How to flush pending operation buffer

[simon-abbott]

Hello,

I have a bit of a conundrum. I'm trying to drop a temporary database after a test run, but it's still there after the test completes. I have traced the issue, and I believe what is happening is that the database is being dropped, but is then immediately being re-created by some buffered commands. Basically I think it's doing the following:

1. Connect
2. Run the tests
3. Drop the DB
4. Execute some commands that were buffered during the test run, which causes mongodb to re-create the database
5. Disconnect

What I would like is a way to wait until the command buffer is empty, so I can move step 4 before step 3, but there I can't find a flush function (or wait, or pause, or anything else that would signal when the queue is empty). Is there a way to do this cleanly? The only way I've found so far is to sleep for a while (await new Promise((resolve) => setTimeout(resolve, 250));) seems to do the trick), but I'd rather not wait for longer than necessary.

I'd also rather not turn off buffering entirely. I know that's an option, but I do want buffering (plus our code is built assuming it's on, and I don't want to risk breaking anything), I just want to be able to flush the buffer manually.

[vkarpov15]

@simon-abbott there isn't currently a way to flush the buffer. However, you shouldn't need to flush the buffer after connecting - Mongoose only buffers commands before you initially connect (so before step 1).

Try enabling Mongoose debug mode, mongoose.set('debug', true), to see what commands are executed in step (4).

Also, consider disabling autoIndex and autoCreate in your tests. mongoose.set('autoIndex', false); mongoose.set('autoCreate', false);. This will prevent Mongoose from automatically creating collections and indexes when you compile a model, which may help fix this problem.