Provide more context variables in update scripts

In addition to `_source`, the following variables are available through
the `ctx` map: `_index`, `_type`, `_id`, `_version`, `_routing`,
`_parent`, `_timestamp`, `_ttl`.

Some of these fields are more useful still within the context of an
Update By Query, see #1607, #2230, #2231.

Author: Olivier Favre

docs/reference/docs/update.asciidoc

@@ -234,3 +234,7 @@ It also allows to update the `ttl` of a document using `ctx._ttl` and
 timestamp using `ctx._timestamp`. Note that if the timestamp is not
 updated and not extracted from the `_source` it will be set to the
 update date.
+
+In addition to `_source`, the following variables are available through
+the `ctx` map: `_index`, `_type`, `_id`, `_version`, `_routing`,
+`_parent`, `_timestamp`, `_ttl`.

src/main/java/org/elasticsearch/action/update/UpdateHelper.java

@@ -41,6 +41,8 @@
 import org.elasticsearch.index.mapper.internal.ParentFieldMapper;
 import org.elasticsearch.index.mapper.internal.RoutingFieldMapper;
 import org.elasticsearch.index.mapper.internal.TTLFieldMapper;
+import org.elasticsearch.index.mapper.internal.TimestampFieldMapper;
+import org.elasticsearch.index.service.IndexService;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.shard.service.IndexShard;
 import org.elasticsearch.script.ExecutableScript;
@@ -74,7 +76,7 @@ public UpdateHelper(Settings settings, ScriptService scriptService) {
     public Result prepare(UpdateRequest request, IndexShard indexShard) {
         long getDate = System.currentTimeMillis();
         final GetResult getResult = indexShard.getService().get(request.type(), request.id(),
-                new String[]{RoutingFieldMapper.NAME, ParentFieldMapper.NAME, TTLFieldMapper.NAME},
+                new String[]{RoutingFieldMapper.NAME, ParentFieldMapper.NAME, TTLFieldMapper.NAME, TimestampFieldMapper.NAME},
                 true, request.version(), request.versionType(), FetchSourceContext.FETCH_SOURCE, false);
 
         if (!getResult.isExists()) {
@@ -148,7 +150,7 @@ public Result prepare(UpdateRequest request, IndexShard indexShard) {
 
         Tuple<XContentType, Map<String, Object>> sourceAndContent = XContentHelper.convertToMap(getResult.internalSourceRef(), true);
         String operation = null;
-        String timestamp;
+        String timestamp = null;
         Long ttl = null;
         final Map<String, Object> updatedSourceAsMap;
         final XContentType updateSourceContentType = sourceAndContent.v1();
@@ -176,7 +178,17 @@ public Result prepare(UpdateRequest request, IndexShard indexShard) {
                 operation = "none";
             }
         } else {
-            Map<String, Object> ctx = new HashMap<>(2);
+            Map<String, Object> ctx = new HashMap<>(16);
+            Long originalTtl = getResult.getFields().containsKey(TTLFieldMapper.NAME) ? (Long) getResult.field(TTLFieldMapper.NAME).getValue() : null;
+            Long originalTimestamp = getResult.getFields().containsKey(TimestampFieldMapper.NAME) ? (Long) getResult.field(TimestampFieldMapper.NAME).getValue() : null;
+            ctx.put("_index", getResult.getIndex());
+            ctx.put("_type", getResult.getType());
+            ctx.put("_id", getResult.getId());
+            ctx.put("_version", getResult.getVersion());
+            ctx.put("_routing", routing);
+            ctx.put("_parent", parent);
+            ctx.put("_timestamp", originalTimestamp);
+            ctx.put("_ttl", originalTtl);
             ctx.put("_source", sourceAndContent.v2());
 
             try {
@@ -190,7 +202,14 @@ public Result prepare(UpdateRequest request, IndexShard indexShard) {
             }
 
             operation = (String) ctx.get("op");
-            timestamp = (String) ctx.get("_timestamp");
+
+            Object fetchedTimestamp = ctx.get("_timestamp");
+            if (fetchedTimestamp != null) {
+                timestamp = fetchedTimestamp.toString();
+            } else if (originalTimestamp != null) {
+                // No timestamp has been given in the update script, so we keep the previous timestamp if there is one
+                timestamp = originalTimestamp.toString();
+            }
 
             ttl = getTTLFromScriptContext(ctx);
 

src/test/java/org/elasticsearch/update/UpdateTests.java

@@ -461,6 +461,99 @@ public void testUpdateRequestWithScriptAndShouldUpsertDoc() throws Exception {
         }
     }
 
