feat: add notifications filtering by processors

Signed-off-by: Yaron Dayagi <ydayagi@redhat.com>

.changeset/large-months-decide.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-notifications-node': major
+---
+
+add notifications filtering by processors

.changeset/polite-otters-talk.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-notifications-backend-module-email': minor
+---
+
+add notification filters

.changeset/wild-ears-walk.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-notifications-backend': major
+---
+
+adding filtering of notifications by processors

plugins/notifications-backend-module-email/config.d.ts

@@ -15,6 +15,7 @@
  */
 
 import { HumanDuration } from '@backstage/types';
+import { NotificationSeverity } from '@backstage/plugin-notifications-common';
 
 export interface Config {
   /**
@@ -117,6 +118,20 @@ export interface Config {
            */
           ttl?: HumanDuration;
         };
+        filter?: {
+          /**
+           * Minimum severity. A notification with lower severity will not be emailed
+           */
+          minSeverity?: NotificationSeverity;
+          /**
+           * Maximum severity. A notification with higher severity will not be emailed
+           */
+          maxSeverity?: NotificationSeverity;
+          /**
+           * A notification who's topic is in this array will not be emailed
+           */
+          excludedTopics?: string[];
+        };
       };
     };
   };

plugins/notifications-backend-module-email/src/processor/NotificationsEmailProcessor.ts

@@ -15,6 +15,7 @@
  */
 import {
   NotificationProcessor,
+  NotificationProcessorFilters,
   NotificationSendOptions,
 } from '@backstage/plugin-notifications-node';
 import {
@@ -28,7 +29,11 @@ import {
   CATALOG_FILTER_EXISTS,
   CatalogClient,
 } from '@backstage/catalog-client';
-import { Notification } from '@backstage/plugin-notifications-common';
+import {
+  Notification,
+  notificationSeverities,
+  NotificationSeverity,
+} from '@backstage/plugin-notifications-common';
 import {
   createSendmailTransport,
   createSesTransport,
@@ -51,6 +56,7 @@ export class NotificationsEmailProcessor implements NotificationProcessor {
   private readonly concurrencyLimit: number;
   private readonly throttleInterval: number;
   private readonly frontendBaseUrl: string;
+  private readonly filter: NotificationProcessorFilters;
 
   constructor(
     private readonly logger: LoggerService,
@@ -80,6 +86,30 @@ export class NotificationsEmailProcessor implements NotificationProcessor {
       ? durationToMilliseconds(readDurationFromConfig(cacheConfig))
       : 3_600_000;
     this.frontendBaseUrl = config.getString('app.baseUrl');
+    this.filter = {};
+    const minSeverity = emailProcessorConfig.getOptionalString(
+      'filter.minSeverity',
+    ) as NotificationSeverity;
+    if (minSeverity) {
+      if (notificationSeverities.includes(minSeverity)) {
+        this.filter.minSeverity = minSeverity;
+      } else {
+        throw new Error(`Invalid minSeverity: ${minSeverity}`);
+      }
+    }
+    const maxSeverity = emailProcessorConfig.getOptionalString(
+      'filter.maxSeverity',
+    ) as NotificationSeverity;
+    if (maxSeverity) {
+      if (notificationSeverities.includes(maxSeverity)) {
+        this.filter.maxSeverity = maxSeverity;
+      } else {
+        throw new Error(`Invalid maxSeverity: ${maxSeverity}`);
+      }
+    }
+    this.filter.excludedTopics = emailProcessorConfig.getOptionalStringArray(
+      'filter.excludedTopics',
+    );
   }
 
   private async getTransporter() {
@@ -312,4 +342,8 @@ export class NotificationsEmailProcessor implements NotificationProcessor {
 
     await this.sendTemplateEmail(notification, emails);
   }
+
+  getNotificationFilters(): NotificationProcessorFilters {
+    return this.filter;
+  }
 }

plugins/notifications-backend/src/service/router.ts

@@ -48,7 +48,9 @@ import { SignalsService } from '@backstage/plugin-signals-node';
 import {
   NewNotificationSignal,
   Notification,
+  NotificationPayload,
   NotificationReadSignal,
+  notificationSeverities,
   NotificationStatus,
 } from '@backstage/plugin-notifications-common';
 import { parseEntityOrderFieldParams } from './parseEntityOrderFieldParams';
@@ -177,9 +179,46 @@ export async function createRouter(
     return users;
   };
 
