Update to encryption key provider interface (#1351)

Signed-off-by: Christian Mesh <christianmesh1@gmail.com>

internal/encryption/base.go

@@ -36,14 +36,14 @@ func newBaseEncryption(enc *encryption, target *config.TargetConfig, enforced bo
 	}
 	// This performs a e2e validation run of the config -> methods flow.  It serves as a validation step and allows us to
 	// return detailed diagnostics here and simple errors below
-	_, diags := base.buildTargetMethods(make(map[keyprovider.Addr]any))
+	_, diags := base.buildTargetMethods(make(map[keyprovider.Addr][]byte))
 	return base, diags
 }
 
 type basedata struct {
-	Meta    map[keyprovider.Addr]any `json:"meta"`
-	Data    []byte                   `json:"encrypted_data"`
-	Version string                   `json:"encryption_version"` // This is both a sigil for a valid encrypted payload and a future compatability field
+	Meta    map[keyprovider.Addr][]byte `json:"meta"`
+	Data    []byte                      `json:"encrypted_data"`
+	Version string                      `json:"encryption_version"` // This is both a sigil for a valid encrypted payload and a future compatability field
 }
 
 func IsEncryptionPayload(data []byte) (bool, error) {
@@ -64,7 +64,7 @@ func (s *baseEncryption) encrypt(data []byte) ([]byte, error) {
 	}
 
 	es := basedata{
-		Meta:    make(map[keyprovider.Addr]any),
+		Meta:    make(map[keyprovider.Addr][]byte),
 		Version: encryptionVersion,
 	}
 

internal/encryption/keyprovider.go

@@ -6,11 +6,10 @@
 package encryption
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 
-	"github.com/go-viper/mapstructure/v2"
-
 	"github.com/opentofu/opentofu/internal/encryption/config"
 
 	"github.com/hashicorp/hcl/v2"
@@ -164,36 +163,9 @@ func (e *targetBuilder) setupKeyProvider(cfg config.KeyProviderConfig, stack []c
 	if diags.HasErrors() {
 		return diags
 	}
-	// Add the metadata
-	if meta, ok := e.keyProviderMetadata[metakey]; ok {
-		decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
-			// We want all metadata fields to be consumed:
-			ErrorUnused: true,
-			// Fill the results in this struct:
-			Result: &keyProviderConfig,
-			// Use the "meta" tag:
-			TagName: "meta",
-			// Ignore fields not tagged with "meta":
-			IgnoreUntaggedFields: true,
-		})
-		if err != nil {
-			return append(diags, &hcl.Diagnostic{
-				Severity: hcl.DiagError,
-				Summary:  "Unable to decode encrypted metadata (did you change your encryption config?)",
-				Detail:   fmt.Sprintf("initializing metadata decoder for %s failed with error: %s", metakey, err.Error()),
-			})
-		}
-		if err := decoder.Decode(meta); err != nil {
-			return append(diags, &hcl.Diagnostic{
-				Severity: hcl.DiagError,
-				Summary:  "Unable to decode encrypted metadata (did you change your encryption config?)",
-				Detail:   fmt.Sprintf("decoding %s failed with error: %s", metakey, err.Error()),
-			})
-		}
-	}
 
 	// Build the Key Provider from the configuration
-	keyProvider, err := keyProviderConfig.Build()
+	keyProvider, keyMetaIn, err := keyProviderConfig.Build()
 	if err != nil {
 		return append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,
@@ -202,7 +174,19 @@ func (e *targetBuilder) setupKeyProvider(cfg config.KeyProviderConfig, stack []c
 		})
 	}
 
-	output, err := keyProvider.Provide()
+	// Add the metadata
+	if meta, ok := e.keyProviderMetadata[metakey]; ok {
+		err := json.Unmarshal(meta, keyMetaIn)
+		if err != nil {
+			return append(diags, &hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "Unable to decode encrypted metadata (did you change your encryption config?)",
+				Detail:   fmt.Sprintf("metadata decoder for %s failed with error: %s", metakey, err.Error()),
+			})
+		}
+	}
+
+	output, keyMetaOut, err := keyProvider.Provide(keyMetaIn)
 	if err != nil {
 		return append(diags, &hcl.Diagnostic{
 			Severity: hcl.DiagError,
@@ -211,8 +195,20 @@ func (e *targetBuilder) setupKeyProvider(cfg config.KeyProviderConfig, stack []c
 		})
 	}
 
