persistent openapi specification

docs/asciidoc/modules/openapi.adoc

@@ -128,7 +128,14 @@ To avoid this behaviour you can specify maven build phase which suits your needs
 |`openapi.yaml`
 |Set openAPI template file path.
 
-|===
+|`copyOpenApiSpecTo`
+|
+|Copy the generated OpenAPI spec to the given file in the project repository. The format is
+determined by the file extension: `.yaml`, `.yml` or `.json`. Example:
+
+    <copyOpenApiSpecTo>${project.basedir}/docs/openapi.yaml</copyOpenApiSpecTo>
+
+|`===
 
 === Usage
 

modules/jooby-maven-plugin/src/main/java/io/jooby/maven/OpenAPIMojo.java

@@ -10,9 +10,14 @@
 import static org.apache.maven.plugins.annotations.ResolutionScope.COMPILE_PLUS_RUNTIME;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Optional;
 
@@ -53,6 +58,9 @@ public class OpenAPIMojo extends BaseMojo {
 
   @Parameter private List<File> adoc;
 
+  @Parameter(property = "openAPI.copyOpenApiSpecTo")
+  private File copyOpenApiSpecTo;
+
   @Override
   protected void doExecute(List<MavenProject> projects, String mainClass) throws Exception {
     ClassLoader classLoader = createClassLoader(projects);
@@ -84,10 +92,48 @@ protected void doExecute(List<MavenProject> projects, String mainClass) throws E
     var result = tool.generate(mainClass);
 
     var adocPath = ofNullable(adoc).orElse(List.of()).stream().map(File::toPath).toList();
+    var written = new ArrayList<Path>();
     for (var format : OpenAPIGenerator.Format.values()) {
-      tool.export(result, format, Map.of("adoc", adocPath))
-          .forEach(output -> getLog().info("  writing: " + output));
+      written.addAll(tool.export(result, format, Map.of("adoc", adocPath)));
+    }
+    written.forEach(output -> getLog().info("  writing: " + output));
+
+    if (copyOpenApiSpecTo != null) {
+      var destination = copyOpenApiSpecTo.toPath();
+      copySpec(written, destination);
+      getLog().info("  copying: " + destination);
+    }
+  }
+
+  public static void copySpec(List<Path> written, Path destination) throws IOException {
+    var format = specFormat(destination);
+    var source =
+        written.stream()
+            .filter(path -> path.getFileName().toString().endsWith("." + format.extension()))
+            .findFirst()
+            .orElseThrow(
+                () ->
+                    new IOException(
+                        String.format(
+                            "OpenAPI %s output not found for copyOpenApiSpecTo: %s",
+                            format.name(), destination)));
+    var parent = destination.getParent();
+    if (parent != null) {
+      Files.createDirectories(parent);
     }
+    Files.copy(source, destination, StandardCopyOption.REPLACE_EXISTING);
+  }
+
+  public static OpenAPIGenerator.Format specFormat(Path destination) {
+    var name = destination.getFileName().toString().toLowerCase(Locale.ROOT);
+    if (name.endsWith(".json")) {
+      return OpenAPIGenerator.Format.JSON;
+    }
+    if (name.endsWith(".yaml") || name.endsWith(".yml")) {
+      return OpenAPIGenerator.Format.YAML;
+    }
+    throw new IllegalArgumentException(
+        "copyOpenApiSpecTo must end with .yaml, .yml or .json: " + destination);
   }
 
   private Optional<String> trim(String value) {
@@ -186,4 +232,30 @@ public void setJavadoc(String javadoc) {
   public String getJavadoc() {
     return javadoc;
   }
+
+  /**
+   * Copy the generated OpenAPI spec to the given file. The format is determined by the file
+   * extension: <code>.yaml</code>, <code>.yml</code> or <code>.json</code>.
+   *
+   * @return Destination file.
+   */
+  public @Nullable File getCopyOpenApiSpecTo() {
+    return copyOpenApiSpecTo;
+  }
+
+  /**
+   * Copy the generated OpenAPI spec to the given file. The format is determined by the file
+   * extension: <code>.yaml</code>, <code>.yml</code> or <code>.json</code>.
+   *
+   * <p>Example:
+   *
+   * <pre>{@code
+   * <copyOpenApiSpecTo>${project.basedir}/docs/openapi.yaml</copyOpenApiSpecTo>
+   * }</pre>
+   *
+   * @param copyOpenApiSpecTo Destination file.
+   */
+  public void setCopyOpenApiSpecTo(@Nullable File copyOpenApiSpecTo) {
+    this.copyOpenApiSpecTo = copyOpenApiSpecTo;
+  }
 }

modules/jooby-maven-plugin/src/test/java/io/jooby/maven/OpenAPIMojoTest.java

@@ -0,0 +1,57 @@
+package io.jooby.maven;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import io.jooby.openapi.OpenAPIGenerator;
+
+public class OpenAPIMojoTest {
+
+  @Test
+  public void specFormat() {
+    assertEquals(
+        OpenAPIGenerator.Format.YAML, OpenAPIMojo.specFormat(Path.of("docs/openapi.yaml")));
+    assertEquals(
+        OpenAPIGenerator.Format.YAML, OpenAPIMojo.specFormat(Path.of("docs/openapi.yml")));
+    assertEquals(
+        OpenAPIGenerator.Format.JSON, OpenAPIMojo.specFormat(Path.of("docs/openapi.json")));
+    assertThrows(
+        IllegalArgumentException.class, () -> OpenAPIMojo.specFormat(Path.of("docs/openapi.txt")));
+  }
+
+  @Test
+  public void copyYamlSpec(@TempDir Path tempDir) throws Exception {
+    var outputDir = tempDir.resolve("classes/myapp");
+    Files.createDirectories(outputDir);
+    var source = outputDir.resolve("App.yaml");
+    Files.writeString(source, "openapi: 3.0.1");
+
+    var destination = tempDir.resolve("docs/openapi.yml");
+    OpenAPIMojo.copySpec(List.of(source), destination);
+
+    assertTrue(Files.isRegularFile(destination));
+    assertEquals(Files.readString(source), Files.readString(destination));
+  }
+
+  @Test
+  public void copyJsonSpec(@TempDir Path tempDir) throws Exception {
+    var outputDir = tempDir.resolve("classes/myapp");
+    Files.createDirectories(outputDir);
+    var source = outputDir.resolve("App.json");
+    Files.writeString(source, "{\"openapi\":\"3.0.1\"}");
+
+    var destination = tempDir.resolve("docs/openapi.json");
+    OpenAPIMojo.copySpec(List.of(source), destination);
+
+    assertTrue(Files.isRegularFile(destination));
+    assertEquals(Files.readString(source), Files.readString(destination));
+  }
+}