Firestore emulator sometimes fails on data export when stopped

[madmacc]

Describe your environment:

• Operating System version: Windows 10
• Browser version: Chrome 88.0.4324.104
• Firebase SDK version: 8.0.0
• Firebase Product: Firestore local emulator

Problem:
When I stop my local firestore emulator most of the time it exports the data fine. However sometimes is has an error and it deletes my export files so I lose all my data. Nothing seems to appear in the logs.
I am using:
firebase emulators:start --import=emulator/emulator-export-data --export-on-exit=emulator/emulator-export-data

Then:
Ctrl+C
to stop the emulator.

I get the following in the terminal:

i emulators: Received SIGINT (Ctrl-C) for the first time. Starting a clean shutdown.
i emulators: Please wait for a clean shutdown or send the SIGINT (Ctrl-C) signal again to stop right now.
i Automatically exporting data using --export-on-exit "emulator/emulator-export-data" please wait for the export to finish...
i Found running emulator hub for project hivepass-dev at http://localhost:4401
i Deleting directory R:\hivepass\HivePassApp\emulator\emulator-export-data\firestore_export
i Exporting data to: R:\hivepass\HivePassApp\emulator\emulator-export-data
! Export request failed, see emulator logs for more information.
! Automatic export to "emulator/emulator-export-data" failed, going to exit now...
i emulators: Shutting down emulators.
i ui: Stopping Emulator UI
! Emulator UI has exited upon receiving signal: SIGINT
i hosting: Stopping Hosting Emulator
i firestore: Stopping Firestore Emulator
! Firestore Emulator has exited upon receiving signal: SIGINT
i auth: Stopping Authentication Emulator
i hub: Stopping emulator hub
i logging: Stopping Logging Emulator

There is not much in the firestore-debug.log in the root:

INFO: Detected non-HTTP/2 connection.
Jan 28, 2021 12:46:37 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
INFO: Detected non-HTTP/2 connection.
Jan 28, 2021 12:46:38 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
INFO: Detected non-HTTP/2 connection.
Jan 28, 2021 12:46:38 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
INFO: Detected non-HTTP/2 connection.
Jan 28, 2021 12:46:39 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
INFO: Detected non-HTTP/2 connection.
Jan 28, 2021 12:46:39 PM io.gapi.emulators.netty.HttpVersionRoutingHandler channelRead
INFO: Detected non-HTTP/2 connection.

[schmidt-sebastian]

@yuchenshi - Can you take a look at this?

[sam-gc]

Hi @madmacc, thanks for the report.

Would you mind expanding a bit about the steps you're taking before seeing this issue? For example, how much data is being saved? What SDKs are you using? Are you using any of the other emulators in conjunction with Firestore?

[madmacc]

Sure @samhorlbeck.
The data is only 130k.
I am running the following emulators. Firestore, Auth, Functions
However I am running the functions emulator as a separate instance as the functions folder is in a different project/location and I can't figure out how to run all of them with one command.

I am using v9.2.1 of the firebase-tools.

Let me know if you need any more information.

[sam-gc]

What is your general use case? Can you discern any particular action that reliably causes the data to not be saved correctly? Basically I'm just trying to get a sense of how we could start to debug this issue and potentially reproduce it.

[madmacc]

Unfortunately not. I'm sure there is some reason but it seems random to me at this stage.
I can run it loading the previously exported data. Add some more data and then stop it by hitting ctrl+c in the terminal.
It will sometimes export ok and sometimes not. It only deletes the firestore_export folder not the firebase-export-metadata.json file.

At the moment when it is successful I manually copy the exported data to a safe location so it is not deleted.

I was hoping the logs would show something but they don't unless I am looking in the wrong place. Root of the project firestore-debug.log.

I am just testing an web application locally using the firebase js sdk and angularfire.