Apollo Uplink

When using managed federation, your federated gateway regularly polls an endpoint called Apollo Uplink for its latest supergraph schema and other configuration:

To maximize uptime, Uplink is hosted simultaneously at two endpoints, one in GCP and one in AWS:

• GCP: https://uplink.api.apollographql.com/

• AWS: https://aws.uplink.api.apollographql.com/

By default in versions of @apollo/gateway v0.45.0 and later, your gateway polls Uplink every ten seconds. Every time it does so, it cycles between Uplink endpoints in round-robin fashion.

Whenever a poll request fails, the gateway retries that request (again, using round robin). It continues retrying until a request succeeds, or until reaching the defined maximum number of retries.

Even if a particular poll request fails all of its retries, the gateway continues polling as usual at the next interval (with its own set of retries if needed). In the meantime, the gateway continues using its most recent successfully obtained configuration.

Versions of @apollo/gateway prior to v0.45.0 don't support multiple Uplink endpoints and only use the GCP endpoint by default.

Configuring polling behavior

You can configure the following aspects of your gateway's polling behavior:

• The number of retries your gateway performs for a failed poll request

• The interval at which your gateway polls

• The list of Uplink URLs your gateway uses

Retry limit

You can configure how many times your gateway retries a single failed poll request like so:

1const { ApolloGateway } = require('@apollo/gateway');
2
3// ...
4
5const gateway = new ApolloGateway({
6  uplinkMaxRetries: 2
7});

By default, the gateway retries a single poll request a number of times equal to three times the number of Uplink URLs (this is almost always 6 times).

Even if a particular poll request fails all of its retries, the gateway continues polling as usual at the next interval (with its own set of retries if needed). In the meantime, the gateway continues using its most recently obtained configuration.

Poll interval

You can configure the interval at which your gateway polls Apollo Uplink like so:

1const { ApolloGateway } = require('@apollo/gateway');
2
3// ...
4
5const gateway = new ApolloGateway({
6  pollIntervalInMs: 15000 // 15 seconds
7});

The pollIntervalInMs option specifies the polling interval in milliseconds. This value must be at least 10000 (which is also the default value).

Uplink URLs (advanced)

⚠️ Most gateways never need to configure their list of Apollo Uplink URLs. Consult this section only if advised to do so.

You can provide a custom list of URLs for the gateway to use when polling Uplink. You can provide this list either in the ApolloGateway constructor or as an environment variable.

ApolloGateway constructor

Provide a custom list of Uplink URLs to the ApolloGateway constructor like so:

1const { ApolloGateway } = require('@apollo/gateway');
2
3// ...
4
5const gateway = new ApolloGateway({
6  uplinkEndpoints: [
7    // Omits AWS endpoint
8    'https://uplink.api.apollographql.com/'
9  ]
10});

This example omits the AWS endpoint, which means it's never polled.

Note that if you also provide a list of endpoints via environment variable, the environment variable takes precedence.

Environment variable

You can provide a comma-separated list of Uplink URLs as the value of the APOLLO_SCHEMA_CONFIG_DELIVERY_ENDPOINT environment variable in your gateway's environment:

1APOLLO_SCHEMA_CONFIG_DELIVERY_ENDPOINT=https://aws.uplink.api.apollographql.com/,https://uplink.api.apollographql.com/

Schema size limit

Supergraph schemas provided by Uplink cannot exceed 6MB in size. The vast majority of supergraph schemas are well below this limit.

If your supergraph schema does exceed 6MB, you can set up a build status webhook for your graph. Whenever you're notified of a successful supergraph schema composition, your webhook can fetch the latest supergraph schema via the Rover CLI.

Legacy endpoint (deprecated)

Instead of using Uplink, @apollo/gateway versions 0.33 and earlier poll a Google Cloud Storage URL to obtain their subgraph schemas and then run composition locally. This polling method is deprecated and might be removed in the future.

If you're using an earlier version of @apollo/gateway, we strongly recommend updating to the latest version to poll Uplink instead.