Question/Request: Directory for data that should persist over updates.

[John Lenton]

On 28 January 2016 at 13:44, Lefteris Karapetsas <lefteris at slock.it> wrote:
>
> Some snaps, including mine need to store some data, a database let's
> say, or in my case a whole blockchain. So far I was instructed to do
> that at $SNAP_APP_DATA_PATH. This works fine for now but whenever
> the user updates the snap from what I understand this whole
> directory will be copied into the next version's directory, to
> enable the transaction updating and rollback nature of Snappy
> Ubuntu.
>
> This is not going to work for my snap and I need to ask if there is
> any directory where I can store data for the application that will
> persist over any update. If not then this is something that really
> should be added at some point since I suppose many snaps will need
> to utilize behaviour like this.

Right now there isn't a way to do this, but we do want to do something
like this for 16.04. We still haven't decided whether it'll be a
separate directory (and associated environment variable), or whether
it'll be a fixed directory under $SNAP_DATA (and $SNAP_USER_DATA).

We'll let you know via this mailing list when there's something ready
for testing.

Thanks,