Port provider_meta functionality from core.

Port the functionality added in hashicorp/terraform#22583 that allows
providers to receive arbitrary, provider-definable module-scoped
information from configs.

helper/schema/provider.go

@@ -52,6 +52,14 @@ type Provider struct {
 	// and must *not* implement Create, Update or Delete.
 	DataSourcesMap map[string]*Resource
 
+	// ProviderMetaSchema is the schema for the configuration of the meta
+	// information for this provider. If this provider has no meta info,
+	// this can be omitted. This functionality is currently experimental
+	// and subject to change or break without warning; it should only be
+	// used by providers that are collaborating on its use with the
+	// Terraform team.
+	ProviderMetaSchema map[string]*Schema
+
 	// ConfigureFunc is a function for configuring the provider. If the
 	// provider doesn't need to be configured, this can be omitted.
 	//

helper/schema/resource.go

@@ -330,6 +330,10 @@ func (r *Resource) Apply(
 		return s, append(diags, diag.FromErr(err))
 	}
 
+	if s != nil && data != nil {
+		data.providerMeta = s.ProviderMeta
+	}
+
 	// Instance Diff shoould have the timeout info, need to copy it over to the
 	// ResourceData meta
 	rt := ResourceTimeout{}
@@ -537,6 +541,10 @@ func (r *Resource) RefreshWithoutUpgrade(
 		}
 		data.timeouts = &rt
 
+		if s != nil {
+			data.providerMeta = s.ProviderMeta
+		}
+
 		exists, err := r.Exists(data, meta)
 		if err != nil {
 			return s, append(diags, diag.FromErr(err))
@@ -553,6 +561,10 @@ func (r *Resource) RefreshWithoutUpgrade(
 	}
 	data.timeouts = &rt
 
+	if s != nil {
+		data.providerMeta = s.ProviderMeta
+	}
+
 	diags = append(diags, r.read(ctx, data, meta)...)
 
 	state := data.State()

helper/schema/resource_data.go

@@ -7,6 +7,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/hashicorp/go-cty/cty"
+	"github.com/hashicorp/go-cty/cty/gocty"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/terraform"
 )
 
@@ -19,12 +21,13 @@ import (
 // The most relevant methods to take a look at are Get and Set.
 type ResourceData struct {
 	// Settable (internally)
-	schema   map[string]*Schema
-	config   *terraform.ResourceConfig
-	state    *terraform.InstanceState
-	diff     *terraform.InstanceDiff
-	meta     map[string]interface{}
-	timeouts *ResourceTimeout
+	schema       map[string]*Schema
+	config       *terraform.ResourceConfig
+	state        *terraform.InstanceState
+	diff         *terraform.InstanceDiff
+	meta         map[string]interface{}
+	timeouts     *ResourceTimeout
+	providerMeta cty.Value
 
 	// Don't set
 	multiReader *MultiLevelFieldReader
@@ -506,3 +509,10 @@ func (d *ResourceData) get(addr []string, source getSource) getResult {
 		Schema:         schema,
 	}
 }
+
+func (d *ResourceData) GetProviderMeta(dst interface{}) error {
+	if d.providerMeta.IsNull() {
+		return nil
+	}
+	return gocty.FromCtyValue(d.providerMeta, &dst)
+}

internal/helper/plugin/grpc_provider.go

@@ -68,6 +68,10 @@ func (s *GRPCProviderServer) GetSchema(_ context.Context, req *proto.GetProvider
 		Block: convert.ConfigSchemaToProto(s.getProviderSchemaBlock()),
 	}
 
+	resp.ProviderMeta = &proto.Schema{
+		Block: convert.ConfigSchemaToProto(s.getProviderMetaSchemaBlock()),
+	}
+
 	for typ, res := range s.provider.ResourcesMap {
 		resp.ResourceSchemas[typ] = &proto.Schema{
 			Version: int64(res.SchemaVersion),
@@ -89,6 +93,10 @@ func (s *GRPCProviderServer) getProviderSchemaBlock() *configschema.Block {
 	return schema.InternalMap(s.provider.Schema).CoreConfigSchema()
 }
 
+func (s *GRPCProviderServer) getProviderMetaSchemaBlock() *configschema.Block {
+	return schema.InternalMap(s.provider.ProviderMetaSchema).CoreConfigSchema()
+}
+
 func (s *GRPCProviderServer) getResourceSchemaBlock(name string) *configschema.Block {
 	res := s.provider.ResourcesMap[name]
 	return res.CoreConfigSchema()
@@ -540,6 +548,16 @@ func (s *GRPCProviderServer) ReadResource(ctx context.Context, req *proto.ReadRe
 	}
 	instanceState.Meta = private
 
+	pmSchemaBlock := s.getProviderMetaSchemaBlock()
+	if pmSchemaBlock != nil && req.ProviderMeta != nil {
+		providerSchemaVal, err := msgpack.Unmarshal(req.ProviderMeta.Msgpack, pmSchemaBlock.ImpliedType())
+		if err != nil {
+			resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, err)
+			return resp, nil
+		}
+		instanceState.ProviderMeta = providerSchemaVal
+	}
+
 	newInstanceState, diags := res.RefreshWithoutUpgrade(ctx, instanceState, s.provider.Meta())
 	resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, diags)
 	if diags.HasError() {
@@ -639,6 +657,16 @@ func (s *GRPCProviderServer) PlanResourceChange(ctx context.Context, req *proto.
 
 	priorState.Meta = priorPrivate
 
+	pmSchemaBlock := s.getProviderMetaSchemaBlock()
+	if pmSchemaBlock != nil && req.ProviderMeta != nil {
+		providerSchemaVal, err := msgpack.Unmarshal(req.ProviderMeta.Msgpack, pmSchemaBlock.ImpliedType())
+		if err != nil {
+			resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, err)
+			return resp, nil
+		}
+		priorState.ProviderMeta = providerSchemaVal
+	}
+
 	// Ensure there are no nulls that will cause helper/schema to panic.
 	if err := validateConfigNulls(proposedNewStateVal, nil); err != nil {
 		resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, err)
@@ -900,6 +928,16 @@ func (s *GRPCProviderServer) ApplyResourceChange(ctx context.Context, req *proto
 		}
 	}
 
+	pmSchemaBlock := s.getProviderMetaSchemaBlock()
+	if pmSchemaBlock != nil && req.ProviderMeta != nil {
+		providerSchemaVal, err := msgpack.Unmarshal(req.ProviderMeta.Msgpack, pmSchemaBlock.ImpliedType())
+		if err != nil {
+			resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, err)
+			return resp, nil
+		}
+		priorState.ProviderMeta = providerSchemaVal
+	}
+
 	newInstanceState, diags := res.Apply(ctx, priorState, diff, s.provider.Meta())
 	resp.Diagnostics = convert.AppendProtoDiag(resp.Diagnostics, diags)
 

terraform/state.go

@@ -1356,6 +1356,8 @@ type InstanceState struct {
 	// and collections.
 	Meta map[string]interface{} `json:"meta"`
 
+	ProviderMeta cty.Value
+
 	// Tainted is used to mark a resource for recreation.
 	Tainted bool `json:"tainted"`