Simpan Pinjam Simulation App

Parts of docker compose content are adapted from MongoDB Kafka Connector Quick Start for v1.6 of the connector .

Prepare the environment first:

cd docker
docker images | grep quickstart | awk '{print $3}' | xargs docker rmi
docker-compose up

# open on another terminal
docker exec -it db bash -c 'psql -U postgres < /tmp/create-schema-data.sql'
# enter shell container to setup the kafka-mongodb sink connector and then check our data from mongo shell
docker exec -it shell bash

./initialize-container.sh

mongosh mongodb://mongo1:27017/?replicaSet=rs0
use quickstart
db.sink.find()

Diving in

General flow:

@startuml
participant "REST Controller" as controller
participant "Request Handler" as requestHandler
participant "Transaction Handler" as transactionHandler
database "PostgreSQL" as db
queue "Kafka" as queue
database "MongoDB" as mongo
controller -> requestHandler: forward transaction
requestHandler -> requestHandler: initialize timeout timer
requestHandler -> transactionHandler: forward transaction
transactionHandler -> transactionHandler: validate and process transaction
transactionHandler --> requestHandler: send transaction status
requestHandler -> db: save the transaction
db --> requestHandler: notify the data has been saved/failed
requestHandler -> queue: publish saved transaction into Kafka
requestHandler -> controller: flush the response
queue --> mongo: save transaction log into MongoDB;\nutilizing Kafka connect, sink connector
@enduml

It is worth mentioning that integration point of Spring Web and Akka is reactive pattern of Spring WebFlux against asynchronous execution of Akka. You can see this in the controller.

Please check SimjamApplicationTests.java for the integration test, also a simulation where concurrent test is done against multiple accounts try to make a deposit or loan. A simulation was done where you can see an example of the output in simulation.log. To check the failed cases, you can run:

grep -e failed -e asked simulation.log

and you should see the following output:

[INFO] [11/28/2021 19:31:18.131] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#5 asked for a loan 7000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.131] [simjim-showcase-akka.actor.default-dispatcher-7] [akka://simjim-showcase/user/$e] account user#5 failed to make a loan 7000.0
[INFO] [11/28/2021 19:31:18.132] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#4 asked for a loan 7000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.132] [simjim-showcase-akka.actor.default-dispatcher-8] [akka://simjim-showcase/user/$d] account user#4 failed to make a loan 7000.0
[INFO] [11/28/2021 19:31:18.132] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#1 asked for a loan 5000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.132] [simjim-showcase-akka.actor.default-dispatcher-10] [akka://simjim-showcase/user/$a] account user#1 failed to make a loan 5000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#9 asked for a loan 6000.0 while the current balance is 2000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-8] [akka://simjim-showcase/user/$i] account user#9 failed to make a loan 6000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#14 asked for a loan 5000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-10] [akka://simjim-showcase/user/$n] account user#14 failed to make a loan 5000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#16 asked for a loan 8000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-7] [akka://simjim-showcase/user/$p] account user#16 failed to make a loan 8000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#17 asked for a loan 7000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-4] [akka://simjim-showcase/user/$q] account user#17 failed to make a loan 7000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-6] [akka://simjim-showcase/user/$r] account user#18 failed to make a loan 7000.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#18 asked for a loan 7000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.133] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#19 asked for a loan 8000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.134] [simjim-showcase-akka.actor.default-dispatcher-6] [akka://simjim-showcase/user/$s] account user#19 failed to make a loan 8000.0
[INFO] [11/28/2021 19:31:18.134] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#20 asked for a loan 3000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.134] [simjim-showcase-akka.actor.default-dispatcher-7] [akka://simjim-showcase/user/$t] account user#20 failed to make a loan 3000.0
[INFO] [11/28/2021 19:31:18.134] [simjim-showcase-akka.actor.default-dispatcher-11] [akka://simjim-showcase/user/groupManager/random] Group random; user#21 asked for a loan 4000.0 while the current balance is 0.0
[INFO] [11/28/2021 19:31:18.134] [simjim-showcase-akka.actor.default-dispatcher-10] [akka://simjim-showcase/user/$u] account user#21 failed to make a loan 4000.0
[INFO] [11/28/2021 19:31:18.135] [simjim-showcase-akka.actor.default-dispatcher-7] [akka://simjim-showcase/user/groupManager/random] Group random; user#43 asked for a loan 9000.0 while the current balance is 5000.0
[INFO] [11/28/2021 19:31:18.135] [simjim-showcase-akka.actor.default-dispatcher-8] [akka://simjim-showcase/user/$Q] account user#43 failed to make a loan 9000.0
[INFO] [11/28/2021 19:31:19.474] [simjim-showcase-akka.actor.default-dispatcher-13] [akka://simjim-showcase/user/groupManager/random] Group random; user#79 asked for a loan 9000.0 while the current balance is 3000.0
[INFO] [11/28/2021 19:31:19.474] [simjim-showcase-akka.actor.default-dispatcher-7] [akka://simjim-showcase/user/$ob] account user#79 failed to make a loan 9000.0
[INFO] [11/28/2021 19:31:19.494] [simjim-showcase-akka.actor.default-dispatcher-8] [akka://simjim-showcase/user/$+] account user#63 failed to make a loan 5000.0
[INFO] [11/28/2021 19:31:19.494] [simjim-showcase-akka.actor.default-dispatcher-14] [akka://simjim-showcase/user/groupManager/random] Group random; user#63 asked for a loan 5000.0 while the current balance is 2000.0
[INFO] [11/28/2021 19:31:19.514] [simjim-showcase-akka.actor.default-dispatcher-10] [akka://simjim-showcase/user/groupManager/random] Group random; user#39 asked for a loan 9000.0 while the current balance is 3000.0
[INFO] [11/28/2021 19:31:19.514] [simjim-showcase-akka.actor.default-dispatcher-6] [akka://simjim-showcase/user/$M] account user#39 failed to make a loan 9000.0

Please check TransactionHandlerActorTest.java for the balance calculation unit test.

Run the following to execute all tests:

mvn clean test

By the end of the test, there should be one transaction logged in MongoDB (check it through shell container, mongo shell):

rs0 [primary] quickstart> db.sink.find()
[
  {
    _id: ObjectId("61a33f7212b4404e66eb8bad"),
    amount: 1000000,
    code: Long("0"),
    social_number: Long("1"),
    group_id: Long("93"),
    group_name: 'desa',
    account_name: 'Wawan Setiawan',
    transaction_timestamp: '2020-08-17T09:00:00',
    id: Long("81")
  }
]