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mongodb/jstests/libs/change_stream_util.js
2019-07-27 11:02:23 -04:00

443 lines
19 KiB
JavaScript

/*
* A class with helper functions which operate on change streams. The class maintains a list of
* opened cursors and kills them on cleanup.
*/
load("jstests/libs/fixture_helpers.js"); // For FixtureHelpers.
/**
* Enumeration of the possible types of change streams.
*/
const ChangeStreamWatchMode = Object.freeze({
kCollection: 1,
kDb: 2,
kCluster: 3,
});
/**
* Helper function used internally by ChangeStreamTest. If no passthrough is active, it is exactly
* the same as calling db.runCommand. If a passthrough is active and has defined a function
* 'changeStreamPassthroughAwareRunCommand', then this method will be overridden to allow individual
* streams to explicitly exempt themselves from being modified by the passthrough.
*/
function isChangeStreamPassthrough() {
return typeof changeStreamPassthroughAwareRunCommand != 'undefined';
}
/**
* Helper function to retrieve the type of change stream based on the passthrough suite in which the
* test is being run. If no passthrough is active, this method returns the kCollection watch mode.
*/
function changeStreamPassthroughType() {
return typeof ChangeStreamPassthroughHelpers === 'undefined'
? ChangeStreamWatchMode.kCollection
: ChangeStreamPassthroughHelpers.passthroughType();
}
const runCommandChangeStreamPassthroughAware =
(!isChangeStreamPassthrough() ? ((db, cmdObj) => db.runCommand(cmdObj))
: changeStreamPassthroughAwareRunCommand);
/**
* Asserts that the given opType triggers an invalidate entry depending on the type of change
* stream.
* - single collection streams: drop, rename, and dropDatabase.
* - whole DB streams: dropDatabase.
* - whole cluster streams: none.
* Returns the invalidate document if there was one, or null otherwise.
*/
function assertInvalidateOp({cursor, opType}) {
if (!isChangeStreamPassthrough() ||
(changeStreamPassthroughType() == ChangeStreamWatchMode.kDb && opType == "dropDatabase")) {
assert.soon(() => cursor.hasNext());
const invalidate = cursor.next();
assert.eq(invalidate.operationType, "invalidate");
assert(cursor.isExhausted());
assert(cursor.isClosed());
return invalidate;
}
return null;
}
/**
* Helper to check whether a change stream event matches the given expected event. Ignores the
* resume token and clusterTime unless they are explicitly listed in the expectedEvent.
*/
function assertChangeStreamEventEq(actualEvent, expectedEvent) {
const testEvent = Object.assign({}, actualEvent);
if (!expectedEvent.hasOwnProperty("_id")) {
delete testEvent._id; // Remove the resume token, if present.
}
if (!expectedEvent.hasOwnProperty("clusterTime")) {
delete testEvent.clusterTime; // Remove the cluster time, if present.
}
// The change stream transaction passthrough causes operations to have txnNumber and lsid
// values that the test doesn't expect, which can cause comparisons to fail.
if (!expectedEvent.hasOwnProperty("txnNumber")) {
delete testEvent.txnNumber; // Remove the txnNumber, if present.
}
if (!expectedEvent.hasOwnProperty("lsid")) {
delete testEvent.lsid; // Remove the lsid, if present.
}
assert.docEq(testEvent,
expectedEvent,
"Change did not match expected change. Expected change: " + tojson(expectedEvent) +
", Actual change: " + tojson(testEvent));
}
function ChangeStreamTest(_db, name = "ChangeStreamTest") {
load("jstests/libs/namespace_utils.js"); // For getCollectionNameFromFullNamespace.
// Keeps track of cursors opened during the test so that we can be sure to
// clean them up before the test completes.
let _allCursors = [];
let self = this;
// Prevent accidental usages of the default db.
const db = null;
/**
* Starts a change stream cursor with the given pipeline on the given collection. It uses
* the 'aggregateOptions' if provided and saves the cursor so that it can be cleaned up later.
* If 'doNotModifyInPassthroughs' is 'true' and the test is running in a $changeStream
* upconversion passthrough, then this stream will not be modified and will run as though no
* passthrough were active.
*
* Returns the cursor returned by the 'aggregate' command.
