You ultimate goal will be to create two services, service A and service B, and use a messaging system to connect them to single business process.

Mandatory Acceptance criterias:

• Service A will send messages to service B
• Service B will track a balance containing money in some storage. It will receive messages from service A and add to the balance accordingly.
• Services have no concept of "users", and this kind of development is not necessary for task at hand.
• No authentication is necessary on any of the services
• "EUR" should be the only supported currency in this initial version.
• Both services must be documented with README.md files explaining following, project purpose, how to setup it, how to run it.

Bonus points:

• Services as docker containers
• Unit test
• Handling concurrent messages on Service B

Service A

Service A has two task:

1. Accept HTTP request that carry money information
2. Generate AMQP messages towards "Service B"

HTTP API

• HTTP API must be able to accept following HTTP payload:

{
  "amount": 1123.4,
  "currency": "EUR",
}

• Amount is sent as decimal representation.
• Amount property must not be lower than -100000000 EUR, and larger than +100000000 EUR.
• Valid requests must generate HTTP/200 requests
• Invalid requests must generate HTTP/400 responses
• HTTP API must be documented via projects README.md

Messaging API

• Messaging API must generate valid messages for Service B to consume after HTTP api described above is invoked.
• All Messaging infrastructure (except definitions necessary for service B to consume messages) must be defined as part of service A
• Example message sent over message broker:

{
  "amount": 112304,
  "currency": "EUR",
}

• Amount is sent as minimal currency denomination representation (e.g. cents, this means that 1 EUR is sent as amount 100, and 100.19 EUR is sent as amount 10019)

Tech requirements (use one of following)

• Language: PHP, Java, golang
• Messaging: Any AMQP broker (e.g. Rabbit MQ)

Service B

• Service accepts AMQP messages generated by Service A
• Service must have account entity stored in database, described by two properties, balance and updatedAt

Handling messages

• Initial balance must be set at 0
• Initial updatedAt must be set at NULL

As a result of each message processing, following must happen:

• Balance must increased or decreased based on amount property
• updatedAt property must be updated so that it reflect last balance change

HTTP API

• HTTP API must have single route that exposes state of balance

Tech requirements (use one of following)

• Language: PHP, Java, golang
• Storage: Mariadb/Mysql, PostgreSql

Donation

If this project help you reduce time to develop, you can give me a cup of coffee :)