fix: remove GCF transaction fallback

dev/src/index.ts

@@ -363,18 +363,6 @@ export class Firestore implements firestore.Firestore {
    */
   private bulkWritersCount = 0;
 
-  // GCF currently tears down idle connections after two minutes. Requests
-  // that are issued after this period may fail. On GCF, we therefore issue
-  // these requests as part of a transaction so that we can safely retry until
-  // the network link is reestablished.
-  //
-  // The environment variable FUNCTION_TRIGGER_TYPE is used to detect the GCF
-  // environment.
-  /** @private */
-  _preferTransactions: boolean;
-  /** @private */
-  _lastSuccessfulRequest = 0;
-
   /**
    * @param {Object=} settings [Configuration object](#/docs).
    * @param {string=} settings.projectId The project ID from the Google
@@ -449,20 +437,6 @@ export class Firestore implements firestore.Firestore {
       backoffFactor: retryConfig.retry_delay_multiplier,
     };
 
-    // GCF currently tears down idle connections after two minutes. Requests
-    // that are issued after this period may fail. On GCF, we therefore issue
-    // these requests as part of a transaction so that we can safely retry until
-    // the network link is reestablished.
-    //
-    // The environment variable FUNCTION_TRIGGER_TYPE is used to detect the GCF
-    // environment.
-    this._preferTransactions = process.env.FUNCTION_TRIGGER_TYPE !== undefined;
-    this._lastSuccessfulRequest = 0;
-
-    if (this._preferTransactions) {
-      logger('Firestore', null, 'Detected GCF environment');
-    }
-
     const maxIdleChannels =
       this._settings.maxIdleChannels === undefined
         ? DEFAULT_MAX_IDLE_CHANNELS
@@ -1284,9 +1258,7 @@ export class Firestore implements firestore.Firestore {
 
       try {
         await backoff.backoffAndWait();
-        const result = await func();
-        this._lastSuccessfulRequest = new Date().getTime();
-        return result;
+        return await func();
       } catch (err) {
         lastError = err;
 
@@ -1445,7 +1417,6 @@ export class Firestore implements firestore.Firestore {
           'Received response: %j',
           result
         );
-        this._lastSuccessfulRequest = new Date().getTime();
         return result;
       } catch (err) {
         logger('Firestore.request', requestTag, 'Received error:', err);

dev/src/transaction.ts

@@ -384,7 +384,7 @@ export class Transaction implements firestore.Transaction {
    */
   commit(): Promise<void> {
     return this._writeBatch
-      .commit_({
+      ._commit({
         transactionId: this._transactionId,
         requestTag: this._requestTag,
       })

dev/src/write-batch.ts

@@ -545,7 +545,7 @@ export class WriteBatch implements firestore.WriteBatch {
     // Capture the error stack to preserve stack tracing across async calls.
     const stack = Error().stack!;
 
-    return this.commit_().catch(err => {
+    return this._commit().catch(err => {
       throw wrapError(err, stack);
     });
   }
@@ -596,7 +596,7 @@ export class WriteBatch implements firestore.WriteBatch {
    * this request.
    * @returns  A Promise that resolves when this batch completes.
    */
-  async commit_(commitOptions?: {
+  async _commit(commitOptions?: {
     transactionId?: Uint8Array;
     requestTag?: string;
   }): Promise<WriteResult[]> {
@@ -608,26 +608,13 @@ export class WriteBatch implements firestore.WriteBatch {
 
     const database = this._firestore.formattedName;
 
-    // On GCF, we periodically force transactional commits to allow for
-    // request retries in case GCF closes our backend connection.
-    const explicitTransaction = commitOptions && commitOptions.transactionId;
-    if (!explicitTransaction && this._shouldCreateTransaction()) {
-      logger('WriteBatch.commit', tag, 'Using transaction for commit');
-      return this._firestore
-        .request<api.IBeginTransactionRequest, api.IBeginTransactionResponse>(
-          'beginTransaction',
-          {database},
-          tag
-        )
-        .then(resp => {
-          return this.commit_({transactionId: resp.transaction!});
-        });
-    }
-
     const request: api.ICommitRequest = {
       database,
       writes: this._ops.map(op => op()),
     };
+    if (commitOptions?.transactionId) {
+      request.transaction = commitOptions.transactionId;
+    }
 
     logger(
       'WriteBatch.commit',
@@ -636,9 +623,6 @@ export class WriteBatch implements firestore.WriteBatch {
       request.writes!.length
     );
 
-    if (explicitTransaction) {
-      request.transaction = explicitTransaction;
-    }
     const response = await this._firestore.request<
       api.ICommitRequest,
       api.CommitResponse
@@ -652,26 +636,6 @@ export class WriteBatch implements firestore.WriteBatch {
     );
   }
 
-  /**
-   * Determines whether we should issue a transactional commit. On GCF, this
-   * happens after two minutes of idleness.
-   *
-   * @private
-   * @returns Whether to use a transaction.
-   */
-  private _shouldCreateTransaction(): boolean {
-    if (!this._firestore._preferTransactions) {
-      return false;
-    }
-
-    if (this._firestore._lastSuccessfulRequest) {
-      const now = new Date().getTime();
-      return now - this._firestore._lastSuccessfulRequest > GCF_IDLE_TIMEOUT_MS;
-    }
-
-    return true;
-  }
-
   /**
    * Resets the WriteBatch and dequeues all pending operations.
    * @private

dev/test/write-batch.ts

@@ -433,59 +433,6 @@ describe('batch support', () => {
       });
     });
   });
-
-  it('uses transactions on GCF', () => {
-    // We use this environment variable during initialization to detect whether
-    // we are running on GCF.
-    process.env.FUNCTION_TRIGGER_TYPE = 'http-trigger';
-
-    let beginCalled = 0;
-    let commitCalled = 0;
-
-    const overrides: ApiOverride = {
-      beginTransaction: () => {
-        ++beginCalled;
-        return response({transaction: Buffer.from('foo')});
-      },
-      commit: () => {
-        ++commitCalled;
-        return response({
-          commitTime: {
-            nanos: 0,
-            seconds: 0,
-          },
-        });
-      },
-    };
-
-    return createInstance(overrides).then(firestore => {
-      firestore['_preferTransactions'] = true;
-      firestore['_lastSuccessfulRequest'] = 0;
-
-      return firestore
-        .batch()
-        .commit()
-        .then(() => {
-          // The first commit always uses a transcation.
-          expect(beginCalled).to.equal(1);
-          expect(commitCalled).to.equal(1);
-          return firestore.batch().commit();
-        })
-        .then(() => {
-          // The following commits don't use transactions if they happen
-          // within two minutes.
-          expect(beginCalled).to.equal(1);
-          expect(commitCalled).to.equal(2);
-          firestore['_lastSuccessfulRequest'] = 1337;
-          return firestore.batch().commit();
-        })
-        .then(() => {
-          expect(beginCalled).to.equal(2);
-          expect(commitCalled).to.equal(3);
-          delete process.env.FUNCTION_TRIGGER_TYPE;
-        });
-    });
-  });
 });
 
 describe('bulkCommit support', () => {