fix(ChangeStream): whitelist change stream resumable errors

  - Changes which errors are considered resumable on change streams,
    adding support for the new ResumableChangeStreamError label.
  - Removes ElectionInProgress (216) from ResumableChangeStreamError.
  - Updates ChangeStream prose tests which described startAfter 
    behavior for unsupported server versions.
  - Fixes use of startAfter/resumeAfter when resuming from an
    invalidate event. Implement prose tests #17 and #18.

NODE-2478
NODE-2522

Author: emadum

.travis.yml

@@ -4,7 +4,7 @@ language: node_js
 branches:
   only:
     - master
-    - next
+    - 3.6
 
 before_install:
   # we have to intstall mongo-orchestration ourselves to get around permissions issues in subshells

lib/change_stream.js

@@ -288,7 +288,9 @@ class ChangeStreamCursor extends Cursor {
       ['resumeAfter', 'startAfter', 'startAtOperationTime'].forEach(key => delete result[key]);
 
       if (this.resumeToken) {
-        result.resumeAfter = this.resumeToken;
+        const resumeKey =
+          this.options.startAfter && !this.hasReceived ? 'startAfter' : 'resumeAfter';
+        result[resumeKey] = this.resumeToken;
       } else if (this.startAtOperationTime && maxWireVersion(this.server) >= 7) {
         result.startAtOperationTime = this.startAtOperationTime;
       }
@@ -297,6 +299,26 @@ class ChangeStreamCursor extends Cursor {
     return result;
   }
 
+  cacheResumeToken(resumeToken) {
+    if (this.bufferedCount() === 0 && this.cursorState.postBatchResumeToken) {
+      this.resumeToken = this.cursorState.postBatchResumeToken;
+    } else {
+      this.resumeToken = resumeToken;
+    }
+    this.hasReceived = true;
+  }
+
+  _processBatch(batchName, response) {
+    const cursor = response.cursor;
+    if (cursor.postBatchResumeToken) {
+      this.cursorState.postBatchResumeToken = cursor.postBatchResumeToken;
+
+      if (cursor[batchName].length === 0) {
+        this.resumeToken = cursor.postBatchResumeToken;
+      }
+    }
+  }
+
   _initializeCursor(callback) {
     super._initializeCursor((err, result) => {
       if (err) {
@@ -315,15 +337,9 @@ class ChangeStreamCursor extends Cursor {
         this.startAtOperationTime = response.operationTime;
       }
 
-      const cursor = response.cursor;
-      if (cursor.postBatchResumeToken) {
-        this.cursorState.postBatchResumeToken = cursor.postBatchResumeToken;
-
-        if (cursor.firstBatch.length === 0) {
-          this.resumeToken = cursor.postBatchResumeToken;
-        }
-      }
+      this._processBatch('firstBatch', response);
 
+      this.emit('init', result);
       this.emit('response');
       callback(err, result);
     });
@@ -336,15 +352,9 @@ class ChangeStreamCursor extends Cursor {
         return;
       }
 
-      const cursor = response.cursor;
-      if (cursor.postBatchResumeToken) {
-        this.cursorState.postBatchResumeToken = cursor.postBatchResumeToken;
-
-        if (cursor.nextBatch.length === 0) {
-          this.resumeToken = cursor.postBatchResumeToken;
-        }
-      }
+      this._processBatch('nextBatch', response);
 
+      this.emit('more', response);
       this.emit('response');
       callback(err, response);
     });
@@ -367,6 +377,7 @@ function createChangeStreamCursor(self, options) {
 
   const pipeline = [{ $changeStream: changeStreamStageOptions }].concat(self.pipeline);
   const cursorOptions = applyKnownOptions({}, options, CURSOR_OPTIONS);
+
   const changeStreamCursor = new ChangeStreamCursor(
     self.topology,
     new AggregateOperation(self.parent, pipeline, options),
@@ -465,9 +476,10 @@ function processNewChange(args) {
   const change = args.change;
   const callback = args.callback;
   const eventEmitter = args.eventEmitter || false;
+  const cursor = changeStream.cursor;
 
-  // If the changeStream is closed, then it should not process a change.
-  if (changeStream.isClosed()) {
+  // If the cursor is null, then it should not process a change.
+  if (cursor == null) {
     // We do not error in the eventEmitter case.
     if (eventEmitter) {
       return;
@@ -479,12 +491,12 @@ function processNewChange(args) {
       : changeStream.promiseLibrary.reject(error);
   }
 
-  const cursor = changeStream.cursor;
   const topology = changeStream.topology;
   const options = changeStream.cursor.options;
+  const wireVersion = maxWireVersion(cursor.server);
 
   if (error) {
-    if (isResumableError(error) && !changeStream.attemptingResume) {
+    if (isResumableError(error, wireVersion) && !changeStream.attemptingResume) {
       changeStream.attemptingResume = true;
 
