Add basic support for core GraphQL auto-configuration

spring-graphql-web/src/main/java/org/springframework/boot/graphql/GraphQLAutoConfiguration.java

@@ -0,0 +1,48 @@
+package org.springframework.boot.graphql;
+
+import java.io.File;
+import java.io.FileNotFoundException;
+
+import graphql.GraphQL;
+import graphql.schema.GraphQLSchema;
+import graphql.schema.idl.RuntimeWiring;
+import graphql.schema.idl.SchemaGenerator;
+import graphql.schema.idl.SchemaParser;
+import graphql.schema.idl.TypeDefinitionRegistry;
+
+import org.springframework.beans.factory.ObjectProvider;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.util.ResourceUtils;
+
+@Configuration
+@ConditionalOnClass(GraphQL.class)
+@ConditionalOnMissingBean(GraphQL.class)
+@EnableConfigurationProperties(GraphQLProperties.class)
+public class GraphQLAutoConfiguration {
+
+	@Bean
+	@ConditionalOnMissingBean
+	public RuntimeWiring runtimeWiring(ObjectProvider<RuntimeWiringCustomizer> customizers) {
+		RuntimeWiring.Builder builder = RuntimeWiring.newRuntimeWiring();
+		customizers.orderedStream().forEach(customizer -> customizer.customize(builder));
+		return builder.build();
+	}
+
+	@Bean
+	public GraphQL.Builder graphQLBuilder(GraphQLProperties properties, RuntimeWiring runtimeWiring) throws FileNotFoundException {
+		File schemaFile = ResourceUtils.getFile(properties.getSchema());
+		GraphQLSchema schema = buildSchema(schemaFile, runtimeWiring);
+		return GraphQL.newGraphQL(schema);
+	}
+
+	private GraphQLSchema buildSchema(File schemaFile, RuntimeWiring runtimeWiring) {
+		TypeDefinitionRegistry typeRegistry = new SchemaParser().parse(schemaFile);
+		SchemaGenerator schemaGenerator = new SchemaGenerator();
+		return schemaGenerator.makeExecutableSchema(typeRegistry, runtimeWiring);
+	}
+
+}

spring-graphql-web/src/main/java/org/springframework/boot/graphql/GraphQLProperties.java

@@ -0,0 +1,17 @@
+package org.springframework.boot.graphql;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+@ConfigurationProperties(prefix = "spring.graphql")
+public class GraphQLProperties {
+
+	private String schema = "classpath:schema.graphqls";
+
+	public String getSchema() {
+		return schema;
+	}
+
+	public void setSchema(String schema) {
+		this.schema = schema;
+	}
+}

spring-graphql-web/src/main/java/org/springframework/boot/graphql/RuntimeWiringCustomizer.java

@@ -0,0 +1,10 @@
+package org.springframework.boot.graphql;
+
+import graphql.schema.idl.RuntimeWiring;
+
+@FunctionalInterface
+public interface RuntimeWiringCustomizer {
+
+	void customize(RuntimeWiring.Builder runtimeWiringBuilder);
+
+}

spring-graphql-web/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,4 @@
+org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
+org.springframework.boot.graphql.GraphQLAutoConfiguration,\
+org.springframework.boot.graphql.reactive.GraphQLWebFluxAutoConfiguration,\
+org.springframework.boot.graphql.servlet.GraphQLWebAutoConfiguration