added Scan method in adaptor

go.mod

@@ -2,4 +2,7 @@ module github.com/datasage-io/datasage
 
 go 1.18
 
-require github.com/go-sql-driver/mysql v1.6.0
+require (
+	github.com/go-sql-driver/mysql v1.6.0
+	github.com/lib/pq v1.10.6
+)

go.sum

@@ -1,2 +1,4 @@
 github.com/go-sql-driver/mysql v1.6.0 h1:BCTh4TKNUYmOmMUcQ3IipzF5prigylS7XXjEkfCHuOE=
 github.com/go-sql-driver/mysql v1.6.0/go.mod h1:DCzpHaOWr8IXmIStZouvnhqoel9Qv2LBy8hT2VhHyBg=
+github.com/lib/pq v1.10.6 h1:jbk+ZieJ0D7EVGJYpL9QTz7/YW6UHbmdnZWYyK5cdBs=
+github.com/lib/pq v1.10.6/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=

src/adaptors/mysql.go

@@ -3,6 +3,7 @@ package adaptors
 import (
 	"database/sql"
 	"fmt"
+	"log"
 
 	_ "github.com/go-sql-driver/mysql"
 )
@@ -13,9 +14,9 @@ type Mysql struct {
 	Connc    *sql.DB
 }
 
-func NewMysqlClient(username, password, address, dbname string) (Mysql, error) {
+func NewMysqlClient(username, password, host string) (Mysql, error) {
 	//Create data source name with given information
-	dsn := fmt.Sprintf("%s:%s@tcp(%s)/%s", username, password, address, dbname)
+	dsn := fmt.Sprintf("%s:%s@tcp(%s)/", username, password, host)
 
 	//open connection with database
 	connc, err := sql.Open("mysql", dsn)
@@ -27,3 +28,96 @@ func NewMysqlClient(username, password, address, dbname string) (Mysql, error) {
 func (my *Mysql) Close() {
 	my.Connc.Close()
 }
+
+func (my Mysql) Scan() (DbMetaInfo, error) {
+	var dbMetaInfo DbMetaInfo
+
+	schemas, err := my.GetSchemaDetails()
+	if err != nil {
+		return DbMetaInfo{}, err
+	}
+
+	schemaData := []Schema{}
+	for _, sc := range schemas {
+		tables, err := my.GetTableNamesFromDB(sc)
+		if err != nil {
+			log.Println(err.Error())
+		}
+		tbData := []Table{}
+		for _, tb := range tables {
+			tbcol, err := my.GetTableDetails(sc, tb)
+			if err != nil {
+				log.Println(err.Error())
+			}
+			tbData = append(tbData, tbcol)
+		}
+		schemaData = append(schemaData, Schema{Name: sc, Tables: tbData})
+	}
+
+	dbMetaInfo.Schemas = schemaData
+	return dbMetaInfo, nil
+}
+
+func (mysql Mysql) GetSchemaDetails() ([]string, error) {
+
+	var schemaNames []string
+	rows, Qerr := mysql.Connc.Query("select SCHEMA_NAME from information_schema.schemata order by schema_name")
+	if Qerr != nil {
+		return schemaNames, Qerr
+	}
+	for rows.Next() {
+		var tmp string
+		if err := rows.Scan(&tmp); err != nil {
+			Qerr = err
+		} else {
+			schemaNames = append(schemaNames, tmp)
+		}
+	}
+	return schemaNames, Qerr
+}
+
+func (mysql Mysql) GetTableNamesFromDB(dbname string) ([]string, error) {
+
+	var tableNames []string
+	rows, Qerr := mysql.Connc.Query(`SELECT TABLE_NAME from information_schema.tables 
+									 WHERE table_type = 'BASE TABLE' and table_schema = ?`, dbname)
+	if Qerr != nil {
+		return tableNames, Qerr
+	}
+	for rows.Next() {
+		var tmp string
+		if err := rows.Scan(&tmp); err != nil {
+			Qerr = err
+		} else {
+			tableNames = append(tableNames, tmp)
+		}
+	}
+	return tableNames, Qerr
+}
+
+func (mysql Mysql) GetTableDetails(dbname string, tableName string) (Table, error) {
+	var tableInfo Table
+
+	tableInfo.Name = tableName
+
+	rows, Qerr := mysql.Connc.Query(`SELECT COLUMN_NAME as column_name, 
+											COLUMN_TYPE as column_type, 
+											COLUMN_COMMENT as column_comment 
+											from information_schema.columns 
+											where table_schema = ? and table_name = ?`, dbname, tableName)
+	if Qerr != nil {
+		return tableInfo, Qerr
+	}
+
+	for rows.Next() {
+		tempCol := Column{}
+		if err := rows.Scan(
+			&tempCol.ColumnName, &tempCol.ColumnType,
+			&tempCol.ColumnComment); err != nil {
+			Qerr = err
+		} else {
+			tableInfo.Cols = append(tableInfo.Cols, tempCol)
+		}
+	}
+	return tableInfo, Qerr
+}

