This is for boot time configuration for the kamal proxy. Config in here
doesn't not belong in Kamal::Configuration::Proxy which is for deploy
time configuration for the app itself.
Kamal apps don't contain boot time config, because multiple apps can
share a proxy and the config could conflict.
Add two new hooks pre-app-boot and post-app-boot. They are analagous
to the pre/post proxy reboot hooks.
If the boot strategy deploys in groups, then the hooks are called once
per group of hosts and `KAMAL_HOSTS` contains a comma delimited list of
the hosts in that group.
If all hosts are deployed to at once, then they are called once with
`KAMAL_HOSTS` containing all the hosts.
It is possible to have pauses between groups of hosts in the boot config,
where this is the case the pause happens after the post-app-boot hook is
called.
By default only the primary role runs the proxy. To disable the proxy
for that role, you can set `proxy: false` under it.
For other roles they default to not running the proxy, but you can
enable it by setting `proxy: true` for the role, or alternatively
setting a proxy configuration.
The proxy configuration will be merged into the root proxy configuration.
Remove `stop_wait_time` and `readiness_timeout` from the root config
and remove `deploy_timeout` and `drain_timeout` from the proxy config.
Instead we'll just have `deploy_timeout` and `drain_timeout` in the
root config.
For roles that run the proxy, they are passed to the kamal-proxy deploy
command. Once that returns we can assume the container is ready to
shut down.
For other roles, we'll use the `deploy_timeout` when polling the
container to see if it is ready and the `drain_timeout` when stopping
the container.
Add env files back in for secrets - hides them from process lists and
allows you to pick up the latest env file when running
`kamal app exec` without reusing.
1. Add driver as an option, defaulting to `docker-container`. For a
"native" build you can set it to `docker`
2. Set arch as a array of architectures to build for, defaulting to
`[ "amd64", "arm64" ]` unless you are using the docker driver in
which case we default to not setting a platform
3. Remote is now just a connection string for the remote builder
4. If remote is set, we only use it for non-local arches, if we are
only building for the local arch, we'll ignore it.
Examples:
On arm64, build for arm64 locally, amd64 remotely or
On amd64, build for amd64 locally, arm64 remotely:
```yaml
builder:
remote: ssh://docker@docker-builder
```
On arm64, build amd64 on remote,
On amd64 build locally:
```yaml
builder:
arch:
- amd64
remote:
host: ssh://docker@docker-builder
```
Build amd64 on local:
```yaml
builder:
arch:
- amd64
```
Use docker driver, building for local arch:
```yaml
builder:
driver: docker
```
