HDDS-8214. Recon - OM DB Insights - Key Level Info

hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/api/ContainerEndpoint.java

@@ -481,4 +481,47 @@ private List<ContainerBlockMetadata> getBlocks(
     return blockIds;
   }
 
+  /** This method retrieves set of keys/files/dirs which are mapped to
+   * containers in DELETED state in SCM. */
+  @GET
+  @Path("/mismatch/keys")
+  public Response getDeletedContainerKeysInfo(
+      @DefaultValue(DEFAULT_FETCH_COUNT) @QueryParam(RECON_QUERY_LIMIT)
+      int limit,
+      @DefaultValue(StringUtils.EMPTY) @QueryParam(RECON_QUERY_PREVKEY)
+      String prevKeyPrefix) {
+    List<KeysResponse> keysResponseList = new ArrayList<>();
+    try {
+      Map<Long, ContainerMetadata> omContainers =
+          reconContainerMetadataManager.getContainers(-1, 0);
+      List<ContainerInfo> deletedStateSCMContainers =
+          containerManager.getContainers(HddsProtos.LifeCycleState.DELETED);
+      List<Long> deletedStateSCMContainerIds =
+          deletedStateSCMContainers.stream()
+              .map(containerInfo -> containerInfo.getContainerID()).collect(
+                  Collectors.toList());
+
+      List<Long> omContainerIdsMappedToDeletedSCMContainers =
+          omContainers.entrySet().stream()
+              .filter(
+                  map -> deletedStateSCMContainerIds.contains(map.getKey()))
+              .map(map -> map.getKey()).collect(Collectors.toList());
+
+      omContainerIdsMappedToDeletedSCMContainers.forEach(containerId -> {
+        Response keysForContainer = getKeysForContainer(containerId, limit,
+            prevKeyPrefix);
+        KeysResponse keysResponse = (KeysResponse) keysForContainer.getEntity();
+        keysResponseList.add(keysResponse);
+      });
+    } catch (IOException ex) {
+      throw new WebApplicationException(ex,
+          Response.Status.INTERNAL_SERVER_ERROR);
+    } catch (IllegalArgumentException e) {
+      throw new WebApplicationException(e, Response.Status.BAD_REQUEST);
+    } catch (Exception ex) {
+      throw new WebApplicationException(ex,
+          Response.Status.INTERNAL_SERVER_ERROR);
+    }
+    return Response.ok(keysResponseList).build();
+  }
 }