chore: rearrange audit logging code into enterprise folder (#3741)

coderd/audit/diff.go

@@ -1,16 +1,35 @@
 package audit
 
 import (
-	"database/sql"
-	"fmt"
-	"reflect"
-
-	"github.com/google/uuid"
+	"github.com/coder/coder/coderd/database"
 )
 
-// TODO: this might need to be in the database package.
-type Map map[string]interface{}
+// Auditable is mostly a marker interface. It contains a definitive list of all
+// auditable types. If you want to audit a new type, first define it in
+// AuditableResources, then add it to this interface.
+type Auditable interface {
+	database.APIKey |
+		database.Organization |
+		database.OrganizationMember |
+		database.Template |
+		database.TemplateVersion |
+		database.User |
+		database.Workspace |
+		database.GitSSHKey
+}
 
+// Map is a map of changed fields in an audited resource. It maps field names to
+// the old and new value for that field.
+type Map map[string]OldNew
+
+// OldNew is a pair of values representing the old value and the new value.
+type OldNew struct {
+	Old    any
+	New    any
+	Secret bool
+}
+
+// Empty returns a default value of type T.
 func Empty[T Auditable]() T {
 	var t T
 	return t
@@ -18,153 +37,16 @@ func Empty[T Auditable]() T {
 
 // Diff compares two auditable resources and produces a Map of the changed
 // values.
-func Diff[T Auditable](left, right T) Map {
-	// Values are equal, return an empty diff.
-	if reflect.DeepEqual(left, right) {
-		return Map{}
-	}
+func Diff[T Auditable](a Auditor, left, right T) Map { return a.diff(left, right) }
 
-	return diffValues(left, right, AuditableResources)
+// Differ is used so the enterprise version can implement the diff function in
+// the Auditor feature interface. Only types in the same package as the
+// interface can implement unexported methods.
+type Differ struct {
+	DiffFn func(old, new any) Map
 }
 
-func structName(t reflect.Type) string {
-	return t.PkgPath() + "." + t.Name()
-}
-
-func diffValues[T any](left, right T, table Table) Map {
-	var (
-		baseDiff = Map{}
-
-		leftV = reflect.ValueOf(left)
-
-		rightV = reflect.ValueOf(right)
-		rightT = reflect.TypeOf(right)
-
-		diffKey = table[structName(rightT)]
-	)
-
-	if diffKey == nil {
-		panic(fmt.Sprintf("dev error: type %q (type %T) attempted audit but not auditable", rightT.Name(), right))
-	}
-
-	for i := 0; i < rightT.NumField(); i++ {
-		var (
-			leftF  = leftV.Field(i)
-			rightF = rightV.Field(i)
-
-			leftI  = leftF.Interface()
-			rightI = rightF.Interface()
-
-			diffName = rightT.Field(i).Tag.Get("json")
-		)
-
-		atype, ok := diffKey[diffName]
-		if !ok {
-			panic(fmt.Sprintf("dev error: field %q lacks audit information", diffName))
-		}
-
-		if atype == ActionIgnore {
-			continue
-		}
-
-		// coerce struct types that would produce bad diffs.
-		if leftI, rightI, ok = convertDiffType(leftI, rightI); ok {
-			leftF, rightF = reflect.ValueOf(leftI), reflect.ValueOf(rightI)
-		}
-
-		// If the field is a pointer, dereference it. Nil pointers are coerced
-		// to the zero value of their underlying type.
-		if leftF.Kind() == reflect.Ptr && rightF.Kind() == reflect.Ptr {
-			leftF, rightF = derefPointer(leftF), derefPointer(rightF)
-			leftI, rightI = leftF.Interface(), rightF.Interface()
-		}
-
-		// Recursively walk up nested structs.
-		if rightF.Kind() == reflect.Struct {
-			baseDiff[diffName] = diffValues(leftI, rightI, table)
-			continue
-		}
-
-		if !reflect.DeepEqual(leftI, rightI) {
-			switch atype {
-			case ActionTrack:
-				baseDiff[diffName] = rightI
-			case ActionSecret:
-				baseDiff[diffName] = reflect.Zero(rightF.Type()).Interface()
-			}
-		}
-	}
-
-	return baseDiff
-}
-
-// convertDiffType converts external struct types to primitive types.
-//
-//nolint:forcetypeassert
-func convertDiffType(left, right any) (newLeft, newRight any, changed bool) {
-	switch typed := left.(type) {
-	case uuid.UUID:
-		return typed.String(), right.(uuid.UUID).String(), true
-
-	case uuid.NullUUID:
-		leftStr, _ := typed.MarshalText()
-		rightStr, _ := right.(uuid.NullUUID).MarshalText()
-		return string(leftStr), string(rightStr), true
-
-	case sql.NullString:
-		leftStr := typed.String
-		if !typed.Valid {
-			leftStr = "null"
-		}
-
-		rightStr := right.(sql.NullString).String
-		if !right.(sql.NullString).Valid {
-			rightStr = "null"
-		}
-
-		return leftStr, rightStr, true
-
-	case sql.NullInt64:
-		var leftInt64Ptr *int64
-		var rightInt64Ptr *int64
-		if !typed.Valid {
-			leftInt64Ptr = nil
-		} else {
-			leftInt64Ptr = ptr(typed.Int64)
-		}
-
-		rightInt64Ptr = ptr(right.(sql.NullInt64).Int64)
-		if !right.(sql.NullInt64).Valid {
-			rightInt64Ptr = nil
-		}
-
-		return leftInt64Ptr, rightInt64Ptr, true
-
-	default:
-		return left, right, false
-	}
-}
-
-// derefPointer deferences a reflect.Value that is a pointer to its underlying
-// value. It dereferences recursively until it finds a non-pointer value. If the
-// pointer is nil, it will be coerced to the zero value of the underlying type.
-func derefPointer(ptr reflect.Value) reflect.Value {
-	if !ptr.IsNil() {
-		// Grab the value the pointer references.
-		ptr = ptr.Elem()
-	} else {
-		// Coerce nil ptrs to zero'd values of their underlying type.
-		ptr = reflect.Zero(ptr.Type().Elem())
-	}
-
-	// Recursively deref nested pointers.
-	if ptr.Kind() == reflect.Ptr {
-		return derefPointer(ptr)
-	}
-
-	return ptr
-}
-
-func ptr[T any](x T) *T {
-	return &x
+//nolint:unused
+func (d Differ) diff(old, new any) Map {
+	return d.DiffFn(old, new)
 }