feat: add withReadConcern builder to AbstractCursor (#2645)

This patch adds a builder method to add a read concern to a cursor similar to the existing method to build with a ReadPreference. It also changes `setReadPreference` to `withReadPreference` so the two follow a common convention. NODE-2806
mongodb · Dec 1, 2020 · 0cca729 · 0cca729
1 parent 8d44cc2
commit 0cca729
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Showing 10 changed files with 72 additions and 20 deletions.
diff --git a/docs/reference/content/tutorials/crud.md b/docs/reference/content/tutorials/crud.md
@@ -699,7 +699,8 @@ collection.find({}).max(10)                                    // Set the cursor
 collection.find({}).maxTimeMS(1000)                            // Set the cursor maxTimeMS
 collection.find({}).min(100)                                   // Set the cursor min
 collection.find({}).returnKey(10)                              // Set the cursor returnKey
-collection.find({}).setReadPreference(ReadPreference.PRIMARY)  // Set the cursor readPreference
+collection.find({}).withReadPreference(ReadPreference.PRIMARY) // Set the cursor readPreference
+collection.find({}).withReadConcern('majority')                // Set the cursor readConcern
 collection.find({}).showRecordId(true)                         // Set the cursor showRecordId
 collection.find({}).sort([['a', 1]])                           // Sets the sort order of the cursor query
 collection.find({}).hint('a_1')                                // Set the cursor hint

diff --git a/src/cursor/abstract_cursor.ts b/src/cursor/abstract_cursor.ts
@@ -8,6 +8,7 @@ import type { Topology } from '../sdam/topology';
 import { Readable, Transform } from 'stream';
 import { EventEmitter } from 'events';
 import type { ExecutionResult } from '../operations/execute_operation';
+import { ReadConcern, ReadConcernLike } from '../read_concern';
 
 const kId = Symbol('id');
 const kDocuments = Symbol('documents');
@@ -50,6 +51,7 @@ export type CursorFlag = typeof CURSOR_FLAGS[number];
 export interface AbstractCursorOptions extends BSONSerializeOptions {
   session?: ClientSession;
   readPreference?: ReadPreferenceLike;
+  readConcern?: ReadConcernLike;
   batchSize?: number;
   maxTimeMS?: number;
   comment?: Document | string;
@@ -62,6 +64,7 @@ export interface AbstractCursorOptions extends BSONSerializeOptions {
 export type InternalAbstractCursorOptions = Omit<AbstractCursorOptions, 'readPreference'> & {
   // resolved
   readPreference: ReadPreference;
+  readConcern?: ReadConcern;
 
   // cursor flags, some are deprecated
   oplogReplay?: boolean;
@@ -107,6 +110,11 @@ export abstract class AbstractCursor extends EventEmitter {
       ...pluckBSONSerializeOptions(options)
     };
 
+    const readConcern = ReadConcern.fromOptions(options);
+    if (readConcern) {
+      this[kOptions].readConcern = readConcern;
+    }
+
     if (typeof options.batchSize === 'number') {
       this[kOptions].batchSize = options.batchSize;
     }
@@ -144,6 +152,10 @@ export abstract class AbstractCursor extends EventEmitter {
     return this[kOptions].readPreference;
   }
 
+  get readConcern(): ReadConcern | undefined {
+    return this[kOptions].readConcern;
+  }
+
   get session(): ClientSession | undefined {
     return this[kSession];
   }
@@ -434,7 +446,7 @@ export abstract class AbstractCursor extends EventEmitter {
    *
    * @param readPreference - The new read preference for the cursor.
    */
-  setReadPreference(readPreference: ReadPreferenceLike): this {
+  withReadPreference(readPreference: ReadPreferenceLike): this {
     assertUninitialized(this);
     if (readPreference instanceof ReadPreference) {
       this[kOptions].readPreference = readPreference;
@@ -447,6 +459,21 @@ export abstract class AbstractCursor extends EventEmitter {
     return this;
   }
 
