Based on Fred George's microservice workshop
- Bus with Rabbit MQ
- Microservices with Java
Microservices needs to be super tiny
- a couple of lines of codes (>100).
Microservices should only store the information they care about to make decision
- You can have as many databases as miscroservice
- A reporting database can be use to store and centralise the data, but not for operational work.
If a microservice have only one listener, consider removing that communication from the Bus. They could interface directly to each other before putting the output back on the Bus.
The Bus stores all messages that goes through him
- Get the data out of the bus!
- Refer to external resources via URI.
- Have unique IDs to differentiate packets
- Communication is key, agree on the attributes the microservices will use.
- Use filters on those attributes to solely get the information each services need
Microservices are relatively new and it comes with challenges. There are no pattern or Design book for them, however:
- Fred George's River Pattern is used in this example.
Microservices add complexity and may not fill all needs. They provide
- a good flexibility
- opportunities to aggressively change the behaviour.
They should follow the same framework
- so they are easy to spawn and you don't need to worry about interfaces.
You test a microservice by launching into production right away, you will see the results instantaneously
- Cost of testing vs Cost of productions errors
Import the project, you can build it with Maven and the pom.xml.
Run the Rabbit MQ with docker:
docker-compose upRun the micro services with as argument (locally with 127.0.0.1):
<Rabbit MQ IP> <Rabbit MQ port>
127.0.0.1 5672