Support Docker `volumes` field in Windows. Previously, volumes parser
assumed some Unix-ism (e.g. didn't expect `:` in mount paths).
Here, we use the Docker parser to identify host and container paths.
Docker parsers use different validation logic from our previous unix
implementation: Docker parser accepts single path as a volume entry
(parsing it as a container path with auto-created volume) and enforces
additional checks (e.g. validity of mode). Thereforce, I opted to use
Docker parser only for Windows, and keep Nomad's linux parser to
preserve current behavior.
This command will be used to send a signal to either a single task within an
allocation, or all of the tasks if <task-name> is omitted. If the sent signal
terminates the allocation, it will be treated as if the allocation has crashed,
rather than as if it was operator-terminated.
Signal validation is currently handled by the driver itself and nomad
does not attempt to restrict or validate them.
Fixes https://github.com/hashicorp/nomad/issues/5593
Executor seems to die unexpectedly after nomad agent dies or is
restarted. The crash seems to occur at the first log message after
the nomad agent dies.
To ease debugging we forward executor log messages to executor.log as
well as to Stderr. `go-plugin` sets up plugins with Stderr pointing to
a pipe being read by plugin client, the nomad agent in our case[1].
When the nomad agent dies, the pipe is closed, and any subsequent
executor logs fail with ErrClosedPipe and SIGPIPE signal. SIGPIPE
results into executor process dying.
I considered adding a handler to ignore SIGPIPE, but hc-log library
currently panics when logging write operation fails[2]
This we opt to revert to v0.8 behavior of exclusively writing logs to
executor.log, while we investigate alternative options.
[1] https://github.com/hashicorp/nomad/blob/v0.9.0/vendor/github.com/hashicorp/go-plugin/client.go#L528-L535
[2] https://github.com/hashicorp/nomad/blob/v0.9.0/vendor/github.com/hashicorp/go-hclog/int.go#L320-L323
