generate-database: Add support for marshal to JSON

cmd/generate-database/README.md

@@ -115,7 +115,7 @@ Tag                         | Description
 `primary=yes`               | Assigns column associated with the field to be sufficient for returning a row from the table. Will default to `Name` if unspecified. Fields with this key will be included in the default 'ORDER BY' clause.
 `omit=<Stmt Types>`         | Omits a given field from consideration for the comma separated list of statement types (`create`, `objects-by-Name`, `update`).
 `ignore=yes`                | Outright ignore the struct field as though it does not exist.
-`marshal=yes`               | Marshal/Unmarshal data into the field. The column must be a TEXT column and the type must implement both `Marshal` and `Unmarshal`. This works for entity tables only, and not for association or mapping tables.
+`marshal=<yes/json>`        | Marshal/Unmarshal data into the field. The column must be a TEXT column. If `marshal=yes`, then the type must implement both `Marshal` and `Unmarshal`. If `marshal=json`, the type is marshaled to JSON using the standard library ([json.Marshal](https://pkg.go.dev/encoding/json#Marshal)). This works for entity tables only, and not for association or mapping tables.
 
 ### Go Function Generation
 

cmd/generate-database/db/lex.go

@@ -97,7 +97,12 @@ func destFunc(slice string, typ string, fields []*Field) string {
 	}
 
 	unmarshal := func(declVarName string, field *Field) {
-		writeLine(fmt.Sprintf("err = unmarshal(%s, &%s.%s)", declVarName, varName, field.Name))
+		unmarshalFunc := "unmarshal"
+		if field.Config.Get("marshal") == "json" {
+			unmarshalFunc = "unmarshalJSON"
+		}
+
+		writeLine(fmt.Sprintf("err = %s(%s, &%s.%s)", unmarshalFunc, declVarName, varName, field.Name))
 		checkErr()
 	}
 
@@ -106,7 +111,7 @@ func destFunc(slice string, typ string, fields []*Field) string {
 	declVarNames := make([]string, 0, len(fields))
 	for i, field := range fields {
 		var arg string
-		if util.IsTrue(field.Config.Get("marshal")) {
+		if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
 			declVarName := fmt.Sprintf("%sStr", lex.Minuscule(field.Name))
 			declVarNames = append(declVarNames, declVarName)
 			declVars[declVarName] = field

cmd/generate-database/db/mapping.go

@@ -240,7 +240,7 @@ func (m *Mapping) FieldParamsMarshal(fields []*Field) string {
 			name = lex.Minuscule(m.Name) + field.Name
 		}
 
-		if util.IsTrue(field.Config.Get("marshal")) {
+		if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
 			name = fmt.Sprintf("marshaled%s", field.Name)
 		}
 

cmd/generate-database/db/method.go

@@ -231,8 +231,13 @@ func (m *Method) getMany(buf *file.Buffer) error {
 			var args string
 			for _, name := range filter {
 				for _, field := range mapping.Fields {
-					if name == field.Name && util.IsTrue(field.Config.Get("marshal")) {
-						buf.L("marshaledFilter%s, err := marshal(filter.%s)", name, name)
+					if name == field.Name && util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+						marshalFunc := "marshal"
+						if strings.ToLower(field.Config.Get("marshal")) == "json" {
+							marshalFunc = "marshalJSON"
+						}
+
+						buf.L("marshaledFilter%s, err := %s(filter.%s)", name, marshalFunc, name)
 						m.ifErrNotNil(buf, true, "nil", "err")
 						args += fmt.Sprintf("marshaledFilter%s,", name)
 					} else if name == field.Name {
@@ -563,8 +568,13 @@ func (m *Method) id(buf *file.Buffer) error {
 	m.ifErrNotNil(buf, true, "-1", fmt.Sprintf(`fmt.Errorf("Failed to get \"%s\" prepared statement: %%w", err)`, stmtCodeVar(m.entity, "ID")))
 
 	for _, field := range nk {
-		if util.IsTrue(field.Config.Get("marshal")) {
-			buf.L("marshaled%s, err := marshal(%s)", field.Name, lex.Minuscule(field.Name))
+		if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+			marshalFunc := "marshal"
+			if strings.ToLower(field.Config.Get("marshal")) == "json" {
+				marshalFunc = "marshalJSON"
+			}
+
+			buf.L("marshaled%s, err := %s(%s)", field.Name, marshalFunc, lex.Minuscule(field.Name))
 			m.ifErrNotNil(buf, true, "-1", "err")
 		}
 	}
@@ -608,8 +618,13 @@ func (m *Method) exists(buf *file.Buffer) error {
 	m.ifErrNotNil(buf, true, "false", fmt.Sprintf(`fmt.Errorf("Failed to get \"%s\" prepared statement: %%w", err)`, stmtCodeVar(m.entity, "ID")))
 
