Only use PUT for index creation, not POST. elastic#20001

Currently both `PUT` and `POST` can be used to create indices. This commit
removes support for `POST index_name` so that we can use it to index documents
with auto-generated ids once types are removed.

Relates elastic#15613

core/src/main/java/org/elasticsearch/rest/action/admin/indices/RestCreateIndexAction.java

@@ -43,7 +43,6 @@ public class RestCreateIndexAction extends BaseRestHandler {
     public RestCreateIndexAction(Settings settings, RestController controller) {
         super(settings);
         controller.registerHandler(RestRequest.Method.PUT, "/{index}", this);
-        controller.registerHandler(RestRequest.Method.POST, "/{index}", this);
     }
 
     @SuppressWarnings({"unchecked"})

docs/plugins/mapper-attachments.asciidoc

@@ -45,7 +45,7 @@ Create a property mapping using the new type `attachment`:
 
 [source,js]
 --------------------------
-POST /trying-out-mapper-attachments
+PUT /trying-out-mapper-attachments
 {
   "mappings": {
     "person": {

docs/reference/indices/create-index.asciidoc

@@ -14,15 +14,17 @@ associated with it.
 
 [source,js]
 --------------------------------------------------
-$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
+PUT twitter
+{
     "settings" : {
         "index" : {
             "number_of_shards" : 3, <1>
             "number_of_replicas" : 2 <2>
         }
     }
-}'
+}
 --------------------------------------------------
+// CONSOLE
 <1> Default for `number_of_shards` is 5
 <2> Default for `number_of_replicas` is 1 (ie one replica for each primary shard)
 
@@ -33,27 +35,31 @@ index settings can also be defined with http://www.json.org[JSON]:
 
 [source,js]
 --------------------------------------------------
-$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
+PUT twitter
+{
     "settings" : {
         "index" : {
             "number_of_shards" : 3,
             "number_of_replicas" : 2
         }
     }
-}'
+}
 --------------------------------------------------
+// CONSOLE
 
 or more simplified
 
 [source,js]
 --------------------------------------------------
-$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
+PUT twitter
+{
     "settings" : {
         "number_of_shards" : 3,
         "number_of_replicas" : 2
     }
-}'
+}
 --------------------------------------------------
+// CONSOLE
 
 [NOTE]
 You do not have to explicitly specify `index` section inside the
@@ -72,7 +78,8 @@ The create index API allows to provide a set of one or more mappings:
 
 [source,js]
 --------------------------------------------------
-curl -XPOST localhost:9200/test -d '{
+PUT test
+{
     "settings" : {
         "number_of_shards" : 1
     },
@@ -83,8 +90,9 @@ curl -XPOST localhost:9200/test -d '{
             }
         }
     }
-}'
+}
 --------------------------------------------------
+// CONSOLE
 
 [float]
 [[create-index-aliases]]
@@ -94,7 +102,8 @@ The create index API allows also to provide a set of <<indices-aliases,aliases>>
 
 [source,js]
 --------------------------------------------------
-curl -XPUT localhost:9200/test -d '{
+PUT test
+{
     "aliases" : {
         "alias_1" : {},
         "alias_2" : {
@@ -104,24 +113,9 @@ curl -XPUT localhost:9200/test -d '{
             "routing" : "kimchy"
         }
     }
-}'
---------------------------------------------------
-
-[float]
-=== Creation Date
-
-When an index is created, a timestamp is stored in the index metadata for the creation date.  By 
-default this is automatically generated but it can also be specified using the 
-`creation_date` parameter on the create index API:
-
-[source,js]
---------------------------------------------------
-curl -XPUT localhost:9200/test -d '{
-    "creation_date" : 1407751337000 <1>
-}'
+}
 --------------------------------------------------
-
-<1> `creation_date` is set using epoch time in milliseconds.
+// CONSOLE
 
 [float]
 [[create-index-wait-for-active-shards]]
@@ -138,6 +132,7 @@ what happened:
     "shards_acknowledged": true
 }
 --------------------------------------------------
+// TESTRESPONSE
 
 `acknowledged` indicates whether the index was successfully created in the cluster, while 
 `shards_acknowledged` indices whether the requisite number of shard copies were started for
@@ -156,19 +151,24 @@ the `wait_for_active_shards` value on all subsequent write operations):
 
 [source,js]
 --------------------------------------------------
-curl -XPUT localhost:9200/test -d '{
+PUT test
+{
     "settings": {
         "index.write.wait_for_active_shards": "2"
     }
 }
 --------------------------------------------------
+// CONSOLE
+// TEST[skip:requires two nodes]
 
 or through the request parameter `wait_for_active_shards`:
 
 [source,js]
 --------------------------------------------------
-curl -XPUT localhost:9200/test?wait_for_active_shards=2
+PUT test?wait_for_active_shards=2
 --------------------------------------------------
+// CONSOLE
+// TEST[skip:requires two nodes]
 
 A detailed explanation of `wait_for_active_shards` and its possible values can be found 
 <<index-wait-for-active-shards,here>>.

docs/reference/migration/migrate_5_0/rest.asciidoc

@@ -15,6 +15,11 @@ endpoint should be used in lieu of optimize.
 The `GET` HTTP verb for `/_forcemerge` is no longer supported, please use the
 `POST` HTTP verb.
 
+==== Index creation endpoint only accepts `PUT`
+
+It used to be possible to create an index by either calling `PUT index_name`
+or `POST index_name`. Only the former is now supported.
+
 ==== Removed `mem` section from `/_cluster/stats` response
 
 The `mem` section contained only one value, the total memory available

docs/reference/search/suggesters/phrase-suggest.asciidoc

@@ -23,7 +23,7 @@ work. The `reverse` analyzer is used only in the last example.
 
 [source,js]
 --------------------------------------------------
-POST test
+PUT test
 {
   "settings": {
     "index": {

rest-api-spec/src/main/resources/rest-api-spec/api/indices.create.json

@@ -1,7 +1,7 @@
 {
   "indices.create": {
     "documentation": "http://www.elastic.co/guide/en/elasticsearch/reference/master/indices-create-index.html",
-    "methods": ["PUT", "POST"],
+    "methods": ["PUT"],
     "url": {
       "path": "/{index}",
       "paths": ["/{index}"],