Apollo Federation Demo

A learning example

Presentation

You can download a presentation here

Prerequisites

You'll need to have either: Node version 16 and npm version 7.

Frontend

The repo also includes a client folder, which includes the frontend for the an app.

To run the client:

1. Open a new terminal window, and navigate to the client folder.
2. Run npm install & npm start. This will install all packages in the client and start the application in localhost:3000.

Backend

You will work in three main folders:

• router (or gateway)
• subgraph-projects
• subgraph-demands

Server	Port	Description
router	4000	The backend code for the router
subgraph-projects	4001	The backend code for the projects subgraph.
subgraph-demands	4002	The backend code for the demands subgraph.

Subgraph-projects

To run the servers in the subgraph-projects folder:

1. Open a new terminal window, and navigate to subgraph-projects.
2. Run npm install && npm start. This will install all packages in the main server, then start the main server at http://localhost:4000.
3. In a web browser, open Apollo Studio Sandbox for http://localhost:4001. You should be able to run queries against your gateway server. Some test queries are included in the following section.
4. Check sub-graph projects

rover subgraph check --name projects --schema  ./subgraph-projects/projects.graphql ${APOLLO_GRAPH_REF}@current

1. Publish sub-graph projects

rover subgraph publish ${APOLLO_GRAPH_REF}@current \
  --name projects \
  --schema ./subgraph-projects/projects.graphql

Subgraph-demands

To run the servers in the subgraph-demands folder:

1. Open a new terminal window, and navigate to subgraph-demands.
2. Run npm install && npm start. This will install all packages in the main server, then start the main server at http://localhost:4000.
3. In a web browser, open Apollo Studio Sandbox for http://localhost:4002. You should be able to run queries against your gateway server. Some test queries are included in the following section.
4. Check sub-graph demands

rover subgraph check --name demands --schema  ./subgraph-demands/demands.graphql ${APOLLO_GRAPH_REF}@current

1. Publish sub-graph demands

rover subgraph publish ${APOLLO_GRAPH_REF}@current \
  --name demands \
  --schema ./subgraph-demands/demands.graphql

Gateway

Run router

APOLLO_KEY=service:Archlet-test-Graph:${APOLLO_KEY} APOLLO_GRAPH_REF=${APOLLO_GRAPH_REF}@current ./router --config ./config.yaml

Schema checks - verify the safety of changes to your graph

Certain changes to your graph's schema (such as removing a field or type) might break one of your application's clients.

You can review the results of schema checks inside Apollo Studio or run a command

rover subgraph check Archlet-test-Graph@current  --name projects --schema ./subgraph-projects/projects.graphql

Each change to the schema is labeled either PASS or FAIL.

Schema checks are especially useful when you add them to your CI pipeline.

Queries examples

1. Get all projects

   query GetProjects {
     projects {
       id
       name
       description
       type
       biddingTypeId
     }
   }

2. Get demands

   query GetDemands {
     demands {
       id
       name
       volume
     }
   }