Rework caching

This does a *lot* of things. Essentially, it replaces the existing
individual proxy- and autoproxy caches on the bot end with a
global cache (in Core) that handles all the caching at once, and
automatically invalidates the cache once something changes in the
datastore.

This allows us to do proxying and autoproxying with *zero database
queries* (best-case).

PluralKit.Core/Stores.cs

@@ -6,6 +6,8 @@ using System.Threading.Tasks;
 using Dapper;
 using NodaTime;
 
+using PluralKit.Core;
+
 using Serilog;
 
 namespace PluralKit {
@@ -76,6 +78,7 @@ namespace PluralKit {
 
     public class SystemGuildSettings
     {
+        public ulong Guild { get; set; }
         public bool ProxyEnabled { get; set; } = true;
 
         public AutoproxyMode AutoproxyMode { get; set; } = AutoproxyMode.Off;
@@ -84,6 +87,8 @@ namespace PluralKit {
 
     public class MemberGuildSettings
     {
+        public int Member { get; set; }
+        public ulong Guild { get; set; }
         public string DisplayName { get; set; }
     }
 
@@ -425,11 +430,13 @@ namespace PluralKit {
     public class PostgresDataStore: IDataStore {
         private DbConnectionFactory _conn;
         private ILogger _logger;
+        private ProxyCache _cache;
 
-        public PostgresDataStore(DbConnectionFactory conn, ILogger logger)
+        public PostgresDataStore(DbConnectionFactory conn, ILogger logger, ProxyCache cache)
         {
             _conn = conn;
             _logger = logger;
+            _cache = cache;
         }
 
         public async Task<IEnumerable<PKMember>> GetConflictingProxies(PKSystem system, ProxyTag tag)
@@ -467,6 +474,7 @@ namespace PluralKit {
                     settings.AutoproxyMode,
                     settings.AutoproxyMember
                 });
+            await _cache.InvalidateSystem(system);
         }
 
         public async Task<PKSystem> CreateSystem(string systemName = null) {
@@ -481,6 +489,7 @@ namespace PluralKit {
                 system = await conn.QuerySingleAsync<PKSystem>("insert into systems (hid, name) values (@Hid, @Name) returning *", new { Hid = hid, Name = systemName });
 
             _logger.Information("Created system {System}", system.Id);
+            // New system has no accounts, therefore nothing gets cached, therefore no need to invalidate caches right here
             return system;
         }
 
@@ -491,6 +500,7 @@ namespace PluralKit {
                 await conn.ExecuteAsync("insert into accounts (uid, system) values (@Id, @SystemId) on conflict do nothing", new { Id = accountId, SystemId = system.Id });
 
             _logger.Information("Linked system {System} to account {Account}", system.Id, accountId);
+            await _cache.InvalidateSystem(system);
         }
 
         public async Task RemoveAccount(PKSystem system, ulong accountId) {
@@ -498,6 +508,7 @@ namespace PluralKit {
                 await conn.ExecuteAsync("delete from accounts where uid = @Id and system = @SystemId", new { Id = accountId, SystemId = system.Id });
 
             _logger.Information("Unlinked system {System} from account {Account}", system.Id, accountId);
+            await _cache.InvalidateSystem(system);
         }
 
         public async Task<PKSystem> GetSystemByAccount(ulong accountId) {
@@ -526,12 +537,15 @@ namespace PluralKit {
                 await conn.ExecuteAsync("update systems set name = @Name, description = @Description, tag = @Tag, avatar_url = @AvatarUrl, token = @Token, ui_tz = @UiTz, description_privacy = @DescriptionPrivacy, member_list_privacy = @MemberListPrivacy, front_privacy = @FrontPrivacy, front_history_privacy = @FrontHistoryPrivacy where id = @Id", system);
 
             _logger.Information("Updated system {@System}", system);
+            await _cache.InvalidateSystem(system);
         }
 
         public async Task DeleteSystem(PKSystem system) {
             using (var conn = await _conn.Obtain())
                 await conn.ExecuteAsync("delete from systems where id = @Id", system);
+            
             _logger.Information("Deleted system {System}", system.Id);
+            await _cache.InvalidateSystem(system);
         }
 
         public async Task<IEnumerable<ulong>> GetSystemAccounts(PKSystem system)
@@ -568,6 +582,7 @@ namespace PluralKit {
                 });
 
             _logger.Information("Created member {Member}", member.Id);
+            await _cache.InvalidateSystem(system);
             return member;
         }
 
@@ -598,6 +613,7 @@ namespace PluralKit {
 
                 tx.Commit();
                 _logger.Information("Created {MemberCount} members for system {SystemID}", names.Count(), system.Hid);
+                await _cache.InvalidateSystem(system);
                 return results;
             }
         }
@@ -630,6 +646,7 @@ namespace PluralKit {
                 await conn.ExecuteAsync("update members set name = @Name, display_name = @DisplayName, description = @Description, color = @Color, avatar_url = @AvatarUrl, birthday = @Birthday, pronouns = @Pronouns, proxy_tags = @ProxyTags, keep_proxy = @KeepProxy, member_privacy = @MemberPrivacy where id = @Id", member);
 
             _logger.Information("Updated member {@Member}", member);
+            await _cache.InvalidateSystem(member.System);
         }
 
         public async Task DeleteMember(PKMember member) {
@@ -637,6 +654,7 @@ namespace PluralKit {
                 await conn.ExecuteAsync("delete from members where id = @Id", member);
 
             _logger.Information("Deleted member {@Member}", member);
+            await _cache.InvalidateSystem(member.System);
         }
 
         public async Task<MemberGuildSettings> GetMemberGuildSettings(PKMember member, ulong guild)
@@ -653,6 +671,7 @@ namespace PluralKit {
             await conn.ExecuteAsync(
                 "insert into member_guild (member, guild, display_name) values (@Member, @Guild, @DisplayName) on conflict (member, guild) do update set display_name = @Displayname",
                 new {Member = member.Id, Guild = guild, DisplayName = settings.DisplayName});
+            await _cache.InvalidateSystem(member.System);
         }
 
         public async Task<ulong> GetMemberMessageCount(PKMember member)
@@ -749,7 +768,7 @@ namespace PluralKit {
         }
 
         // Same as GuildConfig, but with ISet<ulong> as long[] instead.
-        private struct DatabaseCompatibleGuildConfig
+        public struct DatabaseCompatibleGuildConfig
         {
             public ulong Id { get; set; }
             public ulong? LogChannel { get; set; }
@@ -768,6 +787,7 @@ namespace PluralKit {
 
         public async Task<GuildConfig> GetOrCreateGuildConfig(ulong guild)
         {
+            // When changing this, also see ProxyCache::GetGuildDataCached
             using (var conn = await _conn.Obtain())
             {
                 return (await conn.QuerySingleOrDefaultAsync<DatabaseCompatibleGuildConfig>(
@@ -787,6 +807,7 @@ namespace PluralKit {
                     Blacklist = cfg.Blacklist.Select(c  => (long) c).ToList()
                 });
             _logger.Information("Updated guild configuration {@GuildCfg}", cfg);
+            _cache.InvalidateGuild(cfg.Id);
         }
 
         public async Task<AuxillaryProxyInformation> GetAuxillaryProxyInformation(ulong guild, PKSystem system, PKMember member)