Files
go-migrate/cmd/go_migrate/inspect-columns.go

280 lines
7.0 KiB
Go

package main
import (
"context"
"database/sql"
"errors"
"fmt"
"strings"
"sync"
"time"
"github.com/jackc/pgx/v5/pgxpool"
_ "github.com/microsoft/go-mssqldb"
log "github.com/sirupsen/logrus"
)
func GetUnifiedType(systemType string) string {
systemType = strings.ToLower(systemType)
if systemType == "varchar" || systemType == "char" || systemType == "nvarchar" || systemType == "nchar" || systemType == "text" || systemType == "ntext" {
return "STRING"
}
if systemType == "int" || systemType == "int4" || systemType == "integer" || systemType == "smallint" || systemType == "int2" || systemType == "bigint" || systemType == "int8" || systemType == "tinyint" {
return "INTEGER"
}
if systemType == "decimal" || systemType == "numeric" {
return "DECIMAL"
}
if systemType == "float" || systemType == "real" || systemType == "double precision" {
return "FLOAT"
}
if systemType == "bit" || systemType == "boolean" {
return "BOOLEAN"
}
if systemType == "date" {
return "DATE"
}
if systemType == "time" || systemType == "time without time zone" {
return "TIME"
}
if systemType == "datetime" || systemType == "datetime2" || systemType == "timestamp" || systemType == "timestamptz" || systemType == "timestamp with time zone" {
return "TIMESTAMP"
}
if systemType == "binary" || systemType == "varbinary" || systemType == "image" || systemType == "bytea" {
return "BINARY"
}
if systemType == "uniqueidentifier" || systemType == "uuid" {
return "UUID"
}
if systemType == "json" {
return "JSON"
}
if systemType == "geometry" || systemType == "geography" {
return "GEOMETRY"
}
return strings.ToUpper(systemType)
}
func MapPostgresColumn(column ColumnType, maxLength *int64, precision *int64, scale *int64) ColumnType {
stringTypes := map[string]bool{
"varchar": true, "char": true, "character": true, "text": true, "character varying": true,
}
decimalTypes := map[string]bool{
"decimal": true, "numeric": true,
}
if stringTypes[column.systemType] {
if maxLength != nil {
column.maxLength = *maxLength
column.hasMaxLength = true
} else {
column.maxLength = -1
column.hasMaxLength = false
}
column.hasPrecisionScale = false
column.precision = -1
column.scale = -1
} else if decimalTypes[column.systemType] {
column.hasMaxLength = false
column.maxLength = -1
if precision != nil && scale != nil {
column.precision = *precision
column.scale = *scale
column.hasPrecisionScale = true
} else {
column.precision = -1
column.scale = -1
column.hasPrecisionScale = false
}
} else {
column.hasMaxLength = false
column.maxLength = -1
column.hasPrecisionScale = false
column.precision = -1
column.scale = -1
}
column.unifiedType = GetUnifiedType(column.systemType)
return column
}
func GetColumnTypesPostgres(db *pgxpool.Pool, migrationJob MigrationJob) ([]ColumnType, error) {
query := `
SELECT
c.column_name AS name,
c.data_type AS user_type,
c.udt_name AS system_type,
(CASE WHEN c.is_nullable = 'YES' THEN TRUE ELSE FALSE END) AS nullable,
c.character_maximum_length AS max_length,
c.numeric_precision AS precision,
c.numeric_scale AS scale
FROM information_schema.columns c
WHERE c.table_schema = $1 AND c.table_name = $2
ORDER BY c.ordinal_position;
`
ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
rows, err := db.Query(ctx, query, migrationJob.Schema, migrationJob.Table)
if err != nil {
return nil, fmt.Errorf("Error querying column types: %w", err)
