Mastering Local Development for GraphQL Federation
A Step-by-Step Guide to Running and Enhancing Your Federated Graph for Rapid Development.
Overview
In development, you aim to test your schema changes as quickly as possible, bypassing the need to check and update your federated graph on the control plane. This approach does not replace the necessity of pushing your subgraph to the control plane in production; however, it serves as a more expedient method for iterating on your graph during the development phase.
If you want to start your router in production with a static config please use the fetch command instead. This will fetch the latest valid production config from the control plane. wgc router compose should only be used for local development.
Prerequisites
Getting started
1. Add your subgraphs
In order to compose locally, we need to create a compose.yaml
file that includes all the subgraphs you wish to include and compose into a federated graph.
The information you are required to provide is as follows:
Property | Description | Required |
---|---|---|
name | The unique name of the subgraph | true |
routing_url | The unique url (endpoint) of the subgraph (typically ends with | true |
introspection.url | Required if you want to dynamically introspect a running subgraph server | false |
introspection.headers | Headers to pass on the introspection request | false |
schema.file | Path to the subgraph GraphQL schema | false |
2. Generate the Router config
After you have configured everything, you can generate the static router config as follows:
This command introspects all your subgraphs and produces a router.json
that can be passed to the router in the next step.
3. Run the config with the router
Create a config.yaml
file in the same directory as your router binary.
We enabled the file watcher to hot-reload the server whenever you regenerate the router.json
file. This is super handy for rapid-development.
If you omit the token, analytics and tracing are disabled. For production create a token wgc router token create
and use polling instead. This ensures that the latest valid config is deployed to your routers automatically.
4. Open the playground
Finally, run the router and go to localhost:3002
. You will see a playground and you're ready to test your changes.
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