Simplify error handling in generator.

generator/internal/metadata/column_meta_data.go

@@ -142,13 +142,10 @@ func (c ColumnMetaData) GoModelTag(isPrimaryKey bool) string {
 	return ""
 }
 
-func getColumnsMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) ([]ColumnMetaData, error) {
+func getColumnsMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) []ColumnMetaData {
 
 	rows, err := db.Query(querySet.ListOfColumnsQuery(), schemaName, tableName)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 	defer rows.Close()
 
 	ret := []ColumnMetaData{}
@@ -157,19 +154,13 @@ func getColumnsMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableN
 		var name, isNullable, dataType, enumName string
 		var isUnsigned bool
 		err := rows.Scan(&name, &isNullable, &dataType, &enumName, &isUnsigned)
-
+		utils.PanicOnError(err)
-		if err != nil {
-			return nil, err
-		}
 
 		ret = append(ret, NewColumnMetaData(name, isNullable == "YES", dataType, enumName, isUnsigned))
 	}
 
 	err = rows.Err()
+	utils.PanicOnError(err)
 
-	if err != nil {
+	return ret
-		return nil, err
-	}
-
-	return ret, nil
 }

generator/internal/metadata/dialect_query_set.go

@@ -11,5 +11,5 @@ type DialectQuerySet interface {
 	ListOfColumnsQuery() string
 	ListOfEnumsQuery() string
 
-	GetEnumsMetaData(db *sql.DB, schemaName string) ([]MetaData, error)
+	GetEnumsMetaData(db *sql.DB, schemaName string) []MetaData
 }

generator/internal/metadata/schema_meta_data.go

@@ -3,6 +3,7 @@ package metadata
 import (
 	"database/sql"
 	"fmt"
+	"github.com/go-jet/jet/internal/utils"
 )
 
 // SchemaMetaData struct
@@ -23,25 +24,11 @@ const (
 )
 
 // GetSchemaMetaData returns schema information from db connection.
-func GetSchemaMetaData(db *sql.DB, schemaName string, querySet DialectQuerySet) (schemaInfo SchemaMetaData, err error) {
+func GetSchemaMetaData(db *sql.DB, schemaName string, querySet DialectQuerySet) (schemaInfo SchemaMetaData) {
 
-	schemaInfo.TablesMetaData, err = getTablesMetaData(db, querySet, schemaName, baseTable)
+	schemaInfo.TablesMetaData = getTablesMetaData(db, querySet, schemaName, baseTable)
-
+	schemaInfo.ViewsMetaData = getTablesMetaData(db, querySet, schemaName, view)
-	if err != nil {
+	schemaInfo.EnumsMetaData = querySet.GetEnumsMetaData(db, schemaName)
-		return
-	}
-
-	schemaInfo.ViewsMetaData, err = getTablesMetaData(db, querySet, schemaName, view)
-
-	if err != nil {
-		return
-	}
-
-	schemaInfo.EnumsMetaData, err = querySet.GetEnumsMetaData(db, schemaName)
-
-	if err != nil {
-		return
-	}
 
 	fmt.Println("	FOUND", len(schemaInfo.TablesMetaData), "table(s),", len(schemaInfo.ViewsMetaData), "view(s),",
 		len(schemaInfo.EnumsMetaData), "enum(s)")
@@ -49,13 +36,10 @@ func GetSchemaMetaData(db *sql.DB, schemaName string, querySet DialectQuerySet)
 	return
 }
 
-func getTablesMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableType string) ([]MetaData, error) {
+func getTablesMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableType string) []MetaData {
 
 	rows, err := db.Query(querySet.ListOfTablesQuery(), schemaName, tableType)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 	defer rows.Close()
 
 	ret := []MetaData{}
@@ -63,24 +47,15 @@ func getTablesMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableTy
 		var tableName string
 
 		err = rows.Scan(&tableName)
-		if err != nil {
+		utils.PanicOnError(err)
-			return nil, err
-		}
 
-		tableInfo, err := GetTableMetaData(db, querySet, schemaName, tableName)
+		tableInfo := GetTableMetaData(db, querySet, schemaName, tableName)
-
-		if err != nil {
-			return nil, err
-		}
 
 		ret = append(ret, tableInfo)
 	}
 
 	err = rows.Err()
+	utils.PanicOnError(err)
 
