Implement MAB's UserActivityTracker and blocking the bridge upon exceeding the user limit

changelog.d/1472.feature

@@ -0,0 +1 @@
+Add optional bridge blocking upon exceeding a monthly active user limit

config.sample.yaml

@@ -567,6 +567,15 @@ ircService:
     # how much time needs to pass between the reply and the original message to switch to the long format
     shortReplyTresholdSeconds: 300
 
+  # Maximum number of montly active users, beyond which the bridge gets blocked (both ways)
+  # RMAUlimit: 100
+
+  # userActivity:
+    # The "grace period" before we start counting users as active
+    # minUserActiveDays: 1
+    # Time before users are considered inactive again
+    # inactiveAfterDays: 30
+
   ircHandler:
     # Should we attempt to match an IRC side mention (nickaname match)
     # with the nickname's owner's matrixId, if we are bridging them?

config.schema.yml

@@ -129,6 +129,15 @@ properties:
                         type: "number"
             passwordEncryptionKeyPath:
                 type: "string"
+            RMAUlimit:
+                type: "integer"
+            userActivity:
+                type: "object"
+                properties:
+                    minUserActiveDays:
+                        type: "number"
+                    inactiveAfterDays:
+                        type: "number"
             matrixHandler:
                 type: "object"
                 properties:

src/bridge/IrcBridge.ts

@@ -34,6 +34,10 @@ import {
     AppService,
     Rules,
     ActivityTracker,
+    BridgeBlocker,
+    UserActivityState,
+    UserActivityTracker,
+    UserActivityTrackerConfig,
 } from "matrix-appservice-bridge";
 import { IrcAction } from "../models/IrcAction";
 import { DataStore } from "../datastore/DataStore";
@@ -95,6 +99,7 @@ export class IrcBridge {
         networkId: string;
     }>;
     private privacyProtection: PrivacyProtection;
+    private bridgeBlocker?: BridgeBlocker;
 
     constructor(
         public readonly config: BridgeConfig,
@@ -121,8 +126,9 @@ export class IrcBridge {
         if (this.config.database.engine === "nedb") {
             const dirPath = this.config.database.connectionString.substring("nedb://".length);
             bridgeStoreConfig = {
-                roomStore: `${dirPath}/rooms.db`,
-                userStore: `${dirPath}/users.db`,
+                roomStore:         `${dirPath}/rooms.db`,
+                userStore:         `${dirPath}/users.db`,
+                userActivityStore: `${dirPath}/user-activity.db`,
             };
         }
         else {
@@ -215,6 +221,10 @@ export class IrcBridge {
             httpMaxSizeBytes: this.config.advanced?.maxTxnSize ?? TXN_SIZE_DEFAULT,
         });
         this.roomConfigs = new RoomConfig(this.bridge, this.config.ircService.perRoomConfig);
+
+        if (this.config.ircService.RMAUlimit) {
+            this.bridgeBlocker = new BridgeBlocker(this.config.ircService.RMAUlimit);
+        }
     }
 
     public async onConfigChanged(newConfig: BridgeConfig) {
@@ -415,6 +425,11 @@ export class IrcBridge {
             labels: ["server"]
         });
 
+        const bridgeBlocked = metrics.addGauge({
+            name: "bridge_blocked",
+            help: "Is the bridge currently blocking messages",
+        });
+
         metrics.addCollector(() => {
             this.ircServers.forEach((server) => {
                 reconnQueue.set({server: server.domain},
@@ -473,6 +488,8 @@ export class IrcBridge {
             Object.entries(ircMetrics).forEach((kv) => {
                 ircHandlerCalls.inc({method: kv[0]}, kv[1]);
             });
+
+            bridgeBlocked.set(this.bridgeBlocker?.isBlocked ? 1 : 0);
         });
 
         metrics.addCollector(async () => {
@@ -569,12 +586,14 @@ export class IrcBridge {
             await this.bridge.loadDatabases();
             const userStore = this.bridge.getUserStore();
             const roomStore = this.bridge.getRoomStore();
+            const userActivityStore = this.bridge.getUserActivityStore();
             log.info("Using NeDBDataStore for Datastore");
-            if (!userStore || !roomStore) {
-                throw Error('Could not load userStore or roomStore');
+            if (!userStore || !roomStore || !userActivityStore) {
+                throw Error('Could not load user(Activity)Store or roomStore');
             }
             this.dataStore = new NeDBDataStore(
                 userStore,
+                userActivityStore,
                 roomStore,
                 this.config.homeserver.domain,
                 pkeyPath,
@@ -636,6 +655,22 @@ export class IrcBridge {
             throw Error("No IRC servers specified.");
         }
 
