Tic Tac Toe

About

The game has some basic rules:

1. There are 2 players
2. Every player is represented by a unique symbol, usually it's X and O
3. The board consists of a 3x3 matrix. A player wins if they can align 3 of their markers in a vertical, horizontal or diagonal line
4. If no more moves are possible, the game should finish

There are some things to be considered for the design of the API:

• It might be possible that some calls need be protected against concurrent access
• The game state should be persisted, use some DB backing for that
• It is recommended to use Spring (Boot) for the implementation

Here is the project plan.

Tech used

• Java 17
• Spring-boot 2.7
• MongoDB (Docker)

Deploying

Locally

• start MongoDB using the docker image

cd mongodb
docker-compose up -d
docker ps

• start the Tic-tac-toe application from the terminal

./gradlew bootRun --args='--spring.profiles.active=local'

• or start the Tic=tac-toe application from IntelliJ TicTacToeApplication.java.
• stop MongoDB

docker-compose stop
docker-compose down

Playing

1. Create a new board and get the board ID

curl -i -H "Content-Type: application/json" -X POST http://localhost:8080/v1/startboard

{"id":"642ede8bc54327371a682936","playerOnTurn":"A","winnerPlayer":"","boardComplete":false,"scores":[]}

2. Show all boards to recover you board ID, see who is the next player, check all positions and if there is a winner

curl http://localhost:8080/v1/showboards | json_pp -json_opt pretty,canonical

[
   {
      "boardComplete" : false,
      "id" : "642ede8bc54327371a682936",
      "playerOnTurn" : "A",
      "scores" : [],
      "winnerPlayer" : ""
   }
]

3. register moves on the board each user at a time

• register a move using the playerOnTurn : A

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "A", "position": 3}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : B

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "B", "position": 1}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : A

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "A", "position": 7}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : B

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "B", "position": 5}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : A

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "A", "position": 9}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : B

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "B", "position": 6}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

• register a move using the playerOnTurn : A

curl -i \
-d '{"boardId":"642ede8bc54327371a682936", "player": "A", "position": 8}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard

4. playerOnTurn : A wins and you cannot register further moves. Check the board again.

curl http://localhost:8080/v1/showboard/642ede8bc54327371a682936 | json_pp -json_opt pretty,canonical

5. start a new board and execute concurrent calls

• delete all boards

curl -i -H "Content-Type: application/json" -X DELETE http://localhost:8080/v1/deleteboards

• start a new board

curl -i -H "Content-Type: application/json" -X POST http://localhost:8080/v1/startboard

• show the new board and copy the boardId

curl http://localhost:8080/v1/showboards | json_pp -json_opt pretty,canonical

• execute concurrent calls with the same user player A to all positions on the board

curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 1}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 2}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 3}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 4}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 5}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 6}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 7}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 8}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 9}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 1}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 2}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 3}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 4}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 5}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 6}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 7}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 8}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard & \
curl -i -d '{"boardId":"6429c954284d5d5a0fcc6e78", "player": "A", "position": 9}' -H "Content-Type: application/json" -X PUT http://localhost:8080/v1/playboard

• check the board state and ensure that player A has recorded only one position on the board

curl http://localhost:8080/v1/showboards | json_pp -json_opt pretty,canonical

6. version 2 of the endpoints is using function approach of spring-webflux. Here is the list of end-points:

curl http://localhost:8080/v2/showboards | json_pp -json_opt pretty,canonical
curl -i -H "Content-Type: application/json" -X POST http://localhost:8080/v2/startboard
curl -i \
-d '{"boardId":"642ee34ebbffa67c4c382f6a", "player": "A", "position": 3}' \
-H "Content-Type: application/json" \
-X PUT http://localhost:8080/v1/playboard
curl -i -H "Content-Type: application/json" -X DELETE http://localhost:8080/v2/deleteboards
curl http://localhost:8080/v2/showboard/642ee34ebbffa67c4c382f6a | json_pp -json_opt pretty,canonical

Tests

./gradlew cleanTest test

Distributed tracing

Start Jaeger docker-compose locally and open its WebUI at http://localhost:16686/.

cd jaeger/
docker-compose up

Start application on debug mode

./gradlew bootRun --args='--spring.profiles.active=debug'