       // stop listening to all events from old cursor
@@ -550,11 +562,7 @@ function processNewChange(args) {
   }
 
   // cache the resume token
-  if (cursor.bufferedCount() === 0 && cursor.cursorState.postBatchResumeToken) {
-    cursor.resumeToken = cursor.cursorState.postBatchResumeToken;
-  } else {
-    cursor.resumeToken = change._id;
-  }
+  cursor.cacheResumeToken(change._id);
 
   // wipe the startAtOperationTime if there was one so that there won't be a conflict
   // between resumeToken and startAtOperationTime if we need to reconnect the cursor

lib/core/utils.js

@@ -83,22 +83,24 @@ function retrieveEJSON() {
  * @param {(Topology|Server)} topologyOrServer
  */
 function maxWireVersion(topologyOrServer) {
-  if (topologyOrServer.ismaster) {
-    return topologyOrServer.ismaster.maxWireVersion;
-  }
+  if (topologyOrServer) {
+    if (topologyOrServer.ismaster) {
+      return topologyOrServer.ismaster.maxWireVersion;
+    }
 
-  if (typeof topologyOrServer.lastIsMaster === 'function') {
-    const lastIsMaster = topologyOrServer.lastIsMaster();
-    if (lastIsMaster) {
-      return lastIsMaster.maxWireVersion;
+    if (typeof topologyOrServer.lastIsMaster === 'function') {
+      const lastIsMaster = topologyOrServer.lastIsMaster();
+      if (lastIsMaster) {
+        return lastIsMaster.maxWireVersion;
+      }
     }
-  }
 
-  if (topologyOrServer.description) {
-    return topologyOrServer.description.maxWireVersion;
+    if (topologyOrServer.description) {
+      return topologyOrServer.description.maxWireVersion;
+    }
   }
 
-  return null;
+  return 0;
 }
 
 /*

lib/error.js

@@ -9,25 +9,34 @@ const GET_MORE_NON_RESUMABLE_CODES = new Set([
   11601 // Interrupted
 ]);
 
-// From spec@https://github.com/mongodb/specifications/blob/7a2e93d85935ee4b1046a8d2ad3514c657dc74fa/source/change-streams/change-streams.rst#resumable-error:
-//
-// An error is considered resumable if it meets any of the following criteria:
-// - any error encountered which is not a server error (e.g. a timeout error or network error)
-// - any server error response from a getMore command excluding those containing the error label
-//   NonRetryableChangeStreamError and those containing the following error codes:
-//   - Interrupted: 11601
-//   - CappedPositionLost: 136
-//   - CursorKilled: 237
-//
-// An error on an aggregate command is not a resumable error. Only errors on a getMore command may be considered resumable errors.
+// From spec@https://github.com/mongodb/specifications/blob/f93d78191f3db2898a59013a7ed5650352ef6da8/source/change-streams/change-streams.rst#resumable-error
+const GET_MORE_RESUMABLE_CODES = new Set([
+  6, // HostUnreachable
+  7, // HostNotFound
+  89, // NetworkTimeout
+  91, // ShutdownInProgress
+  189, // PrimarySteppedDown
+  262, // ExceededTimeLimit
+  9001, // SocketException
+  10107, // NotMaster
+  11600, // InterruptedAtShutdown
+  11602, // InterruptedDueToReplStateChange
+  13435, // NotMasterNoSlaveOk
+  13436, // NotMasterOrSecondary
+  63, // StaleShardVersion
+  150, // StaleEpoch
+  13388, // StaleConfig
+  234, // RetryChangeStream
+  133 // FailedToSatisfyReadPreference
+]);
 
 function isGetMoreError(error) {
   if (error[mongoErrorContextSymbol]) {
     return error[mongoErrorContextSymbol].isGetMore;
   }
 }
 
-function isResumableError(error) {
+function isResumableError(error, wireVersion) {
   if (!isGetMoreError(error)) {
     return false;
   }
@@ -36,10 +45,14 @@ function isResumableError(error) {
     return true;
   }
 
-  return !(
-    GET_MORE_NON_RESUMABLE_CODES.has(error.code) ||
-    error.hasErrorLabel('NonRetryableChangeStreamError')
+  if (wireVersion >= 9) {
+    return error.hasErrorLabel('ResumableChangeStreamError');
+  }
+
+  return (
+    GET_MORE_RESUMABLE_CODES.has(error.code) &&
+    !error.hasErrorLabel('NonResumableChangeStreamError')
   );
 }
 
-module.exports = { GET_MORE_NON_RESUMABLE_CODES, isResumableError };
+module.exports = { GET_MORE_NON_RESUMABLE_CODES, GET_MORE_RESUMABLE_CODES, isResumableError };