Emulator not working on windows with `--snapshot` flag

[bartolomej]

Problem

When I ran the emulator with snapshots flag, it exited with below error:

$ flow emulator --snapshot
time="2022-09-20T13:37:48+02:00" level=info msg=":gear:   Using service account 0xf8d6e0586b0a20c7" serviceAddress=f8d6e0586b0a20c7 serviceHashAlgo=SHA3_256 servicePrivKey=1ef20789108d62d4670ee550e40842e2dd435b9f5a20a7421d54040b959af48d servicePubKey=247e7afc5c17795c6217db9bd0b5d0416d733b57f788fcb0f25e35ecf11c3c202d14b9095d5ac772ec507cd5307fd99806c4b97180658029d9506db0308a9657 serviceSigAlgo=ECDSA_P256
time="2022-09-20T13:37:52+02:00" level=error msg=":exclamation:  Failed to configure storage" error="failed to initialize Badger store: entry not found"

Steps to Reproduce

1. Initialise flow config with flow init
2. Start emulator with --persist flag

OS info:

System type	64-bit operating system, x64-based processor
Edition	Windows 10 Home
Version	21H2
Installed on	‎02/‎09/‎2021
OS build	19044.1889

Acceptance Criteria

The emulator starts succesfully with --persist flag on any platform.

Context

We are working on releasing the flowser desktop app in the scope of https://github.com/onflow/developer-grants/issues/27. This issue is blocking us from testing and releasing the app on Windows.

[bartolomej]

I remember @bluesign mentioning that there were some issues with snapshot feature on Windows, so just mentioning that comment: https://github.com/onflow/flow-emulator/issues/204#issuecomment-1249325026

[bluesign]

Hey @bartolomej ,

badger db we are using currently, has very big files when run in windows. (I contacted them, long story short windows is to blame)

I have a huge structure change in storage going on, want to support redis and sqlite as backend.

When sqlite is ready, snapshot will switch to use that ( in my plan, still need to discuss and confirm with @sideninja ) plan timeline is short. I am searching for some test cases now, implementations are done.

[bartolomej]

@bluesign I see, thanks for the update! I think in that case, we will just disable the snapshot feature on Flowser Windows for now.

Looking forward to the upcomming structural change that you mentioned!