Restore BauweltMember cache and notify all dev servers on member changes

getBauMember never read its cache after the Exposed migration, so every
scoreboard render hit the DB (Too many connections, #479). Cache by
(bauwelt, member) incl. negative results, evict on addMember/remove, and
send BaumemberUpdatePacket to the Bauserver and all dev servers (also on
addmember). BauMemberUpdate clears the cache itself to not depend on
handler order.

BauSystem/BauSystem_Main/src/de/steamwar/bausystem/features/world/BauMemberUpdate.java

@@ -28,6 +28,7 @@ import de.steamwar.bausystem.utils.bossbar.BossBarService;
 import de.steamwar.linkage.Linked;
 import de.steamwar.network.packets.PacketHandler;
 import de.steamwar.network.packets.server.BaumemberUpdatePacket;
+import de.steamwar.sql.BauweltMember;
 import io.papermc.paper.event.player.PlayerPickBlockEvent;
 import org.bukkit.Bukkit;
 import org.bukkit.boss.BarColor;
@@ -57,6 +58,8 @@ public class BauMemberUpdate extends PacketHandler implements Listener {
     }
 
     public static void baumemberUpdate() {
+        // Packet handlers run in no guaranteed order, so don't rely on CoreNetworkHandler having cleared the cache yet.
+        BauweltMember.clear();
         Set<Player> newSpectator = new HashSet<>();
         Set<Player> newBuilder = new HashSet<>();
         Bukkit.getOnlinePlayers().forEach(player -> {

CommonCore/SQL/src/de/steamwar/sql/BauweltMember.kt

@@ -30,6 +30,7 @@ import org.jetbrains.exposed.v1.dao.CompositeEntity
 import org.jetbrains.exposed.v1.dao.CompositeEntityClass
 import org.jetbrains.exposed.v1.jdbc.insertIgnore
 import java.util.*
+import java.util.concurrent.ConcurrentHashMap
 
 object BauweltMemberTable : CompositeIdTable("BauweltMember") {
     val bauweltId = reference("BauweltID", SteamwarUserTable).index()
@@ -48,10 +49,12 @@ object BauweltMemberTable : CompositeIdTable("BauweltMember") {
 
 class BauweltMember(id: EntityID<CompositeID>) : CompositeEntity(id) {
     companion object : CompositeEntityClass<BauweltMember>(BauweltMemberTable) {
-        private val cache = mutableMapOf<Int, BauweltMember>()
+        // Keyed by (bauweltId, memberId). Optional.empty() caches "is not a member", which is the
+        // common case for spectators and would otherwise hit the DB on every permission check.
+        private val cache = ConcurrentHashMap<Pair<Int, Int>, Optional<BauweltMember>>()
 
         private fun cache(member: BauweltMember) =
-            cache.put(member.memberID, member)
+            cache.put(member.bauweltID to member.memberID, Optional.of(member))
 
         @JvmStatic
         fun clear() =
@@ -75,20 +78,20 @@ class BauweltMember(id: EntityID<CompositeID>) : CompositeEntity(id) {
                     it[worldEdit] = false
                     it[world] = false
                 }
-            }
+            }.also { cache.remove(ownerId.value to newMemberId.value) }
 
         @JvmStatic
         @Deprecated("Use getBauMember(bauwelt: Int, member: Int)")
         fun getBauMember(bauwelt: UUID, member: UUID) =
-            useDb {
-                find { (bauweltId eq SteamwarUser.get(bauwelt)!!.id) and (BauweltMemberTable.memberId eq SteamwarUser.get(member)!!.id) }.firstOrNull()?.also { cache(it) }
-            }
+            getBauMember(SteamwarUser.get(bauwelt)!!.id.value, SteamwarUser.get(member)!!.id.value)
 
         @JvmStatic
-        fun getBauMember(bauwelt: Int, member: Int) =
-            useDb {
-                find { (bauweltId eq bauwelt) and (BauweltMemberTable.memberId eq member) }.firstOrNull()?.also { cache(it) }
-            }
+        fun getBauMember(bauwelt: Int, member: Int): BauweltMember? =
+            cache.computeIfAbsent(bauwelt to member) {
+                Optional.ofNullable(useDb {
+                    find { (bauweltId eq bauwelt) and (BauweltMemberTable.memberId eq member) }.firstOrNull()
+                })
+            }.orElse(null)
 
