fix(store-sync): reconnect unresponsive watchLogs socket

.changeset/tiny-parrots-hang.md

@@ -0,0 +1,5 @@
+---
+"@latticexyz/store-sync": patch
+---
+
+Experimental pending logs watcher now reconnects if it loses connection or times out.

packages/store-sync/src/createStoreSync.ts

@@ -39,7 +39,7 @@ import { fromEventSource } from "./fromEventSource";
 import { fetchAndStoreLogs } from "./fetchAndStoreLogs";
 import { isLogsApiResponse } from "./indexer-client/isLogsApiResponse";
 import { toStorageAdatperBlock } from "./indexer-client/toStorageAdapterBlock";
-import { watchLogs } from "./wiresaw";
+import { watchLogs } from "./watchLogs";
 
 const debug = parentDebug.extend("createStoreSync");
 

packages/store-sync/src/wiresaw.ts → packages/store-sync/src/watchLogs.ts

@@ -4,6 +4,9 @@ import { StorageAdapterBlock, StoreEventsLog } from "./common";
 import { storeEventsAbi } from "@latticexyz/store";
 import { logSort } from "@latticexyz/common";
 import { SocketRpcClient, getWebSocketRpcClient } from "viem/utils";
+import { debug as parentDebug } from "./debug";
+
+const debug = parentDebug.extend("watchLogs");
 
 type WatchLogsInput = {
   url: string;
@@ -16,21 +19,63 @@ type WatchLogsResult = {
 };
 
 export function watchLogs({ url, address, fromBlock }: WatchLogsInput): WatchLogsResult {
-  // Buffer the live logs received until the gap from `startBlock` to `currentBlock` is closed
-  let caughtUp = false;
-  const logBuffer: StoreEventsLog[] = [];
-
   const topics = [
     storeEventsAbi.flatMap((event) => encodeEventTopics({ abi: [event], eventName: event.name })),
   ] as LogTopic[]; // https://github.com/wevm/viem/blob/63a5ac86eb9a2962f7323b4cc76ef54f9f5ef7ed/src/actions/public/getLogs.ts#L171
 
+  let resumeBlock = fromBlock;
+
+  let pingTimer: ReturnType<typeof setTimeout> | undefined = undefined;
+  // how often to ping to keep socket alive
+  const pingInterval = 3000;
+  // how long to wait for ping response before we attempt to reconnect
+  const pingTimeout = 5000;
+
   const logs$ = new Observable<StorageAdapterBlock>((subscriber) => {
+    debug("logs$ subscribed");
+
     let client: SocketRpcClient<WebSocket>;
-    getWebSocketRpcClient(url, { keepAlive: true, reconnect: true }).then(async (_client) => {
-      client = _client;
-      client.socket.addEventListener("error", (error) =>
-        subscriber.error({ code: -32603, message: "WebSocket error", data: error }),
-      );
+
+    async function setupClient(): Promise<void> {
+      debug("setupClient called");
+
+      // Buffer the live logs received until the gap from `startBlock` to `currentBlock` is closed
+      let caughtUp = false;
+      const logBuffer: StoreEventsLog[] = [];
+
+      client = await getWebSocketRpcClient(url, { keepAlive: false });
+      debug("got websocket rpc client");
+
+      async function ping(): Promise<void> {
+        try {
+          debug("pinging socket");
+          await client.requestAsync({ body: { method: "net_version" }, timeout: pingTimeout });
+        } catch (error) {
+          debug("ping failed, closing...", error);
+          client.close();
+        }
+      }
+
+      function schedulePing(): void {
+        debug("scheduling next ping");
+        pingTimer = setTimeout(() => ping().then(schedulePing), pingInterval);
+      }
+
+      schedulePing();
+
+      client.socket.addEventListener("error", (error) => {
+        debug("socket error, closing...", error);
+        client.close();
+      });
+
+      client.socket.addEventListener("close", async () => {
+        debug("socket close, setting up new client...");
+        clearTimeout(pingTimer);
+        setupClient().catch((error) => {
+          debug("error trying to setup new client", error);
+          subscriber.error(error);
+        });
+      });
 
       // Start watching pending logs
       const subscriptionId: Hex = (
@@ -41,45 +86,66 @@ export function watchLogs({ url, address, fromBlock }: WatchLogsInput): WatchLog
           },
         })
       ).result;
+      debug("got watchLogs subscription", subscriptionId);
 
       // Listen for wiresaw_watchLogs subscription
       // Need to use low level methods since viem's socekt client only handles `eth_subscription` messages.
       // (https://github.com/wevm/viem/blob/f81d497f2afc11b9b81a79057d1f797694b69793/src/utils/rpc/socket.ts#L178)
       client.socket.addEventListener("message", (message) => {
         const response = JSON.parse(message.data);
         if ("error" in response) {
+          debug("was error, returning error to subscriber");
           // Return JSON-RPC errors to the subscriber
           subscriber.error(response.error);
           return;
         }
 
         // Parse the logs from wiresaw_watchLogs
         if ("params" in response && response.params.subscription === subscriptionId) {
+          debug("parsing logs");
           const logs: RpcLog[] = response.params.result;
           const formattedLogs = logs.map((log) => formatLog(log));
           const parsedLogs = parseEventLogs({ abi: storeEventsAbi, logs: formattedLogs });
+          debug("got logs", parsedLogs);
           if (caughtUp) {
+            debug("handing off logs to subscriber");
             const blockNumber = parsedLogs[0].blockNumber;
             subscriber.next({ blockNumber, logs: parsedLogs });
+            resumeBlock = blockNumber + 1n;
           } else {
+            debug("buffering logs");
             logBuffer.push(...parsedLogs);
           }
+          return;
         }
       });
 
       // Catch up to the pending logs
       try {
-        const initialLogs = await fetchInitialLogs({ client, address, fromBlock, topics });
+        debug("fetching initial logs");
+        const initialLogs = await fetchInitialLogs({ client, address, fromBlock: resumeBlock, topics });
+        debug("got logs", initialLogs);
         const logs = [...initialLogs, ...logBuffer].sort(logSort);
-        const blockNumber = logs.at(-1)?.blockNumber ?? fromBlock;
+        const blockNumber = logs.at(-1)?.blockNumber ?? resumeBlock;
         subscriber.next({ blockNumber, logs: initialLogs });
+        resumeBlock = blockNumber + 1n;
         caughtUp = true;
-      } catch (e) {
+      } catch (error) {
+        debug("could not get initial logs", error);
         subscriber.error("Could not fetch initial wiresaw logs");
       }
+    }
+
+    setupClient().catch((error) => {
+      debug("error setting up initial client", error);
+      subscriber.error(error);
     });
 
-    return () => client?.close();
+    return () => {
+      debug("logs$ subscription closed");
+      clearTimeout(pingTimer);
+      client?.close();
+    };
   });
 
   return { logs$ };