CR: Support overrides to exclusions

Author: original-brownbear

server/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java

@@ -296,30 +296,37 @@ private ImmutableOpenMap<String, List<AliasMetaData>> findAliases(String[] origi
             return ImmutableOpenMap.of();
         }
 
-        List<String> includeAliases = new ArrayList<>();
-        List<String> excludeAliases = new ArrayList<>();
-        boolean wildcardSeen = false;
-        for (final String alias : aliases) {
-            if (Regex.isSimpleMatchPattern(alias)) {
-                wildcardSeen = true;
-            }
-            if (wildcardSeen && alias.charAt(0) == '-') {
-                excludeAliases.add(alias.substring(1));
+        String[] patterns = new String[aliases.length];
+        boolean[] include = new boolean[aliases.length];
+        for (int i = 0; i < aliases.length; i++) {
+            String alias = aliases[i];
+            if (alias.charAt(0) == '-') {
+                patterns[i] = alias.substring(1);
+                include[i] = false;
             } else {
-                includeAliases.add(alias);
+                patterns[i] = alias;
+                include[i] = true;
             }
         }
-        String[] included = includeAliases.toArray(Strings.EMPTY_ARRAY);
-        String[] excluded = excludeAliases.toArray(Strings.EMPTY_ARRAY);
-        boolean matchAllAliases = matchAllAliases(included);
+        boolean matchAllAliases = patterns.length == 0;
         ImmutableOpenMap.Builder<String, List<AliasMetaData>> mapBuilder = ImmutableOpenMap.builder();
         for (String index : concreteIndices) {
             IndexMetaData indexMetaData = indices.get(index);
             List<AliasMetaData> filteredValues = new ArrayList<>();
             for (ObjectCursor<AliasMetaData> cursor : indexMetaData.getAliases().values()) {
                 AliasMetaData value = cursor.value;
-                if ((matchAllAliases || Regex.simpleMatch(included, value.alias()))
-                    && Regex.simpleMatch(excluded, value.alias()) == false) {
+                boolean matched = matchAllAliases;
+                String alias = value.alias();
+                for (int i = 0; i < patterns.length; i++) {
+                    if (include[i]) {
+                        if (matched == false) {
+                            matched = Regex.simpleMatch(patterns[i], alias);
+                        }
+                    } else if (matched) {
+                        matched = Regex.simpleMatch(patterns[i], alias) == false;
+                    }
+                }
+                if (matched) {
                     filteredValues.add(value);
                 }
             }
@@ -333,15 +340,6 @@ private ImmutableOpenMap<String, List<AliasMetaData>> findAliases(String[] origi
         return mapBuilder.build();
     }
 
-    private static boolean matchAllAliases(final String[] aliases) {
-        for (String alias : aliases) {
-            if (alias.equals(ALL)) {
-                return true;
-            }
-        }
-        return aliases.length == 0;
-    }
-
     /**
      * Checks if at least one of the specified aliases exists in the specified concrete indices. Wildcards are supported in the
      * alias names for partial matches.

server/src/test/java/org/elasticsearch/cluster/metadata/MetaDataTests.java

@@ -109,7 +109,7 @@ public void testFindAliases() {
         }
     }
 
-    public void testFindAliasWithMultiIndexAndExclusion() {
+    public void testFindAliasWithExclusion() {
         MetaData metaData = MetaData.builder().put(
             IndexMetaData.builder("index")
                 .settings(Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT))
@@ -118,10 +118,27 @@ public void testFindAliasWithMultiIndexAndExclusion() {
                 .putAlias(AliasMetaData.builder("alias1").build())
                 .putAlias(AliasMetaData.builder("alias2").build())
         ).build();
-        ImmutableOpenMap<String, List<AliasMetaData>> aliases =
-            metaData.findAliases(new GetAliasesRequest().aliases("*", "-alias1"), new String[] {"index"});
+        List<AliasMetaData> aliases =
+            metaData.findAliases(new GetAliasesRequest().aliases("*", "-alias1"), new String[] {"index"}).get("index");
         assertThat(aliases.size(), equalTo(1));
-        assertThat(aliases.get("index").get(0).alias(), equalTo("alias2"));
+        assertThat(aliases.get(0).alias(), equalTo("alias2"));
+    }
+
+    public void testFindAliasWithExclusionAndOverride() {
+        MetaData metaData = MetaData.builder().put(
+            IndexMetaData.builder("index")
+                .settings(Settings.builder().put(IndexMetaData.SETTING_VERSION_CREATED, Version.CURRENT))
+                .numberOfShards(1)
+                .numberOfReplicas(0)
+                .putAlias(AliasMetaData.builder("aa").build())
+                .putAlias(AliasMetaData.builder("ab").build())
+                .putAlias(AliasMetaData.builder("bb").build())
+        ).build();
+        List<AliasMetaData> aliases =
+            metaData.findAliases(new GetAliasesRequest().aliases("a*", "-*b", "b*"), new String[] {"index"}).get("index");
+        assertThat(aliases.size(), equalTo(2));
+        assertThat(aliases.get(0).alias(), equalTo("aa"));
+        assertThat(aliases.get(1).alias(), equalTo("bb"));
     }
 
     public void testIndexAndAliasWithSameName() {