Router Configuration Overview

Running an Apollo Router instance involves some key steps:

• Getting the schema of the federated supergraph that your router is running

• Configuring runtime features declaratively in YAML

• Deploying to different environments (dev, prod, etc.)

• Providing configuration command-line options, YAML, and environment variables at startup

Getting supergraph schema

As the runtime for a federated graph, a router needs to know the schema of the graph it's running. We call the schema for a federated graph a supergraph schema.

You need to configure the router at startup to know where to get its supergraph schema. That configuration depends on whether or not its supergraph schema is managed by GraphOS:

• If your supergraph schema is managed by GraphOS, you can configure your router with the GraphOS graph ref and API key as environment variables (APOLLO_GRAPH_REF and APOLLO_KEY). Based on these, the router can automatically fetch the supergraph schema from GraphOS.

• Otherwise, you can provide the router a supergraph schema file via command line or environment variable.

Configuring features in YAML

Configuring the router's features happens primarily via a YAML configuration file. Named router.yaml by default, the router's YAML configuration file lets you configure all of a router's runtime features declaratively.

Passing configuration at startup

Command-line options, a YAML config, and environment variables are passed to the router at startup.

This example command would be for a router with a GraphOS-managed graph and a custom named myrouter.yaml config file:

APOLLO_KEY="..." APOLLO_GRAPH_REF="..." router --config myrouter.yaml

The router can hot-reload updated configuration. When enabled, changes in router.yaml trigger the router to restart with its updated configuration.