wallet-core,harness: new test, provide reason for exchange entry update conflicts

9 files changed, 203 insertions, 6 deletions

diff --git a/packages/taler-harness/src/harness/harness.ts b/packages/taler-harness/src/harness/harness.ts
index 4fc462ddf..d67ca7c48 100644
--- a/packages/taler-harness/src/harness/harness.ts
+++ b/packages/taler-harness/src/harness/harness.ts
@@ -1468,6 +1468,26 @@ export class ExchangeService implements ExchangeServiceInterface {
     await sh(this.globalState, "rm-secmod-keys", `rm ${eddsaKeydir}/*`);
   }
 
+  /**
+   * Generate a new master public key for the exchange.
+   */
+  async regenerateMasterPub(): Promise<void> {
+    const cfg = Configuration.load(this.configFilename);
+    const masterPrivFile = cfg
+      .getPath("exchange-offline", "master_priv_file")
+      .required();
+    fs.unlinkSync(masterPrivFile);
+    const exchangeMasterKey = createEddsaKeyPair();
+    fs.writeFileSync(masterPrivFile, Buffer.from(exchangeMasterKey.eddsaPriv));
+    cfg.setString(
+      "exchange",
+      "master_public_key",
+      encodeCrock(exchangeMasterKey.eddsaPub),
+    );
+
+    cfg.writeTo(this.configFilename, { excludeDefaults: true });
+  }
+
   async purgeDatabase(): Promise<void> {
     await sh(
       this.globalState,
diff --git a/packages/taler-harness/src/integrationtests/test-exchange-master-pub-change.ts b/packages/taler-harness/src/integrationtests/test-exchange-master-pub-change.ts
new file mode 100644
index 000000000..a66d94b57
--- /dev/null
+++ b/packages/taler-harness/src/integrationtests/test-exchange-master-pub-change.ts
@@ -0,0 +1,114 @@
+/*
+ This file is part of GNU Taler
+ (C) 2020 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+/**
+ * Imports.
+ */
+import {
+  ExchangeUpdateStatus,
+  TalerErrorCode,
+  j2s,
+} from "@gnu-taler/taler-util";
+import { WalletApiOperation } from "@gnu-taler/taler-wallet-core";
+import { defaultCoinConfig } from "../harness/denomStructures.js";
+import {
+  ExchangeService,
+  GlobalTestState,
+  setupDb,
+} from "../harness/harness.js";
+import {
+  createSimpleTestkudosEnvironmentV3,
+  withdrawViaBankV3,
+} from "../harness/helpers.js";
+
+/**
+ * Test the wallet's behavior when the exchange switches to a completely
+ * new master public keyy.
+ */
+export async function runExchangeMasterPubChangeTest(
+  t: GlobalTestState,
+): Promise<void> {
+  // Set up test environment
+
+  const { walletClient, exchange, bankClient, exchangeBankAccount } =
+    await createSimpleTestkudosEnvironmentV3(t);
+
+  const wres = await withdrawViaBankV3(t, {
+    walletClient,
+    amount: "TESTKUDOS:10",
+    bankClient,
+    exchange,
+  });
+
+  await wres.withdrawalFinishedCond;
+
+  t.logStep("withdrawal-done");
+
+  const exchangesListOld = await walletClient.call(
+    WalletApiOperation.ListExchanges,
+    {},
+  );
+
+  console.log(j2s(exchangesListOld));
+
+  await exchange.stop();
+
+  // Instead of reconfiguring the old exchange, we just create a new exchange here
+  // that runs under the same base URL as the old exchange.
+
+  const db2 = await setupDb(t, {
+    nameSuffix: "e2",
+  });
+  const exchange2 = ExchangeService.create(t, {
+    name: "testexchange-2",
+    currency: "TESTKUDOS",
+    httpPort: 8081,
+    database: db2.connStr,
+  });
+
+  await exchange2.addBankAccount("1", exchangeBankAccount);
+  exchange2.addCoinConfigList(defaultCoinConfig.map((x) => x("TESTKUDOS")));
+  await exchange2.start();
+
+  t.logStep("exchange-restarted");
+
+  const err = await t.assertThrowsTalerErrorAsync(async () => {
+    await walletClient.call(WalletApiOperation.UpdateExchangeEntry, {
+      exchangeBaseUrl: exchange.baseUrl,
+      force: true,
+    });
+  });
+
+  console.log("updateExchangeEntry err:", j2s(err));
+
+  const exchangesList = await walletClient.call(
+    WalletApiOperation.ListExchanges,
+    {},
+  );
+
+  console.log(j2s(exchangesList));
+
+  t.assertDeepEqual(
+    exchangesList.exchanges[0].exchangeUpdateStatus,
+    ExchangeUpdateStatus.UnavailableUpdate,
+  );
+  t.assertDeepEqual(
+    exchangesList.exchanges[0].unavailableReason?.code,
+    TalerErrorCode.WALLET_EXCHANGE_ENTRY_UPDATE_CONFLICT,
+  );
+}
+
+runExchangeMasterPubChangeTest.suites = ["wallet", "exchange"];
diff --git a/packages/taler-harness/src/integrationtests/testrunner.ts b/packages/taler-harness/src/integrationtests/testrunner.ts
index 4588310b1..b329036eb 100644
--- a/packages/taler-harness/src/integrationtests/testrunner.ts
+++ b/packages/taler-harness/src/integrationtests/testrunner.ts
@@ -42,6 +42,7 @@ import { runDepositTest } from "./test-deposit.js";
 import { runExchangeDepositTest } from "./test-exchange-deposit.js";
 import { runExchangeManagementFaultTest } from "./test-exchange-management-fault.js";
 import { runExchangeManagementTest } from "./test-exchange-management.js";
+import { runExchangeMasterPubChangeTest } from "./test-exchange-master-pub-change.js";
 import { runExchangePurseTest } from "./test-exchange-purse.js";
 import { runExchangeTimetravelTest } from "./test-exchange-timetravel.js";
 import { runFeeRegressionTest } from "./test-fee-regression.js";
@@ -234,6 +235,7 @@ const allTests: TestMainFunction[] = [
   runWithdrawalHandoverTest,
   runWithdrawalAmountTest,
   runWithdrawalFlexTest,
+  runExchangeMasterPubChangeTest,
 ];
 
