This is a simple Akka Scala application for managing customer loyalty points as part of the Reactive BBQ restaurant system. It is built using Akka HTTP and Akka Cluster Sharding.
The restaurant includes a loyalty program that allows users to accumulate points each time they order. Once they have accumulated enough points they can deduct those points and cash them in for discounts.
This is a skeleton of the Loyalty Service with a minimal feature set. It allows us to award points to an account and deduct points from the account. It also ensures that an account balance never goes below zero (You can't deduct points that you don't have).
Helper scripts have been included to allow you to run multiple instances of the application. These scripts will take care of overriding ports as required.
> runNode1.sh
> runNode2.sh
> runNode3.sh
These scripts override a variety of ports when running the application to ensure there are no port conflicts. Some of those ports are in use at the beginning, others will be enabled as you progress through the exercises. Specifically we override:
akka.http.server.default-http-port- Sets the port that the Akka HTTP server is running on. This is the port you will use to interact with the application via theloyalty.shscript.cinnamon.prometheus.http-server.port- Sets the port that will be used to expose Telemetry for Prometheus. Prometheus is optional. Everything will work fine if you don't have it.akka.remote.artery.canonical.port- Sets the port that will be used by Akka Cluster. This will be enabled later on in the course.akka.management.http.port- Sets the port that will be used to inspect and manage your cluster through Akka Cluster HTTP Management. This will be enabled later on in the course.
Once your application is running another helper script has been provided to interact with the service (loyalty.sh). This script uses curl commands to send HTTP requests to the service.
Syntax
loyalty.sh [option...] [award|deduct|retrieve] [VALUE]
Operations
award- Awards VALUE points to the provided account.deduct- Deducts VALUE points from the provided account.retrieve- Retrieves the information for the provided account.
Options
-aAssign an account Id (default=sample)-pUse a specific port (default=8000)
Loyalty points can be awarded with the following command:
> ./loyalty.sh award 10
This will award 10 points to the default account (sample) on the default port (8000).
If you want to specify the account and port you can use:
> ./loyalty.sh -a MyAccount -p 8001 award 10
This will award 10 points to the account MyAccount on port 8001.
Loyalty points can be deducted with the following command:
> ./loyalty.sh deduct 10
This will deduct 10 points from the default account (sample) on the default port (8000).
If you want to specify the account and port you can use:
> ./loyalty.sh -a MyAccount -p 8001 deduct 10
This will deduct 10 points to the account MyAccount on port 8001.
Remember, you can't deduct points that you don't have.
To view the details for a Loyalty Account, you can use the following command:
> ./loyalty.sh retrieve
This will give you the details for the default account (sample) on the default port (8000).
If you want to specify the account and port you can use:
> ./loyalty.sh -a MyAccount -p 8001 retrieve
The Loyalty Service stores data in a series of files. You will find
these files in the exercises/tmp directory.
Each account created will have it's own file. The file will contain a series of comma separated adjustments to the account (positive numbers award points, negative numbers deduct points).
You can clean up the data by deleting the exercises/tmp folder. Or
for convenience you can run the provided script:
> ./clearData.sh
Tests can be run using the standard testing procedures for SBT:
> sbt test
This class is the application entrypoint. It constructs the other application components, and injects them where needed.
This class defines the HTTP endpoints for the application. Endpoints are included for awarding and deducting loyalty points, as well as retrieving account information.
This class defines the details about a loyalty account. It contains a history of the account adjustments that have been made.
This class creates and manages all the different LoyaltyActors. It will be rendered obsolete in later exercises.
This class processes all the commands for the LoyaltyService including awarding points, deducting points, and retrieving the LoyaltyInformation for an account.
This class acts as an interface to data storage. Currently there are two implementations:
- InMemboryLoyaltyRepository
- FileBasedLoyaltyRepository
In a production application, you would likely provide an implementation that is backed by a database instead. However for the purpose of this course we will simply use the File Based version for most things. The In Memory version is primarily used in tests.