Enhance DevelopmentPluginsProvider to handle plugin directories

README.md

@@ -117,6 +117,16 @@ IntelliJ, using `$MODULE_DIR$` accomplishes this automatically.
 If `VM options` doesn't exist in the dialog, you need to select `Modify options`
 and enable `Add VM options`.
 
+To adjust which plugins are enabled for the development server, adjust the value of
+`plugin.bundles` in `config.properties`. Each entry in this list must represent a plugin
+specified by one of the following options:
+* A path to a `pom.xml` or `*.pom` file describing a Maven project that produces a plugin.
+* Maven coordinates, in the form `<groupId>:<artifactId>[:<extension>[:<classifier>]]:<version>`. The plugin will be loaded via Maven and therefore must be available in your local repository or a remote repository.
+* A path to a plugin directory containing JAR files. See [Deploying a custom plugin](https://trino.io/docs/current/develop/spi-overview.html#deploying-a-custom-plugin) for more details.
+
+If you want to use a plugin in a catalog, you must add a corresponding
+`<catalog_name>.properties` file to `testing/trino-server-dev/etc/catalog`.
+
 ### Running the CLI
 
 Start the CLI to connect to the server and run SQL queries:

testing/trino-server-dev/src/main/java/io/trino/server/DevelopmentPluginsProvider.java

@@ -24,13 +24,17 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.net.MalformedURLException;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.function.Function;
+import java.util.stream.Stream;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static io.trino.server.PluginDiscovery.discoverPlugins;
@@ -83,7 +87,12 @@ private PluginClassLoader doBuildClassLoader(String plugin, Function<List<URL>,
         if (file.isFile() && (file.getName().equals("pom.xml") || file.getName().endsWith(".pom"))) {
             return buildClassLoaderFromPom(file, classLoaderFactory);
         }
-        return buildClassLoaderFromCoordinates(plugin, classLoaderFactory);
+        else if (file.isDirectory()) {
+            return buildClassLoaderFromDirectory(file, classLoaderFactory);
+        }
+        else {
+            return buildClassLoaderFromCoordinates(plugin, classLoaderFactory);
+        }
     }
 
     private PluginClassLoader buildClassLoaderFromPom(File pomFile, Function<List<URL>, PluginClassLoader> classLoaderFactory)
@@ -103,6 +112,24 @@ private PluginClassLoader buildClassLoaderFromPom(File pomFile, Function<List<UR
         return classLoader;
     }
 
+    private static PluginClassLoader buildClassLoaderFromDirectory(File pluginDirectory, Function<List<URL>, PluginClassLoader> classLoaderFactory)
+            throws IOException
+    {
+        Function<Path, URL> pathToUrl = path -> {
+            try {
+                return path.toUri().toURL();
+            }
+            catch (MalformedURLException e) {
+                throw new UncheckedIOException(e);
+            }
+        };
+        List<URL> jars;
+        try (Stream<Path> paths = Files.list(pluginDirectory.toPath())) {
+            jars = paths.map(pathToUrl).collect(toImmutableList());
+        }
+        return classLoaderFactory.apply(jars);
+    }
+
     private PluginClassLoader buildClassLoaderFromCoordinates(String coordinates, Function<List<URL>, PluginClassLoader> classLoaderFactory)
             throws IOException
     {