TIKA-4865 -- tika-grpc: resolve the plugin-roots fallback via DefaultPluginsDir and WARN when no plugins directory exists (#3109)

Author: tballison

CHANGES.txt

@@ -1,5 +1,10 @@
 Release 4.1.0 - unreleased
 
+   * tika-grpc resolves its plugin-roots fallback against the install
+     layout via DefaultPluginsDir instead of a working-directory-relative
+     pf4j default, and a WARN names the resolved directory when no plugins
+     directory exists (TIKA-4865).
+
    * The tika-server full and tika-grpc Docker images install fonts-noto-cjk:
      without any CJK face, PDFs using non-embedded CJK fonts render (and OCR)
      as .notdef boxes in every renderer, even though the images ship Japanese

tika-grpc/src/main/java/org/apache/tika/pipes/grpc/TikaGrpcServerImpl.java

@@ -54,6 +54,7 @@
 import org.apache.tika.pipes.core.PipesParser;
 import org.apache.tika.pipes.core.config.ConfigStore;
 import org.apache.tika.pipes.core.config.ConfigStoreFactory;
+import org.apache.tika.pipes.core.config.DefaultPluginsDir;
 import org.apache.tika.pipes.core.fetcher.FetcherManager;
 import org.apache.tika.pipes.grpc.proto.DeleteFetcherReply;
 import org.apache.tika.pipes.grpc.proto.DeleteFetcherRequest;
@@ -135,8 +136,20 @@ class TikaGrpcServerImpl extends TikaGrpc.TikaImplBase {
             pluginManager.loadPlugins();
             pluginManager.startPlugins();
         } catch (TikaConfigException e) {
-            LOG.warn("Could not load plugin manager, using default: {}", e.getMessage());
-            pluginManager = new org.pf4j.DefaultPluginManager();
+            // plugin-roots not configured: probe the install layout like the
+            // other pipes entry points (TIKA-4864/TIKA-4865)
+            String defaultRoot = DefaultPluginsDir.resolve(TikaGrpcServerImpl.class);
+            LOG.warn("plugin-roots not configured ({}); falling back to {}",
+                    e.getMessage(), defaultRoot);
+            try {
+                pluginManager = TikaPluginManager.loadFromPaths(defaultRoot);
+                pluginManager.loadPlugins();
+                pluginManager.startPlugins();
+            } catch (TikaConfigException | IOException e2) {
+                LOG.warn("could not load plugins from {}, starting with none: {}",
+                        defaultRoot, e2.getMessage());
+                pluginManager = new org.pf4j.DefaultPluginManager();
+            }
         }
 
         if (pluginManager.getPlugins().isEmpty()) {

tika-pipes/tika-pipes-core/src/main/java/org/apache/tika/pipes/core/config/DefaultPluginsDir.java

@@ -19,6 +19,9 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 /**
  * Resolves the default {@code plugins} directory when {@code plugin-roots}
  * is not configured (TIKA-4864). The probe order matches the install
@@ -37,6 +40,8 @@
  */
 public final class DefaultPluginsDir {
 
+    private static final Logger LOG = LoggerFactory.getLogger(DefaultPluginsDir.class);
+
     /**
      * The directory name probed in each location.
      */
@@ -88,6 +93,11 @@ public static Path resolve(Path codeSourceDir, Path cwd) {
                 }
             }
         }
-        return cwd.resolve(PLUGINS_DIR_NAME).toAbsolutePath();
+        Path fallback = cwd.resolve(PLUGINS_DIR_NAME).toAbsolutePath();
+        if (!Files.isDirectory(fallback)) {
+            LOG.warn("no plugins directory found in the install layout or at {}; "
+                    + "pipes plugins will not load unless plugin-roots is configured", fallback);
+        }
+        return fallback;
     }
 }