fix(Spring CodeGen): switch to Spring boot 2.7 style in registering a…

…uto-configurations (#1044)

Spring Boot 2.7 has introduced [changes to how auto-configurations](https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-2.7-Release-Notes#changes-to-auto-configuration) are registered. Both changes are backward compatible, but the older `spring.factories` style [will be removed in Spring Boot 3.0](https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-3.0.0-M5-Release-Notes#auto-configuration-registration). 
Also consider that Spring Boot 2.6.x goes out of support by 11-24-2022, switching this code to 2.7's new style.

src/main/java/com/google/api/generator/spring/SpringWriter.java

@@ -60,7 +60,7 @@ public static CodeGeneratorResponse write(
     }
 
     // write spring.factories file
-    writeSpringFactories(context, jos);
+    writeAutoConfigRegistration(context, jos);
     writeSpringAdditionalMetadataJson(context, jos);
 
     // TODO: metadata and package info not custimized for Spring
@@ -138,14 +138,15 @@ private static void writeMetadataFile(GapicContext context, String path, JarOutp
     }
   }
 
-  private static void writeSpringFactories(GapicContext context, JarOutputStream jos) {
-    String path = "src/main/resources/META-INF";
-    JarEntry jarEntry = new JarEntry(String.format("%s/spring.factories", path));
+  private static void writeAutoConfigRegistration(GapicContext context, JarOutputStream jos) {
+    String path = "src/main/resources/META-INF/spring";
+    JarEntry jarEntry =
+        new JarEntry(
+            String.format(
+                "%s/org.springframework.boot.autoconfigure.AutoConfiguration.imports", path));
     try {
       jos.putNextEntry(jarEntry);
-      StringJoiner sb =
-          new StringJoiner(
-              ",\\\n", "org.springframework.boot.autoconfigure.EnableAutoConfiguration=\\\n", "");
+      StringJoiner sb = new StringJoiner("\n", "", "");
       context
           .services()
           .forEach(

src/main/java/com/google/api/generator/spring/composer/SpringAutoConfigClassComposer.java

@@ -396,7 +396,7 @@ private static MethodDefinition createConstructor(
   private static List<AnnotationNode> createClassAnnotations(
       Service service, Map<String, TypeNode> types, String libName) {
     // @Generated("by gapic-generator-java")
-    // @Configuration(proxyBeanMethods = false)
+    // @AutoConfiguration
     // @ConditionalOnClass(LanguageServiceClient.class)
     // @ConditionalOnProperty(value = "spring.cloud.gcp.language.enabled", matchIfMissing = true)
     // @EnableConfigurationProperties(LanguageProperties.class)
@@ -421,10 +421,7 @@ private static List<AnnotationNode> createClassAnnotations(
             // XXX.class
             .build();
     AnnotationNode configurationNode =
-        AnnotationNode.builder()
-            .setType(types.get("Configuration"))
-            .setDescription("proxyBeanMethods = false") // TODO: change to parameters
-            .build();
+        AnnotationNode.builder().setType(types.get("AutoConfiguration")).build();
     AnnotationNode enableConfigurationPropertiesNode =
         AnnotationNode.builder()
             .setType(types.get("EnableConfigurationProperties"))
@@ -1020,11 +1017,11 @@ private static Map<String, TypeNode> createDynamicTypes(Service service, String
                 .setName("Bean")
                 .setPakkage("org.springframework.context.annotation")
                 .build());
-    TypeNode configuration =
+    TypeNode autoConfiguration =
         TypeNode.withReference(
             VaporReference.builder()
-                .setName("Configuration")
-                .setPakkage("org.springframework.context.annotation")
+                .setName("AutoConfiguration")
+                .setPakkage("org.springframework.boot.autoconfigure")
                 .build());
     TypeNode enableConfigurationProperties =
         TypeNode.withReference(
@@ -1062,7 +1059,7 @@ private static Map<String, TypeNode> createDynamicTypes(Service service, String
     typeMap.put("ServiceSettings", serviceSettings);
     typeMap.put("ServiceSettingsBuilder", serviceSettingsBuilder);
     typeMap.put("Bean", bean);
-    typeMap.put("Configuration", configuration);
+    typeMap.put("AutoConfiguration", autoConfiguration);
     typeMap.put("EnableConfigurationProperties", enableConfigurationProperties);
     typeMap.put("ConditionalOnMissingBean", conditionalOnMissingBean);
     typeMap.put("ConditionalOnProperty", conditionalOnProperty);

src/test/java/com/google/api/generator/spring/SpringAutoConfigClassComposerTest.java

@@ -144,15 +144,15 @@ public void generatePropertiesTest() {
           + "import com.google.showcase.v1beta1.EchoSettings;\n"
           + "import java.io.IOException;\n"
           + "import javax.annotation.Generated;\n"
+          + "import org.springframework.boot.autoconfigure.AutoConfiguration;\n"
           + "import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;\n"
           + "import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;\n"
           + "import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;\n"
           + "import org.springframework.boot.context.properties.EnableConfigurationProperties;\n"
           + "import org.springframework.context.annotation.Bean;\n"
-          + "import org.springframework.context.annotation.Configuration;\n"
           + "\n"
           + "@Generated(\"by gapic-generator-java\")\n"
-          + "@Configuration(\"proxyBeanMethods = false\")\n"
+          + "@AutoConfiguration\n"
           + "@ConditionalOnClass(\"value = EchoClient.class\")\n"
           + "@ConditionalOnProperty(\n"
           + "    \"value = \\\"spring.cloud.gcp.autoconfig.showcase.echo.enabled\\\", matchIfMissing = false\")\n"