Previously, we did not attempt to stop Docker Logger processes until
DestroyTask, which means that under many circumstances, we will never
successfully close the plugin client.
This commit terminates the plugin process when `run` terminates, or when
`DestroyTask` is called.
Steps to repro:
```
$ nomad agent -dev
$ nomad init
$ nomad run example.nomad
$ nomad stop example
$ ps aux | grep nomad # See docker logger process running
$ signal the dev agent
$ ps aux | grep nomad # See docker logger process running
```
plugins/driver: update driver interface to support streaming stats
client/tr: use streaming stats api
TODO:
* how to handle errors and closed channel during stats streaming
* prevent tight loop if Stats(ctx) returns an error
drivers: update drivers TaskStats RPC to handle streaming results
executor: better error handling in stats rpc
docker: better control and error handling of stats rpc
driver: allow stats to return a recoverable error
This PR fixes various instances of plugins being launched without using
the parent loggers. This meant that logs would not all go to the same
output, break formatting etc.
Use `/tmp` as temporary directory for docker driver tests, so tests can
run out of the box without any intervention.
macOS sets tempdir as `/var`, which Docker does not whitelist as a path
that can be bind-mounted.
Re-export the ResourceUsage structs in drivers package to avoid drivers
directly depending on the internal client/structs package directly.
I attempted moving the structs to drivers, but that caused some import
cycles that was a bit hard to disentagle. Alternatively, I added an
alias here that's sufficient for our purposes of avoiding external
drivers depend on internal packages, while allowing us to restructure
packages in future without breaking source compatibility.
This implements the InternalPluginDriver interface in each driver, and
calls the cancellation fn for their respective eventers.
This fixes a per task goroutine leak during test suite execution.
