Add some validations for server configs

server/deployment/src/main/java/io/quarkiverse/openapi/server/generator/deployment/codegen/ApicurioOpenApiServerCodegen.java

@@ -46,16 +46,20 @@ private Path getInputBaseDir(final Path sourceDir, final Config config) {
 
     @Override
     public boolean shouldRun(Path sourceDir, Config config) {
-        if (config.getOptionalValue(CodegenConfig.getSpecPropertyName(), String.class).isEmpty()) {
-            return false;
+        boolean specIsPresent = config.getOptionalValue(CodegenConfig.getSpecPropertyName(), String.class).isPresent();
+        if (!specIsPresent) {
+            log.warn("The {} property is not present, the code generation will be ignored",
+                    CodegenConfig.getSpecPropertyName());
         }
-        Path path = getInputBaseDir(sourceDir, config);
-        return Files.isDirectory(path);
+        return specIsPresent;
     }
 
     @Override
     public boolean trigger(CodeGenContext context) throws CodeGenException {
         final Path openApiDir = getInputBaseDir(context.inputDir(), context.config());
+
+        validateOpenApiDir(context, openApiDir);
+
         final Path outDir = context.outDir();
         final ApicurioCodegenWrapper apicurioCodegenWrapper = new ApicurioCodegenWrapper(
                 context.config(), outDir.toFile());
@@ -92,6 +96,19 @@ public boolean trigger(CodeGenContext context) throws CodeGenException {
         return true;
     }
 
+    private static void validateOpenApiDir(CodeGenContext context, Path openApiDir) throws CodeGenException {
+        if (!Files.exists(openApiDir)) {
+            throw new CodeGenException(
+                    "The OpenAPI input base directory does not exist, please, create the directory on " + context.inputDir());
+        }
+
+        if (!Files.isDirectory(openApiDir)) {
+            throw new CodeGenException(
+                    "The OpenAPI input base directory is not a directory, please, create the directory on "
+                            + context.inputDir());
+        }
+    }
+
     private File convertToJSON(Path yamlPath) throws CodeGenException {
         try {
             ObjectMapper yamlReader = new ObjectMapper(new YAMLFactory());

server/deployment/src/test/java/io/quarkiverse/openapi/server/generator/deployment/CodegenTest.java

@@ -9,6 +9,7 @@
 
 import org.apache.commons.io.FileUtils;
 import org.eclipse.microprofile.config.Config;
+import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
@@ -60,4 +61,14 @@ public void testInputDir() throws CodeGenException {
                 Path.of("target/generated-test-sources/inputDir/io/petstore/PetResource.java")));
     }
 
+    @Test
+    public void shouldGenerateAnErrorWhenInputDirIsNotExist() throws CodeGenException {
+        Config config = MockConfigUtils.getTestConfig("doesNotExistDir.application.properties");
+        CodeGenContext codeGenContext = new CodeGenContext(null, Path.of(OUT_DIR, "inputDir"), WORK_DIR,
+                INPUT_DIR, false, config, true);
+        ApicurioOpenApiServerCodegen apicurioOpenApiServerCodegen = new ApicurioOpenApiServerCodegen();
+
+        Assertions.assertThrows(CodeGenException.class, () -> apicurioOpenApiServerCodegen.trigger(codeGenContext));
+    }
+
 }

server/deployment/src/test/resources/io/quarkiverse/openapi/server/generator/deployment/doesNotExistDir.application.properties

@@ -0,0 +1,2 @@
+quarkus.openapi.generator.spec=petstore-openapi-2.json
+quarkus.openapi.generator.base-package=io.petstore