Add support for inlined user dictionary in the Kuromoji plugin (#45489)

This change adds a new option called user_dictionary_rules to
Kuromoji's tokenizer. It can be used to set additional tokenization rules
to the Japanese tokenizer directly in the settings (instead of using a file).
This commit also adds a check that no rules are duplicated since this is not allowed
in the UserDictionary.

Closes #25343

docs/plugins/analysis-kuromoji.asciidoc

@@ -98,6 +98,39 @@ dictionary to `$ES_HOME/config/userdict_ja.txt`:
 東京スカイツリー,東京 スカイツリー,トウキョウ スカイツリー,カスタム名詞
 -----------------------
 
+--
+
+You can also inline the rules directly in the tokenizer definition using
+the `user_dictionary_rules` option:
+
+[source,js]
+--------------------------------------------------
+PUT nori_sample
+{
+  "settings": {
+    "index": {
+      "analysis": {
+        "tokenizer": {
+          "kuromoji_user_dict": {
+            "type": "kuromoji_tokenizer",
+            "mode": "extended",
+            "user_dictionary_rules": ["東京スカイツリー,東京 スカイツリー,トウキョウ スカイツリー,カスタム名詞"]
+          }
+        },
+        "analyzer": {
+          "my_analyzer": {
+            "type": "custom",
+            "tokenizer": "kuromoji_user_dict"
+          }
+        }
+      }
+    }
+  }
+}
+--------------------------------------------------
+// CONSOLE
+--
+
 `nbest_cost`/`nbest_examples`::
 +
 --

plugins/analysis-kuromoji/src/main/java/org/elasticsearch/index/analysis/KuromojiTokenizerFactory.java

@@ -23,17 +23,22 @@ import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ja.JapaneseTokenizer;
 import org.apache.lucene.analysis.ja.JapaneseTokenizer.Mode;
 import org.apache.lucene.analysis.ja.dict.UserDictionary;
+import org.apache.lucene.analysis.ja.util.CSVUtil;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.index.IndexSettings;
 
 import java.io.IOException;
-import java.io.Reader;
+import java.io.StringReader;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
 
 public class KuromojiTokenizerFactory extends AbstractTokenizerFactory {
 
-    private static final String USER_DICT_OPTION = "user_dictionary";
+    private static final String USER_DICT_PATH_OPTION = "user_dictionary";
+    private static final String USER_DICT_RULES_OPTION = "user_dictionary_rules";
     private static final String NBEST_COST = "nbest_cost";
     private static final String NBEST_EXAMPLES = "nbest_examples";
 
@@ -54,17 +59,33 @@ public class KuromojiTokenizerFactory extends AbstractTokenizerFactory {
     }
 
     public static UserDictionary getUserDictionary(Environment env, Settings settings) {
+        if (settings.get(USER_DICT_PATH_OPTION) != null && settings.get(USER_DICT_RULES_OPTION) != null) {
+            throw new IllegalArgumentException("It is not allowed to use [" + USER_DICT_PATH_OPTION + "] in conjunction" +
+                " with [" + USER_DICT_RULES_OPTION + "]");
+        }
         try {
-            final Reader reader = Analysis.getReaderFromFile(env, settings, USER_DICT_OPTION);
-            if (reader == null) {
+            List<String> ruleList = Analysis.getWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION, false);
+            if (ruleList == null || ruleList.isEmpty()) {
                 return null;
-            } else {
-                try {
-                    return UserDictionary.open(reader);
-                } finally {
-                    reader.close();
+            }
+            Set<String> dup = new HashSet<>();
+            int lineNum = 0;
+            for (String line : ruleList) {
+                // ignore comments
+                if (line.startsWith("#") == false) {
+                    String[] values = CSVUtil.parse(line);
+                    if (dup.add(values[0]) == false) {
+                        throw new IllegalArgumentException("Found duplicate term [" + values[0] + "] in user dictionary " +
+                            "at line [" + lineNum + "]");
                     }
                 }
+                ++ lineNum;
+            }
+            StringBuilder sb = new StringBuilder();
+            for (String line : ruleList) {
+                sb.append(line).append(System.lineSeparator());
+            }
+            return UserDictionary.open(new StringReader(sb.toString()));
         } catch (IOException e) {
             throw new ElasticsearchException("failed to load kuromoji user dictionary", e);
         }

plugins/analysis-kuromoji/src/test/java/org/elasticsearch/index/analysis/KuromojiAnalysisTests.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.analysis;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ja.JapaneseAnalyzer;
@@ -39,6 +40,8 @@ import java.io.StringReader;
 import java.nio.file.Files;
 import java.nio.file.Path;
 