+        const uatConfig = {
+            ...UserActivityTrackerConfig.DEFAULT,
+        };
+        if (this.config.ircService.userActivity?.minUserActiveDays !== undefined) {
+            uatConfig.minUserActiveDays = this.config.ircService.userActivity.minUserActiveDays;
+        }
+        if (this.config.ircService.userActivity?.inactiveAfterDays !== undefined) {
+            uatConfig.inactiveAfterDays = this.config.ircService.userActivity.inactiveAfterDays;
+        }
+        this.bridge.opts.controller.userActivityTracker = new UserActivityTracker(
+            uatConfig,
+            await this.getStore().getUserActivity(),
+            (changes) => this.onUserActivityChanged(changes),
+        );
+        this.bridgeBlocker?.checkLimits(this.bridge.opts.controller.userActivityTracker.countActiveUsers().allUsers);
+
         // run the bridge (needs to be done prior to configure IRC side)
         await this.bridge.listen(port, this.config.homeserver.bindHostname, undefined, this.appservice);
         log.info(`Listening on ${this.config.homeserver.bindHostname || "0.0.0.0"}:${port}`)
@@ -744,6 +779,7 @@ export class IrcBridge {
         });
 
         log.info("Startup complete.");
+
         this.startedUp = true;
     }
 
@@ -849,6 +885,10 @@ export class IrcBridge {
     }
 
     public async sendMatrixAction(room: MatrixRoom, from: MatrixUser, action: MatrixAction): Promise<void> {
+        if (this.bridgeBlocker?.isBlocked) {
+            log.info("Bridge is blocked, dropping Matrix action");
+            return;
+        }
         const intent = this.bridge.getIntent(from.userId);
         const extraContent: Record<string, unknown> = {};
         if (action.replyEvent) {
@@ -955,6 +995,10 @@ export class IrcBridge {
     }
 
     public onEvent(request: BridgeRequestEvent) {
+        if (this.bridgeBlocker?.isBlocked) {
+            log.info("Bridge is blocked, dropping Matrix event");
+            return;
+        }
         request.outcomeFrom(this._onEvent(request));
     }
 
@@ -1297,11 +1341,15 @@ export class IrcBridge {
     }
 
     public async sendIrcAction(ircRoom: IrcRoom, bridgedClient: BridgedClient, action: IrcAction) {
+        if (this.bridgeBlocker?.isBlocked) {
+            log.info("Bridge is blocked, dropping IRC action");
+            return;
+        }
         log.info(
             "Sending IRC message in %s as %s (connected=%s)",
             ircRoom.channel, bridgedClient.nick, Boolean(bridgedClient.status === BridgedClientStatus.CONNECTED)
         );
-        return bridgedClient.sendAction(ircRoom, action);
+        await bridgedClient.sendAction(ircRoom, action);
     }
 
     public async getBotClient(server: IrcServer) {
@@ -1477,4 +1525,11 @@ export class IrcBridge {
         const current = await this.dataStore.getRoomCount();
         return current >= limit;
     }
+
+    private onUserActivityChanged(userActivity: UserActivityState) {
+        for (const userId of userActivity.changed) {
+            this.getStore().storeUserActivity(userId, userActivity.dataSet.users[userId]);
+        }
+        this.bridgeBlocker?.checkLimits(userActivity.activeUsers);
+    }
 }

src/config/BridgeConfig.ts

@@ -59,6 +59,11 @@ export interface BridgeConfig {
             [userIdOrDomain: string]: "admin";
         };
         perRoomConfig?: RoomConfigConfig;
+        RMAUlimit?: number;
+        userActivity?: {
+            minUserActiveDays?: number;
+            inactiveAfterDays?: number;
+        };
     };
     sentry?: {
         enabled: boolean;

src/datastore/DataStore.ts

@@ -14,7 +14,11 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { MatrixRoom, MatrixUser, RoomBridgeStoreEntry as Entry} from "matrix-appservice-bridge";
+import {
+    MatrixRoom, MatrixUser,
+    RoomBridgeStoreEntry as Entry,
+    UserActivity, UserActivitySet
+} from "matrix-appservice-bridge";
 import { IrcRoom } from "../models/IrcRoom";
 import { IrcClientConfig } from "../models/IrcClientConfig";
 import { IrcServer, IrcServerConfig } from "../irc/IrcServer";
@@ -157,6 +161,10 @@ export interface DataStore {
 
     storeUserFeatures(userId: string, features: UserFeatures): Promise<void>;
 