-	if err != nil {
+	return ret
-		return nil, err
-	}
-
-	return ret, nil
 }

generator/internal/metadata/table_meta_data.go

@@ -68,45 +68,31 @@ func (t TableMetaData) GoStructName() string {
 }
 
 // GetTableMetaData returns table info metadata
-func GetTableMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) (tableInfo TableMetaData, err error) {
+func GetTableMetaData(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) (tableInfo TableMetaData) {
 
 	tableInfo.SchemaName = schemaName
 	tableInfo.name = tableName
 
-	tableInfo.PrimaryKeys, err = getPrimaryKeys(db, querySet, schemaName, tableName)
+	tableInfo.PrimaryKeys = getPrimaryKeys(db, querySet, schemaName, tableName)
-	if err != nil {
+	tableInfo.Columns = getColumnsMetaData(db, querySet, schemaName, tableName)
-		return
-	}
-
-	tableInfo.Columns, err = getColumnsMetaData(db, querySet, schemaName, tableName)
-
-	if err != nil {
-		return
-	}
 
 	return
 }
 
-func getPrimaryKeys(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) (map[string]bool, error) {
+func getPrimaryKeys(db *sql.DB, querySet DialectQuerySet, schemaName, tableName string) map[string]bool {
 
 	rows, err := db.Query(querySet.PrimaryKeysQuery(), schemaName, tableName)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 
 	primaryKeyMap := map[string]bool{}
 
 	for rows.Next() {
 		primaryKey := ""
 		err := rows.Scan(&primaryKey)
-
+		utils.PanicOnError(err)
-		if err != nil {
-			return nil, err
-		}
 
 		primaryKeyMap[primaryKey] = true
 	}
 
-	return primaryKeyMap, nil
+	return primaryKeyMap
 }

generator/internal/template/generate.go

@@ -12,106 +12,61 @@ import (
 )
 
 // GenerateFiles generates Go files from tables and enums metadata
-func GenerateFiles(destDir string, schemaInfo metadata.SchemaMetaData, dialect jet.Dialect) error {
+func GenerateFiles(destDir string, schemaInfo metadata.SchemaMetaData, dialect jet.Dialect) {
 	if schemaInfo.IsEmpty() {
-		return nil
+		return
 	}
 
 	fmt.Println("Destination directory:", destDir)
 	fmt.Println("Cleaning up destination directory...")
 	err := utils.CleanUpGeneratedFiles(destDir)
+	utils.PanicOnError(err)
 
-	if err != nil {
+	generateSQLBuilderFiles(destDir, "table", tableSQLBuilderTemplate, schemaInfo.TablesMetaData, dialect)
-		return err
+	generateSQLBuilderFiles(destDir, "view", tableSQLBuilderTemplate, schemaInfo.ViewsMetaData, dialect)
-	}
+	generateSQLBuilderFiles(destDir, "enum", enumSQLBuilderTemplate, schemaInfo.EnumsMetaData, dialect)
 
-	err = generateSQLBuilderFiles(destDir, "table", tableSQLBuilderTemplate, schemaInfo.TablesMetaData, dialect)
+	generateModelFiles(destDir, "table", tableModelTemplate, schemaInfo.TablesMetaData, dialect)
-
+	generateModelFiles(destDir, "view", tableModelTemplate, schemaInfo.ViewsMetaData, dialect)
-	if err != nil {
+	generateModelFiles(destDir, "enum", enumModelTemplate, schemaInfo.EnumsMetaData, dialect)
-		return err
-	}
-
-	err = generateSQLBuilderFiles(destDir, "view", tableSQLBuilderTemplate, schemaInfo.ViewsMetaData, dialect)
-
-	if err != nil {
-		return err
-	}
-
-	err = generateSQLBuilderFiles(destDir, "enum", enumSQLBuilderTemplate, schemaInfo.EnumsMetaData, dialect)
-
-	if err != nil {
-		return err
-	}
-
-	err = generateModelFiles(destDir, "table", tableModelTemplate, schemaInfo.TablesMetaData, dialect)
-
-	if err != nil {
-		return err
-	}
-
-	err = generateModelFiles(destDir, "view", tableModelTemplate, schemaInfo.ViewsMetaData, dialect)
-
-	if err != nil {
-		return err
-	}
-
-	err = generateModelFiles(destDir, "enum", enumModelTemplate, schemaInfo.EnumsMetaData, dialect)
-
-	if err != nil {
-		return err
-	}
 
 	fmt.Println("Done")
-
-	return nil
 }
 
-func generateSQLBuilderFiles(destDir, fileTypes, sqlBuilderTemplate string, metaData []metadata.MetaData, dialect jet.Dialect) error {
+func generateSQLBuilderFiles(destDir, fileTypes, sqlBuilderTemplate string, metaData []metadata.MetaData, dialect jet.Dialect) {
 	if len(metaData) == 0 {
-		return nil
+		return
 	}
 	fmt.Printf("Generating %s sql builder files...\n", fileTypes)
-	return generateGoFiles(destDir, fileTypes, sqlBuilderTemplate, metaData, dialect)
+	generateGoFiles(destDir, fileTypes, sqlBuilderTemplate, metaData, dialect)
 }
 
