refactor: organize plugin to support multiple services (#1)

Co-authored-by: Michael Li <michael.li@hashicorp.com>

plugin/service/host/attributes.go

@@ -0,0 +1,90 @@
+package host
+
+import (
+	"fmt"
+
+	cred "github.com/hashicorp/boundary-plugin-host-aws/internal/credential"
+	"github.com/hashicorp/boundary-plugin-host-aws/internal/errors"
+	"github.com/hashicorp/boundary-plugin-host-aws/internal/values"
+	"github.com/mitchellh/mapstructure"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/structpb"
+)
+
+// CatalogAttributes is a Go-native representation of the Attributes
+// map.
+type CatalogAttributes struct {
+	*cred.CredentialAttributes
+}
+
+func getCatalogAttributes(in *structpb.Struct) (*CatalogAttributes, error) {
+	unknownFields := values.StructFields(in)
+	badFields := make(map[string]string)
+
+	var err error
+	credAttributes, err := cred.GetCredentialAttributes(in)
+	if err != nil {
+		return nil, err
+	}
+
+	for s := range unknownFields {
+		switch s {
+		// Ignore knownFields from CredentialAttributes
+		case cred.ConstRegion:
+			continue
+		case cred.ConstDisableCredentialRotation:
+			continue
+		default:
+			badFields[fmt.Sprintf("attributes.%s", s)] = "unrecognized field"
+		}
+	}
+
+	if len(badFields) > 0 {
+		return nil, errors.InvalidArgumentError("Invalid arguments in catalog attributes", badFields)
+	}
+
+	return &CatalogAttributes{
+		CredentialAttributes: credAttributes,
+	}, nil
+}
+
+// SetAttributes is a Go-native representation of the Attributes map that can be
+// used for decoding the incoming map via mapstructure.
+type SetAttributes struct {
+	Filters []string
+}
+
+func getSetAttributes(in *structpb.Struct) (*SetAttributes, error) {
+	var setAttrs SetAttributes
+
+	// Quick validation to ensure that there's no non-filter attributes
+	// here for now. Make this more complex if we add more attributes
+	// to host sets.
+	unknownFields := values.StructFields(in)
+	badFields := make(map[string]string)
+	delete(unknownFields, ConstDescribeInstancesFilters)
+	for a := range unknownFields {
+		badFields[fmt.Sprintf("attributes.%s", a)] = "unrecognized field"
+	}
+	if len(badFields) > 0 {
+		return nil, errors.InvalidArgumentError("Error in the attributes provided", badFields)
+	}
+
+	// Mapstructure complains if it expects a slice as output and sees a scalar
+	// value. Rather than use WeakDecode and risk unintended consequences, I'm
+	// manually making this change if necessary.
+	inMap := in.AsMap()
+	if filtersRaw, ok := inMap[ConstDescribeInstancesFilters]; ok {
+		switch filterVal := filtersRaw.(type) {
+		case string:
+			inMap[ConstDescribeInstancesFilters] = []string{filterVal}
+		}
+	}
+
+	if err := mapstructure.Decode(inMap, &setAttrs); err != nil {
+		return nil, status.Errorf(codes.InvalidArgument, "error decoding set attributes: %s", err)
+	}
+
+	return &setAttrs, nil
+}