[7.16] System index deprecation warning is not critical (#79633) (#80370)

* System index deprecation warning is not critical (#79633)

When we planned to fully cut off access to system
indices in 8.0, we needed our system index deprecation
warning to be critical. Now that we are merely hiding
system indices, avoiding system index access is no
longer critical, and there is very little that users can
do to change their access patterns. Therefore, we
should log the warning at WARN level, rather than at
CRITICAL.

* Restore production code changes

Author: williamrandolph

server/src/main/java/org/elasticsearch/action/admin/indices/alias/get/TransportGetAliasesAction.java

@@ -183,7 +183,7 @@ private static void checkSystemIndexAccess(
             }
         });
         if (systemIndicesNames.isEmpty() == false) {
-            deprecationLogger.critical(
+            deprecationLogger.warn(
                 DeprecationCategory.API,
                 "open_system_index_access",
                 "this request accesses system indices: {}, but in a future major version, direct access to system "

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

@@ -427,7 +427,7 @@ private void checkSystemIndexAccess(Context context, Set<Index> concreteIndices,
 
         if (resolvedSystemIndices.isEmpty() == false) {
             Collections.sort(resolvedSystemIndices);
-            deprecationLogger.critical(
+            deprecationLogger.warn(
                 DeprecationCategory.API,
                 "open_system_index_access",
                 "this request accesses system indices: {}, but in a future major version, direct access to system "

server/src/test/java/org/elasticsearch/action/admin/indices/alias/get/TransportGetAliasesActionTests.java

@@ -7,6 +7,7 @@
  */
 package org.elasticsearch.action.admin.indices.alias.get;
 
+import org.apache.logging.log4j.Level;
 import org.elasticsearch.Version;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.AliasMetadata;
@@ -122,8 +123,12 @@ public void testDeprecationWarningEmittedForTotalWildcard() {
         assertThat(result.get(".b").size(), equalTo(1));
         assertThat(result.get("c").size(), equalTo(1));
         assertWarnings(
-            "this request accesses system indices: [.b], but in a future major version, direct access to system "
-                + "indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.b], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
     }
 
@@ -149,8 +154,12 @@ public void testDeprecationWarningEmittedWhenSystemIndexIsRequested() {
         assertThat(result.size(), equalTo(1));
         assertThat(result.get(".b").size(), equalTo(1));
         assertWarnings(
-            "this request accesses system indices: [.b], but in a future major version, direct access to system "
-                + "indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.b], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
     }
 
@@ -175,8 +184,12 @@ public void testDeprecationWarningEmittedWhenSystemIndexIsRequestedByAlias() {
         assertThat(result.size(), equalTo(1));
         assertThat(result.get(".b").size(), equalTo(1));
         assertWarnings(
-            "this request accesses system indices: [.b], but in a future major version, direct access to system "
-                + "indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.b], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
     }
 

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

@@ -8,6 +8,7 @@
 
 package org.elasticsearch.cluster.metadata;
 
+import org.apache.logging.log4j.Level;
 import org.elasticsearch.Version;
 import org.elasticsearch.action.DocWriteRequest;
 import org.elasticsearch.action.IndicesRequest;
@@ -2308,8 +2309,12 @@ public void testFullWildcardSystemIndexResolutionDeprecated() {
         List<String> indexNames = resolveConcreteIndexNameList(state, request);
         assertThat(indexNames, containsInAnyOrder("some-other-index", ".ml-stuff", ".ml-meta", ".watches"));
         assertWarnings(
-            "this request accesses system indices: [.ml-meta, .ml-stuff, .watches], but in a future major version, "
-                + "direct access to system indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.ml-meta, .ml-stuff, .watches], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
 
     }
@@ -2322,10 +2327,13 @@ public void testSingleSystemIndexResolutionDeprecated() {
         List<String> indexNames = resolveConcreteIndexNameList(state, request);
         assertThat(indexNames, containsInAnyOrder(".ml-meta"));
         assertWarnings(
-            "this request accesses system indices: [.ml-meta], but in a future major version, direct access "
-                + "to system indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.ml-meta], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
-
     }
 
     public void testWildcardSystemIndexReslutionSingleMatchDeprecated() {
@@ -2336,8 +2344,12 @@ public void testWildcardSystemIndexReslutionSingleMatchDeprecated() {
         List<String> indexNames = resolveConcreteIndexNameList(state, request);
         assertThat(indexNames, containsInAnyOrder(".watches"));
         assertWarnings(
-            "this request accesses system indices: [.watches], but in a future major version, direct access "
-                + "to system indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.watches], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
 
     }
@@ -2350,8 +2362,12 @@ public void testWildcardSystemIndexResolutionMultipleMatchesDeprecated() {
         List<String> indexNames = resolveConcreteIndexNameList(state, request);
         assertThat(indexNames, containsInAnyOrder(".ml-meta", ".ml-stuff"));
         assertWarnings(
-            "this request accesses system indices: [.ml-meta, .ml-stuff], but in a future major version, direct access "
-                + "to system indices will be prevented by default"
+            true,
+            new DeprecationWarning(
+                Level.WARN,
+                "this request accesses system indices: [.ml-meta, .ml-stuff], "
+                    + "but in a future major version, direct access to system indices will be prevented by default"
+            )
         );
 
     }
@@ -2405,8 +2421,12 @@ public void testExternalSystemIndexAccess() {
                 List<String> indexNames = resolveConcreteIndexNameList(state, request);
                 assertThat(indexNames, contains(".external-sys-idx"));
                 assertWarnings(
-                    "this request accesses system indices: [.external-sys-idx], but in a future major version, direct access "
-                        + "to system indices will be prevented by default"
+                    true,
+                    new DeprecationWarning(
+                        Level.WARN,
+                        "this request accesses system indices: [.external-sys-idx], "
+                            + "but in a future major version, direct access to system indices will be prevented by default"
+                    )
                 );
             }
         }
@@ -2418,8 +2438,12 @@ public void testExternalSystemIndexAccess() {
                 List<String> indexNames = resolveConcreteIndexNameList(state, request);
                 assertThat(indexNames, contains(".external-sys-idx"));
                 assertWarnings(
-                    "this request accesses system indices: [.external-sys-idx], but in a future major version, direct access "
-                        + "to system indices will be prevented by default"
+                    true,
+                    new DeprecationWarning(
+                        Level.WARN,
+                        "this request accesses system indices: [.external-sys-idx], "
+                            + "but in a future major version, direct access to system indices will be prevented by default"
+                    )
                 );
             }
         }