 export interface TestRunSpec {
diff --git a/packages/taler-util/src/errors.ts b/packages/taler-util/src/errors.ts
index d68177e4e..6becf7963 100644
--- a/packages/taler-util/src/errors.ts
+++ b/packages/taler-util/src/errors.ts
@@ -171,6 +171,9 @@ export interface DetailsMap {
     tosStatus: string;
     currentEtag: string | undefined;
   };
+  [TalerErrorCode.WALLET_EXCHANGE_ENTRY_UPDATE_CONFLICT]: {
+    detail?: string;
+  };
 }
 
 type ErrBody<Y> = Y extends keyof DetailsMap ? DetailsMap[Y] : empty;
@@ -240,6 +243,21 @@ type TalerHttpErrorsDetails = {
 export type TalerHttpError =
   TalerHttpErrorsDetails[keyof TalerHttpErrorsDetails];
 
+/**
+ * Construct typed error details.
+ * Fills in the hint with a default based on the error code name.
+ */
+export function makeTalerErrorDetail<C extends TalerErrorCode>(
+  code: C,
+  errBody: ErrBody<C>,
+  hint?: string,
+): TalerErrorDetail {
+  if (!hint) {
+    hint = getDefaultHint(code);
+  }
+  return { code, hint, ...errBody };
+}
+
 export class TalerError<T = any> extends Error {
   errorDetail: TalerErrorDetail & T;
   cause: Error | undefined;
diff --git a/packages/taler-util/src/taler-error-codes.ts b/packages/taler-util/src/taler-error-codes.ts
index f77357407..a1b6ccc77 100644
--- a/packages/taler-util/src/taler-error-codes.ts
+++ b/packages/taler-util/src/taler-error-codes.ts
@@ -4137,6 +4137,14 @@ export enum TalerErrorCode {
 
