Add support for rest_total_hits_as_int (#36051)

The support for rest_total_hits_as_int has already been merged to 6x
in #35848 so this change adds this new option to master. The plan was
to add this new option as part of #35848 but we've decided to wait a few
days before merging this breaking change so this commit just handles
the new option as a noop exactly like 6x for now. This will allow
users to migrate to this parameter before #35848 is merged.

Relates #33028

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestMultiSearchTemplateAction.java

@@ -31,7 +31,9 @@ import org.elasticsearch.rest.action.search.RestMultiSearchAction;
 import org.elasticsearch.rest.action.search.RestSearchAction;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
@@ -40,7 +42,15 @@ import static org.elasticsearch.rest.RestRequest.Method.POST;
 public class RestMultiSearchTemplateAction extends BaseRestHandler {
     private static final DeprecationLogger deprecationLogger = new DeprecationLogger(
         LogManager.getLogger(RestMultiSearchAction.class));
-    private static final Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TYPED_KEYS_PARAM);
+
+    private static final Set<String> RESPONSE_PARAMS;
+
+    static {
+        final Set<String> responseParams = new HashSet<>(
+            Arrays.asList(RestSearchAction.TYPED_KEYS_PARAM, RestSearchAction.TOTAL_HIT_AS_INT_PARAM)
+        );
+        RESPONSE_PARAMS = Collections.unmodifiableSet(responseParams);
+    }
 
     private final boolean allowExplicitIndex;
 

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/RestSearchTemplateAction.java

@@ -30,7 +30,9 @@ import org.elasticsearch.rest.action.RestStatusToXContentListener;
 import org.elasticsearch.rest.action.search.RestSearchAction;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
@@ -38,7 +40,14 @@ import static org.elasticsearch.rest.RestRequest.Method.POST;
 
 public class RestSearchTemplateAction extends BaseRestHandler {
 
-    private static final Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TYPED_KEYS_PARAM);
+    private static final Set<String> RESPONSE_PARAMS;
+
+    static {
+        final Set<String> responseParams = new HashSet<>(
+            Arrays.asList(RestSearchAction.TYPED_KEYS_PARAM, RestSearchAction.TOTAL_HIT_AS_INT_PARAM)
+        );
+        RESPONSE_PARAMS = Collections.unmodifiableSet(responseParams);
+    }
 
     public RestSearchTemplateAction(Settings settings, RestController controller) {
         super(settings);

modules/lang-mustache/src/test/resources/rest-api-spec/test/lang_mustache/30_search_template.yml

@@ -124,3 +124,30 @@
   - match: { hits.total: 1 }
   - length: { hits.hits: 1 }
   - length: { profile: 1 }
+
+---
+"Test with rest_total_hits_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+
+  - do:
+      index:
+        index:  test
+        type:   type
+        id:     1
+        body:   {}
+
+  - do:
+      put_script:
+        id: "template_1"
+        body: { "script": { "lang": "mustache", "source": { "query": { "match_all": {} } } } }
+
+  - match: { acknowledged: true }
+
+  - do:
+      search_template:
+        rest_total_hits_as_int: true
+        body: { "id": "template_1", "params": {} }
+
+  - match: { hits.total: 0 }

modules/lang-mustache/src/test/resources/rest-api-spec/test/lang_mustache/50_multi_search_template.yml

@@ -156,3 +156,47 @@ setup:
   - match:  { responses.0.hits.total:     2  }
   - match:  { responses.1.hits.total:     1  }
   - match:  { responses.2.hits.total:     1  }
+
+
+  - do:
+      put_script:
+        id: stored_template_1
+        body: { "script": { "lang" : "mustache", "source": { "query": {"match": {"{{field}}": "{{value}}" }}}}}
+  - match: { acknowledged: true }
+
+---
+"Test with rest_total_hits_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+
+  - do:
+      put_script:
+        id: stored_template_1
+        body: { "script": { "lang": "mustache", "source": { "query": {"match": {"{{field}}": "{{value}}" }}}}}
+  - match: { acknowledged: true }
+
+  - do:
+      msearch_template:
+        rest_total_hits_as_int: true
+        body:
+        - index: index_*
+        - id: stored_template_1
+          params:
+            field: "foo"
+            value: "foo"
+        - index: _all
+        - id: stored_template_1
+          params:
+            field: "foo"
+            value: "bar"
+        - index: index_2
+        - id: stored_template_1
+          params:
+            field: "foo"
+            value: "foo"
+
+  - match:  { responses.0.hits.total:     2  }
+  - match:  { responses.1.hits.total:     1  }
+  - match:  { responses.2.hits.total:     1  }
+

