feat: make plugin FQN configs optional with strict-or-graceful loading

bifromq-plugin/bifromq-plugin-auth-provider-helper/src/main/java/org/apache/bifromq/plugin/authprovider/AuthProviderManager.java

@@ -40,6 +40,7 @@
 import org.apache.bifromq.type.ClientInfo;
 import io.micrometer.core.instrument.Timer;
 import java.util.Map;
+import java.util.TreeMap;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
@@ -64,17 +65,22 @@ public AuthProviderManager(String authProviderFQN,
         this.settingProvider = settingProvider;
         this.eventCollector = eventCollector;
         Map<String, IAuthProvider> availAuthProviders = pluginMgr.getExtensions(IAuthProvider.class)
-            .stream().collect(Collectors.toMap(e -> e.getClass().getName(), e -> e));
+            .stream().collect(Collectors.toMap(e -> e.getClass().getName(), e -> e,
+                        (k,v) -> v, TreeMap::new));
         if (availAuthProviders.isEmpty()) {
             pluginLog.warn("No auth provider plugin available, use DEV ONLY one instead");
             delegate = new DevOnlyAuthProvider();
         } else {
             if (authProviderFQN == null) {
-                pluginLog.warn("Auth provider plugin type not specified, use DEV ONLY one instead");
-                delegate = new DevOnlyAuthProvider();
+                if (availAuthProviders.size() > 1) {
+                    pluginLog.info("Auth provider plugin type not specified, use the first found");
+                }
+                String firstAuthProviderFQN = availAuthProviders.keySet().iterator().next();
+                pluginLog.info("Auth provider plugin loaded: {}", firstAuthProviderFQN);
+                delegate = availAuthProviders.get(firstAuthProviderFQN);
             } else if (!availAuthProviders.containsKey(authProviderFQN)) {
-                pluginLog.warn("Auth provider plugin type '{}' not found, use DEV ONLY one instead", authProviderFQN);
-                delegate = new DevOnlyAuthProvider();
+                pluginLog.warn("Auth provider plugin type '{}' not found, so the system will shut down.", authProviderFQN);
+                throw new AuthProviderPluginException("Auth provider plugin type '%s' not found, so the system will shut down.", authProviderFQN);
             } else {
                 pluginLog.info("Auth provider plugin type: {}", authProviderFQN);
                 delegate = availAuthProviders.get(authProviderFQN);

bifromq-plugin/bifromq-plugin-auth-provider-helper/src/main/java/org/apache/bifromq/plugin/authprovider/AuthProviderPluginException.java

@@ -0,0 +1,31 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+
+package org.apache.bifromq.plugin.authprovider;
+
+import org.pf4j.util.StringUtils;
+
+public class AuthProviderPluginException extends RuntimeException {
+
+    public AuthProviderPluginException(String message, Object... args) {
+        super(StringUtils.format(message, args));
+    }
+
+}

bifromq-plugin/bifromq-plugin-auth-provider-helper/src/test/java/org/apache/bifromq/plugin/authprovider/AuthProviderManagerTest.java

@@ -41,6 +41,7 @@
 import org.apache.bifromq.plugin.authprovider.type.MQTT5ExtendedAuthData;
 import org.apache.bifromq.plugin.authprovider.type.MQTT5ExtendedAuthResult;
 import org.apache.bifromq.plugin.authprovider.type.MQTTAction;
+import org.apache.bifromq.plugin.authprovider.type.Ok;
 import org.apache.bifromq.plugin.authprovider.type.PubAction;
 import org.apache.bifromq.plugin.authprovider.type.Reject;
 import org.apache.bifromq.plugin.authprovider.type.SubAction;
@@ -52,6 +53,8 @@
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.Metrics;
 import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.concurrent.CompletableFuture;
 import lombok.extern.slf4j.Slf4j;
@@ -133,18 +136,52 @@ public void pluginSpecified() {
     }
 
     @Test
+    public void pluginNotSpecifiedWithSingleProvider() {
+        manager = new AuthProviderManager(null, pluginManager, settingProvider, eventCollector);
+        when(mockProvider.auth(mockAuth3Data)).thenReturn(
+            CompletableFuture.completedFuture(MQTT3AuthResult.newBuilder()
+                .setReject(Reject.newBuilder().setCode(Reject.Code.BadPass).build()).build()));
+        MQTT3AuthResult result = manager.auth(mockAuth3Data).join();
+        assertEquals(result.getTypeCase(), MQTT3AuthResult.TypeCase.REJECT);
+        assertEquals(result.getReject().getCode(), Reject.Code.BadPass);
+        manager.close();
+    }
+
+    @Test
+    public void pluginNotSpecifiedWithMultipleProviders() {
+        IAuthProvider provider1 = new FirstTestAuthProvider();
+        IAuthProvider provider2 = new SecondTestAuthProvider();
+
+        when(pluginManager.getExtensions(IAuthProvider.class)).thenReturn(
+            Arrays.asList(provider1, provider2));
+        manager = new AuthProviderManager(null, pluginManager, settingProvider, eventCollector);
+
+        MQTT3AuthResult result = manager.auth(mockAuth3Data).join();
+        // Deterministically selects the provider with lexicographically smallest class name
+        assertEquals(result.getOk().getTenantId(), "FirstProvider");
+        manager.close();
+    }
+
+    @Test
+    public void pluginNotSpecifiedWithMultipleSortByKeyProviders() {
+        IAuthProvider provider1 = new FirstTestAuthProvider();
+        IAuthProvider provider2 = new SecondTestAuthProvider();
+
+        when(pluginManager.getExtensions(IAuthProvider.class)).thenReturn(
+                Arrays.asList(provider2, provider1));
+        manager = new AuthProviderManager(null, pluginManager, settingProvider, eventCollector);
+
+        MQTT3AuthResult result = manager.auth(mockAuth3Data).join();
+        // Deterministically selects the provider with lexicographically smallest class name
+        assertEquals(result.getOk().getTenantId(), "FirstProvider");
+        manager.close();
+    }
+
+
+    @Test(expectedExceptions = AuthProviderPluginException.class)
     public void pluginNotFound() {
         manager = new AuthProviderManager("Fake", pluginManager, settingProvider, eventCollector);
-        MQTT3AuthResult result = manager.auth(mockAuth3Data).join();
-        assertEquals(result.getTypeCase(), MQTT3AuthResult.TypeCase.OK);
-        assertEquals(result.getOk().getTenantId(), "DevOnly");
 
