Imagine you want to run a component of a distributed system in an (more or less) isolated environment. This might be your laptop or CI. In case you are running query/response scenarios over RabbitMQ/AMQP you need components that answer your queries. Of course one could spin up those components itself in a container and use them. But those components have dependencies as well that'd need to be started. In the worst case you need to start the whole distributed system locally.
FakeData is written to be a generic, configurable provider that enables lightweight response providers.
This small program connects to a given RabbitMQ server, declares a topic where to which it binds a queue on which it consumes so called query messages. Concrete names for exchange, queue and routing key used to bind the queue have to be configured in a file config.properties.
The query messages need to provide a reply_to property that contains an AMQP address to which the response message shall be sent. The format is [exchange_name]/[routing_key] or just [exchange_name].
The program will not fill the response with any dynamic data but with the contents of a file found at the configured filename.
Simply call
go get github.com/rjayasinghe/fakedata
or clone the repository and call
go build fakedata.go
You will need a configuration file that is named config.properties:
rabbitmq.port=5672
rabbitmq.hostname=localhost
rabbitmq.username=guest
rabbitmq.password=guest
# how the queries exchange is named
rabbitmq.queries.exchange=queries
# which queue shall be created for this fakedata instance
rabbitmq.queries.queue=fakedata.queries
# which routing key is used to bind the created queue
rabbitmq.queries.routingkey=orders.all
# how long to wait after a connection failure
rabbitmq.timeout=5s
# the name of the datafile
filename=orders.json
If you are running your data consuming application in a container environment it is obvious to run this program in a container itself.
Configuration and data files are need to reside in the same directory as the executable itself. In a docker-compose scenario you'd mount as volumes like this:
volumes:
- ./docker/fakedata-orders/config.properties:/config.properties
- ./docker/fakedata-orders/orders.json:/orders.json
- Tests ;-)