add convert cli

cli/src/main/java/com/github/slamdev/openapispringgenerator/cli/Application.java

@@ -2,7 +2,7 @@
 
 import picocli.CommandLine;
 
-@CommandLine.Command(subcommands = {Generate.class, Validate.class})
+@CommandLine.Command(subcommands = {Generate.class, Validate.class, Convert.class})
 public class Application {
 
     public static void main(String[] args) {

cli/src/main/java/com/github/slamdev/openapispringgenerator/cli/Convert.java

@@ -0,0 +1,42 @@
+package com.github.slamdev.openapispringgenerator.cli;
+
+import com.github.slamdev.openapispringgenerator.lib.generator.OpenAPIYamlCodegen;
+import io.swagger.codegen.v3.ClientOptInput;
+import io.swagger.codegen.v3.DefaultGenerator;
+import io.swagger.codegen.v3.config.CodegenConfigurator;
+import io.swagger.codegen.v3.generators.openapi.OpenAPIGenerator;
+import picocli.CommandLine;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+@CommandLine.Command(name = "convert", mixinStandardHelpOptions = true, description = "convert to OpenAPI v3")
+public class Convert implements Runnable {
+
+    @CommandLine.Option(names = {"-f", "--input-file"}, required = true, description = "path to a spec file")
+    private Path specFile;
+
+    @CommandLine.Option(names = {"-o", "--output-file"}, required = true, description = "path to store the generated file")
+    private Path outputFile;
+
+    @Override
+    public void run() {
+        Path abs = outputFile.toAbsolutePath();
+        CodegenConfigurator configurator = new CodegenConfigurator();
+        configurator.setLang(OpenAPIYamlCodegen.class.getName());
+        configurator.setOutputDir(abs.getParent().toString());
+        configurator.addAdditionalProperty(OpenAPIGenerator.OUTPUT_NAME, abs.getFileName().toString());
+        configurator.addAdditionalProperty(OpenAPIGenerator.FLATTEN_SPEC, true);
+        try {
+            configurator.setInputSpec(new String(Files.readAllBytes(specFile)));
+        } catch (IOException e) {
+            throw new IllegalStateException(e);
+        }
+        ClientOptInput input = configurator.toClientOptInput();
+        DefaultGenerator generator = new DefaultGenerator();
+        generator.opts(input);
+        generator.setGenerateSwaggerMetadata(false);
+        generator.generate();
+    }
+}

lib/build.gradle

@@ -10,13 +10,13 @@ dependencies {
     // override to support https://github.com/jknack/handlebars.java/pull/893/files
     runtimeOnly 'com.github.jknack:handlebars:4.3.0'
     // TODO upgrade to support inheritance
-    api('io.swagger.codegen.v3:swagger-codegen-generators:1.0.29') {
+    api('io.swagger.codegen.v3:swagger-codegen-generators:1.0.30') {
         exclude group: 'io.swagger', module: 'swagger-codegen'
         exclude module: 'guava'
         exclude module: 'logback-classic'
         exclude module: 'logback-core'
     }
-    api('org.openapitools:openapi-generator:5.2.1') {
+    api('org.openapitools:openapi-generator:5.3.0') {
         exclude module: 'guava'
         exclude module: 'slf4j-simple'
     }

lib/src/main/java/com/github/slamdev/openapispringgenerator/lib/generator/OpenAPIYamlCodegen.java

@@ -0,0 +1,12 @@
+package com.github.slamdev.openapispringgenerator.lib.generator;
+
+import io.swagger.codegen.v3.generators.openapi.OpenAPIYamlGenerator;
+
+public class OpenAPIYamlCodegen extends OpenAPIYamlGenerator {
+
+    @Override
+    public void processOpts() {
+        super.processOpts();
+        supportingFiles.clear();
+    }
+}