src/adaptors/postgres.go

@@ -1 +1,128 @@
 package adaptors
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+
+	_ "github.com/lib/pq"
+)
+
+type Postgres struct {
+	ConecStr string
+	Connc    *sql.DB
+}
+
+//BUG: solve Postgres client connection string error
+func NewPostgresClient(username, password, host string) (Postgres, error) {
+
+	dsn := fmt.Sprintf("host=%s port=5432 dbname='postgres' user=%s password=%s sslmode=disable",
+		host, username, password)
+
+	connc, err := sql.Open("postgres", dsn)
+
+	return Postgres{ConecStr: dsn, Connc: connc}, err
+}
+
+func (pg Postgres) Close() error {
+	return pg.Connc.Close()
+}
+func (pg Postgres) Scan() (DbMetaInfo, error) {
+	var dbMetaInfo DbMetaInfo
+
+	schemas, err := pg.GetSchemaDetails()
+	if err != nil {
+		return DbMetaInfo{}, err
+	}
+
+	schemaData := []Schema{}
+	for _, sc := range schemas {
+		tables, err := pg.GetTableNamesFromDB(sc)
+		if err != nil {
+			log.Println(err.Error())
+		}
+		tbData := []Table{}
+		for _, tb := range tables {
+			tbcol, err := pg.GetTableDetails(sc, tb)
+			if err != nil {
+				log.Println(err.Error())
+			}
+			tbData = append(tbData, tbcol)
+		}
+		schemaData = append(schemaData, Schema{Name: sc, Tables: tbData})
+	}
+
+	dbMetaInfo.Schemas = schemaData
+	return dbMetaInfo, nil
+
+}
+func (pg Postgres) GetSchemaDetails() ([]string, error) {
+
+	var schemaNames []string
+	rows, Qerr := pg.Connc.Query("SELECT datname FROM pg_database")
+	if Qerr != nil {
+		return schemaNames, Qerr
+	}
+	for rows.Next() {
+		var tmp string
+		if err := rows.Scan(&tmp); err != nil {
+			Qerr = err
+		} else {
+			schemaNames = append(schemaNames, tmp)
+		}
+	}
+	return schemaNames, Qerr
+}
+
+func (pg Postgres) GetTableNamesFromDB(dbname string) ([]string, error) {
+
+	var tableNames []string
+	rows, Qerr := pg.Connc.Query(`SELECT table_name FROM information_schema.tables 
+								  WHERE table_schema='public' AND table_type = 'BASE TABLE' AND table_catalog=$1`, dbname)
+	if Qerr != nil {
+		return tableNames, Qerr
+	}
+	for rows.Next() {
+		var tmp string
+		if err := rows.Scan(&tmp); err != nil {
+			Qerr = err
+		} else {
+			tableNames = append(tableNames, tmp)
+		}
+	}
+	return tableNames, Qerr
+}
+
+func (pg Postgres) GetTableDetails(dbname string, tableName string) (Table, error) {
+	var tableInfo Table
+
+	tableInfo.Name = tableName
+
+	q := fmt.Sprintf(`
+		SELECT  column_name,
+			    data_type as column_type,
+			    col_description('public.%s'::regclass, ordinal_position)
+				from information_schema.columns where table_name=$1
+		`, tableName)
+
+	rows, Qerr := pg.Connc.Query(q, tableName)
+	if Qerr != nil {
+		return tableInfo, Qerr
+	}
+
+	for rows.Next() {
+		tempCol := Column{}
+		tempComment := sql.NullString{}
+		if err := rows.Scan(
+			&tempCol.ColumnName, &tempCol.ColumnType,
+			&tempComment); err != nil {
+			Qerr = err
+		} else {
+			if tempComment.Valid {
+				tempCol.ColumnComment = tempComment.String
+			}
+			tableInfo.Cols = append(tableInfo.Cols, tempCol)
+		}
+	}
+	return tableInfo, Qerr
+}

src/main.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"log"
+
+	"github.com/datasage-io/datasage/src/adaptors"
+)
+
+func main() {
+	adpt, err := adaptors.New(adaptors.AdaptorConfig{
+		Type:     "mysql",
+		Username: "appuser",
+		Password: "appuserpassword",
+		Host:     "localhost:3306"})
+
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+	info, err := adpt.Scan()
+
+	if err != nil {
+		log.Fatal(err.Error())
+	}
+
+	for _, sc := range info.Schemas {
+		log.Println("DB name:= ", sc.Name)
+
+		for _, tb := range sc.Tables {
+			log.Println("Table Name:= ", tb.Name)
+
+			for _, cols := range tb.Cols {
+				log.Println("columns:= ", cols)
+			}
+		}
+	}
+}