GraphQL Federation

This project name is Library Manager, consists of 4 microservices which exposing its API in GraphQL. These microservices will sit behind Apollo Router and act as federated GraphQL APIs. The name of the microservices as follows:

1. User (this microservice will handle user/member/visitor related logic)
2. Employee (this microservice will handle employee related logic)
3. Shelf (this microservice will handle shelf related logic which will be used by books)
4. Book (this microservice will handle book related logic)

This federated graphql will share their schema through this specification.

Requirements

This project requires us to install Rover and Router from ApolloGraphQL. You can refer to this documentation and this documentation to install those 2 binaries. Basically you can run these commands to install those 2 binaries:

Rover

curl -sSL https://rover.apollo.dev/nix/latest | sh

Router

curl -sSL https://router.apollo.dev/download/nix/latest | sh

Running This Project

To run this project you can do these steps:

1. Composing supergraph file using Rover.
2. Running Router with supergraph file produced in step 1.
3. Run GraphQL APIs as subgraph.

Supergraph Composition

After you install those binaries, the next step is composing supergraph from your subgraph, you can do this by 2 methods:

1. Local GraphQl files
2. Introspection to all GraphQL APIs

In this project we use the first method. To achieve this, we define our supergraph in a file named supergraph.yaml in this repository. We can run composition by running this command:

rover supergraph compose --config supergraph.yaml > supergraph.graphql

or using executable script in this project:

./compose

In above command, we use rover binary to compose supergraph by using supergraph.yaml configuration file and then write the result to a file named supergraph.graphql under same directory.

Running Router

After composing supergraph, the next step is running our router. Router in the front server for our supergraph, that is why it needs us to specify supergraph definition when want to run it. In previous step we already have supergraph.graphql file needed by router to run, so what we need is running the router. You can run the router by executing this command:

./router --dev --supergraph supergraph.graphql

or using executable script in this project:

./routerrun

Then you can open your router dashboard with this url: http://localhost:4000

Running GraphQL APIs

The next step is running all graphql apis federated to this federation as specified in supergraph.yaml. In this repository, graphql apis as subgraph is defined in subgraph directory. You can refer to how to run each api in their respective README.md folder.