 
   /**
+   * An exchange entry could not be updated, as the exchange's new details conflict with the new details.
+   * Returned with an HTTP status code of #MHD_HTTP_UNINITIALIZED (0).
+   * (A value of 0 indicates that the error is generated client-side).
+   */
+  WALLET_EXCHANGE_ENTRY_UPDATE_CONFLICT = 7038,
+
+
+  /**
    * We encountered a timeout with our payment backend.
    * Returned with an HTTP status code of #MHD_HTTP_GATEWAY_TIMEOUT (504).
    * (A value of 0 indicates that the error is generated client-side).
diff --git a/packages/taler-util/src/wallet-types.ts b/packages/taler-util/src/wallet-types.ts
index 82ccb4fc4..099e5c060 100644
--- a/packages/taler-util/src/wallet-types.ts
+++ b/packages/taler-util/src/wallet-types.ts
@@ -1391,6 +1391,8 @@ export interface ExchangeListItem {
    * to update the exchange info.
    */
   lastUpdateErrorInfo?: OperationErrorInfo;
+
+  unavailableReason?: TalerErrorDetail;
 }
 
 const codecForAuditorDenomSig = (): Codec<AuditorDenomSig> =>
diff --git a/packages/taler-wallet-core/src/db.ts b/packages/taler-wallet-core/src/db.ts
index 07caa630b..7c2380e2d 100644
--- a/packages/taler-wallet-core/src/db.ts
+++ b/packages/taler-wallet-core/src/db.ts
@@ -677,6 +677,8 @@ export interface ExchangeEntryRecord {
 
   updateStatus: ExchangeEntryDbUpdateStatus;
 
+  unavailableReason?: TalerErrorDetail;
+
   /**
    * If set to true, the next update to the exchange
    * status will request /keys with no-cache headers set.
diff --git a/packages/taler-wallet-core/src/exchanges.ts b/packages/taler-wallet-core/src/exchanges.ts
index 903f79dcd..3bec30587 100644
--- a/packages/taler-wallet-core/src/exchanges.ts
+++ b/packages/taler-wallet-core/src/exchanges.ts
@@ -45,6 +45,7 @@ import {
   ExchangeListItem,
   ExchangeSignKeyJson,
   ExchangeTosStatus,
+  ExchangeUpdateStatus,
   ExchangeWireAccount,
   ExchangesListResponse,
   FeeDescription,
@@ -87,6 +88,7 @@ import {
   hashDenomPub,
   j2s,
   makeErrorDetail,
+  makeTalerErrorDetail,
   parsePaytoUri,
 } from "@gnu-taler/taler-util";
 import {
@@ -325,7 +327,7 @@ async function makeExchangeListItem(
     scopeInfo = await internalGetExchangeScopeInfo(tx, exchangeDetails);
   }
 
-  return {
+  const listItem: ExchangeListItem = {
     exchangeBaseUrl: r.baseUrl,
     masterPub: exchangeDetails?.masterPublicKey,
     noFees: r.noFees ?? false,
@@ -346,6 +348,14 @@ async function makeExchangeListItem(
       url: r.baseUrl,
     },
   };
+  switch (listItem.exchangeUpdateStatus) {
+    case ExchangeUpdateStatus.UnavailableUpdate:
+      if (r.unavailableReason) {
+        listItem.unavailableReason = r.unavailableReason;
+      }
+      break;
+  }
+  return listItem;
 }
 
