Added request for edge id batch request to coordinator rsm

src/coordinator/coordinator.hpp

@@ -52,6 +52,15 @@ struct AllocateHlcBatchResponse {
   Hlc high;
 };
 
+struct AllocateEdgeIdBatchRequest {
+  size_t batch_size;
+};
+
+struct AllocateEdgeIdBatchResponse {
+  uint64_t low;
+  uint64_t high;
+};
+
 struct SplitShardRequest {
   Hlc previous_shard_map_version;
   Label label;
@@ -78,10 +87,10 @@ struct DeregisterStorageEngineResponse {
   bool success;
 };
 
-using WriteRequests = std::variant<AllocateHlcBatchRequest, SplitShardRequest, RegisterStorageEngineRequest,
-                                   DeregisterStorageEngineRequest>;
-using WriteResponses = std::variant<AllocateHlcBatchResponse, SplitShardResponse, RegisterStorageEngineResponse,
-                                    DeregisterStorageEngineResponse>;
+using WriteRequests = std::variant<AllocateHlcBatchRequest, AllocateEdgeIdBatchRequest, SplitShardRequest,
+                                   RegisterStorageEngineRequest, DeregisterStorageEngineRequest>;
+using WriteResponses = std::variant<AllocateHlcBatchResponse, AllocateEdgeIdBatchResponse, SplitShardResponse,
+                                    RegisterStorageEngineResponse, DeregisterStorageEngineResponse>;
 
 using ReadRequests = std::variant<HlcRequest, GetShardMapRequest>;
 using ReadResponses = std::variant<HlcResponse, GetShardMapResponse>;
@@ -103,6 +112,9 @@ class Coordinator {
   uint64_t highest_allocated_timestamp_;
   uint64_t highest_reserved_timestamp_;
 
+  /// Query engines need to periodically request batches of unique edge IDs.
+  uint64_t highest_allocated_edge_id_;
+
   /// Increment our
   ReadResponses Read(HlcRequest hlc_request) {
     HlcResponse res{};
@@ -129,16 +141,31 @@ class Coordinator {
     return res;
   }
 
-  WriteResponses Apply(AllocateHlcBatchRequest &&ahr) {
+  WriteResponses ApplyWrite(AllocateHlcBatchRequest &&ahr) {
     AllocateHlcBatchResponse res{};
 
     return res;
   }
 
+  WriteResponses ApplyWrite(AllocateEdgeIdBatchRequest &&ahr) {
+    AllocateEdgeIdBatchResponse res{};
+
+    uint64_t low = highest_allocated_edge_id_;
+
+    highest_allocated_edge_id_ += ahr.batch_size;
+
+    uint64_t high = highest_allocated_edge_id_;
+
+    res.low = low;
+    res.high = high;
+
+    return res;
+  }
+
   /// This splits the shard immediately beneath the provided
   /// split key, keeping the assigned peers identical for now,
   /// but letting them be gradually migrated over time.
-  WriteResponses Apply(SplitShardRequest &&split_shard_request) {
+  WriteResponses ApplyWrite(SplitShardRequest &&split_shard_request) {
     SplitShardResponse res{};
 
     if (split_shard_request.previous_shard_map_version != shard_map_.shard_map_version) {
@@ -153,7 +180,7 @@ class Coordinator {
 
   /// This adds the provided storage engine to the standby storage engine pool,
   /// which can be used to rebalance storage over time.
-  WriteResponses Apply(RegisterStorageEngineRequest &&register_storage_engine_request) {
+  WriteResponses ApplyWrite(RegisterStorageEngineRequest &&register_storage_engine_request) {
     RegisterStorageEngineResponse res{};
     // TODO
 
@@ -162,7 +189,7 @@ class Coordinator {
 
   /// This begins the process of draining the provided storage engine from all raft
   /// clusters that it might be participating in.
-  WriteResponses Apply(DeregisterStorageEngineRequest &&register_storage_engine_request) {
+  WriteResponses ApplyWrite(DeregisterStorageEngineRequest &&register_storage_engine_request) {
     DeregisterStorageEngineResponse res{};
     // TODO
     // const Address &address = register_storage_engine_request.address;
@@ -196,7 +223,7 @@ class Coordinator {
   }
 
   WriteResponses Apply(WriteRequests requests) {
-    return std::visit([&](auto &&requests) { return Apply(requests); }, std::move(requests));
+    return std::visit([&](auto &&requests) { return ApplyWrite(std::move(requests)); }, std::move(requests));
   }
 };