         @JvmStatic
         @Deprecated("Use getMembers(bauwelt: Int)")
@@ -140,8 +143,11 @@ class BauweltMember(id: EntityID<CompositeID>) : CompositeEntity(id) {
     fun isWorld() =
         world
 
-    fun remove() =
+    fun remove() {
+        val key = bauweltID to memberID
         useDb {
             delete()
         }
+        cache.remove(key)
+    }
 }

VelocityCore/src/de/steamwar/velocitycore/commands/BauCommand.java

@@ -19,6 +19,7 @@
 
 package de.steamwar.velocitycore.commands;
 
+import com.velocitypowered.api.proxy.server.RegisteredServer;
 import de.steamwar.command.PreviousArguments;
 import de.steamwar.command.SWCommand;
 import de.steamwar.command.TypeMapper;
@@ -45,7 +46,9 @@ import de.steamwar.velocitycore.network.NetworkSender;
 import de.steamwar.velocitycore.util.BauLock;
 
 import java.io.File;
+import java.util.ArrayList;
 import java.util.Collection;
+import java.util.UUID;
 import java.util.function.Consumer;
 
 @Linked
@@ -72,6 +75,7 @@ public class BauCommand extends SWCommand {
     @Register(value = "addmember", description = "BAU_ADDMEMBER_USAGE")
     public void addmember(Chatter sender, @Validator("addMemberTarget") SteamwarUser target) {
         BauweltMember.addMember(sender.user().getUUID(), target.getUUID());
+        sendBaumemberUpdate(sender.user().getUUID());
         sender.system("BAU_ADDMEMBER_ADDED");
         Chatter.of(target.getUUID()).system("BAU_ADDMEMBER_ADDED_TARGET", sender);
     }
@@ -161,10 +165,7 @@ public class BauCommand extends SWCommand {
         withMember(owner, user, target -> {
             setter.accept(target);
 
-            Bauserver bauserver = Bauserver.get(owner.user().getUUID());
-            if (bauserver != null) {
-                bauserver.getRegisteredServer().getPlayersConnected().stream().findAny().ifPresent(player -> NetworkSender.send(player, new BaumemberUpdatePacket()));
-            }
+            sendBaumemberUpdate(owner.user().getUUID());
 
             Chatter.of(user.getUUID()).system("BAU_MEMBER_SET_TARGET", owner, new Message(permName));
             owner.system("BAU_MEMBER_SET", new Message(permName));
@@ -184,9 +185,7 @@ public class BauCommand extends SWCommand {
                 }
             });
 
-            if (bauserver != null) {
-                bauserver.getRegisteredServer().getPlayersConnected().stream().findAny().ifPresent(player -> NetworkSender.send(player, new BaumemberUpdatePacket()));
-            }
+            sendBaumemberUpdate(owner.user().getUUID());
 
             try {
                 deletePlayerData(owner, user);
@@ -289,6 +288,23 @@ public class BauCommand extends SWCommand {
         BauLock.setLocked(sender, BauLockState.OPEN);
     }
 
+    /**
+     * Tells the owner's Bauserver and every dev server to drop their cached {@link BauweltMember}s,
+     * since those run in separate processes and would otherwise keep serving stale permissions.
+     * Plugin messages need a connected player, so servers without players are skipped.
+     */
+    private static void sendBaumemberUpdate(UUID owner) {
+        Bauserver bauserver = Bauserver.get(owner);
+        if (bauserver != null) {
+            sendBaumemberUpdate(bauserver.getRegisteredServer());
+        }
+        new ArrayList<>(DevCommand.getDevServers().values()).forEach(BauCommand::sendBaumemberUpdate);
+    }
+
+    private static void sendBaumemberUpdate(RegisteredServer server) {
+        server.getPlayersConnected().stream().findAny().ifPresent(player -> NetworkSender.send(player, new BaumemberUpdatePacket()));
+    }
+
     private static void withMember(Chatter owner, SteamwarUser member, Consumer<BauweltMember> function) {
         if (member == null) {
             owner.system("UNKNOWN_PLAYER");