Snap install does not replace file atomically

[Pat Viafore]

Use case:

We have jenkins running with periodic jobs to build a snap and then install the snap to the slave.

At the same time, we have jobs that are using the snap, and they will fail occasionally with the snap not being found. It feels like we're in a brief window where our old snap is removed and the new snap is installed.

Is there any way where the install of the snap can be atomic?

[Ian Johnson (anonymouse67)]

When you say some jobs are using the snap, do you mean using the applications exposed from the snap in $SNAP/bin?

While it's unclear exactly what is not atomic here, it sounds like this might be fixed somewhat by using refresh awareness, but it's not clear to me if the snap is actually being refreshed or not. See https://forum.snapcraft.io/t/wip-refresh-app-awareness/10736 for details of how to try this out and see if it fixes anything for you.

[Zygmunt Krynicki (zyga)]

It's true that a "snap refresh" is not atomic in the sense that a concurrently racing process attempting to spawn an application which happens to be a snap will see a window during which that snap is not going to exist.