Send batch immediately when full in HttpBatchClient

CHANGELOG.md

@@ -13,8 +13,11 @@ and this project adheres to
   fields you want to change ([#1309]).
 - @cosmjs/tendermint-rpc: Add missing exports `HttpBatchClient`,
   `HttpBatchClientOptions`, `RpcClient` ([#1311]).
+- @cosmjs/tendermint-rpc: Send batch immediately when full in `HttpBatchClient`
+  ([#1310]).
 
 [#1309]: https://github.com/cosmos/cosmjs/issues/1309
+[#1310]: https://github.com/cosmos/cosmjs/issues/1310
 [#1311]: https://github.com/cosmos/cosmjs/issues/1311
 
 ### Fixed

packages/tendermint-rpc/src/rpcclients/httpbatchclient.spec.ts

@@ -30,4 +30,23 @@ describe("HttpBatchClient", () => {
 
     client.disconnect();
   });
+
+  it("dispatches requests as soon as batch size limit is reached", async () => {
+    pendingWithoutTendermint();
+    const client = new HttpBatchClient(tendermintUrl, {
+      dispatchInterval: 3600_000 /* 1h to make test time out if this is not working */,
+      batchSizeLimit: 3,
+    });
+
+    const healthResponse = await Promise.all([
+      client.execute(createJsonRpcRequest("health")),
+      client.execute(createJsonRpcRequest("health")),
+      client.execute(createJsonRpcRequest("health")),
+    ]);
+    expect(healthResponse[0].result).toEqual({});
+    expect(healthResponse[1].result).toEqual({});
+    expect(healthResponse[2].result).toEqual({});
+
+    client.disconnect();
+  });
 });

packages/tendermint-rpc/src/rpcclients/httpbatchclient.ts

@@ -10,7 +10,9 @@ import { HttpEndpoint } from "./httpclient";
 import { hasProtocol, RpcClient } from "./rpcclient";
 
 export interface HttpBatchClientOptions {
+  /** Interval for dispatching batches (in milliseconds) */
   dispatchInterval: number;
+  /** Max number of items sent in one request */
   batchSizeLimit: number;
 }
 
@@ -58,6 +60,11 @@ export class HttpBatchClient implements RpcClient {
   public async execute(request: JsonRpcRequest): Promise<JsonRpcSuccessResponse> {
     return new Promise((resolve, reject) => {
       this.queue.push({ request, resolve, reject });
+
+      if (this.queue.length >= this.options.batchSizeLimit) {
+        // this train is full, let's go
+        this.tick();
+      }
     });
   }
 
@@ -71,27 +78,43 @@ export class HttpBatchClient implements RpcClient {
     }
   }
 
-  private async tick(): Promise<void> {
+  /**
+   * This is called in an interval where promise rejections cannot be handled.
+   * So this is not async and HTTP errors need to be handled by the queued promises.
+   */
+  private tick(): void {
     // Avoid race conditions
-    const queue = this.queue.splice(0, this.options.batchSizeLimit);
+    const batch = this.queue.splice(0, this.options.batchSizeLimit);
 
-    if (!queue.length) return;
+    if (!batch.length) return;
 
-    const request = queue.map((s) => s.request);
-    const raw = await http("POST", this.url, this.headers, request);
-    // Requests with a single entry return as an object
-    const arr = Array.isArray(raw) ? raw : [raw];
+    const requests = batch.map((s) => s.request);
+    const requestIds = requests.map((request) => request.id);
 
-    arr.forEach((el) => {
-      const req = queue.find((s) => s.request.id === el.id);
-      if (!req) return;
-      const { reject, resolve } = req;
-      const response = parseJsonRpcResponse(el);
-      if (isJsonRpcErrorResponse(response)) {
-        reject(new Error(JSON.stringify(response.error)));
-      } else {
-        resolve(response);
-      }
-    });
+    http("POST", this.url, this.headers, requests).then(
+      (raw) => {
+        // Requests with a single entry return as an object
+        const arr = Array.isArray(raw) ? raw : [raw];
+
+        arr.forEach((el) => {
+          const req = batch.find((s) => s.request.id === el.id);
+          if (!req) return;
+          const { reject, resolve } = req;
+          const response = parseJsonRpcResponse(el);
+          if (isJsonRpcErrorResponse(response)) {
+            reject(new Error(JSON.stringify(response.error)));
+          } else {
+            resolve(response);
+          }
+        });
+      },
+      (error) => {
+        for (const requestId of requestIds) {
+          const req = batch.find((s) => s.request.id === requestId);
+          if (!req) return;
+          req.reject(error);
+        }
+      },
+    );
   }
 }