rest-api-spec/src/main/resources/rest-api-spec/api/msearch.json

@@ -38,6 +38,11 @@
           "type" : "number",
           "description" : "The number of concurrent shard requests each sub search executes concurrently. This value should be used to limit the impact of the search on the cluster in order to limit the number of concurrent shard requests",
           "default" : "The default grows with the number of nodes in the cluster but is at most 256."
+        },
+        "rest_total_hits_as_int" : {
+          "type" : "boolean",
+          "description" : "This parameter is ignored in this version. It is used in the next major version to control whether the rest response should render the total.hits as an object or a number",
+          "default" : false
         }
       }
     },

rest-api-spec/src/main/resources/rest-api-spec/api/msearch_template.json

@@ -28,6 +28,11 @@
         "max_concurrent_searches" : {
           "type" : "number",
           "description" : "Controls the maximum number of concurrent searches the multi search api will execute"
+        },
+        "rest_total_hits_as_int" : {
+          "type" : "boolean",
+          "description" : "This parameter is ignored in this version. It is used in the next major version to control whether the rest response should render the total.hits as an object or a number",
+          "default" : false
         }
       }
     },

rest-api-spec/src/main/resources/rest-api-spec/api/scroll.json

@@ -19,6 +19,11 @@
         "scroll_id": {
           "type" : "string",
           "description" : "The scroll ID for scrolled search"
+        },
+        "rest_total_hits_as_int" : {
+          "type" : "boolean",
+          "description" : "This parameter is ignored in this version. It is used in the next major version to control whether the rest response should render the total.hits as an object or a number",
+          "default" : false
         }
       }
     },

rest-api-spec/src/main/resources/rest-api-spec/api/search.json

@@ -182,6 +182,11 @@
           "type" : "number",
           "description" : "A threshold that enforces a pre-filter roundtrip to prefilter search shards based on query rewriting if the number of shards the search request expands to exceeds the threshold. This filter roundtrip can limit the number of shards significantly if for instance a shard can not match any documents based on it's rewrite method ie. if date filters are mandatory to match but the shard bounds and the query are disjoint.",
           "default" : 128
+        },
+        "rest_total_hits_as_int" : {
+          "type" : "boolean",
+          "description" : "This parameter is ignored in this version. It is used in the next major version to control whether the rest response should render the total.hits as an object or a number",
+          "default" : false
         }
       }
     },

rest-api-spec/src/main/resources/rest-api-spec/api/search_template.json

@@ -62,6 +62,11 @@
         "typed_keys": {
           "type" : "boolean",
           "description" : "Specify whether aggregation and suggester names should be prefixed by their respective types in the response"
+        },
+        "rest_total_hits_as_int" : {
+          "type" : "boolean",
+          "description" : "This parameter is ignored in this version. It is used in the next major version to control whether the rest response should render the total.hits as an object or a number",
+          "default" : false
         }
       }
     },

rest-api-spec/src/main/resources/rest-api-spec/test/msearch/10_basic.yml

@@ -93,3 +93,28 @@ setup:
   - match:  { responses.3.error.root_cause.0.reason: "/no.such.index/" }
   - match:  { responses.3.error.root_cause.0.index: index_3 }
   - match:  { responses.4.hits.total:     4  }
+
+---
+"Search with rest_total_hits_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+
+  - do:
+      msearch:
+        rest_total_hits_as_int: true
+        body:
+          - index: index_*
+          - query:
+              match: {foo: foo}
+          - index: index_2
+          - query:
+              match_all: {}
+          - index: index_1
+          - query:
+              match: {foo: foo}
+
+  - match:  { responses.0.hits.total:     2  }
+  - match:  { responses.1.hits.total:     1  }
+  - match:  { responses.2.hits.total:     1  }
+

