feat(composition): default to routing url from graph registry (#873)

crates/rover-client/src/operations/subgraph/fetch/fetch_query.graphql

@@ -5,6 +5,7 @@ query SubgraphFetchQuery($graph_id: ID!, $variant: String!) {
       ... on FederatedImplementingServices {
         services {
           name
+          url
           activePartialSchema {
             sdl
           }

crates/rover-client/src/operations/subgraph/fetch/runner.rs

@@ -35,11 +35,13 @@ fn get_sdl_from_response_data(
 ) -> Result<FetchResponse, RoverClientError> {
     let graph_ref = input.graph_ref.clone();
     let service_list = get_services_from_response_data(graph_ref, response_data)?;
-    let sdl_contents = get_sdl_for_service(&input.subgraph, service_list)?;
+    let subgraph = get_subgraph(&input.subgraph, service_list)?;
     Ok(FetchResponse {
         sdl: Sdl {
-            contents: sdl_contents,
-            r#type: SdlType::Subgraph,
+            contents: subgraph.sdl,
+            r#type: SdlType::Subgraph {
+                routing_url: subgraph.url,
+            },
         },
     })
 }
@@ -74,17 +76,22 @@ fn get_services_from_response_data(
     }
 }
 
-fn get_sdl_for_service(
-    subgraph_name: &str,
-    services: ServiceList,
-) -> Result<String, RoverClientError> {
+struct Subgraph {
+    url: Option<String>,
+    sdl: String,
+}
+
+fn get_subgraph(subgraph_name: &str, services: ServiceList) -> Result<Subgraph, RoverClientError> {
     // find the right service by name
     let service = services.iter().find(|svc| svc.name == subgraph_name);
 
-    // if there is a service, get it's active sdl, otherwise, error and list
+    // if there is a service, get its active sdl, otherwise, error and list
     // available services to fetch
     if let Some(service) = service {
-        Ok(service.active_partial_schema.sdl.clone())
+        Ok(Subgraph {
+            url: service.url.clone(),
+            sdl: service.active_partial_schema.sdl.clone(),
+        })
     } else {
         let valid_subgraphs: Vec<String> = services.iter().map(|svc| svc.name.clone()).collect();
 
@@ -175,9 +182,9 @@ mod tests {
           }
         ]);
         let service_list: ServiceList = serde_json::from_value(json_service_list).unwrap();
-        let output = get_sdl_for_service("accounts2", service_list);
+        let output = get_subgraph("accounts2", service_list);
         assert_eq!(
-            output.unwrap(),
+            output.unwrap().sdl,
             "extend type User @key(fields: \"id\") {\n  id: ID! @external\n  age: Int\n}\n"
                 .to_string()
         );
@@ -200,7 +207,7 @@ mod tests {
           }
         ]);
         let service_list: ServiceList = serde_json::from_value(json_service_list).unwrap();
-        let output = get_sdl_for_service("harambe-was-an-inside-job", service_list);
+        let output = get_subgraph("harambe-was-an-inside-job", service_list);
         assert!(output.is_err());
     }
 

crates/rover-client/src/shared/fetch_response.rs

@@ -16,6 +16,6 @@ pub struct Sdl {
 #[serde(rename_all(serialize = "lowercase"))]
 pub enum SdlType {
     Graph,
-    Subgraph,
+    Subgraph { routing_url: Option<String> },
     Supergraph,
 }

src/command/output.rs

@@ -75,7 +75,7 @@ impl RoverOutput {
             }
             RoverOutput::FetchResponse(fetch_response) => {
                 match fetch_response.sdl.r#type {
-                    SdlType::Graph | SdlType::Subgraph => print_descriptor("SDL"),
+                    SdlType::Graph | SdlType::Subgraph { .. } => print_descriptor("SDL"),
                     SdlType::Supergraph => print_descriptor("Supergraph SDL"),
                 }
                 print_content(&fetch_response.sdl.contents);
@@ -469,7 +469,9 @@ mod tests {
         let mock_fetch_response = FetchResponse {
             sdl: Sdl {
                 contents: "sdl contents".to_string(),
-                r#type: SdlType::Subgraph,
+                r#type: SdlType::Subgraph {
+                    routing_url: Some("http://localhost:8000/graphql".to_string()),
+                },
             },
         };
         let actual_json: JsonOutput = RoverOutput::FetchResponse(mock_fetch_response).into();

src/command/supergraph/compose/do_compose.rs

@@ -66,6 +66,13 @@ pub(crate) fn get_subgraph_definitions(
 ) -> Result<Vec<SubgraphDefinition>> {
     let mut subgraphs = Vec::new();
 
+    let err_no_routing_url = || {
+        let err = anyhow!("No routing_url found for schema file.");
+        let mut err = RoverError::new(err);
+        err.set_suggestion(Suggestion::ValidComposeRoutingUrl);
+        err
+    };
+
     for (subgraph_name, subgraph_data) in &supergraph_config.subgraphs {
         match &subgraph_data.schema {
             SchemaSource::File { file } => {
@@ -85,12 +92,10 @@ pub(crate) fn get_subgraph_definitions(
                     err
                 })?;
 
-                let url = &subgraph_data.routing_url.clone().ok_or_else(|| {
-                    let err = anyhow!("No routing_url found for schema file.");
-                    let mut err = RoverError::new(err);
-                    err.set_suggestion(Suggestion::ValidComposeRoutingUrl);
-                    err
-                })?;
+                let url = &subgraph_data
+                    .routing_url
+                    .clone()
+                    .ok_or_else(err_no_routing_url)?;
 
                 let subgraph_definition = SubgraphDefinition::new(subgraph_name, url, &schema);
                 subgraphs.push(subgraph_definition);
@@ -111,8 +116,8 @@ pub(crate) fn get_subgraph_definitions(
                 )?;
                 let schema = introspection_response.result;
 
-                // We don't require a routing_url for this variant of a schema,
-                // if none are provided, just use an empty string.
+                // We don't require a routing_url in config for this variant of a schema,
+                // if one isn't provided, just use the URL they passed for introspection.
                 let url = &subgraph_data
                     .routing_url
                     .clone()
@@ -136,12 +141,19 @@ pub(crate) fn get_subgraph_definitions(
                     &client,
                 )?;
 
-                // We don't require a routing_url for this variant of a schema,
-                // if none are provided, just use an empty string.
-                //
-                // TODO: this should eventually get the url from the registry
-                // and use that when no routing_url is provided.
-                let url = &subgraph_data.routing_url.clone().unwrap_or_default();
+                // We don't require a routing_url in config for this variant of a schema,
+                // if one isn't provided, just use the routing URL from the graph registry (if it exists).
+                let url = if let rover_client::shared::SdlType::Subgraph {
+                    routing_url: Some(graph_registry_routing_url),
+                } = result.sdl.r#type
+                {
+                    Ok(subgraph_data
+                        .routing_url
+                        .clone()
+                        .unwrap_or(graph_registry_routing_url))
+                } else {
+                    Err(err_no_routing_url())
+                }?;
 
                 let subgraph_definition =
                     SubgraphDefinition::new(subgraph_name, url, &result.sdl.contents);