Rover subgraph Commands

A subgraph is a graph that contributes to the composition of a federated supergraph:

Rover commands that interact with subgraphs begin with rover subgraph.

Fetching a subgraph schema

These commands enable you to fetch the schema for a single subgraph in a supergraph. To instead fetch the API schema for a supergraph, use rover graph fetch. To fetch the supergraph schema, use rover supergraph fetch.

subgraph fetch

This command requires authenticating Rover with GraphOS.

You can use Rover to fetch the current schema of any subgraph that belongs to a graph variant or schema proposal that Rover has access to.

Run the subgraph fetch command, like so:

1rover subgraph fetch my-graph@my-variant --name accounts

The argument my-graph@my-variant in the example above is a graph ref that specifies the ID of the Studio graph you're fetching from, along with which variant you're fetching.

The --name option is required.** It specifies which subgraph you're fetching the schema for.

Fetch subgraph schemas from proposals

To fetch a subgraph schema from a schema proposal, use the proposal's ID instead of a variant name like so:

1rover subgraph fetch my-graph@p-101 --name accounts

A proposal's ID is always prefixed with p- and followed by a number. You can find the proposal ID in the proposal's URL in GraphOS Studio. For example, a proposal with the following URL has an ID of p-101.

https://studio.apollographql.com/graph/Example-supergraph/proposal/p-101/home

subgraph introspect

If you need to obtain a running subgraph's schema, you can use Rover to execute an enhanced introspection query on it. This is especially helpful if the subgraph doesn't define its schema via SDL (as is the case with graphql-kotlin).

Use the subgraph introspect command, like so:

1rover subgraph introspect http://localhost:4001

The subgraph must be reachable by Rover. The subgraph does not need to have introspection enabled.

Unlike a standard introspection query, the result of rover subgraph introspect does include certain directives (specifically, directives related to federation like @key). This is possible because the command uses a separate introspection mechanism provided by the Apollo Federation subgraph specification.

Watching for schema changes

If you pass --watch to rover subgraph introspect, Rover introspects your subgraph every second. Whenever the returned schema differs from the previously returned schema, Rover outputs the updated schema. This is most useful when combined with the --output <OUTPUT_FILE> argument which will write the introspection response out to a file whenever its contents change.

Including headers

If the endpoint you're trying to reach requires HTTP headers, you can use the --header (-H) flag to pass key:value pairs of headers. If you have multiple headers to pass, provide the flag multiple times. If a header includes any spaces, the pair must be quoted.

1rover subgraph introspect http://localhost:4001 --header "Authorization: Bearer token329r"

Output format

1rover subgraph introspect http://localhost:4001\
2  | rover subgraph publish my-graph@dev\
3  --schema - --name accounts\
4  --routing-url https://my-running-subgraph.com/api

By default, both subgraph fetch and subgraph introspect output fetched SDL to stdout. This is useful for providing the schema as input to other Rover commands:

1rover subgraph introspect http://localhost:4000 | rover subgraph check my-graph --schema -

You can also save the output to a local .graphql file like so:

1# Creates accounts-schema.graphql or overwrites if it already exists
2rover subgraph introspect http://localhost:4000 --output accounts-schema.graphql

For more on passing values via stdout, see Using stdout.

Listing subgraphs in a supergraph

subgraph list

This command requires authenticating Rover with GraphOS.

You can use the subgraph list to list all of a particular supergraph's available subgraphs in GraphOS:

1rover subgraph list my-supergraph@staging

This command lists all subgraphs for the specified variant, including their routing URLs and when they were last updated (in local time). A link to view this information in GraphOS Studio is also provided.

1Subgraphs:
2
3+----------+-------------- --------------+----------------------------+
4| Name     | Routing Url                 | Last Updated               |
5+----------+-----------------------------+----------------------------+
6| reviews  | https://reviews.my-app.com  | 2020-10-21 12:23:28 -04:00 |
7+----------+----------------------------------------+-----------------+
8| books    | https://books.my-app.com    | 2020-09-20 13:58:27 -04:00 |
9+----------+----------------------------------------+-----------------+
10| accounts | https://accounts.my-app.com | 2020-09-20 12:23:36 -04:00 |
11+----------+----------------------------------------+-----------------+
12| products | https://products.my-app.com | 2020-09-20 12:23:28 -04:00 |
13+----------+----------------------------------------+-----------------+
14
15View full details at https://studio.apollographql.com/graph/my-supergraph/service-list

Publishing a subgraph schema to GraphOS

subgraph publish

This command requires authenticating Rover with GraphOS.

You can use Rover to publish schema changes to a subgraph that belongs to a supergraph variant or schema proposal that Rover has access to.

Use the subgraph publish command, like so:

1rover subgraph publish my-supergraph@my-variant \
2  --schema "./accounts/schema.graphql" \
3  --name accounts \
4  --routing-url "https://my-running-subgraph.com/api"

The argument my-supergraph@my-variant in the example above is a graph ref that specifies the ID of the GraphOS graph you're publishing to, along with which variant you're publishing to.

Options include:

Creating variants

You can use the subgraph publish command to create a new variant, but not a new graph.

• If the graph exists in the graph registry but the variant does not, a new variant is created on publish.

• If the graph doesn't exist, the command fails.

Validating subgraph schema changes

subgraph check

This command requires authenticating Rover with GraphOS.

Before you publish subgraph schema changes to GraphOS, you can check those changes to confirm that you aren't introducing breaking changes to your application clients.

To do so, you can run the subgraph check command:

1# using a schema file
2rover subgraph check my-graph@my-variant --schema ./schema.graphql --name accounts
3
4# using piped input to stdin
5rover subgraph introspect http://localhost:4000 \
6  | rover subgraph check my-graph@my-variant \
7  --schema - --name accounts

As shown, arguments and options are similar to subgraph publish.

To configure the behavior of schema checks (such as the time range of past operations to check against), see the documentation for schema checks.

If you don't want to wait for the check to complete, you can run the command with the --background flag. You can then look up the check's result in GraphOS Studio on the Checks tab.

Running checks in CI

If you're running schema checks in CI, you might want to pass the --background flag to rover subgraph check. This flag instructs Rover to initiate schema checks but not await their result. If you've connected GraphOS Studio to your GitHub repository, the integration detects the checks execution and adds a status to the associated pull request.

subgraph lint

This command requires authenticating Rover with GraphOS.

You can run the GraphOS schema linter against your local subgraph schema to identify any violations of formatting and naming best practices:

1rover subgraph lint --name products --schema ./products-schema.graphql my-graph@my-variant

The argument my-graph@my-variant in the example above is a graph ref that specifies the ID of the graph you're comparing your schema changes against, along with which variant you're comparing against.

Schema linting also runs as one of the checks included in subgraph check. Use this command to perform one-off linting.

Options include:

Deleting a subgraph

subgraph delete

This command requires authenticating Rover with GraphOS.

You can delete a single subgraph from a federated variant by running rover subgraph delete:

1# ⚠️ This action is irreversible!
2rover subgraph delete my-graph@my-variant --name subgraph-to-delete

This command prompts you for confirmation because the action is irreversible. You can bypass confirmation by passing the --confirm flag.

This command fails with an error if any other subgraph references types that originate in this subgraph.

To delete an entire federated graph instead of a single subgraph, see Deleting a variant.