rest-api-spec/src/main/resources/rest-api-spec/test/scroll/10_basic.yml

@@ -281,3 +281,67 @@
 
   - length: {hits.hits:      1    }
   - match: { hits.max_score: null }
+
+---
+"Scroll with rest_total_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+  - do:
+      indices.create:
+        index: test_scroll
+  - do:
+      index:
+        index:  test_scroll
+        type:   test
+        id:     42
+        body:   { foo: 1 }
+
+  - do:
+      index:
+        index:  test_scroll
+        type:   test
+        id:     43
+        body:   { foo: 2 }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        index: test_scroll
+        size: 1
+        scroll: 1m
+        sort: foo
+        rest_total_hits_as_int: true
+        body:
+          query:
+            match_all: {}
+
+  - set: {_scroll_id: scroll_id}
+  - match: {hits.total:      2    }
+  - length: {hits.hits:      1    }
+  - match: {hits.hits.0._id: "42" }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        body: { "scroll_id": "$scroll_id", "scroll": "1m"}
+
+  - match: {hits.total:      2    }
+  - length: {hits.hits:      1    }
+  - match: {hits.hits.0._id: "43" }
+
+  - do:
+      scroll:
+        rest_total_hits_as_int: true
+        scroll_id: $scroll_id
+        scroll: 1m
+
+  - match: {hits.total:      2    }
+  - length: {hits.hits:      0    }
+
+  - do:
+      clear_scroll:
+        scroll_id: $scroll_id
+

rest-api-spec/src/main/resources/rest-api-spec/test/search/20_default_values.yml

@@ -72,3 +72,13 @@ setup:
             match:
               foo: bar
 
+---
+"Search with rest_total_hits_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+  - do:
+      search:
+        rest_total_hits_as_int: true
+
+  - match: {hits.total: 2}

server/src/main/java/org/elasticsearch/rest/action/search/RestMultiSearchAction.java

@@ -40,7 +40,9 @@ import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.search.builder.SearchSourceBuilder;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
@@ -53,7 +55,14 @@ public class RestMultiSearchAction extends BaseRestHandler {
     public static final String TYPES_DEPRECATION_MESSAGE = "[types removal]" +
         " Specifying types in multi search requests is deprecated.";
 
-    private static final Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TYPED_KEYS_PARAM);
+    private static final Set<String> RESPONSE_PARAMS;
+
+    static {
+        final Set<String> responseParams = new HashSet<>(
+            Arrays.asList(RestSearchAction.TYPED_KEYS_PARAM, RestSearchAction.TOTAL_HIT_AS_INT_PARAM)
+        );
+        RESPONSE_PARAMS = Collections.unmodifiableSet(responseParams);
+    }
 
     private final boolean allowExplicitIndex;
 

server/src/main/java/org/elasticsearch/rest/action/search/RestSearchAction.java

@@ -45,6 +45,7 @@ import org.elasticsearch.search.suggest.term.TermSuggestionBuilder.SuggestMode;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Set;
 import java.util.function.IntConsumer;
 
@@ -55,7 +56,13 @@ import static org.elasticsearch.search.suggest.SuggestBuilders.termSuggestion;
 
 public class RestSearchAction extends BaseRestHandler {
     public static final String TYPED_KEYS_PARAM = "typed_keys";
-    private static final Set<String> RESPONSE_PARAMS = Collections.singleton(TYPED_KEYS_PARAM);
+    public static final String TOTAL_HIT_AS_INT_PARAM = "rest_total_hits_as_int";
+    private static final Set<String> RESPONSE_PARAMS;
+
+    static {
+        final Set<String> responseParams = new HashSet<>(Arrays.asList(TYPED_KEYS_PARAM, TOTAL_HIT_AS_INT_PARAM));
+        RESPONSE_PARAMS = Collections.unmodifiableSet(responseParams);
+    }
 
     private static final DeprecationLogger deprecationLogger = new DeprecationLogger(LogManager.getLogger(RestSearchAction.class));
     public static final String TYPES_DEPRECATION_MESSAGE = "[types removal]" +

server/src/main/java/org/elasticsearch/rest/action/search/RestSearchScrollAction.java

