The grpc protocol requires strings to be valid utf8, but because
provisioners often don't have control over the command output, invalid
utf8 sequences can make it into the response causing grpc transport
errors.
Replace all invalid utf sequences with the standard utf replacement
character in the provisioner output. The code is a direct copy from the
go1.13 std library, and can be replaced with strings.ToValidUTF8 once
it's available.
The main significant change here is that the package name for the proto
definition is "tfplugin5", which is important because this name is part
of the wire protocol for references to types defined in our package.
Along with that, we also move the generated package into "internal" to
make it explicit that importing the generated Go package from elsewhere is
not the right approach for externally-implemented SDKs, which should
instead vendor the proto definition they are using and generate their
own stubs to ensure that the wire protocol is the only hard dependency
between Terraform Core and plugins.
After this is merged, any provider binaries built against our
helper/schema package will need to be rebuilt so that they use the new
"tfplugin5" package name instead of "proto".
In a future commit we will include more elaborate and organized
documentation on how an external codebase might make use of our RPC
interface definition to implement an SDK, but the primary concern here
is to ensure we have the right wire package name before release.
Managing which function need to be shared between the terraform plugin
and the helper plugin without creating cycles was becoming difficult.
Move all functions related to converting between terraform and proto
type into plugin/convert.
The new helper/plugin package contains the grpc servers for handling the
new plugin protocol
The GRPCProviderServer and GRPCProvisionerServer handle the grpc plugin
protocol, and convert the requests to the legacy schema.Provider and
schema.Provisioner methods.
James Bardin