*/
self.startWatchingChanges = function(
{pipeline, collection, aggregateOptions, doNotModifyInPassthroughs}) {
aggregateOptions = aggregateOptions || {};
aggregateOptions.cursor = aggregateOptions.cursor || {batchSize: 1};
// The 'collection' argument may be a collection name, DBCollection object, or '1' which
// indicates all collections in _db.
assert(collection instanceof DBCollection || typeof collection === "string" ||
collection === 1);
const collName = (collection instanceof DBCollection ? collection.getName() : collection);
let res = assert.commandWorked(runCommandChangeStreamPassthroughAware(
_db,
Object.merge({aggregate: collName, pipeline: pipeline}, aggregateOptions),
doNotModifyInPassthroughs));
assert.neq(res.cursor.id, 0);
_allCursors.push({db: _db.getName(), coll: collName, cursorId: res.cursor.id});
return res.cursor;
};
/**
* Returns a change stream cursor that listens for every change in the cluster. Assumes that the
* ChangeStreamTest has been created on the 'admin' db, and will assert if not. It uses the
* 'aggregateOptions' if provided and saves the cursor so that it can be cleaned up later.
*/
self.startWatchingAllChangesForCluster = function(aggregateOptions) {
return self.startWatchingChanges({
pipeline: [{$changeStream: {allChangesForCluster: true}}],
collection: 1,
aggregateOptions: aggregateOptions
});
};
/**
* Issues a 'getMore' on the provided cursor and returns the cursor returned.
*/
self.getNextBatch = function(cursor) {
const collName = getCollectionNameFromFullNamespace(cursor.ns);
return assert
.commandWorked(_db.runCommand({getMore: cursor.id, collection: collName, batchSize: 1}))
.cursor;
};
/**
* Returns the next batch of documents from the cursor. This encapsulates logic for checking
* if it's the first batch or another batch afterwards.
*/
function getBatchFromCursorDocument(cursor) {
return (cursor.nextBatch === undefined) ? cursor.firstBatch : cursor.nextBatch;
}
/**
* Returns the next document from a cursor or returns null if there wasn't one.
* This does not issue any getMores, instead relying off the batch inside 'cursor'.
*/
function getNextDocFromCursor(cursor) {
let nextBatch = getBatchFromCursorDocument(cursor);
if (nextBatch.length === 0) {
return null;
}
assert.eq(nextBatch.length, 1, "Batch length wasn't 0 or 1: " + tojson(cursor));
return nextBatch[0];
}
/**
* Checks if the change has been invalidated.
*/
function isInvalidated(change) {
return change.operationType === "invalidate";
}
/**
* Asserts that the last observed change was the change we expect to see. This also asserts
* that if we do not expect the cursor to be invalidated, that we do not see the cursor
* invalidated. Omits the observed change's resume token and cluster time from the comparison,
* unless the expected change explicitly lists an '_id' or 'clusterTime' field to compare
* against.
*/
function assertChangeIsExpected(
expectedChanges, numChangesSeen, observedChanges, expectInvalidate) {
if (expectedChanges) {
assertChangeStreamEventEq(observedChanges[numChangesSeen],
expectedChanges[numChangesSeen]);
} else if (!expectInvalidate) {
assert(!isInvalidated(observedChanges[numChangesSeen]),
"Change was invalidated when it should not have been. Number of changes seen: " +
numChangesSeen + ", observed changes: " + tojson(observedChanges) +
", expected changes: " + tojson(expectedChanges));
}
}
/**
* Iterates through the change stream and asserts that the next changes are the expected ones.
* This can be provided with either an expected size or a list of expected changes.
* If 'expectInvalidate' is provided, then it will expect the change stream to be invalidated
* at the end. The caller is still expected to provide an invalidate entry in 'expectedChanges'.
*
* Returns a list of the changes seen.