-  const processOptions = async (opts: NotificationSendOptions) => {
-    let ret = opts;
+  const filterProcessors = (payload: NotificationPayload) => {
+    const result: NotificationProcessor[] = [];
+
     for (const processor of processors) {
+      if (processor.getNotificationFilters) {
+        const filters = processor.getNotificationFilters();
+        if (filters.minSeverity) {
+          if (
+            notificationSeverities.indexOf(payload.severity ?? 'normal') >
+            notificationSeverities.indexOf(filters.minSeverity)
+          ) {
+            continue;
+          }
+        }
+
+        if (filters.maxSeverity) {
+          if (
+            notificationSeverities.indexOf(payload.severity ?? 'normal') <
+            notificationSeverities.indexOf(filters.maxSeverity)
+          ) {
+            continue;
+          }
+        }
+
+        if (filters.excludedTopics && payload.topic) {
+          if (filters.excludedTopics.includes(payload.topic)) {
+            continue;
+          }
+        }
+      }
+      result.push(processor);
+    }
+
+    return result;
+  };
+
+  const processOptions = async (opts: NotificationSendOptions) => {
+    const filtered = filterProcessors(opts.payload);
+    let ret = opts;
+    for (const processor of filtered) {
       try {
         ret = processor.processOptions
           ? await processor.processOptions(ret)
@@ -197,8 +236,9 @@ export async function createRouter(
     notification: Notification,
     opts: NotificationSendOptions,
   ) => {
+    const filtered = filterProcessors(notification.payload);
     let ret = notification;
-    for (const processor of processors) {
+    for (const processor of filtered) {
       try {
         ret = processor.preProcess
           ? await processor.preProcess(ret, opts)
@@ -216,7 +256,8 @@ export async function createRouter(
     notification: Notification,
     opts: NotificationSendOptions,
   ) => {
-    for (const processor of processors) {
+    const filtered = filterProcessors(notification.payload);
+    for (const processor of filtered) {
       if (processor.postProcess) {
         try {
           await processor.postProcess(notification, opts);

plugins/notifications-node/api-report.md

@@ -8,6 +8,7 @@ import { DiscoveryService } from '@backstage/backend-plugin-api';
 import { ExtensionPoint } from '@backstage/backend-plugin-api';
 import { Notification as Notification_2 } from '@backstage/plugin-notifications-common';
 import { NotificationPayload } from '@backstage/plugin-notifications-common';
+import { NotificationSeverity } from '@backstage/plugin-notifications-common';
 import { ServiceRef } from '@backstage/backend-plugin-api';
 
 // @public (undocumented)
@@ -23,6 +24,7 @@ export class DefaultNotificationService implements NotificationService {
 // @public
 export interface NotificationProcessor {
   getName(): string;
+  getNotificationFilters?(): NotificationProcessorFilters;
   postProcess?(
     notification: Notification_2,
     options: NotificationSendOptions,
@@ -36,6 +38,13 @@ export interface NotificationProcessor {
   ): Promise<NotificationSendOptions>;
 }
 
+// @public (undocumented)
+export type NotificationProcessorFilters = {
+  minSeverity?: NotificationSeverity;
+  maxSeverity?: NotificationSeverity;
+  excludedTopics?: string[];
+};
+
 // @public (undocumented)
 export type NotificationRecipients =
   | {

plugins/notifications-node/src/extensions.ts

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 import { createExtensionPoint } from '@backstage/backend-plugin-api';
-import { Notification } from '@backstage/plugin-notifications-common';
+import {
+  Notification,
+  NotificationSeverity,
+} from '@backstage/plugin-notifications-common';
 import { NotificationSendOptions } from './service';
 
 /**
@@ -90,6 +93,11 @@ export interface NotificationProcessor {
     notification: Notification,
     options: NotificationSendOptions,
   ): Promise<void>;
+
+  /**
+   * notification filters are used to call the processor only in certain conditions
+   */
+  getNotificationFilters?(): NotificationProcessorFilters;
 }
 
 /**
@@ -108,3 +116,12 @@ export const notificationsProcessingExtensionPoint =
   createExtensionPoint<NotificationsProcessingExtensionPoint>({
     id: 'notifications.processing',
   });
+
+/**
+ * @public
+ */
+export type NotificationProcessorFilters = {
+  minSeverity?: NotificationSeverity;
+  maxSeverity?: NotificationSeverity;
+  excludedTopics?: string[];
+};