-	e.keyProviderMetadata[metakey] = output.Metadata
+	if keyMetaOut != nil {
+		e.keyProviderMetadata[metakey], err = json.Marshal(keyMetaOut)
+
+		if err != nil {
+			return append(diags, &hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "Unable to encode encrypted metadata",
+				Detail:   fmt.Sprintf("metadata encoder for %s failed with error: %s", metakey, err.Error()),
+			})
+		}
+	}
+
 	e.keyValues[cfg.Type][cfg.Name] = output.Cty()
 
 	return nil
+
 }

internal/encryption/keyprovider/keyprovider.go

@@ -5,8 +5,11 @@
 
 package keyprovider
 
+// Reference to struct with json tags
+type KeyMeta any
+
 type Config interface {
-	Build() (KeyProvider, error)
+	Build() (KeyProvider, KeyMeta, error)
 }
 
 type Descriptor interface {
@@ -24,5 +27,5 @@ type Descriptor interface {
 
 type KeyProvider interface {
 	// Provide provides an encryption and decryption keys. If the process fails, it returns an error.
-	Provide() (Output, error)
+	Provide(KeyMeta) (Output, KeyMeta, error)
 }

internal/encryption/keyprovider/output.go

@@ -11,7 +11,6 @@ import "github.com/zclconf/go-cty/cty"
 type Output struct {
 	EncryptionKey []byte `hcl:"encryption_key" cty:"encryption_key" json:"encryption_key" yaml:"encryption_key"`
 	DecryptionKey []byte `hcl:"decryption_key" cty:"decryption_key" json:"decryption_key" yaml:"decryption_key"`
-	Metadata      any
 }
 
 func (o *Output) Cty() cty.Value {

internal/encryption/keyprovider/static/config.go

@@ -16,10 +16,10 @@ type Config struct {
 	Key string `hcl:"key"`
 }
 
-func (c Config) Build() (keyprovider.KeyProvider, error) {
+func (c Config) Build() (keyprovider.KeyProvider, keyprovider.KeyMeta, error) {
 	decodedData, err := hex.DecodeString(c.Key)
 	if err != nil {
-		return nil, fmt.Errorf("failed to hex-decode the provided key (%w)", err)
+		return nil, nil, fmt.Errorf("failed to hex-decode the provided key (%w)", err)
 	}
-	return &staticKeyProvider{decodedData}, nil
+	return &staticKeyProvider{decodedData}, nil, nil
 }

internal/encryption/keyprovider/static/provider.go

@@ -12,9 +12,9 @@ type staticKeyProvider struct {
 	key []byte
 }
 
-func (p staticKeyProvider) Provide() (keyprovider.Output, error) {
+func (p staticKeyProvider) Provide(meta keyprovider.KeyMeta) (keyprovider.Output, keyprovider.KeyMeta, error) {
 	return keyprovider.Output{
 		EncryptionKey: p.key,
 		DecryptionKey: p.key,
-	}, nil
+	}, nil, nil
 }

internal/encryption/keyprovider/static/provider_test.go

@@ -52,13 +52,13 @@ func TestKeyProvider(t *testing.T) {
 				c.Key = tc.key
 			}
 
-			keyProvider, buildErr := c.Build()
+			keyProvider, keyMeta, buildErr := c.Build()
 			if tc.expectSuccess {
 				if buildErr != nil {
 					t.Fatalf("unexpected error: %v", buildErr)
 				}
 
-				output, err := keyProvider.Provide()
+				output, _, err := keyProvider.Provide(keyMeta)
 				if err != nil {
 					t.Fatalf("unexpected error: %v", err)
 				}

internal/encryption/targets.go

@@ -24,7 +24,7 @@ type targetBuilder struct {
 	// Used to evaluate hcl expressions
 	ctx *hcl.EvalContext
 
-	keyProviderMetadata map[keyprovider.Addr]any
+	keyProviderMetadata map[keyprovider.Addr][]byte
 
 	// Used to build EvalContext (and related mappings)
 	keyValues    map[string]map[string]cty.Value
@@ -32,7 +32,7 @@ type targetBuilder struct {
 	methods      map[method.Addr]method.Method
 }
 
-func (base *baseEncryption) buildTargetMethods(meta map[keyprovider.Addr]any) ([]method.Method, hcl.Diagnostics) {
+func (base *baseEncryption) buildTargetMethods(meta map[keyprovider.Addr][]byte) ([]method.Method, hcl.Diagnostics) {
 	var diags hcl.Diagnostics
 
 	builder := &targetBuilder{

internal/varhcl/vardecode.go

@@ -54,7 +54,9 @@ func findVariablesInBodyStruct(body hcl.Body, val reflect.Value) ([]hcl.Traversa
 
 	for name := range tags.Attributes {
 		attr := content.Attributes[name]
-		variables = append(variables, attr.Expr.Variables()...)
+		if attr != nil {
+			variables = append(variables, attr.Expr.Variables()...)
+		}
 	}
 
 	blocksByType := content.Blocks.ByType()