*/
self.assertNextChangesEqual = function(
{cursor, expectedChanges, expectedNumChanges, expectInvalidate, skipFirstBatch}) {
expectInvalidate = expectInvalidate || false;
skipFirstBatch = skipFirstBatch || false;
// Assert that the expected length matches the length of the expected batch.
if (expectedChanges !== undefined && expectedNumChanges !== undefined) {
assert.eq(expectedChanges.length,
expectedNumChanges,
"Expected change's size must match expected number of changes");
}
// Convert 'expectedChanges' to an array, even if it contains just a single element.
if (expectedChanges !== undefined && !(expectedChanges instanceof Array)) {
let arrayVersion = new Array;
arrayVersion.push(expectedChanges);
expectedChanges = arrayVersion;
}
// Set the expected number of changes based on the size of the expected change list.
if (expectedNumChanges === undefined) {
assert.neq(expectedChanges, undefined);
expectedNumChanges = expectedChanges.length;
}
let changes = [];
for (let i = 0; i < expectedNumChanges; i++) {
// Since the first change may be on the original cursor, we need to check for that
// change on the cursor before we move the cursor forward.
if (i === 0 && !skipFirstBatch) {
changes[0] = getNextDocFromCursor(cursor);
if (changes[0]) {
assertChangeIsExpected(expectedChanges, 0, changes, expectInvalidate);
continue;
}
}
assert.soon(function() {
// We need to replace the cursor variable so we return the correct cursor.
cursor = self.getNextBatch(cursor);
changes[i] = getNextDocFromCursor(cursor);
return changes[i] !== null;
}, "timed out waiting for another result from the change stream");
assertChangeIsExpected(expectedChanges, i, changes, expectInvalidate);
}
// If we expect invalidation, the final change should have operation type "invalidate".
if (expectInvalidate) {
assert(isInvalidated(changes[changes.length - 1]),
"Last change was not invalidated when it was expected: " + tojson(changes));
// We make sure that the next batch kills the cursor after an invalidation entry.
let finalCursor = self.getNextBatch(cursor);
assert.eq(finalCursor.id, 0, "Final cursor was not killed: " + tojson(finalCursor));
}
return changes;
};
/**
* Retrieves the next batch in the change stream and confirms that it is empty.
*/
self.assertNoChange = function(cursor) {
cursor = self.getNextBatch(cursor);
assert.eq(0, cursor.nextBatch.length, () => "Cursor had changes: " + tojson(cursor));
};
/**
* Gets the next document in the change stream. This always executes a 'getMore' first.
* If the current batch has a document in it, that one will be ignored.
*/
self.getOneChange = function(cursor, expectInvalidate = false) {
changes = self.assertNextChangesEqual({
cursor: cursor,
expectedNumChanges: 1,
expectInvalidate: expectInvalidate,
skipFirstBatch: true
});
return changes[0];
};
/**
* Kills all outstanding cursors.
*/
self.cleanUp = function() {
for (let testCursor of _allCursors) {
if (typeof testCursor.coll === "string") {
assert.commandWorked(_db.getSiblingDB(testCursor.db).runCommand({
killCursors: testCursor.coll,
cursors: [testCursor.cursorId]
}));
} else if (testCursor.coll == 1) {
// Collection '1' indicates that the change stream was opened against an entire
// database and is considered 'collectionless'.
assert.commandWorked(_db.getSiblingDB(testCursor.db).runCommand({
killCursors: "$cmd.aggregate",
cursors: [testCursor.cursorId]
}));
}
}
};
/**
* Returns the document to be used for the value of a $changeStream stage, given a watchMode
* of type ChangeStreamWatchMode and optional resumeAfter value.
*/
self.getChangeStreamStage = function(watchMode, resumeAfter) {
const changeStreamDoc = {};
if (resumeAfter) {
changeStreamDoc.resumeAfter = resumeAfter;
}
if (watchMode == ChangeStreamWatchMode.kCluster) {
changeStreamDoc.allChangesForCluster = true;
}
return changeStreamDoc;
};
/**
* Create a change stream of the given watch mode (see ChangeStreamWatchMode) on the given
* collection. Will resume from a given point if resumeAfter is specified.
