Allow migrations to target a specific database (#62)

* Ensure current non-suffixed migrations are executed for every supported DB type.

cockroach.go

@@ -30,6 +30,10 @@ type cockroach struct {
 	ConnectionDetails *ConnectionDetails
 }
 
+func (p *cockroach) Name() string {
+	return "cockroach"
+}
+
 func (p *cockroach) Details() *ConnectionDetails {
 	return p.ConnectionDetails
 }

dialect.go

@@ -16,6 +16,7 @@ func init() {
 }
 
 type dialect interface {
+	Name() string
 	URL() string
 	MigrationURL() string
 	Details() *ConnectionDetails

file_migrator.go

@@ -2,6 +2,7 @@ package pop
 
 import (
 	"bytes"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
@@ -48,12 +49,22 @@ func (fm *FileMigrator) findMigrations() error {
 				return nil
 			}
 			m := matches[0]
+			var dbType string
+			if m[3] == "" {
+				dbType = "all"
+			} else {
+				dbType = m[3][1:]
+				if !DialectSupported(dbType) {
+					return fmt.Errorf("unsupported dialect %s", dbType)
+				}
+			}
 			mf := Migration{
 				Path:      p,
 				Version:   m[1],
 				Name:      m[2],
-				Direction: m[3],
-				Type:      m[4],
+				DBType:    dbType,
+				Direction: m[4],
+				Type:      m[5],
 				Runner: func(mf Migration, tx *Connection) error {
 					f, err := os.Open(p)
 					if err != nil {

migration_box.go

@@ -1,6 +1,8 @@
 package pop
 
 import (
+	"fmt"
+
 	"github.com/gobuffalo/packr"
 	"github.com/pkg/errors"
 )
@@ -39,12 +41,22 @@ func (fm *MigrationBox) findMigrations() error {
 			return nil
 		}
 		m := matches[0]
+		var dbType string
+		if m[3] == "" {
+			dbType = "all"
+		} else {
+			dbType = m[3][1:]
+			if !DialectSupported(dbType) {
+				return fmt.Errorf("unsupported dialect %s", dbType)
+			}
+		}
 		mf := Migration{
 			Path:      p,
 			Version:   m[1],
 			Name:      m[2],
-			Direction: m[3],
-			Type:      m[4],
+			DBType:    dbType,
+			Direction: m[4],
+			Type:      m[5],
 			Runner: func(mf Migration, tx *Connection) error {
 				content, err := migrationContent(mf, tx, f)
 				if err != nil {

migration_box_test.go

@@ -0,0 +1,21 @@
+package pop_test
+
+import (
+	"testing"
+
+	"github.com/gobuffalo/packr"
+
+	"github.com/gobuffalo/pop"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_MigrationBox(t *testing.T) {
+	r := require.New(t)
+
+	b, err := pop.NewMigrationBox(packr.NewBox("./migrations/multiple"), PDB)
+	r.NoError(err)
+	r.Equal(3, len(b.Migrations["up"]))
+	r.Equal("mysql", b.Migrations["up"][0].DBType)
+	r.Equal("postgres", b.Migrations["up"][1].DBType)
+	r.Equal("all", b.Migrations["up"][2].DBType)
+}

migration_info.go

@@ -14,6 +14,8 @@ type Migration struct {
 	Direction string
 	// Type of migration (sql)
 	Type string
+	// DB type (all|postgres|mysql...)
+	DBType string
 	// Runner function to run/execute the migration
 	Runner func(Migration, *Connection) error
 }

migrator.go

@@ -12,7 +12,7 @@ import (
 	"github.com/pkg/errors"
 )
 
-var mrx = regexp.MustCompile("(\\d+)_(.+)\\.(up|down)\\.(sql|fizz)")
+var mrx = regexp.MustCompile(`(\d+)_([^\.]+)(\.[a-z]+)?\.(up|down)\.(sql|fizz)`)
 
 // NewMigrator returns a new "blank" migrator. It is recommended
 // to use something like MigrationBox or FileMigrator. A "blank"
@@ -45,6 +45,10 @@ func (m Migrator) Up() error {
 		mfs := m.Migrations["up"]
 		sort.Sort(mfs)
 		for _, mi := range mfs {
+			if mi.DBType != "all" && mi.DBType != c.Dialect.Name() {
+				// Skip migration for non-matching dialect
+				continue
+			}
 			exists, err := c.Where("version = ?", mi.Version).Exists("schema_migration")
 			if err != nil {
 				return errors.Wrapf(err, "problem checking for migration version %s", mi.Version)

mysql.go

@@ -22,6 +22,10 @@ type mysql struct {
 	ConnectionDetails *ConnectionDetails
 }
 
+func (m *mysql) Name() string {
+	return "mysql"
+}
+
 func (m *mysql) Details() *ConnectionDetails {
 	return m.ConnectionDetails
 }

pop.go

@@ -8,6 +8,7 @@ import (
 	"github.com/fatih/color"
 )
 
+// AvailableDialects lists the available database dialects
 var AvailableDialects = []string{"postgres", "mysql", "cockroach"}
 
 // Debug mode, to toggle verbose log traces
@@ -38,3 +39,13 @@ var Log = func(s string, args ...interface{}) {
 		logger.Println(s)
 	}
 }
+
+// DialectSupported checks support for the given database dialect
+func DialectSupported(d string) bool {
+	for _, ad := range AvailableDialects {
+		if ad == d {
+			return true
+		}
+	}
+	return false
+}

postgresql.go

@@ -29,6 +29,10 @@ type postgresql struct {
 	ConnectionDetails *ConnectionDetails
 }
 
+func (p *postgresql) Name() string {
+	return "postgresql"
+}
+
 func (p *postgresql) Details() *ConnectionDetails {
 	return p.ConnectionDetails
 }

sqlite.go

@@ -33,6 +33,10 @@ type sqlite struct {
 	ConnectionDetails *ConnectionDetails
 }
 
+func (m *sqlite) Name() string {
+	return "sqlite3"
+}
+
 func (m *sqlite) Details() *ConnectionDetails {
 	return m.ConnectionDetails
 }