}
defer rows.Close()
var colTypes []ColumnType
for rows.Next() {
var column ColumnType
var scanMaxLength *int64
var scanPrecision *int64
var scanScale *int64
if err := rows.Scan(
&column.name,
&column.userType,
&column.systemType,
&column.nullable,
&scanMaxLength,
&scanPrecision,
&scanScale,
); err != nil {
return nil, fmt.Errorf("Error scanning column type results: %w", err)
}
colTypes = append(colTypes, MapPostgresColumn(column, scanMaxLength, scanPrecision, scanScale))
}
return colTypes, nil
}
func MapMssqlColumn(column ColumnType) ColumnType {
stringTypes := map[string]bool{
"varchar": true, "char": true, "nvarchar": true, "nchar": true, "text": true, "ntext": true,
}
decimalTypes := map[string]bool{
"decimal": true, "numeric": true,
}
if stringTypes[column.systemType] {
column.hasMaxLength = true
if column.systemType == "nvarchar" || column.systemType == "nchar" {
if column.maxLength > 0 {
column.maxLength = column.maxLength / 2
}
}
column.hasPrecisionScale = false
column.precision = -1
column.scale = -1
} else if decimalTypes[column.systemType] {
column.hasMaxLength = false
column.maxLength = -1
column.hasPrecisionScale = true
} else {
column.hasMaxLength = false
column.maxLength = -1
column.hasPrecisionScale = false
column.precision = -1
column.scale = -1
}
column.unifiedType = GetUnifiedType(column.systemType)
return column
}
func GetColumnTypesMssql(db *sql.DB, migrationJob MigrationJob) ([]ColumnType, error) {
query := `
SELECT
c.name AS name,
t.name AS user_type,
CASE WHEN t.is_user_defined = 0 THEN t.name ELSE bt.name END AS system_type,
c.is_nullable AS nullable,
c.max_length AS max_length,
c.precision AS precision,
c.scale AS scale
FROM sys.columns c
JOIN sys.types t ON c.user_type_id = t.user_type_id
LEFT JOIN sys.types bt ON t.is_user_defined = 1 AND bt.user_type_id = t.system_type_id
JOIN sys.tables st ON c.object_id = st.object_id
JOIN sys.schemas s ON st.schema_id = s.schema_id
WHERE s.name = @schema AND st.name = @table
ORDER BY c.column_id;
`
ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
defer cancel()
rows, err := db.QueryContext(ctx, query, sql.Named("schema", migrationJob.Schema), sql.Named("table", migrationJob.Table))
if err != nil {
return nil, fmt.Errorf("Error querying column types: %w", err)
}
defer rows.Close()
var colTypes []ColumnType
for rows.Next() {
var column ColumnType
if err := rows.Scan(
&column.name,
&column.userType,
&column.systemType,
&column.nullable,
&column.maxLength,
&column.precision,
&column.scale,
); err != nil {
return nil, fmt.Errorf("Error scanning column type results: %W", err)
}
colTypes = append(colTypes, MapMssqlColumn(column))
}
return colTypes, nil
}
func GetColumnTypes(sourceDb *sql.DB, targetDb *pgxpool.Pool, migrationJob MigrationJob) ([]ColumnType, []ColumnType, error) {
var sourceDbErr error
var targetDbErr error
var sourceColTypes []ColumnType
var targetColTypes []ColumnType
var wg sync.WaitGroup
wg.Go(func() {
sourceColTypes, sourceDbErr = GetColumnTypesMssql(sourceDb, migrationJob)
if sourceDbErr != nil {
log.Error("Error (sourceDb): ", sourceDbErr)
}
})
wg.Go(func() {
targetColTypes, targetDbErr = GetColumnTypesPostgres(targetDb, migrationJob)
if targetDbErr != nil {
log.Error("Error (targetDb): ", targetDbErr)
}
})
wg.Wait()
if sourceDbErr != nil || targetDbErr != nil {
return nil, nil, errors.New("Error querying column types")
}
return sourceColTypes, targetColTypes, nil
}