 export interface ExchangeWireDetails {
@@ -1476,16 +1486,18 @@ export async function updateExchangeFromUrlHandler(
         detailsPointerChanged = true;
       }
       let detailsIncompatible = false;
+      let conflictHint: string | undefined = undefined;
       if (existingDetails) {
         if (existingDetails.masterPublicKey !== keysInfo.masterPublicKey) {
           detailsIncompatible = true;
           detailsPointerChanged = true;
-        }
-        if (existingDetails.currency !== keysInfo.currency) {
+          conflictHint = "master public key changed";
+        } else if (existingDetails.currency !== keysInfo.currency) {
           detailsIncompatible = true;
           detailsPointerChanged = true;
+          conflictHint = "currency changed";
         }
-        // FIXME: We need to do some consistency checks!
+        // FIXME: We need to do some more consistency checks!
       }
       if (detailsIncompatible) {
         logger.warn(
@@ -1494,6 +1506,12 @@ export async function updateExchangeFromUrlHandler(
         // We don't support this gracefully right now.
         // See https://bugs.taler.net/n/8576
         r.updateStatus = ExchangeEntryDbUpdateStatus.UnavailableUpdate;
+        r.unavailableReason = makeTalerErrorDetail(
+          TalerErrorCode.WALLET_EXCHANGE_ENTRY_UPDATE_CONFLICT,
+          {
+            detail: conflictHint,
+          },
+        );
         r.updateRetryCounter = (r.updateRetryCounter ?? 0) + 1;
         r.nextUpdateStamp = computeDbBackoff(r.updateRetryCounter);
         r.nextRefreshCheckStamp = timestampPreciseToDb(
@@ -1506,6 +1524,7 @@ export async function updateExchangeFromUrlHandler(
           newExchangeState: getExchangeState(r),
         };
       }
+      delete r.unavailableReason;
       r.updateRetryCounter = 0;
       const newDetails: ExchangeDetailsRecord = {
         auditors: keysInfo.auditors,
diff --git a/packages/taler-wallet-core/src/shepherd.ts b/packages/taler-wallet-core/src/shepherd.ts
index 470f45aff..2b529fb4b 100644
--- a/packages/taler-wallet-core/src/shepherd.ts
+++ b/packages/taler-wallet-core/src/shepherd.ts
@@ -145,6 +145,14 @@ function taskGivesLiveness(taskId: string): boolean {
 }
 
 export interface TaskScheduler {
+  /**
+   * Ensure that the task scheduler is running.
+   *
+   * If it is not running, start it, with previous
+   * tasks loaded from the database.
+   *
+   * Returns after the scheduler is running.
+   */
   ensureRunning(): Promise<void>;
   startShepherdTask(taskId: TaskIdStr): void;
   stopShepherdTask(taskId: TaskIdStr): void;
@@ -188,6 +196,9 @@ export class TaskSchedulerImpl implements TaskScheduler {
     }
   }
 
+  /**
+   * @see TaskScheduler.ensureRunning
+   */
   async ensureRunning(): Promise<void> {
     if (this.isRunning) {
       return;
@@ -261,7 +272,7 @@ export class TaskSchedulerImpl implements TaskScheduler {
     const tasksIds = [...this.sheps.keys()];
     logger.info(`reloading shepherd with ${tasksIds.length} tasks`);
     for (const taskId of tasksIds) {
-      await this.stopShepherdTask(taskId);
+      this.stopShepherdTask(taskId);
     }
     for (const taskId of tasksIds) {
       this.startShepherdTask(taskId);
@@ -276,9 +287,10 @@ export class TaskSchedulerImpl implements TaskScheduler {
         return;
       }
       logger.trace(
-        `Waiting old task to complete the loop in cancel mode ${taskId}`,
+        `Waiting for old task to complete the loop in cancel mode ${taskId}`,
       );
       await oldShep.latch;
+      logger.trace(`Old task ${taskId} completed in cancel mode`);
     }
     logger.trace(`Creating new shepherd for ${taskId}`);
     const newShep: ShepherdInfo = {