chore: move signals client to fronend plugin

Signed-off-by: Heikki Hellgren <heikki.hellgren@op.fi>

plugins/signals-react/src/api/SignalsClient.ts

@@ -1,131 +0,0 @@
-/*
- * Copyright 2023 The Backstage Authors
- *
- * Licensed 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.
- */
-import { SignalsApi } from './SignalsApi';
-import { JsonObject } from '@backstage/types';
-import { DiscoveryApi } from '@backstage/core-plugin-api';
-
-/** @public */
-export class SignalsClient implements SignalsApi {
-  static instance: SignalsClient | null = null;
-  private ws: WebSocket | null = null;
-  private discoveryApi: DiscoveryApi;
-  private cbs: Map<string, (message: JsonObject) => void> = new Map();
-  private queue: JsonObject[] = [];
-  private reconnectTimeout: any;
-
-  static create(options: { discoveryApi: DiscoveryApi }) {
-    if (!SignalsClient.instance) {
-      SignalsClient.instance = new SignalsClient(options);
-    }
-    return SignalsClient.instance;
-  }
-
-  private constructor(options: { discoveryApi: DiscoveryApi }) {
-    this.discoveryApi = options.discoveryApi;
-  }
-
-  subscribe(onMessage: (message: JsonObject) => void, topic: string): void {
-    // Do not allow to subscribe to same topic multiple times
-    if (this.cbs.has(topic)) {
-      return;
-    }
-
-    this.cbs.set(topic, onMessage);
-    this.connect().then(() => {
-      this.send({ action: 'subscribe', topic });
-    });
-  }
-
-  unsubscribe(topic: string): void {
-    this.cbs.delete(topic);
-    this.send({ action: 'unsubscribe', topic });
-  }
-
-  private send(data?: JsonObject): void {
-    if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
-      if (data) {
-        this.queue.push(data);
-      }
-      return;
-    }
-
-    // First send queue
-    for (const msg of this.queue) {
-      this.ws!.send(JSON.stringify(msg));
-    }
-    this.queue = [];
-    if (data) {
-      this.ws!.send(JSON.stringify(data));
-    }
-  }
-
-  private async connect() {
-    if (this.ws) {
-      return;
-    }
-
-    const apiUrl = `${await this.discoveryApi.getBaseUrl('signals')}`;
-    const url = new URL(apiUrl);
-    url.protocol = url.protocol === 'http:' ? 'ws' : 'wss';
-    this.ws = new WebSocket(url.toString());
-
-    this.ws.onmessage = (data: MessageEvent) => {
-      try {
-        const json = JSON.parse(data.data) as JsonObject;
-        if (json.topic) {
-          const cb = this.cbs.get(json.topic as string);
-          if (cb) {
-            cb(json.message as JsonObject);
-          }
-        }
-      } catch (e) {
-        // NOOP
-      }
-    };
-
-    this.ws.onerror = () => {
-      this.reconnect();
-    };
-
-    this.ws.onclose = () => {
-      this.reconnect();
-    };
-
-    while (this.ws.readyState !== WebSocket.OPEN) {
-      await new Promise(r => setTimeout(r, 10));
-    }
-    this.send();
-  }
-
-  private reconnect() {
-    if (this.reconnectTimeout) {
-      clearTimeout(this.reconnectTimeout);
-    }
-
-    this.reconnectTimeout = setTimeout(() => {
-      if (this.ws) {
-        this.ws.close();
-      }
-      this.ws = null;
-      this.connect().then(() => {
-        // Resubscribe to existing topics in case we lost connection
-        for (const topic of this.cbs.keys()) {
-          this.send({ action: 'subscribe', topic });
-        }
-      });
-    }, 5000);
-  }
-}

plugins/signals-react/src/api/index.ts

@@ -14,4 +14,3 @@
  * limitations under the License.
  */
 export * from './SignalsApi';
-export * from './SignalsClient';

plugins/signals-react/src/hooks/useSignalsApi.ts

@@ -13,18 +13,17 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { SignalsClient } from '../api';
-import { discoveryApiRef, useApi } from '@backstage/core-plugin-api';
-import { JSONObject } from '@apollo/explorer/src/helpers/types';
+import { signalsApiRef } from '../api';
+import { useApi } from '@backstage/core-plugin-api';
+import { JsonObject } from '@backstage/types';
 import { useEffect } from 'react';
 
 /** @public */
 export const useSignalsApi = (
   topic: string,
-  onMessage: (message: JSONObject) => void,
+  onMessage: (message: JsonObject) => void,
 ) => {
-  const discovery = useApi(discoveryApiRef);
-  const signals = SignalsClient.create({ discoveryApi: discovery });
+  const signals = useApi(signalsApiRef);
   useEffect(() => {
     signals.subscribe(onMessage, topic);
   }, [signals, onMessage, topic]);