Wallets service

Wallets service provides API for creating and fetching wallets, making deposits and transfers between wallets, fetching transfers history.

Balance is stored in USD cents. Balance in 100 means $1.00. Numeric(or decimal) type also could be used. But in case of USD it seems over engineered.

Running

Database schema in ./.postgres_init/schema.sql. Schema apply on database while initial start. For recreating database rm -r .postgres_data/ .redis_data/

Run service with

$ docker-compose up wallet
[+] Running 4/4
 ⠿ Network wallets-service_default       Created                        
 ⠿ Container wallets-service_redis_1     Started                        
 ⠿ Container wallets-service_postgres_1  Started                        
 ⠿ Container wallets-service_wallet_1    Started

Common response codes

1. 200 – success;
2. 201 – idempotency key duplication;
3. 400 – request parameters or idempotency key error;
4. 402 – insufficient balance in case of transfer;
5. 404 – wallet not found;
6. 405 – request method mismatch;
7. 409 – wallet already created(creating with name of existing one);
8. 500 – internal error;

Error details provides with JSON

{
  "ok": 0,
  "message": "reason"
}

Create wallet

Request

$ curl --location --request POST 'localhost:8080/wallet' \
--header 'Idempotency-Key: XXXYYY' \
--header 'Content-Type: application/json' \
--data-raw '{
    "wallet_name": "myWallet"
}'

Response

In case of error, standart explanation

Fetch wallet

Request

$ curl --location --request GET 'localhost:8080/wallet/myWallet'

Response

{
    "name": "myWallet",
    "balance": 0
}

In case of error, standart explanation

Deposit

Request

$ curl --location --request POST 'localhost:8080/deposit' \
--header 'Idempotency-Key: XXXXYYYY' \
--header 'Content-Type: application/json' \
--data-raw '{
    "wallet_name": "myWallet",
    "amount": "1000"
}'

Response

In case of error, standart explanation

Transfer

Request

$ curl --location --request POST 'localhost:8080/transfer' \
--header 'Idempotency-Key: XXXXXYYYYY' \
--header 'Content-Type: application/json' \
--data-raw '{
    "wallet_name_from": "myWallet",
    "wallet_name_to": "anotherWallet",
    "amount": "500"
}'

Response

In case of error, standart explanation

History

Request

curl --location --request GET 'localhost:8080/history/myWallet'

Optional parameters

1. direction – deposit or transfer;
2. start_date – date in format YYYY-MM-DD(inclusively);
3. end_date – date in format YYYY-MM-DD(inclusively);
4. limit, offset_by_id - limit and offset can be used for pagination;

Response

id,amount,direction,meta,time
1,1000,deposit,"{""source"": ""unknown""}",2021-07-30T09:44:40.69095Z
1,-500,transfer,"{""destination"": ""anotherWallet""}",2021-07-30T09:46:37.625009Z

In case of error, standart explanation

Configuration

Configuration provided from environment variables

Name	Descrption	Constraint
BIND_ADDR	Address for binding	Not empty
GRACEFUL_SHUTDOWN_TIMEOUT_SEC	Waiting time before force service shutdown. -1 - unlimited	Greater or equal than -1
DB_TYPE	RDBMS database type	psql for PostgreSQL
DB_HOST	Database host	Not empty
DB_PORT	Database port	Not empty
DB_DATABASE_NAME	Database name	Not empty
DB_USER	Database user	Not empty
DB_PASSWORD	Database password	Not empty
IDEMPOTENCY_REDIS_ADDR	Address of redis which set up for idempotency keys keeping	Any valid address representation
IDEMPOTENCY_REDIS_PASSWORD	Password of redis which set up for idempotency keys keeping	Any