 	for _, field := range nk {
-		if util.IsTrue(field.Config.Get("marshal")) {
-			buf.L("marshaled%s, err := marshal(%s)", field.Name, lex.Minuscule(field.Name))
+		if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+			marshalFunc := "marshal"
+			if strings.ToLower(field.Config.Get("marshal")) == "json" {
+				marshalFunc = "marshalJSON"
+			}
+
+			buf.L("marshaled%s, err := %s(%s)", field.Name, marshalFunc, lex.Minuscule(field.Name))
 			m.ifErrNotNil(buf, true, "false", "err")
 		}
 	}
@@ -726,8 +741,13 @@ func (m *Method) create(buf *file.Buffer, replace bool) error {
 
 		buf.L("// Populate the statement arguments. ")
 		for i, field := range fields {
-			if util.IsTrue(field.Config.Get("marshal")) {
-				buf.L("marshaled%s, err := marshal(object.%s)", field.Name, field.Name)
+			if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+				marshalFunc := "marshal"
+				if strings.ToLower(field.Config.Get("marshal")) == "json" {
+					marshalFunc = "marshalJSON"
+				}
+
+				buf.L("marshaled%s, err := %s(object.%s)", field.Name, marshalFunc, field.Name)
 				m.ifErrNotNil(buf, true, "-1", "err")
 				buf.L("args[%d] = marshaled%s", i, field.Name)
 			} else {
@@ -880,8 +900,13 @@ func (m *Method) rename(buf *file.Buffer) error {
 	m.ifErrNotNil(buf, true, fmt.Sprintf(`fmt.Errorf("Failed to get \"%s\" prepared statement: %%w", err)`, stmtCodeVar(m.entity, "rename")))
 
 	for _, field := range nk {
-		if util.IsTrue(field.Config.Get("marshal")) {
-			buf.L("marshaled%s, err := marshal(%s)", field.Name, lex.Minuscule(field.Name))
+		if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+			marshalFunc := "marshal"
+			if strings.ToLower(field.Config.Get("marshal")) == "json" {
+				marshalFunc = "marshalJSON"
+			}
+
+			buf.L("marshaled%s, err := %s(%s)", field.Name, marshalFunc, lex.Minuscule(field.Name))
 			m.ifErrNotNil(buf, true, "err")
 		}
 	}
@@ -999,8 +1024,13 @@ func (m *Method) update(buf *file.Buffer) error {
 		fields := updateMapping.ColumnFields("ID") // This exclude the ID column, which is autogenerated.
 		params := make([]string, len(fields))
 		for i, field := range fields {
-			if util.IsTrue(field.Config.Get("marshal")) {
-				buf.L("marshaled%s, err := marshal(object.%s)", field.Name, field.Name)
+			if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+				marshalFunc := "marshal"
+				if strings.ToLower(field.Config.Get("marshal")) == "json" {
+					marshalFunc = "marshalJSON"
+				}
+
+				buf.L("marshaled%s, err := %s(object.%s)", field.Name, marshalFunc, field.Name)
 				m.ifErrNotNil(buf, true, "err")
 				params[i] = fmt.Sprintf("marshaled%s", field.Name)
 			} else {
@@ -1111,8 +1141,13 @@ func (m *Method) delete(buf *file.Buffer, deleteOne bool) error {
 		buf.L("stmt, err := Stmt(db, %s)", stmtCodeVar(m.entity, "delete", FieldNames(activeFilters)...))
 
 		for _, field := range activeFilters {
-			if util.IsTrue(field.Config.Get("marshal")) {
-				buf.L("marshaled%s, err := marshal(%s)", field.Name, lex.Minuscule(field.Name))
+			if util.IsNeitherFalseNorEmpty(field.Config.Get("marshal")) {
+				marshalFunc := "marshal"
+				if strings.ToLower(field.Config.Get("marshal")) == "json" {
+					marshalFunc = "marshalJSON"
+				}
+
+				buf.L("marshaled%s, err := %s(%s)", field.Name, marshalFunc, lex.Minuscule(field.Name))
 				m.ifErrNotNil(buf, true, "err")
 			}
 		}

cmd/generate-database/db/parse.go

@@ -14,6 +14,7 @@ import (
 	"strings"
 
