SERVER-63728 Differentiate observers by role in cumulative metrics

Differentiate observers by role so that recipient and coordinator
estimates can be reported separately. Additionally, split reporting into
high/low estimates and replace placeholder values in the ServerStatus
report with those estimates.

1 files changed, 49 insertions, 0 deletions

diff --git a/src/mongo/db/s/sharding_data_transform_metrics.cpp b/src/mongo/db/s/sharding_data_transform_metrics.cpp
new file mode 100644
index 00000000000..7c5ba3b39c4
--- /dev/null
+++ b/src/mongo/db/s/sharding_data_transform_metrics.cpp
@@ -0,0 +1,49 @@
+/**
+ *    Copyright (C) 2022-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the Server Side Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/s/sharding_data_transform_metrics.h"
+#include "mongo/stdx/unordered_map.h"
+
+namespace mongo {
+
+namespace {
+const stdx::unordered_map<ShardingDataTransformMetrics::Role, StringData> roleToName = {
+    {ShardingDataTransformMetrics::Role::kCoordinator, "Coordinator"_sd},
+    {ShardingDataTransformMetrics::Role::kDonor, "Donor"_sd},
+    {ShardingDataTransformMetrics::Role::kRecipient, "Recipient"_sd},
+};
+}
+
+StringData ShardingDataTransformMetrics::getRoleName(Role role) {
+    auto it = roleToName.find(role);
+    invariant(it != roleToName.end());
+    return it->second;
+}
+
+}  // namespace mongo