+  /**
+   * Set the ReadPreference for the cursor.
+   *
+   * @param readPreference - The new read preference for the cursor.
+   */
+  withReadConcern(readConcern: ReadConcernLike): this {
+    assertUninitialized(this);
+    const resolvedReadConcern = ReadConcern.fromOptions({ readConcern });
+    if (resolvedReadConcern) {
+      this[kOptions].readConcern = resolvedReadConcern;
+    }
+
+    return this;
+  }
+
   /**
    * Set a maxTimeMS on the cursor query, allowing for hard timeout limits on queries (Only supported on MongoDB 2.6 or higher)
    *

diff --git a/src/gridfs-stream/download.ts b/src/gridfs-stream/download.ts
@@ -349,7 +349,7 @@ function init(stream: GridFSBucketReadStream): void {
     stream.s.cursor = stream.s.chunks.find(filter).sort({ n: 1 });
 
     if (stream.s.readPreference) {
-      stream.s.cursor.setReadPreference(stream.s.readPreference);
+      stream.s.cursor.withReadPreference(stream.s.readPreference);
     }
 
     stream.s.expectedEnd = Math.ceil(doc.length / doc.chunkSize);

diff --git a/src/operations/find.ts b/src/operations/find.ts
@@ -173,8 +173,8 @@ export class FindOperation extends CommandOperation<FindOptions, Document> {
       findCommand.maxTimeMS = options.maxTimeMS;
     }
 
-    if (this.readConcern && (!this.session || !this.session.inTransaction())) {
-      findCommand.readConcern = this.readConcern;
+    if (this.readConcern) {
+      findCommand.readConcern = this.readConcern.toJSON();
     }
 
     if (options.max) {

diff --git a/src/read_concern.ts b/src/read_concern.ts
@@ -1,3 +1,5 @@
+import type { Document } from './bson';
+
 /** @public */
 export enum ReadConcernLevel {
   local = 'local',
@@ -78,4 +80,8 @@ export class ReadConcern {
   static get SNAPSHOT(): string {
     return ReadConcernLevel.snapshot;
   }
+
+  toJSON(): Document {
+    return { level: this.level };
+  }
 }
diff --git a/test/functional/apm.test.js b/test/functional/apm.test.js
@@ -373,7 +373,7 @@ describe('APM', function () {
               .batchSize(2)
               .comment('some comment')
               .maxTimeMS(5000)
-              .setReadPreference(ReadPreference.PRIMARY)
+              .withReadPreference(ReadPreference.PRIMARY)
               .addCursorFlag('noCursorTimeout', true)
               .toArray();
           })
@@ -445,7 +445,7 @@ describe('APM', function () {
               .batchSize(2)
               .comment('some comment')
               .maxTimeMS(5000)
-              .setReadPreference(ReadPreference.PRIMARY)
+              .withReadPreference(ReadPreference.PRIMARY)
               .addCursorFlag('noCursorTimeout', true)
               .toArray();
           })

diff --git a/test/functional/buffering_proxy.test.js b/test/functional/buffering_proxy.test.js
@@ -217,7 +217,7 @@ describe.skip('Buffering Proxy', function () {
 
               db.collection('test')
                 .find({})
-                .setReadPreference(new ReadPreference(ReadPreference.SECONDARY))
+                .withReadPreference(new ReadPreference(ReadPreference.SECONDARY))
                 .toArray(function (err) {
                   expect(err).to.not.exist;
                   results.push('find');
@@ -439,7 +439,7 @@ describe.skip('Buffering Proxy', function () {
 
               db.collection('test')
                 .find({})
-                .setReadPreference(new ReadPreference(ReadPreference.SECONDARY))
+                .withReadPreference(new ReadPreference(ReadPreference.SECONDARY))
                 .toArray(function (err) {
                   expect(err).to.not.exist;
                   results.push('find');

diff --git a/test/functional/cursor.test.js b/test/functional/cursor.test.js
@@ -2321,19 +2321,37 @@ describe('Cursor', function () {
         try {
           db.collection('shouldFailToSetReadPreferenceOnCursor')
             .find()
-            .setReadPreference('notsecondary');
+            .withReadPreference('notsecondary');
           test.ok(false);
         } catch (err) {} // eslint-disable-line
 
         db.collection('shouldFailToSetReadPreferenceOnCursor')
           .find()
-          .setReadPreference('secondary');
+          .withReadPreference('secondary');
 
         done();
       });
     }
   });
 