+    @Test
+    public void testContextVariables() throws Exception {
+        createTestIndex();
+
+        // Add child type for testing the _parent context variable
+        client().admin().indices().preparePutMapping("test")
+                .setType("subtype1")
+                .setSource(XContentFactory.jsonBuilder()
+                        .startObject()
+                        .startObject("subtype1")
+                        .startObject("_parent").field("type", "type1").endObject()
+                        .startObject("_timestamp").field("enabled", true).field("store", "yes").endObject()
+                        .startObject("_ttl").field("enabled", true).field("store", "yes").endObject()
+                        .endObject()
+                        .endObject())
+                .execute().actionGet();
+        ensureGreen();
+
+        // Index some documents
+        long timestamp = System.currentTimeMillis();
+        client().prepareIndex()
+                .setIndex("test")
+                .setType("type1")
+                .setId("parentId1")
+                .setTimestamp(String.valueOf(timestamp-1))
+                .setSource("field1", 0, "content", "bar")
+                .execute().actionGet();
+
+        client().prepareIndex()
+                .setIndex("test")
+                .setType("subtype1")
+                .setId("id1")
+                .setParent("parentId1")
+                .setRouting("routing1")
+                .setTimestamp(String.valueOf(timestamp))
+                .setTTL(111211211)
+                .setSource("field1", 1, "content", "foo")
+                .execute().actionGet();
+        long postIndexTs = System.currentTimeMillis();
+
+        // Update the first object and note context variables values
+        Map<String, Object> scriptParams = new HashMap<>();
+        scriptParams.put("delim", "_");
+        UpdateResponse updateResponse = client().prepareUpdate("test", "subtype1", "id1")
+                .setRouting("routing1")
+                .setScript(
+                        "assert ctx._index == \"test\" : \"index should be \\\"test\\\"\"\n" +
+                        "assert ctx._type == \"subtype1\" : \"type should be \\\"subtype1\\\"\"\n" +
+                        "assert ctx._id == \"id1\" : \"id should be \\\"id1\\\"\"\n" +
+                        "assert ctx._version == 1 : \"version should be 1\"\n" +
+                        "assert ctx._parent == \"parentId1\" : \"parent should be \\\"parentId1\\\"\"\n" +
+                        "assert ctx._routing == \"routing1\" : \"routing should be \\\"routing1\\\"\"\n" +
+                        "assert ctx._timestamp == " + timestamp + " : \"timestamp should be " + timestamp + "\"\n" +
+                        "def now = new Date().getTime()\n" +
+                        "assert (111211211 - ctx._ttl) <= (now - " + postIndexTs + ") : \"ttl is not within acceptable range\"\n" +
+                        "ctx._source.content = ctx._source.content + delim + ctx._source.content;\n" +
+                        "ctx._source.field1 += 1;\n",
+                        ScriptService.ScriptType.INLINE)
+                .setScriptParams(scriptParams)
+                .execute().actionGet();
+
+        assertEquals(2, updateResponse.getVersion());
+
+        GetResponse getResponse = client().prepareGet("test", "subtype1", "id1").setRouting("routing1").execute().actionGet();
+        assertEquals(2, getResponse.getSourceAsMap().get("field1"));
+        assertEquals("foo_foo", getResponse.getSourceAsMap().get("content"));
+
+        // Idem with the second object
+        scriptParams = new HashMap<>();
+        scriptParams.put("delim", "_");
+        updateResponse = client().prepareUpdate("test", "type1", "parentId1")
+                .setScript(
+                        "assert ctx._index == \"test\" : \"index should be \\\"test\\\"\"\n" +
+                        "assert ctx._type == \"type1\" : \"type should be \\\"type1\\\"\"\n" +
+                        "assert ctx._id == \"parentId1\" : \"id should be \\\"parentId1\\\"\"\n" +
+                        "assert ctx._version == 1 : \"version should be 1\"\n" +
+                        "assert ctx._parent == null : \"parent should be null\"\n" +
+                        "assert ctx._routing == null : \"routing should be null\"\n" +
+                        "assert ctx._timestamp == " + (timestamp - 1) + " : \"timestamp should be " + (timestamp - 1) + "\"\n" +
+                        "assert ctx._ttl == null : \"ttl should be null\"\n" +
+                        "ctx._source.content = ctx._source.content + delim + ctx._source.content;\n" +
+                        "ctx._source.field1 += 1;\n",
+                        ScriptService.ScriptType.INLINE)
+                .setScriptParams(scriptParams)
+                .execute().actionGet();
+
+        assertEquals(2, updateResponse.getVersion());
+
+        getResponse = client().prepareGet("test", "type1", "parentId1").execute().actionGet();
+        assertEquals(1, getResponse.getSourceAsMap().get("field1"));
+        assertEquals("bar_bar", getResponse.getSourceAsMap().get("content"));
+    }
+
     @Test
     @Slow
     public void testConcurrentUpdateWithRetryOnConflict() throws Exception {