[protobuf-schema] Add support for aggregating generated protobuf models into a single file

bin/configs/protobuf-schema-config.yaml

@@ -8,6 +8,7 @@ additionalProperties:
   numberedFieldNumberList: true
   startEnumsWithUnspecified: true
   wrapComplexType: false
+  aggregateModelsName: data
 typeMappings:
   object: "google.protobuf.Struct"
 importMappings:

docs/generators/protobuf-schema.md

@@ -19,6 +19,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 | Option | Description | Values | Default |
 | ------ | ----------- | ------ | ------- |
 |addJsonNameAnnotation|Append "json_name" annotation to message field when the specification name differs from the protobuf field name| |false|
+|aggregateModelsName|Aggregated model filename. If set, all generated models will be combined into this single file.| |null|
 |numberedFieldNumberList|Field numbers in order.| |false|
 |startEnumsWithUnspecified|Introduces "UNSPECIFIED" as the first element of enumerations.| |false|
 |wrapComplexType|Generate Additional message for complex type| |true|

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ProtobufSchemaCodegen.java

@@ -42,6 +42,8 @@
 import java.util.*;
 import java.util.Map.Entry;
 import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+
 import com.google.common.base.CaseFormat;
 
 import static org.openapitools.codegen.utils.StringUtils.*;
@@ -64,10 +66,14 @@ public class ProtobufSchemaCodegen extends DefaultCodegen implements CodegenConf
 
     public static final String WRAP_COMPLEX_TYPE = "wrapComplexType";
 
+    public static final String AGGREGATE_MODELS_NAME = "aggregateModelsName";
+
     private final Logger LOGGER = LoggerFactory.getLogger(ProtobufSchemaCodegen.class);
 
     @Setter protected String packageName = "openapitools";
 
+    @Setter protected String aggregateModelsName = null;
+
     private boolean numberedFieldNumberList = false;
 
     private boolean startEnumsWithUnspecified = false;
@@ -186,6 +192,7 @@ public ProtobufSchemaCodegen() {
         addSwitch(START_ENUMS_WITH_UNSPECIFIED, "Introduces \"UNSPECIFIED\" as the first element of enumerations.", startEnumsWithUnspecified);
         addSwitch(ADD_JSON_NAME_ANNOTATION, "Append \"json_name\" annotation to message field when the specification name differs from the protobuf field name", addJsonNameAnnotation);
         addSwitch(WRAP_COMPLEX_TYPE, "Generate Additional message for complex type", wrapComplexType);
+        addOption(AGGREGATE_MODELS_NAME, "Aggregated model filename. If set, all generated models will be combined into this single file.", null);
     }
 
     @Override
@@ -228,6 +235,10 @@ public void processOpts() {
             this.wrapComplexType = convertPropertyToBooleanAndWriteBack(WRAP_COMPLEX_TYPE);
         }
 
+        if (additionalProperties.containsKey(AGGREGATE_MODELS_NAME)) {
+            this.setAggregateModelsName((String) additionalProperties.get(AGGREGATE_MODELS_NAME));
+        }
+
         supportingFiles.add(new SupportingFile("README.mustache", "", "README.md"));
     }
 
@@ -650,7 +661,35 @@ public Map<String, ModelsMap> postProcessAllModels(Map<String, ModelsMap> objs)
                         .forEach(importFromList -> this.addImport(objs, parentCM, importFromList));
             }
         }
-        return objs;
+        return aggregateModelsName == null ? objs : aggregateModels(objs);
+    }
+
+    /**
+     * Aggregates all individual model definitions into a single entry.
+     *
+     * @param objs the original map of model names to their respective entries
+     * @return a new {@link Map} containing a single entry keyed by {@code aggregateModelsName} with
+     *         combined models and imports from all provided entries
+     */
+    public Map<String, ModelsMap> aggregateModels(Map<String, ModelsMap> objs) {
+        Map<String, ModelsMap> objects = new HashMap<>();
+        ModelsMap aggregateObj = objs.values().stream()
+                .findFirst()
+                .orElse(new ModelsMap());
+
+        List<ModelMap> models = objs.values().stream()
+                .flatMap(modelsMap -> modelsMap.getModels().stream())
+                .collect(Collectors.toList());
+
+        Set<Map<String, String>> imports = objs.values().stream()
+                .flatMap(modelsMap -> modelsMap.getImports().stream())
+                .filter(importMap -> !importMap.get("import").startsWith("models/"))
+                .collect(Collectors.toSet());
+
+        aggregateObj.setModels(models);
+        aggregateObj.setImports(new ArrayList<>(imports));
+        objects.put(this.aggregateModelsName, aggregateObj);
+        return objects;
     }
 
     public void addImport(Map<String, ModelsMap> objs, CodegenModel cm, String importValue) {
@@ -907,6 +946,11 @@ public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<Mo
             }
         }
 
+        if (this.aggregateModelsName != null) {
+            List<Map<String, String>> aggregate_imports = Collections.singletonList(Collections
+                    .singletonMap(IMPORT, toModelImport(this.aggregateModelsName)));
+            objs.setImports(aggregate_imports);
+        }
         return objs;
     }
 

modules/openapi-generator/src/main/resources/protobuf-schema/model.mustache

@@ -50,4 +50,5 @@ import public "{{{.}}}.proto";
 }
 {{/isEnum}}
 {{/model}}
+
 {{/models}}

samples/config/petstore/protobuf-schema-config-complex/models/cat.proto

@@ -20,3 +20,4 @@ message Cat {
   int32 age = 2;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/category.proto

@@ -23,3 +23,4 @@ message Category {
   map<string, StringArray> document = 3;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/dog.proto

@@ -28,3 +28,4 @@ message Dog {
   Breed breed = 2;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/pet.proto

@@ -21,3 +21,4 @@ message Pet {
   Category category = 2;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/string_array.proto

@@ -18,3 +18,4 @@ message StringArray {
   repeated string string_array = 1;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/string_map.proto

@@ -18,3 +18,4 @@ message StringMap {
   map<string, string> string_map = 1;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/tag.proto

@@ -21,3 +21,4 @@ message Tag {
   TagName name = 2;
 
 }
+

samples/config/petstore/protobuf-schema-config-complex/models/tag_name.proto

@@ -23,3 +23,4 @@ message TagName {
         StringMap map = 3;
     }
 }
+

samples/config/petstore/protobuf-schema-config/.openapi-generator/FILES

@@ -1,15 +1,5 @@
 README.md
-models/api_response.proto
-models/cat.proto
-models/category.proto
-models/dog.proto
-models/order.proto
-models/other_test.proto
-models/pet.proto
-models/pets_get_request.proto
-models/pets_post_request.proto
-models/tag.proto
-models/user.proto
+models/data.proto
 services/default_service.proto
 services/pet_service.proto
 services/store_service.proto