The env check is not needded anymore as all the commands rely on the
env files having already been created remotely.
The only place the env is needed is when running `kamal env push` and
that will still raise an apropriate error.
When calling `kamal app exec` for new non interactive containers, run
the command per role on each server and include the role config
including the environment.
Fixes: https://github.com/basecamp/kamal/issues/492
Adding -T to the copy command ensures that the files are copied at the
same level into the target directory whether it exists or not.
That allows us to drop the `/*` which was not picking up hidden files.
Fixes: https://github.com/basecamp/kamal/issues/465
Kamal needs images to have the service label so it can track them for
pruning. Images built by Kamal will have the label, but externally built
ones may not.
Without it images will build up over time. The worst case is an outage
if all the hosts disks fill up at the same time.
We'll add a check for the label and halt if it is not there.
If you always want to use a destination, and have a base deploy.yml file
that doesn't specify any hosts, then if you forget to specific the
destination you will get a cryptic error.
Add a "require_destination" setting you can use to avoid this.
An interrupted deployment can leave older containers lying around. To
ensure they are cleaned up subsequently, stop stale containers during
deployments instead of just reporting them.
During deployments both the old and new containers will be active for a
small period of time. There also may be lagging requests for older CSS
and JS after the deployment.
This can lead to 404s if a request for old assets hits a new container
or visa-versa.
This PR makes sure that both sets of assets are available throughout the
deployment from before the new version of the app is booted.
This can be configured by setting the asset path:
```yaml
asset_path: "/rails/public/assets"
```
The process is:
1. We extract the assets out of the container, with docker run, docker
cp, docker stop. Docker run sets the container command to "sleep" so
this needs to be available in the container.
2. We create an asset volume directory on the host for the new version
of the app on the host and copy the assets in there.
3. If there is a previous deployment we also copy the new assets into
its asset volume and copy the older assets into the new asset volume.
4. We start the new container mapping the asset volume over the top of
the container's asset path.
This means the both the old and new versions have replaced the asset
path with a volume containing both sets of assets and should be able
to serve any request during the deployment. The older assets will
continue to be available until the next deployment.