+    getUserActivity(): Promise<UserActivitySet>;
+
+    storeUserActivity(userId: string, activity: UserActivity): Promise<void>;
+
     storePass(userId: string, domain: string, pass: string): Promise<void>;
 
     removePass(userId: string, domain: string): Promise<void>;

src/datastore/NedbDataStore.ts

@@ -18,8 +18,12 @@ import { IrcRoom } from "../models/IrcRoom";
 import { IrcClientConfig, IrcClientConfigSeralized } from "../models/IrcClientConfig"
 import { getLogger } from "../logging";
 
-import { MatrixRoom, MatrixUser, RemoteUser, RemoteRoom,
-    UserBridgeStore, RoomBridgeStore, RoomBridgeStoreEntry as Entry } from "matrix-appservice-bridge";
+import {
+    MatrixRoom, MatrixUser, RemoteUser, RemoteRoom,
+    UserBridgeStore, UserActivityStore,
+    RoomBridgeStore, RoomBridgeStoreEntry as Entry,
+    UserActivity, UserActivitySet
+} from "matrix-appservice-bridge";
 import { DataStore, RoomOrigin, ChannelMappings, UserFeatures } from "./DataStore";
 import { IrcServer, IrcServerConfig } from "../irc/IrcServer";
 import { StringCrypto } from "./StringCrypto";
@@ -35,6 +39,7 @@ export class NeDBDataStore implements DataStore {
     private cryptoStore?: StringCrypto;
     constructor(
         private userStore: UserBridgeStore,
+        private userActivityStore: UserActivityStore,
         private roomStore: RoomBridgeStore,
         private bridgeDomain: string,
         pkeyPath?: string) {
@@ -586,6 +591,14 @@ export class NeDBDataStore implements DataStore {
         await this.userStore.setMatrixUser(matrixUser);
     }
 
+    public async getUserActivity(): Promise<UserActivitySet> {
+        return this.userActivityStore.getActivitySet();
+    }
+
+    public async storeUserActivity(userId: string, activity: UserActivity) {
+        this.userActivityStore.storeUserActivity(userId, activity);
+    }
+
     public async storePass(userId: string, domain: string, pass: string) {
         const config = await this.getIrcClientConfig(userId, domain);
         if (!config) {

src/datastore/postgres/PgDataStore.ts

@@ -21,7 +21,9 @@ import {
     MatrixRoom,
     RemoteRoom,
     RoomBridgeStoreEntry as Entry,
-    MatrixRoomData
+    MatrixRoomData,
+    UserActivitySet,
+    UserActivity,
 } from "matrix-appservice-bridge";
 import { DataStore, RoomOrigin, ChannelMappings, UserFeatures } from "../DataStore";
 import { IrcRoom } from "../../models/IrcRoom";
@@ -52,7 +54,7 @@ interface RoomRecord {
 export class PgDataStore implements DataStore {
     private serverMappings: {[domain: string]: IrcServer} = {};
 
-    public static readonly LATEST_SCHEMA = 6;
+    public static readonly LATEST_SCHEMA = 7;
     private pgPool: Pool;
     private hasEnded = false;
     private cryptoStore?: StringCrypto;
@@ -556,6 +558,24 @@ export class PgDataStore implements DataStore {
         await this.pgPool.query(statement, [userId, JSON.stringify(features)]);
     }
 
+    public async getUserActivity(): Promise<UserActivitySet> {
+        const res = await this.pgPool.query('SELECT * FROM user_activity');
+        const users: {[mxid: string]: UserActivity} = {};
+        for (const row of res.rows) {
+            users[row['user_id']] = row['data'];
+        }
+        return { users };
+    }
+
+    public async storeUserActivity(userId: string, activity: UserActivity) {
+        const stmt = PgDataStore.BuildUpsertStatement(
+            'user_activity',
+            '(user_id)',
+            ['user_id', 'data'],
+        );
+        await this.pgPool.query(stmt, [userId, JSON.stringify(activity)]);
+    }
+
     public async storePass(userId: string, domain: string, pass: string, encrypt = true): Promise<void> {
         let password = pass;
         if (encrypt) {

src/datastore/postgres/schema/v7.ts

@@ -0,0 +1,10 @@
+import { PoolClient } from "pg";
+
+export async function runSchema(connection: PoolClient) {
+    await connection.query(`
+    CREATE TABLE user_activity (
+        user_id TEXT UNIQUE,
+        data JSON
+    );
+    `);
+}