-func generateModelFiles(destDir, fileTypes, modelTemplate string, metaData []metadata.MetaData, dialect jet.Dialect) error {
+func generateModelFiles(destDir, fileTypes, modelTemplate string, metaData []metadata.MetaData, dialect jet.Dialect) {
 	if len(metaData) == 0 {
-		return nil
+		return
 	}
 	fmt.Printf("Generating %s model files...\n", fileTypes)
-	return generateGoFiles(destDir, "model", modelTemplate, metaData, dialect)
+	generateGoFiles(destDir, "model", modelTemplate, metaData, dialect)
 }
 
-func generateGoFiles(dirPath, packageName string, template string, metaDataList []metadata.MetaData, dialect jet.Dialect) error {
+func generateGoFiles(dirPath, packageName string, template string, metaDataList []metadata.MetaData, dialect jet.Dialect) {
 	modelDirPath := filepath.Join(dirPath, packageName)
 
 	err := utils.EnsureDirPath(modelDirPath)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return err
-	}
 
 	autoGenWarning, err := GenerateTemplate(autoGenWarningTemplate, nil, dialect)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return err
-	}
 
 	for _, metaData := range metaDataList {
 		text, err := GenerateTemplate(template, metaData, dialect, map[string]interface{}{"package": packageName})
-
+		utils.PanicOnError(err)
-		if err != nil {
-			return err
-		}
 
 		err = utils.SaveGoFile(modelDirPath, utils.ToGoFileName(metaData.Name()), append(autoGenWarning, text...))
-
+		utils.PanicOnError(err)
-		if err != nil {
-			return err
-		}
 	}
 
-	return nil
+	return
 }
 
 // GenerateTemplate generates template with template text and template data.

generator/mysql/mysql_generator.go

@@ -22,50 +22,34 @@ type DBConnection struct {
 }
 
 // Generate generates jet files at destination dir from database connection details
-func Generate(destDir string, dbConn DBConnection) error {
+func Generate(destDir string, dbConn DBConnection) (err error) {
-	db, err := openConnection(dbConn)
+	defer utils.ErrorCatch(&err)
-	if err != nil {
+
-		return err
+	db := openConnection(dbConn)
-	}
 	defer utils.DBClose(db)
 
 	fmt.Println("Retrieving database information...")
 	// No schemas in MySQL
-	dbInfo, err := metadata.GetSchemaMetaData(db, dbConn.DBName, &mySqlQuerySet{})
+	dbInfo := metadata.GetSchemaMetaData(db, dbConn.DBName, &mySqlQuerySet{})
-
-	if err != nil {
-		return err
-	}
 
 	genPath := path.Join(destDir, dbConn.DBName)
 
-	err = template.GenerateFiles(genPath, dbInfo, mysql.Dialect)
+	template.GenerateFiles(genPath, dbInfo, mysql.Dialect)
-
-	if err != nil {
-		return err
-	}
 
 	return nil
 }
 
-func openConnection(dbConn DBConnection) (*sql.DB, error) {
+func openConnection(dbConn DBConnection) *sql.DB {
 	var connectionString = fmt.Sprintf("%s:%s@tcp(%s:%d)/%s", dbConn.User, dbConn.Password, dbConn.Host, dbConn.Port, dbConn.DBName)
 	if dbConn.Params != "" {
 		connectionString += "?" + dbConn.Params
 	}
-	db, err := sql.Open("mysql", connectionString)
-
 	fmt.Println("Connecting to MySQL database: " + connectionString)
-
+	db, err := sql.Open("mysql", connectionString)
-	if err != nil {
+	utils.PanicOnError(err)
-		return nil, err
-	}
 
 	err = db.Ping()
+	utils.PanicOnError(err)
 
-	if err != nil {
+	return db
-		return nil, err
-	}
-
-	return db, nil
 }

generator/mysql/query_set.go

@@ -3,6 +3,7 @@ package mysql
 import (
 	"database/sql"
 	"github.com/go-jet/jet/generator/internal/metadata"
+	"github.com/go-jet/jet/internal/utils"
 	"strings"
 )
 
