-delivery-service-quote
Lambda: sls-rbi-dev-plk-orders-delivery-service-apply-quote ( intl-orders-service)
Which get the message and updates the current order in the database (dynamodb)
BE Proposal
Enhance this lambda function (dev-plk-delivery-on-apply-quote) to not overwrite discount and service fees with zeroes. It should keep the value from launchdarkly.
Configure launchdarkly to fit business needs enabling FE to show fees and discounts properly.
discount <> 0
serviceFee <> 0
fee <> 0
FE impacts
When discount, fee and service fee come to FE, intl-whitelabel-app can be changed to display FREE fees as according to UX (figma). The design screens should be adapted to consider them accordingly. In such case, depending on the launchdarkly config ( fee tier), we may have a different value for fee, service and discount. In principle, to minimize BE impacts, we may continue using a single field for discount. It’s up to the FE display "FREE” for the related use-cases. E.g:
discount == fee + servicefee
FREE fee
FREE service fee
discount == fee, but discount < fee+servicefee
FREE fee
X.XX service fee
discount < fee
X.XX fee
X.XX service fee
Other configurations may not be supported
Feature control
As usual the activation of this feature should be done using LD feature flag in both FE and BE. Later it can leverage a new sanity config (toogle) under guest checkout.
Enhancements
Since, in the future, we may have partners who calculates delivery fees not only based on LD, we can have an additional config for FREE delivery fee / FREE delivery service fee, where BE (intl-delivery-service) would override LD values - meaning that discount can be set with the same amount of the fee or fee + service fee.
Architecture
In partners service, create quote flow calls both in delivery : quote_create and quote_apply
Configured webhooks*:
Possible existing bugs
During this discovery, strange behaviors were detected. They are detailed here
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