[cli] Enable recommendations on validate command (#292)

Author: jimschubert

modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Validate.java

@@ -21,7 +21,9 @@
 import io.airlift.airline.Option;
 
 import io.swagger.parser.OpenAPIParser;
+import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.parser.core.models.SwaggerParseResult;
+import org.openapitools.codegen.utils.ModelUtils;
 
 import java.util.HashSet;
 import java.util.List;
@@ -34,26 +36,58 @@ public class Validate implements Runnable {
             description = "location of the OpenAPI spec, as URL or file (required)")
     private String spec;
 
+    @Option(name = { "--recommend"}, title = "recommend spec improvements")
+    private Boolean recommend;
+
     @Override
     public void run() {
         System.out.println("Validating spec (" + spec + ")");
 
         SwaggerParseResult result = new OpenAPIParser().readLocation(spec, null, null);
         List<String> messageList = result.getMessages();
-        Set<String> messages = new HashSet<String>(messageList);
+        Set<String> errors = new HashSet<String>(messageList);
+        Set<String> warnings = new HashSet<String>();
 
-        if (messages.size() > 0) {
-            StringBuilder sb = new StringBuilder();
-            sb.append(System.lineSeparator());
-            for (String message : messages) {
-                sb.append(String.format("\t- %s%s", message, System.lineSeparator()));
+        StringBuilder sb = new StringBuilder();
+        OpenAPI specification = result.getOpenAPI();
+
+        if (Boolean.TRUE.equals(recommend)) {
+            if (specification != null) {
+                // Add information about unused models to the warnings set.
+                List<String> unusedModels = ModelUtils.getUnusedSchemas(specification);
+                if (unusedModels != null) {
+                    unusedModels.forEach(name -> warnings.add("Unused model: " + name));
+                }
             }
+        }
+
+        if (errors.size() > 0) {
+            sb.append("Errors:").append(System.lineSeparator());
+            errors.forEach(msg ->
+                    sb.append("\t-").append(msg).append(System.lineSeparator())
+            );
+        }
+
+        if (!warnings.isEmpty()) {
+            sb.append("Warnings: ").append(System.lineSeparator());
+            warnings.forEach(msg ->
+                    sb.append("\t-").append(msg).append(System.lineSeparator())
+            );
+        }
+
+        if (!errors.isEmpty()) {
             sb.append(System.lineSeparator());
-            sb.append("[error] Spec is invalid.");
+            sb.append("[error] Spec has ").append(errors.size()).append(" errors.");
             System.err.println(sb.toString());
             System.exit(1);
+        } else if (!warnings.isEmpty()) {
+            sb.append(System.lineSeparator());
+            sb.append("[info] Spec has ").append(warnings.size()).append(" recommendation(s).");
         } else {
-            System.out.println("No validation errors detected.");
+            // we say "issues" here rather than "errors" to account for both errors and issues.
+            sb.append("No validation issues detected.");
         }
+
+        System.out.println(sb.toString());
     }
 }