@@ -50,13 +51,10 @@ WHERE c.table_schema = ? AND DATA_TYPE = 'enum';
 `
 }
 
-func (m *mySqlQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]metadata.MetaData, error) {
+func (m *mySqlQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) []metadata.MetaData {
 
 	rows, err := db.Query(m.ListOfEnumsQuery(), schemaName)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 	defer rows.Close()
 
 	ret := []metadata.MetaData{}
@@ -65,9 +63,7 @@ func (m *mySqlQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]metad
 		var enumName string
 		var enumValues string
 		err = rows.Scan(&enumName, &enumValues)
-		if err != nil {
+		utils.PanicOnError(err)
-			return nil, err
-		}
 
 		enumValues = strings.Replace(enumValues[1:len(enumValues)-1], "'", "", -1)
 
@@ -78,11 +74,8 @@ func (m *mySqlQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]metad
 	}
 
 	err = rows.Err()
+	utils.PanicOnError(err)
 
-	if err != nil {
+	return ret
-		return nil, err
-	}
-
-	return ret, nil
 
 }

generator/postgres/postgres_generator.go

@@ -25,31 +25,20 @@ type DBConnection struct {
 }
 
 // Generate generates jet files at destination dir from database connection details
-func Generate(destDir string, dbConn DBConnection) error {
+func Generate(destDir string, dbConn DBConnection) (err error) {
+	defer utils.ErrorCatch(&err)
 
 	db, err := openConnection(dbConn)
+	utils.PanicOnError(err)
 	defer utils.DBClose(db)
 
-	if err != nil {
-		return err
-	}
-
 	fmt.Println("Retrieving schema information...")
-	schemaInfo, err := metadata.GetSchemaMetaData(db, dbConn.SchemaName, &postgresQuerySet{})
+	schemaInfo := metadata.GetSchemaMetaData(db, dbConn.SchemaName, &postgresQuerySet{})
-
-	if err != nil {
-		return err
-	}
 
 	genPath := path.Join(destDir, dbConn.DBName, dbConn.SchemaName)
+	template.GenerateFiles(genPath, schemaInfo, postgres.Dialect)
 
-	err = template.GenerateFiles(genPath, schemaInfo, postgres.Dialect)
+	return
-
-	if err != nil {
-		return err
-	}
-
-	return nil
 }
 
 func openConnection(dbConn DBConnection) (*sql.DB, error) {

generator/postgres/query_set.go

@@ -3,6 +3,7 @@ package postgres
 import (
 	"database/sql"
 	"github.com/go-jet/jet/generator/internal/metadata"
+	"github.com/go-jet/jet/internal/utils"
 )
 
 // postgresQuerySet is dialect query set for PostgreSQL
@@ -45,12 +46,9 @@ WHERE n.nspname = $1
 ORDER BY n.nspname, t.typname, e.enumsortorder;`
 }
 
-func (p *postgresQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]metadata.MetaData, error) {
+func (p *postgresQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) []metadata.MetaData {
 	rows, err := db.Query(p.ListOfEnumsQuery(), schemaName)
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 	defer rows.Close()
 
 	enumsInfosMap := map[string][]string{}
@@ -58,9 +56,7 @@ func (p *postgresQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]me
 		var enumName string
 		var enumValue string
 		err = rows.Scan(&enumName, &enumValue)
-		if err != nil {
+		utils.PanicOnError(err)
-			return nil, err
-		}
 
 		enumValues := enumsInfosMap[enumName]
 
@@ -70,10 +66,7 @@ func (p *postgresQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]me
 	}
 
 	err = rows.Err()
-
+	utils.PanicOnError(err)
-	if err != nil {
-		return nil, err
-	}
 
 	ret := []metadata.MetaData{}
 
@@ -84,5 +77,5 @@ func (p *postgresQuerySet) GetEnumsMetaData(db *sql.DB, schemaName string) ([]me
 		})
 	}
 
-	return ret, nil
+	return ret
 }

internal/utils/utils.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"database/sql"
+	"fmt"
 	"github.com/go-jet/jet/internal/3rdparty/snaker"
 	"go/format"
 	"os"
@@ -146,3 +147,20 @@ func PanicOnError(err error) {
 		panic(err)
 	}
 }
+
+// ErrorCatch is used in defer to recover from panics and to set err
+func ErrorCatch(err *error) {
+	recovered := recover()
+
+	if recovered == nil {
+		return
+	}
+
+	recoveredErr, isError := recovered.(error)
+
+	if isError {
+		*err = recoveredErr
+	} else {
+		*err = fmt.Errorf("%v", recovered)
+	}
+}