GED202204 Adding federation base to allow providers without runtime support

Author: kmoore-intuit

src/main/java/com/intuit/graphql/orchestrator/ServiceProvider.java

@@ -34,7 +34,10 @@ default ServiceType getSeviceType() {
     return ServiceType.GRAPHQL;
   }
 
+  default boolean isFederationProvider() { return getSeviceType() == ServiceType.FEDERATION_SUBGRAPH; }
+
   enum ServiceType {
+    FEDERATION_SUBGRAPH,
     GRAPHQL,
     REST
   }

src/main/java/com/intuit/graphql/orchestrator/stitching/XtextStitcher.java

@@ -142,7 +142,7 @@ private Map<String, BatchLoader> getBatchLoaders(Map<String, XtextGraph> xtextGr
 
     HashMap<String, BatchLoader> batchLoaderMap = new HashMap<>();
     xtextGraphMap.forEach((namespace, graph) -> {
-      if (graph.getServiceProvider().getSeviceType() == ServiceType.GRAPHQL) {
+      if (graph.getServiceProvider().getSeviceType() == ServiceType.GRAPHQL || graph.getServiceProvider().isFederationProvider()) {
         batchLoaderMap.put(namespace,
             GraphQLServiceBatchLoader
                 .newQueryExecutorBatchLoader()

src/main/java/com/intuit/graphql/orchestrator/xtext/XtextGraphBuilder.java

@@ -4,27 +4,34 @@
 import com.intuit.graphql.orchestrator.ServiceProvider;
 import com.intuit.graphql.orchestrator.schema.Operation;
 import com.intuit.graphql.orchestrator.utils.XtextUtils;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.EnumMap;
 import java.util.Map;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.io.IOUtils;
 import org.eclipse.xtext.resource.XtextResourceSet;
 
 public class XtextGraphBuilder {
 
   public static XtextGraph build(ServiceProvider serviceProvider) {
-
     XtextResourceSet xtextResourceSet = XtextResourceSetBuilder.newBuilder()
-        .files(serviceProvider.sdlFiles())
-        .build();
+            .files(serviceProvider.sdlFiles())
+            .isFederatedResourceSet(serviceProvider.isFederationProvider())
+            .build();
 
     final Map<Operation, ObjectTypeDefinition> operationMap = new EnumMap<>(Operation.class);
     for (Operation operation : Operation.values()) {
       XtextUtils.findOperationType(operation, xtextResourceSet)
-          .ifPresent(operationType -> operationMap.put(operation, operationType));
+              .ifPresent(operationType -> operationMap.put(operation, operationType));
     }
 
     return XtextGraph.newBuilder().xtextResourceSet(xtextResourceSet)
-        .serviceProvider(serviceProvider)
-        .operationMap(operationMap).build();
+            .serviceProvider(serviceProvider)
+            .operationMap(operationMap).build();
   }
 
 }

src/main/java/com/intuit/graphql/orchestrator/xtext/XtextResourceSetBuilder.java

@@ -7,21 +7,27 @@
 import com.intuit.graphql.orchestrator.schema.SchemaParseException;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.Charset;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
+
+import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.io.IOUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.xtext.EcoreUtil2;
 import org.eclipse.xtext.resource.IResourceFactory;
 import org.eclipse.xtext.resource.XtextResource;
 import org.eclipse.xtext.resource.XtextResourceSet;
 import org.eclipse.xtext.util.CancelIndicator;
+import org.eclipse.xtext.util.Files;
 import org.eclipse.xtext.validation.CheckMode;
 import org.eclipse.xtext.validation.IResourceValidator;
 import org.eclipse.xtext.validation.Issue;
 
+@Slf4j
 /**
  * The Xtext resource set builder.
  */
@@ -30,6 +36,9 @@ public class XtextResourceSetBuilder {
   private XtextResourceSet graphqlResourceSet;
   private static Injector GRAPHQL_INJECTOR = new GraphQLStandaloneSetupGenerated().createInjectorAndDoEMFRegistration();
   private Map<String, String> files = new ConcurrentHashMap<>();
+  private boolean isFederatedResourceSet = false;
+
+  public static final String FEDERATION_DIRECTIVES = getFederationDirectives();
 
   private XtextResourceSetBuilder() {
   }
@@ -57,20 +66,36 @@ public XtextResourceSetBuilder file(String fileName, String file) {
     return this;
   }
 
+  public XtextResourceSetBuilder isFederatedResourceSet(boolean isFederatedResourceSet) {
+    this.isFederatedResourceSet = isFederatedResourceSet;
+    return this;
+  }
+
   /**
    * Build xtext resource set.
    *
    * @return the xtext resource set
    */
   public XtextResourceSet build() {
     graphqlResourceSet = GRAPHQL_INJECTOR.getInstance(XtextResourceSet.class);
-    files.forEach((fileName, content) -> {
+
+    if(isFederatedResourceSet) {
+      String content = FEDERATION_DIRECTIVES + "\n" + StringUtils.join(files.values(), "\n");
+
       try {
-        createGraphqlResourceFromString(content, fileName);
+        createGraphqlResourceFromString(content, "appended_federation");
       } catch (IOException e) {
-        throw new SchemaParseException("Unable to parse file:" + fileName, e);
+        throw new SchemaParseException("Unable to parse file: appended federation file", e);
       }
-    });
+    } else {
+      files.forEach((fileName, content) -> {
+        try {
+          createGraphqlResourceFromString(content, fileName);
+        } catch (IOException e) {
+          throw new SchemaParseException("Unable to parse file:" + fileName, e);
+        }
+      });
+    }
 
     List<Issue> issues = validate();
     if (!issues.isEmpty()) {
@@ -100,8 +125,8 @@ private List<Issue> validate() {
     IResourceValidator validator = GRAPHQL_INJECTOR.getInstance(IResourceValidator.class);
     // collect issues
     return graphqlResourceSet.getResources().stream()
-        .flatMap(resource -> validator.validate(resource, CheckMode.ALL, CancelIndicator.NullImpl).stream()
-        ).collect(Collectors.toList());
+            .flatMap(resource -> validator.validate(resource, CheckMode.ALL, CancelIndicator.NullImpl).stream()
+            ).collect(Collectors.toList());
 
   }
 
@@ -116,7 +141,22 @@ public static XtextResourceSetBuilder newBuilder() {
 
   public static XtextResourceSet singletonSet(String fileName, String file) {
     return newBuilder()
-        .file(fileName, file)
-        .build();
+            .file(fileName, file)
+            .build();
+  }
+
+  private static String getFederationDirectives() {
+    String directives = "";
+    try {
+      directives = IOUtils.toString(
+              XtextResourceSetBuilder.class.getClassLoader()
+                      .getResourceAsStream( "federation_built_in_directives.graphqls"),
+              Charset.defaultCharset()
+      );
+    } catch (IOException ex) {
+      log.error("Failed to read resource");
+    }
+
+    return directives;
   }
 }

src/main/resources/federation_built_in_directives.graphqls

@@ -0,0 +1,5 @@
+directive @key(fields: String) on OBJECT | INTERFACE
+directive @extends on OBJECT | INTERFACE
+directive @external on FIELD_DEFINITION
+directive @provides(fields: String!) on FIELD_DEFINITION
+directive @requires(fields: String!) on FIELD_DEFINITION