SOLR-4653: Solr configuration should log inaccessible/ non-existent relative paths in lib dir=...

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1463836 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -156,6 +156,9 @@ Optimizations
 Other Changes
 ----------------------
 
+* SOLR-4653: Solr configuration should log inaccessible/ non-existent relative paths in lib 
+  dir=... (Dawid Weiss)
+
 * SOLR-4317: SolrTestCaseJ4: Can't avoid "collection1" convention (Tricia Jenkins, via Erick Erickson)
 
 * SOLR-4571: SolrZkClient#setData should return Stat object. (Mark Miller)

solr/core/src/java/org/apache/solr/core/SolrConfig.java

@@ -462,10 +462,10 @@ public class SolrConfig extends Config {
         String baseDir = DOMUtil.getAttr(node, "dir");
         String path = DOMUtil.getAttr(node, "path");
         if (null != baseDir) {
-          // :TODO: add support for a simpler 'glob' mutually eclusive of regex
+          // :TODO: add support for a simpler 'glob' mutually exclusive of regex
           String regex = DOMUtil.getAttr(node, "regex");
           FileFilter filter = (null == regex) ? null : new RegexFileFilter(regex);
-          getResourceLoader().addToClassLoader(baseDir, filter);
+          getResourceLoader().addToClassLoader(baseDir, filter, false);
         } else if (null != path) {
           getResourceLoader().addToClassLoader(path);
         } else {

solr/core/src/java/org/apache/solr/core/SolrResourceLoader.java

@@ -111,7 +111,7 @@ public class SolrResourceLoader implements ResourceLoader
     }
     
     this.classLoader = createClassLoader(null, parent);
-    addToClassLoader("./lib/", null);
+    addToClassLoader("./lib/", null, true);
     reloadLuceneSPI();
     this.coreProperties = coreProperties;
   }
@@ -135,17 +135,35 @@ public class SolrResourceLoader implements ResourceLoader
    * only be called prior to using this ResourceLoader to get any resources, otherwise
    * it's behavior will be non-deterministic. You also have to {link @reloadLuceneSPI}
    * before using this ResourceLoader.
+   * 
+   * <p>This method will quietly ignore missing or non-directory <code>baseDir</code>
+   *  folder. 
    *
    * @param baseDir base directory whose children (either jars or directories of
    *                classes) will be in the classpath, will be resolved relative
    *                the instance dir.
    * @param filter The filter files must satisfy, if null all files will be accepted.
+   * @param quiet  Be quiet if baseDir does not point to a directory or if no file is 
+   *               left after applying the filter. 
    */
-  void addToClassLoader(final String baseDir, final FileFilter filter) {
+  void addToClassLoader(final String baseDir, final FileFilter filter, boolean quiet) {
     File base = FileUtils.resolvePath(new File(getInstanceDir()), baseDir);
-    this.classLoader = replaceClassLoader(classLoader, base, filter);
+    if (base != null && base.exists() && base.isDirectory()) {
+      File[] files = base.listFiles(filter);
+      if (!quiet && (files == null || files.length == 0)) {
+        log.warn("No files added to classloader from lib: "
+            + baseDir + " (resolved as: " + base.getAbsolutePath() + ").");
+      } else {
+        this.classLoader = replaceClassLoader(classLoader, base, filter);
+      }
+    } else {
+      if (!quiet) {
+        log.warn("Can't find (or read) directory to add to classloader: "
+            + baseDir + " (resolved as: " + base.getAbsolutePath() + ").");
+      }
+    }
   }
-  
+
   /**
    * Adds the specific file/dir specified to the ClassLoader used by this
    * ResourceLoader.  This method <b>MUST</b>
@@ -174,7 +192,7 @@ public class SolrResourceLoader implements ResourceLoader
   /**
    * Reloads all Lucene SPI implementations using the new classloader.
    * This method must be called after {@link #addToClassLoader(String)}
-   * and {@link #addToClassLoader(String,FileFilter)} before using
+   * and {@link #addToClassLoader(String,FileFilter,boolean)} before using
    * this ResourceLoader.
    */
   void reloadLuceneSPI() {

solr/example/solr/collection1/conf/solrconfig.xml

@@ -82,9 +82,9 @@
   <lib dir="../../../dist/" regex="solr-velocity-\d.*\.jar" />
 
   <!-- If a 'dir' option (with or without a regex) is used and nothing
-       is found that matches, it will be ignored
+       is found that matches, a warning will be logged.
     -->
-  <lib dir="/total/crap/dir/ignored" /> 
+  <lib dir="/non/existent/dir/yields/warning" /> 
 
   <!-- an exact 'path' can be used instead of a 'dir' to specify a 
        specific jar file.  This will cause a serious error to be logged