When serializing structs with msgpack, only consider type tags of
`codec`.
Hashicorp/go-msgpack (based on ugorji/go) defaults to interpretting
`codec` tag if it's available, but falls to using `json` if `codec`
isn't present.
This behavior is surprising in cases where we want to serialize json
differently from msgpack, e.g. serializing `ConsulExposeConfig`.
Our testing so far indicates that ugorji/go/codec maintains backward
compatiblity with the version we are using now, for purposes of Nomad
serialization.
Using latest ugorji/go allows us to get back to using upstream library,
get get the optimizations benefits in RPC paths (including code
generation optimizations).
ugorji/go introduced two significant changes:
* time binary format in debb8e2d2e. Setting `h.BasicHandle.TimeNotBuiltin = true` restores old behavior
* ugorji/go started honoring `json` tag as well:
v1.1.4 is the latest but has a bug in handling RawString that's fixed in
d09a80c1e0
.
This PR plumbs the plugins done ctx through the base and driver plugin
clients (device already had it). Further, it adds generic handling of
gRPC stream errors.
Introduce a device manager that manages the lifecycle of device plugins
on the client. It fingerprints, collects stats, and forwards Reserve
requests to the correct plugin. The manager, also handles device plugins
failing and validates their output.
Driver plugin framework to facilitate development of driver plugins.
Implementing plugins only need to implement the DriverPlugin interface.
The framework proxies this interface to the go-plugin GRPC interface generated
from the driver.proto spec.
A testing harness is provided to allow implementing drivers to test the full
lifecycle of the driver plugin. An example use:
func TestMyDriver(t *testing.T) {
harness := NewDriverHarness(t, &MyDiverPlugin{})
// The harness implements the DriverPlugin interface and can be used as such
taskHandle, err := harness.StartTask(...)
}
This PR introduces:
* An example device plugin that exposes files as devices for testing.
* Helpers for serving a device plugin
* A launcher binary that allows interacting with a device plugin without
needing a Nomad client.