-        boolean allow = manager.check(ClientInfo.getDefaultInstance(), MQTTAction.newBuilder()
-            .setSub(SubAction.getDefaultInstance()).build()).join();
-        assertTrue(allow);
-        allow = manager.check(ClientInfo.getDefaultInstance(), MQTTAction.newBuilder()
-            .setSub(SubAction.getDefaultInstance()).build()).join();
-        assertTrue(allow);
         manager.close();
     }
 
@@ -404,4 +441,31 @@ public void byPassCheckResultError() {
         assertEquals(meterRegistry.find(CALL_FAIL_COUNTER).tag(TAG_METHOD, "AuthProvider/check").counter().count(),
             0);
     }
+
+    static class FirstTestAuthProvider implements IAuthProvider {
+        @Override
+        public CompletableFuture<MQTT3AuthResult> auth(MQTT3AuthData authData) {
+            return CompletableFuture.completedFuture(MQTT3AuthResult.newBuilder()
+                .setOk(Ok.newBuilder().setTenantId("FirstProvider").build()).build());
+        }
+
+        @Override
+        public CompletableFuture<Boolean> check(ClientInfo client, MQTTAction action) {
+            return CompletableFuture.completedFuture(true);
+        }
+    }
+
+    static class SecondTestAuthProvider implements IAuthProvider {
+        @Override
+        public CompletableFuture<MQTT3AuthResult> auth(MQTT3AuthData authData) {
+            return CompletableFuture.completedFuture(MQTT3AuthResult.newBuilder()
+                .setOk(Ok.newBuilder().setTenantId("SecondProvider").build()).build());
+        }
+
+        @Override
+        public CompletableFuture<Boolean> check(ClientInfo client, MQTTAction action) {
+            return CompletableFuture.completedFuture(true);
+        }
+
+    }
 }

bifromq-plugin/bifromq-plugin-resource-throttler-helper/src/main/java/org/apache/bifromq/plugin/resourcethrottler/ResourceThrottlerException.java

@@ -0,0 +1,31 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+
+package org.apache.bifromq.plugin.resourcethrottler;
+
+import org.pf4j.util.StringUtils;
+
+public class ResourceThrottlerException extends RuntimeException {
+
+    public ResourceThrottlerException(String message, Object... args) {
+        super(StringUtils.format(message, args));
+    }
+
+}

bifromq-plugin/bifromq-plugin-resource-throttler-helper/src/main/java/org/apache/bifromq/plugin/resourcethrottler/ResourceThrottlerManager.java

@@ -23,6 +23,7 @@
 import io.micrometer.core.instrument.Metrics;
 import io.micrometer.core.instrument.Timer;
 import java.util.Map;
+import java.util.TreeMap;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 import lombok.extern.slf4j.Slf4j;
@@ -41,18 +42,24 @@ public class ResourceThrottlerManager implements IResourceThrottler, AutoCloseab
     public ResourceThrottlerManager(String resourceThrottlerFQN, PluginManager pluginMgr) {
         Map<String, IResourceThrottler> availResourceThrottlers =
             pluginMgr.getExtensions(IResourceThrottler.class).stream()
-                .collect(Collectors.toMap(e -> e.getClass().getName(), e -> e));
+                .collect(Collectors.toMap(e -> e.getClass().getName(), e -> e,
+                        (k,v) -> v, TreeMap::new));
         if (availResourceThrottlers.isEmpty()) {
             pluginLog.warn("No resource throttler plugin available, use DEV ONLY one instead");
             delegate = new DevOnlyResourceThrottler();
         } else {
             if (resourceThrottlerFQN == null) {
-                pluginLog.warn("Resource throttler type class not specified, use DEV ONLY one instead");
-                delegate = new DevOnlyResourceThrottler();
+                if (availResourceThrottlers.size() > 1) {
+                    pluginLog.info("Resource throttler plugin type not specified, use the first found");
+                }
+                String firstResourceThrottlerFQN = availResourceThrottlers.keySet().iterator().next();
+                pluginLog.info("Resource throttler plugin loaded: {}", firstResourceThrottlerFQN);
+                delegate = availResourceThrottlers.get(firstResourceThrottlerFQN);
             } else if (!availResourceThrottlers.containsKey(resourceThrottlerFQN)) {
-                pluginLog.warn("Resource throttler type '{}' not found, use DEV ONLY one instead",
+                pluginLog.warn("Resource throttler type '{}' not found, so the system will shut down.",
                     resourceThrottlerFQN);
-                delegate = new DevOnlyResourceThrottler();
+                throw new ResourceThrottlerException("Resource throttler type '%s' not found, so the system will shut down.",
+                        resourceThrottlerFQN);
             } else {
                 pluginLog.info("Resource throttler loaded: {}", resourceThrottlerFQN);
                 delegate = availResourceThrottlers.get(resourceThrottlerFQN);