@@ -29,12 +29,16 @@ import org.elasticsearch.rest.action.RestStatusToXContentListener;
 import org.elasticsearch.search.Scroll;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.Set;
 
 import static org.elasticsearch.common.unit.TimeValue.parseTimeValue;
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 import static org.elasticsearch.rest.RestRequest.Method.POST;
 
 public class RestSearchScrollAction extends BaseRestHandler {
+    Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TOTAL_HIT_AS_INT_PARAM);
+
     public RestSearchScrollAction(Settings settings, RestController controller) {
         super(settings);
 
@@ -70,4 +74,9 @@ public class RestSearchScrollAction extends BaseRestHandler {
             }});
         return channel -> client.searchScroll(searchScrollRequest, new RestStatusToXContentListener<>(channel));
     }
+
+    @Override
+    protected Set<String> responseParams() {
+        return RESPONSE_PARAMS;
+    }
 }

x-pack/plugin/rollup/src/main/java/org/elasticsearch/xpack/rollup/rest/RestRollupSearchAction.java

@@ -16,9 +16,13 @@ import org.elasticsearch.rest.action.search.RestSearchAction;
 import org.elasticsearch.xpack.core.rollup.action.RollupSearchAction;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.Set;
 
 public class RestRollupSearchAction extends BaseRestHandler {
 
+    private static final Set<String> RESPONSE_PARAMS = Collections.singleton(RestSearchAction.TOTAL_HIT_AS_INT_PARAM);
+
     public RestRollupSearchAction(Settings settings, RestController controller) {
         super(settings);
         controller.registerHandler(RestRequest.Method.GET, "_rollup_search", this);
@@ -39,4 +43,9 @@ public class RestRollupSearchAction extends BaseRestHandler {
     public String getName() {
         return "rollup_search_action";
     }
+
+    @Override
+    protected Set<String> responseParams() {
+        return RESPONSE_PARAMS;
+    }
 }

x-pack/plugin/src/test/resources/rest-api-spec/test/rollup/rollup_search.yml

@@ -154,6 +154,33 @@ setup:
   - match: { aggregations.histo.buckets.3.key_as_string: "2017-01-01T08:00:00.000Z" }
   - match: { aggregations.histo.buckets.3.doc_count: 20 }
 
+---
+"Basic Search with rest_total_hits_as_int":
+  - skip:
+      version: " - 6.5.99"
+      reason: rest_total_hits_as_int was introduced in 6.6.0
+  - do:
+      xpack.rollup.rollup_search:
+        index: "foo_rollup"
+        body:
+          size: 0
+          aggs:
+            histo:
+              date_histogram:
+                field: "timestamp"
+                interval: "1h"
+                time_zone: "UTC"
+
+  - length: { aggregations.histo.buckets: 4 }
+  - match: { aggregations.histo.buckets.0.key_as_string: "2017-01-01T05:00:00.000Z" }
+  - match: { aggregations.histo.buckets.0.doc_count: 1 }
+  - match: { aggregations.histo.buckets.1.key_as_string: "2017-01-01T06:00:00.000Z" }
+  - match: { aggregations.histo.buckets.1.doc_count: 2 }
+  - match: { aggregations.histo.buckets.2.key_as_string: "2017-01-01T07:00:00.000Z" }
+  - match: { aggregations.histo.buckets.2.doc_count: 10 }
+  - match: { aggregations.histo.buckets.3.key_as_string: "2017-01-01T08:00:00.000Z" }
+  - match: { aggregations.histo.buckets.3.doc_count: 20 }
+
 ---
 "Formatted Date Histo":