 	"github.com/lxc/incus/v6/cmd/generate-database/lex"
+	"github.com/lxc/incus/v6/shared/util"
 )
 
 // FiltersFromStmt parses all filtering statement defined for the given entity. It
@@ -374,6 +375,11 @@ func parseField(f *types.Var, structTag string, kind string, pkgName string) (*F
 		if err != nil {
 			return nil, fmt.Errorf("Parse 'db' structure tag: %w", err)
 		}
+
+		err = validateFieldConfig(config)
+		if err != nil {
+			return nil, fmt.Errorf("Invalid struct tag for field %q: %v", name, err)
+		}
 	}
 
 	// Ignore fields that are marked with `db:"omit"`.
@@ -440,3 +446,58 @@ func parseType(x types.Type, pkgName string) string {
 		return ""
 	}
 }
+
+func validateFieldConfig(config url.Values) error {
+	for tag, values := range config {
+		switch tag {
+		case
+			"sql",
+			"coalesce",
+			"join",
+			"leftjoin",
+			"joinon",
+			"omit":
+
+			_, err := exactlyOneValue(tag, values)
+			return err
+
+		case
+			"order",
+			"primary",
+			"ignore":
+
+			value, err := exactlyOneValue(tag, values)
+			if err != nil {
+				return err
+			}
+
+			if !util.IsTrue(value) && !util.IsFalse(value) {
+				return fmt.Errorf("Unexpected value %q for %q tag", value, tag)
+			}
+
+		case "marshal":
+			value, err := exactlyOneValue(tag, values)
+			if err != nil {
+				return err
+			}
+
+			if !util.IsTrue(value) && !util.IsFalse(value) && strings.ToLower(value) != "json" {
+				return fmt.Errorf("Unexpected value %q for %q tag", value, tag)
+			}
+		}
+	}
+
+	return nil
+}
+
+func exactlyOneValue(tag string, values []string) (string, error) {
+	if len(values) == 0 {
+		return "", fmt.Errorf("Missing value for %q tag", tag)
+	}
+
+	if len(values) > 1 {
+		return "", fmt.Errorf("More than one value for %q tag", tag)
+	}
+
+	return values[0], nil
+}

cmd/generate-database/file/boilerplate/boilerplate.go

@@ -3,6 +3,7 @@ package boilerplate
 import (
 	"context"
 	"database/sql"
+	"encoding/json"
 	"errors"
 	"fmt"
 )
@@ -127,6 +128,19 @@ func unmarshal(data string, v any) error {
 	return unmarshaler.UnmarshalDB(data)
 }
 
+func marshalJSON(v any) (string, error) {
+	marshalled, err := json.Marshal(v)
+	if err != nil {
+		return "", err
+	}
+
+	return string(marshalled), nil
+}
+
+func unmarshalJSON(data string, v any) error {
+	return json.Unmarshal([]byte(data), v)
+}
+
 // dest is a function that is expected to return the objects to pass to the
 // 'dest' argument of sql.Rows.Scan(). It is invoked by SelectObjects once per
 // yielded row, and it will be passed the index of the row being scanned.

cmd/generate-database/file/boilerplate/boilerplate_test.go

@@ -10,6 +10,8 @@ func Test(t *testing.T) {
 	_ = defaultMapErr
 	_ = marshal
 	_ = unmarshal
+	_ = marshalJSON
+	_ = unmarshalJSON
 	_ = selectObjects
 	_ = scan
 }

shared/util/boolean.go

@@ -10,6 +10,13 @@ func IsTrue(value string) bool {
 	return slices.Contains([]string{"true", "1", "yes", "on"}, strings.ToLower(value))
 }
 
+// IsNeitherFalseNorEmpty is true, if value is neither false nor empty,
+// which is the contrary to IsFalseOrEmpty.
+func IsNeitherFalseNorEmpty(value string) bool {
+	isFalseOrEmtpy := IsFalseOrEmpty(value)
+	return !isFalseOrEmtpy
+}
+
 // IsTrueOrEmpty returns true if value is empty or if IsTrue() returns true.
 func IsTrueOrEmpty(value string) bool {
 	return value == "" || IsTrue(value)