*/
self.getChangeStream = function({watchMode, coll, resumeAfter}) {
return self.startWatchingChanges({
pipeline: [{$changeStream: self.getChangeStreamStage(watchMode, resumeAfter)}],
collection: (watchMode == ChangeStreamWatchMode.kCollection ? coll : 1),
// Use a batch size of 0 to prevent any notifications from being returned in the first
// batch. These would be ignored by ChangeStreamTest.getOneChange().
aggregateOptions: {cursor: {batchSize: 0}},
});
};
/**
* Asserts that the change stream cursor given by 'cursor' returns at least one 'dropType'
* notification before returning the next notification given by 'expectedNext'. If running in a
* sharded passthrough suite, the expectation is to receive a 'dropType' notification from each
* shard that has at least one chunk. If the change stream is watching the single collection,
* then the first drop will invalidate the stream.
*
* Returns an array of documents which includes all drop events consumed and the expected change
* itself.
*/
self.consumeDropUpTo = function({cursor, dropType, expectedNext, expectInvalidate}) {
expectInvalidate = expectInvalidate || false;
let results = [];
let change = self.getOneChange(cursor, expectInvalidate);
while (change.operationType == dropType) {
results.push(change);
change = self.getOneChange(cursor, expectInvalidate);
}
results.push(change);
assertChangeIsExpected([expectedNext], 0, [change], expectInvalidate);
return results;
};
/**
* Asserts that the notifications from the change stream cursor include 0 or more 'drop'
* notifications followed by a 'dropDatabase' notification.
*
* Returns the list of notifications.
*/
self.assertDatabaseDrop = function({cursor, db}) {
return self.consumeDropUpTo({
cursor: cursor,
dropType: "drop",
expectedNext: {operationType: "dropDatabase", ns: {db: db.getName()}}
});
};
}
/**
* Asserts that the given pipeline will eventually return an error with the provided code,
* either in the initial aggregate, or a subsequent getMore. Throws an exception if there are
* any results from running the pipeline, or if it doesn't throw an error within the window of
* assert.soon(). If 'doNotModifyInPassthroughs' is 'true' and the test is running in a
* $changeStream upconversion passthrough, then this stream will not be modified and will run as
* though no passthrough were active.
*/
ChangeStreamTest.assertChangeStreamThrowsCode = function assertChangeStreamThrowsCode(
{db, collName, pipeline, expectedCode, doNotModifyInPassthroughs}) {
try {
const res = assert.commandWorked(runCommandChangeStreamPassthroughAware(
db,
{aggregate: collName, pipeline: pipeline, cursor: {batchSize: 1}},
doNotModifyInPassthroughs));
// Extract the collection name from the cursor since the change stream may be on the whole
// database. The 'collName' parameter will be the integer 1 in that case and the getMore
// command requires 'collection' to be a string.
const getMoreCollName = getCollectionNameFromFullNamespace(res.cursor.ns);
assert.commandWorked(
db.runCommand({getMore: res.cursor.id, collection: getMoreCollName, batchSize: 1}));
} catch (error) {
assert.eq(error.code, expectedCode, `Caught unexpected error: ${tojson(error)}`);
return true;
}
assert(false, "expected this to be unreachable");
};
/**
* Static method for determining which database to run the change stream aggregation on based on
* the watchMode.
*/
ChangeStreamTest.getDBForChangeStream = function(watchMode, dbObj) {
if (watchMode == ChangeStreamWatchMode.kCluster) {
return dbObj.getSiblingDB("admin");
}
return dbObj;
};
/**
* A set of functions to help validate the behaviour of $changeStreams for a given namespace.
*/
function assertChangeStreamNssBehaviour(dbName, collName = "test", options, assertFunc) {
const testDb = db.getSiblingDB(dbName);
options = (options || {});
const res = testDb.runCommand(
Object.assign({aggregate: collName, pipeline: [{$changeStream: options}], cursor: {}}));
return assertFunc(res);
}
function assertValidChangeStreamNss(dbName, collName = "test", options) {
const res = assertChangeStreamNssBehaviour(dbName, collName, options, assert.commandWorked);
assert.commandWorked(db.getSiblingDB(dbName).runCommand(
{killCursors: (collName == 1 ? "$cmd.aggregate" : collName), cursors: [res.cursor.id]}));
}
function assertInvalidChangeStreamNss(dbName, collName = "test", options) {
assertChangeStreamNssBehaviour(
dbName,
collName,
options,
(res) => assert.commandFailedWithCode(
res, [ErrorCodes.InvalidNamespace, ErrorCodes.InvalidOptions]));
}