taler-typescript-core

commit 63854330be05f77652955fe4654713081855c7bf
parent 516ae509b978eb0b6fb1647c094d37d012e498a6
Author: Florian Dold <florian@dold.me>
Date:   Wed,  1 Jul 2026 15:29:09 +0200

wallet-core: implement traffic control dev experiment

Diffstat:
M
packages/taler-wallet-core/src/dev-experiments.ts
 | 
87
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
M
packages/taler-wallet-core/src/wallet.ts
 | 
13
++++++++++++-

2 files changed, 95 insertions(+), 5 deletions(-)
diff --git a/packages/taler-wallet-core/src/dev-experiments.ts b/packages/taler-wallet-core/src/dev-experiments.ts
@@ -31,7 +31,6 @@ import {
   Amounts,
   ContractTermsUtil,
   DenomLossEventType,
-  TalerDevExperimentUri,
   Duration,
   Logger,
   MerchantContractTermsV0,
@@ -39,6 +38,7 @@ import {
   PeerContractTerms,
   RefreshReason,
   Result,
+  TalerDevExperimentUri,
   TalerError,
   TalerErrorCode,
   TalerPreciseTimestamp,
@@ -173,6 +173,29 @@ export async function applyDevExperiment(
       wex.ws.devExperimentState.merchantDepositInsufficient = true;
       return;
     }
+    case "start-tc": {
+      const maybeFloatParam = (name: string) => {
+        const val = parsedUri.query?.get(name);
+        if (val == null) {
+          return undefined;
+        }
+        if (typeof val === "string") {
+          return Number.parseFloat(val);
+        }
+        throw Error("unsupported parameter");
+      };
+      wex.ws.devExperimentState.tc = {
+        delayResponseMs: maybeFloatParam("delay_resp"),
+        dropRequestProbability: maybeFloatParam("drop_req"),
+        dropResponseProbability: maybeFloatParam("drop_resp"),
+        fake500Probability: maybeFloatParam("fake_500"),
+      };
+      return;
+    }
+    case "stop-tc": {
+      wex.ws.devExperimentState.tc = undefined;
+      return;
+    }
     case "start-fakeprotover": {
       const baseUrl = parsedUri.query?.get("base_url");
       if (!baseUrl) {
@@ -734,7 +757,10 @@ async function addFakeTx(
   }
 }
 
-function mockResponseJson(resp: HttpResponse, respJson: any): HttpResponse {
+function mockResponseReplacementJson(
+  resp: HttpResponse,
+  respJson: any,
+): HttpResponse {
   const textEncoder = new TextEncoder();
   return {
     requestMethod: resp.requestMethod,
@@ -777,6 +803,19 @@ function mockInternalServerError(resp: HttpResponse): HttpResponse {
   };
 }
 
+function waitMs(tMs: number): Promise<void> {
+  return new Promise<void>((resolve) => {
+    setTimeout(() => resolve(), tMs);
+  });
+}
+
+function evalFailProbability(p: number | undefined): boolean {
+  if (p == null) {
+    return true;
+  }
+  return Math.random() >= p;
+}
+
 export class DevExperimentHttpLib implements HttpRequestLibrary {
   _isDevExperimentLib = true;
   underlyingLib: HttpRequestLibrary;
@@ -815,7 +854,7 @@ export class DevExperimentHttpLib implements HttpRequestLibrary {
           logger.info(`replacing proto version with ${fakeSt.fakeVer}`);
           const respJson = await resp.json();
           respJson.version = fakeSt.fakeVer;
-          return mockResponseJson(resp, respJson);
+          return mockResponseReplacementJson(resp, respJson);
         }
       }
     } else if (this.devExperimentState.blockPayResponse) {
@@ -827,6 +866,46 @@ export class DevExperimentHttpLib implements HttpRequestLibrary {
         return mockInternalServerError(realResp);
       }
     }
-    return this.underlyingLib.fetch(url, opt);
+    if (
+      evalFailProbability(this.devExperimentState.tc?.dropRequestProbability)
+    ) {
+      await waitMs(5000);
+      throw TalerError.fromDetail(
+        TalerErrorCode.WALLET_UNEXPECTED_REQUEST_ERROR,
+        {
+          requestUrl: url,
+          requestMethod: method,
+          httpStatusCode: 0,
+        },
+        `Request timed out after ${5000} ms`,
+      );
+    }
+    const resp = await this.underlyingLib.fetch(url, opt);
+    if (evalFailProbability(this.devExperimentState.tc?.fake500Probability)) {
+      return mockInternalServerError(resp);
+    }
+    if (
+      evalFailProbability(this.devExperimentState.tc?.dropResponseProbability)
+    ) {
+      await waitMs(5000);
+      throw TalerError.fromDetail(
+        TalerErrorCode.WALLET_UNEXPECTED_REQUEST_ERROR,
+        {
+          requestUrl: url,
+          requestMethod: method,
+          httpStatusCode: 0,
+        },
+        `Request timed out after ${5000} ms`,
+      );
+    }
+    // Delay response if requested
+    {
+      const delayMs = this.devExperimentState.tc?.delayResponseMs;
+      if (delayMs != null) {
+        logger.info(`delaying response by ${delayMs}ms`);
+        await waitMs(delayMs);
+      }
+    }
+    return resp;
   }
 }
diff --git a/packages/taler-wallet-core/src/wallet.ts b/packages/taler-wallet-core/src/wallet.ts
@@ -2124,7 +2124,7 @@ export async function handleTestingWaitExchangeReady(
   await waitReadyExchange(wex, req.exchangeBaseUrl, {
     noBail: req.noBail,
     forceUpdate: req.forceUpdate,
-    waitAutoRefresh: req.waitAutoRefresh
+    waitAutoRefresh: req.waitAutoRefresh,
   });
   return {};
 }
@@ -3197,6 +3197,17 @@ export interface DevExperimentState {
 
   /** Migration test for confirmPay */
   flagConfirmPayNoWait?: boolean;
+
+  tc?: {
+    dropRequestProbability?: number;
+    dropResponseProbability?: number;
+    /**
+     * Fake a 500 response *after* the request has been sent
+     * and the real response has been received.
+     */
+    fake500Probability?: number;
+    delayResponseMs?: number;
+  };
 }
 
 export class Cache<T> {