payments

Overview

• Simple REST api application to support concurrent money transfer requests
• Application server listens on localhost:8080
• Uses In-memmory synchronized datastore with minimalistic locking
• Ability to Create, get, list accounts and transfer money between accounts
• Validations
  • Duplicate Acount
  • Account Doesn't Exist
  • Insufficient Funds for transfer
  • Illegal transfer amount (< 0)
• Libraries
  • Jetty server
  • Jersey
  • swagger code-gen
  • Jackson
  • Junit5
  • lombok
  • Jersey Test Framework

RUN

1. Easy Start
   • source start.sh
   • sets up shell with easy access commands like createAccount, getAccount, transfer etc.
   • Logs available in nohup.out
2. Using Java:
   • java -jar target/payments-1.0-SNAPSHOT-jar-with-dependencies.jar

STOP

1. ./stop.sh
   • Uses lsof to find the process running on port 8080 and kills it
2. kill -9 'process_id_of_process_running_on_port_8080_here'

TEST

1. createAccount accountId1 accountBalance1
2. createAccount accountId2 accountBalance2
3. transfer accountId1 accountId2 amount
4. getAccount accountId1
5. getAccount accountId2
6. getAllAccounts

Sample Session

➜ payments git:(master) source start.sh

starting application [2] 90326 appending output to nohup.out

➜ payments git:(master) getAllAccounts

curl -i -X GET 'localhost:8080/v1/accounts/' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:49:20 GMT Content-Type: application/json Content-Length: 2 Server: Jetty(9.4.z-SNAPSHOT)

[]%

➜ payments git:(master) createAccount 1 100

curl -i -X POST 'localhost:8080/v1/accounts/' -H 'Content-type: application/json' -d '{"id": "1", "balance": "100"}' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:49:25 GMT Content-Type: application/json Content-Length: 24 Server: Jetty(9.4.z-SNAPSHOT)

{"id":"1","balance":100}%

➜ payments git:(master) createAccount 2 300

curl -i -X POST 'localhost:8080/v1/accounts/' -H 'Content-type: application/json' -d '{"id": "2", "balance": "300"}' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:49:34 GMT Content-Type: application/json Content-Length: 24 Server: Jetty(9.4.z-SNAPSHOT)

{"id":"2","balance":300}%

➜ payments git:(master) transfer 1 2 30

curl -i -X POST 'localhost:8080/v1/transfers/' -H 'Content-type: application/json' -d '{"from": "1", "to": "2", "amount": "30"}' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:49:41 GMT Content-Type: application/json Content-Length: 54 Server: Jetty(9.4.z-SNAPSHOT)

{"from":"1","fromBalance":70,"to":"2","toBalance":330}%

➜ payments git:(master) transfer 1 3 100

curl -i -X POST 'localhost:8080/v1/transfers/' -H 'Content-type: application/json' -d '{"from": "1", "to": "3", "amount": "100"}' HTTP/1.1 404 Not Found Date: Wed, 24 Jul 2019 04:49:47 GMT Content-Type: application/json Content-Length: 31 Server: Jetty(9.4.z-SNAPSHOT)

Account with id 3 doesn't exist%

➜ payments git:(master) getAccount 1

curl -i -X GET 'localhost:8080/v1/accounts/1' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:49:56 GMT Content-Type: application/json Content-Length: 23 Server: Jetty(9.4.z-SNAPSHOT)

{"id":"1","balance":70}%

➜ payments git:(master) getAllAccounts

curl -i -X GET 'localhost:8080/v1/accounts/' HTTP/1.1 200 OK Date: Wed, 24 Jul 2019 04:50:00 GMT Content-Type: application/json Content-Length: 50 Server: Jetty(9.4.z-SNAPSHOT)

[{"id":"1","balance":70},{"id":"2","balance":330}]%