Add DiskStatistics grpc method to ServerService

DiskStatistics method returns available and used space for each gitaly
storage. Praefect calls all nodes and agregates results from all of
them.

Signed-off-by: Mateusz Nowotyński <maxmati4@gmail.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/proto/server.proto b/proto/server.proto
index 6774eeae4..68e39f2fe 100644
--- a/proto/server.proto
+++ b/proto/server.proto
@@ -13,6 +13,12 @@ service ServerService {
       scope_level: SERVER
     };
   }
+  rpc DiskStatistics(DiskStatisticsRequest) returns (DiskStatisticsResponse) {
+    option (op_type) = {
+      op: ACCESSOR
+      scope_level: SERVER
+    };
+  }
 }
 
 message ServerInfoRequest {}
@@ -30,3 +36,17 @@ message ServerInfoResponse {
   string git_version = 2;
   repeated StorageStatus storage_statuses = 3;
 }
+
+message DiskStatisticsRequest {}
+
+message DiskStatisticsResponse {
+  message StorageStatus {
+// When both available and used fields are equal 0 that means that
+// Gitaly was unable to determine storage stats.
+    string storage_name = 1;
+    int64 available = 2;
+    int64 used = 3;
+  }
+
+  repeated StorageStatus storage_statuses = 1;
+}