Store stard status in the database

PluralKit.Core/Database/Database.cs

@@ -19,7 +19,7 @@ namespace PluralKit.Core
     internal class Database: IDatabase
     {
         private const string RootPath = "PluralKit.Core.Database"; // "resource path" root for SQL files
-        private const int TargetSchemaVersion = 13;
+        private const int TargetSchemaVersion = 14;
         
         private readonly CoreConfig _config;
         private readonly ILogger _logger;

PluralKit.Core/Database/Migrations/14.sql

@@ -0,0 +1,15 @@
+-- SCHEMA VERSION 14: 2021-06-10 --
+-- Add shard status table --
+
+create table shards (
+    id int not null primary key,
+    
+    -- 0 = down, 1 = up
+    status smallint not null default 0,
+    
+    ping float,
+    last_heartbeat timestamptz,
+    last_connection timestamptz
+);
+
+update info set schema_version = 14;

PluralKit.Core/Database/Repository/ModelRepository.Shards.cs

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+
+using Dapper;
+
+using NodaTime;
+
+namespace PluralKit.Core
+{
+    public partial class ModelRepository
+    {
+        public Task<IEnumerable<PKShardInfo>> GetShards(IPKConnection conn) =>
+            conn.QueryAsync<PKShardInfo>("select * from shards");
+
+        public Task SetShardStatus(IPKConnection conn, int shard, PKShardInfo.ShardStatus status) =>
+            conn.ExecuteAsync(
+                "insert into shards (id, status) values (@Id, @Status) on conflict (id) do update set status = @Status",
+                new {Id = shard, Status = status});
+
+        public Task RegisterShardHeartbeat(IPKConnection conn, int shard, Duration ping) =>
+            conn.ExecuteAsync(
+                "insert into shards (id, last_heartbeat, ping) values (@Id, now(), @Ping) on conflict (id) do update set last_heartbeat = now(), ping = @Ping",
+                new {Id = shard, Ping = ping.TotalSeconds});
+
+        public Task RegisterShardConnection(IPKConnection conn, int shard) =>
+            conn.ExecuteAsync(
+                "insert into shards (id, last_connection) values (@Id, now()) on conflict (id) do update set last_connection = now()",
+                new {Id = shard});
+    }
+}