Billing microservice

Service that listens on rabbit queue for commands, performs operations with accounts and sends results into specified rabbit channels for unsuccessful and successful results.

Interacting format

Operation header data

Every input message must contain these fields:

{
	"cons_id": 0, // Consumer id
	"op_id": 15,  // Operation id
	"op_code": 3, // Operation code
...
}

Response messages

Response for each message is reported in output_channel or error_channel. Response message contains operation header data for tracking.

Response example

{
	"cons_id": 0,
	"op_id": 5,
	"op_code": 1,
	"res_code": 0, //Result code, 0 corresponds to Ok
	"msg": "Account FTA1 created"
}

Common possible error res_codes:

ErrWrongFormat          = 101
ErrUnknownOperationCode = 102

Create account

Operation code: 1 Example:

{
	"cons_id": 0,
	"op_id": 0,
	"op_code": 1, // Operation code 1
	"acc_id": "FTA1" // External Account ID
}

Possible error codes:

ErrAccountAlreadyExists = 103
ErrEmptyID              = 106
ErrSpaces               = 107
ErrIDTooLong            = 109 // ID must be less than 20 symbols

Add amount to account

Operation code: 2

{
	"cons_id": 0,
	"op_id": 2,
	"op_code": 2,
	"acc_id": "FTA1",
	"amount": -100.20 // Negative amount may be used to write-off funds
}

Possible error codes:

ErrAccountDoesNotExist  = 104
ErrInsufficient         = 105

Transfer amount between accounts

Operation code: 3

{
	"cons_id": 0,
	"op_id": 15,
	"op_code": 3,
	"amount": 1000,   // Negative amount here is forbidden
	"src_id": "FTA1", //Source account
	"tgt_id": "FTA2"  //Target account
}

Possible error codes:

ErrAccountAlreadyExists = 103
ErrAccountDoesNotExist  = 104
ErrInsufficient         = 105

Tests

To run unit tests:

make test

Launch

To setup local environment MySQL and RabbitMQ instances required, you may use docker-compose.yml from repo

1. Clone the repository.
2. Install dependencies, create the config file.
3. For first time make database migrations
4. Launch the project.

git clone https://github.com/eugeneverywhere/billing.git && cd billing
make setup && make config
make db:migrate
make run