+import static org.apache.lucene.analysis.BaseTokenStreamTestCase.assertTokenStreamContents;
+import static org.hamcrest.CoreMatchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.instanceOf;
@@ -307,4 +310,55 @@ public class KuromojiAnalysisTests extends ESTestCase {
         tokenizer.setReader(new StringReader(source));
         assertSimpleTSOutput(tokenFilter.create(tokenizer), expected);
     }
+
+    public void testKuromojiAnalyzerUserDict() throws Exception {
+        Settings settings = Settings.builder()
+            .put("index.analysis.analyzer.my_analyzer.type", "kuromoji")
+            .putList("index.analysis.analyzer.my_analyzer.user_dictionary_rules", "c++,c++,w,w", "制限スピード,制限スピード,セイゲンスピード,テスト名詞")
+            .build();
+        TestAnalysis analysis = createTestAnalysis(settings);
+        Analyzer analyzer = analysis.indexAnalyzers.get("my_analyzer");
+        try (TokenStream stream = analyzer.tokenStream("", "制限スピード")) {
+            assertTokenStreamContents(stream, new String[]{"制限スピード"});
+        }
+
+        try (TokenStream stream = analyzer.tokenStream("", "c++world")) {
+            assertTokenStreamContents(stream, new String[]{"c++", "world"});
+        }
+    }
+
+    public void testKuromojiAnalyzerInvalidUserDictOption() throws Exception {
+        Settings settings = Settings.builder()
+            .put("index.analysis.analyzer.my_analyzer.type", "kuromoji")
+            .put("index.analysis.analyzer.my_analyzer.user_dictionary", "user_dict.txt")
+            .putList("index.analysis.analyzer.my_analyzer.user_dictionary_rules", "c++,c++,w,w")
+            .build();
+        IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> createTestAnalysis(settings));
+        assertThat(exc.getMessage(), containsString("It is not allowed to use [user_dictionary] in conjunction " +
+            "with [user_dictionary_rules]"));
+    }
+
+    public void testKuromojiAnalyzerDuplicateUserDictRule() throws Exception {
+        Settings settings = Settings.builder()
+            .put("index.analysis.analyzer.my_analyzer.type", "kuromoji")
+            .putList("index.analysis.analyzer.my_analyzer.user_dictionary_rules",
+                "c++,c++,w,w", "#comment", "制限スピード,制限スピード,セイゲンスピード,テスト名詞", "制限スピード,制限スピード,セイゲンスピード,テスト名詞")
+            .build();
+        IllegalArgumentException exc = expectThrows(IllegalArgumentException.class, () -> createTestAnalysis(settings));
+        assertThat(exc.getMessage(), containsString("[制限スピード] in user dictionary at line [3]"));
+    }
+
+    private TestAnalysis createTestAnalysis(Settings analysisSettings) throws IOException {
+        InputStream dict = KuromojiAnalysisTests.class.getResourceAsStream("user_dict.txt");
+        Path home = createTempDir();
+        Path config = home.resolve("config");
+        Files.createDirectory(config);
+        Files.copy(dict, config.resolve("user_dict.txt"));
+        Settings settings = Settings.builder()
+            .put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT)
+            .put(Environment.PATH_HOME_SETTING.getKey(), home)
+            .put(analysisSettings)
+            .build();
+        return AnalysisTestsHelper.createTestAnalysisFromSettings(settings, new AnalysisKuromojiPlugin());
+    }
 }

plugins/analysis-nori/src/main/java/org/elasticsearch/index/analysis/NoriTokenizerFactory.java

@@ -51,7 +51,7 @@ public class NoriTokenizerFactory extends AbstractTokenizerFactory {
             throw new IllegalArgumentException("It is not allowed to use [" + USER_DICT_PATH_OPTION + "] in conjunction" +
                 " with [" + USER_DICT_RULES_OPTION + "]");
         }
-        List<String> ruleList = Analysis.getWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION);
+        List<String> ruleList = Analysis.getWordList(env, settings, USER_DICT_PATH_OPTION, USER_DICT_RULES_OPTION, true);
         StringBuilder sb = new StringBuilder();
         if (ruleList == null || ruleList.isEmpty()) {
             return null;

server/src/main/java/org/elasticsearch/index/analysis/Analysis.java

@@ -221,7 +221,7 @@ public class Analysis {
      *          If the word list cannot be found at either key.
      */
     public static List<String> getWordList(Environment env, Settings settings, String settingPrefix) {
-        return getWordList(env, settings, settingPrefix + "_path", settingPrefix);
+        return getWordList(env, settings, settingPrefix + "_path", settingPrefix, true);
     }
 
     /**
@@ -231,7 +231,8 @@ public class Analysis {
      * @throws IllegalArgumentException
      *          If the word list cannot be found at either key.
      */
-    public static List<String> getWordList(Environment env, Settings settings, String settingPath, String settingList) {
+    public static List<String> getWordList(Environment env, Settings settings,
+                                           String settingPath, String settingList, boolean removeComments) {
         String wordListPath = settings.get(settingPath, null);
 
         if (wordListPath == null) {
@@ -246,7 +247,7 @@ public class Analysis {
         final Path path = env.configFile().resolve(wordListPath);
 
         try {
-            return loadWordList(path, "#");
+            return loadWordList(path, removeComments);
         } catch (CharacterCodingException ex) {
             String message = String.format(Locale.ROOT,
                 "Unsupported character encoding detected while reading %s: %s - files must be UTF-8 encoded",
@@ -258,15 +259,15 @@ public class Analysis {
         }
     }
 
-    private static List<String> loadWordList(Path path, String comment) throws IOException {
+    private static List<String> loadWordList(Path path, boolean removeComments) throws IOException {
         final List<String> result = new ArrayList<>();
         try (BufferedReader br = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
             String word;
             while ((word = br.readLine()) != null) {
-                if (!Strings.hasText(word)) {
+                if (Strings.hasText(word) == false) {
                     continue;
                 }
-                if (!word.startsWith(comment)) {
+                if (removeComments == false || word.startsWith("#") == false) {
                     result.add(word.trim());
                 }
             }