+  it('should allow setting the cursors readConcern through a builder', {
+    metadata: { requires: { mongodb: '>=3.2' } },
+    test: withMonitoredClient(['find'], function (client, events, done) {
+      const db = client.db(this.configuration.db);
+      const cursor = db.collection('foo').find().withReadConcern('local');
+      expect(cursor).property('readConcern').to.have.property('level').equal('local');
+
+      cursor.toArray(err => {
+        expect(err).to.not.exist;
+
+        expect(events).to.have.length(1);
+        const findCommand = events[0];
+        expect(findCommand).nested.property('command.readConcern').to.eql({ level: 'local' });
+        done();
+      });
+    })
+  });
+
   it('shouldNotFailDueToStackOverflowEach', {
     // Add a tag that our runner can trigger on
     // in this case we are setting that node needs to be higher than 0.10.X to run

diff --git a/test/functional/max_staleness.test.js b/test/functional/max_staleness.test.js
@@ -166,7 +166,7 @@ describe('Max Staleness', function () {
         // Get a db with a new readPreference
         db.collection('test')
           .find({})
-          .setReadPreference(readPreference)
+          .withReadPreference(readPreference)
           .toArray(function (err) {
             expect(err).to.not.exist;
             expect(test.checkCommand).to.eql({

diff --git a/test/functional/readpreference.test.js b/test/functional/readpreference.test.js
@@ -478,15 +478,15 @@ describe('ReadPreference', function () {
       })
     });
 
-    it('should set hedge using [.setReadPreference & empty hedge] ', {
+    it('should set hedge using [.withReadPreference & empty hedge] ', {
       metadata: { requires: { mongodb: '>=3.6.0' } },
       test: withMonitoredClient(['find'], function (client, events, done) {
         const rp = new ReadPreference(ReadPreference.SECONDARY, null, { hedge: {} });
         client
           .db(this.configuration.db)
           .collection('test')
           .find({})
-          .setReadPreference(rp)
+          .withReadPreference(rp)
           .toArray(err => {
             expect(err).to.not.exist;
             const expected = { mode: ReadPreference.SECONDARY, hedge: {} };
@@ -496,15 +496,15 @@ describe('ReadPreference', function () {
       })
     });
 
-    it('should set hedge using [.setReadPreference & enabled hedge] ', {
+    it('should set hedge using [.withReadPreference & enabled hedge] ', {
       metadata: { requires: { mongodb: '>=3.6.0' } },
       test: withMonitoredClient(['find'], function (client, events, done) {
         const rp = new ReadPreference(ReadPreference.SECONDARY, null, { hedge: { enabled: true } });
         client
           .db(this.configuration.db)
           .collection('test')
           .find({})
-          .setReadPreference(rp)
+          .withReadPreference(rp)
           .toArray(err => {
             expect(err).to.not.exist;
             const expected = { mode: ReadPreference.SECONDARY, hedge: { enabled: true } };
@@ -514,7 +514,7 @@ describe('ReadPreference', function () {
       })
     });
 
-    it('should set hedge using [.setReadPreference & disabled hedge] ', {
+    it('should set hedge using [.withReadPreference & disabled hedge] ', {
       metadata: { requires: { mongodb: '>=3.6.0' } },
       test: withMonitoredClient(['find'], function (client, events, done) {
         const rp = new ReadPreference(ReadPreference.SECONDARY, null, {
@@ -524,7 +524,7 @@ describe('ReadPreference', function () {
           .db(this.configuration.db)
           .collection('test')
           .find({})
-          .setReadPreference(rp)
+          .withReadPreference(rp)
           .toArray(err => {
             expect(err).to.not.exist;
             const expected = { mode: ReadPreference.SECONDARY, hedge: { enabled: false } };
@@ -534,15 +534,15 @@ describe('ReadPreference', function () {
       })
     });
 
-    it('should set hedge using [.setReadPreference & undefined hedge] ', {
+    it('should set hedge using [.withReadPreference & undefined hedge] ', {
       metadata: { requires: { mongodb: '>=3.6.0' } },
       test: withMonitoredClient(['find'], function (client, events, done) {
         const rp = new ReadPreference(ReadPreference.SECONDARY, null);
         client
           .db(this.configuration.db)
           .collection('test')
           .find({})
-          .setReadPreference(rp)
+          .withReadPreference(rp)
           .toArray(err => {
             expect(err).to.not.exist;
             const expected = { mode: ReadPreference.SECONDARY };