Add Migrator.LoadMigrations

migrate/migrate.go

@@ -3,6 +3,9 @@ package migrate
 import (
 	"fmt"
 	"github.com/JackC/pgx"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
 )
 
 type BadVersionError string
@@ -19,6 +22,14 @@ func (e IrreversibleMigrationError) Error() string {
 	return fmt.Sprintf("Irreversible migration: %d - %s", e.m.Sequence, e.m.Name)
 }
 
+type NoMigrationsFoundError struct {
+	Path string
+}
+
+func (e NoMigrationsFoundError) Error() string {
+	return fmt.Sprintf("No migrations found at %s", e.Path)
+}
+
 type Migration struct {
 	Sequence int32
 	Name     string
@@ -40,6 +51,33 @@ func NewMigrator(conn *pgx.Connection, versionTable string) (m *Migrator, err er
 	return
 }
 
+func (m *Migrator) LoadMigrations(path string) error {
+	paths, err := filepath.Glob(filepath.Join(path, "*.sql"))
+	if err != nil {
+		return err
+	}
+	if len(paths) == 0 {
+		return NoMigrationsFoundError{Path: path}
+	}
+
+	for _, p := range paths {
+		body, err := ioutil.ReadFile(p)
+		if err != nil {
+			return err
+		}
+
+		pieces := strings.SplitN(string(body), "---- create above / drop below ----", 2)
+		var upSQL, downSQL string
+		upSQL = strings.TrimSpace(pieces[0])
+		if len(pieces) == 2 {
+			downSQL = strings.TrimSpace(pieces[1])
+		}
+		m.AppendMigration(filepath.Base(p), upSQL, downSQL)
+	}
+
+	return nil
+}
+
 func (m *Migrator) AppendMigration(name, upSQL, downSQL string) {
 	m.Migrations = append(m.Migrations, &Migration{Sequence: int32(len(m.Migrations)) + 1, Name: name, UpSQL: upSQL, DownSQL: downSQL})
 	return

migrate/migrate_test.go

@@ -102,6 +102,41 @@ func (s *MigrateSuite) TestAppendMigration(c *C) {
 	c.Assert(m.Migrations[0].DownSQL, Equals, downSQL)
 }
 
+func (s *MigrateSuite) TestLoadMigrationsMissingDirectory(c *C) {
+	m := s.createEmptyMigrator(c)
+	err := m.LoadMigrations("testdata/missing")
+	c.Assert(err, ErrorMatches, "No migrations found at testdata/missing")
+}
+
+func (s *MigrateSuite) TestLoadMigrationsEmptyDirectory(c *C) {
+	m := s.createEmptyMigrator(c)
+	err := m.LoadMigrations("testdata/empty")
+	c.Assert(err, ErrorMatches, "No migrations found at testdata/empty")
+}
+
+func (s *MigrateSuite) TestLoadMigrations(c *C) {
+	m := s.createEmptyMigrator(c)
+	err := m.LoadMigrations("testdata/sample")
+	c.Assert(err, IsNil)
+	c.Assert(m.Migrations, HasLen, 3)
+
+	c.Check(m.Migrations[0].Name, Equals, "001_create_t1.sql")
+	c.Check(m.Migrations[0].UpSQL, Equals, `create table t1(
+  id serial primary key
+);`)
+	c.Check(m.Migrations[0].DownSQL, Equals, "drop table t1;")
+
+	c.Check(m.Migrations[1].Name, Equals, "002_create_t2.sql")
+	c.Check(m.Migrations[1].UpSQL, Equals, `create table t2(
+  id serial primary key
+);`)
+	c.Check(m.Migrations[1].DownSQL, Equals, "drop table t2;")
+
+	c.Check(m.Migrations[2].Name, Equals, "003_irreversible.sql")
+	c.Check(m.Migrations[2].UpSQL, Equals, "drop table t2;")
+	c.Check(m.Migrations[2].DownSQL, Equals, "")
+}
+
 func (s *MigrateSuite) TestMigrate(c *C) {
 	m := s.createSampleMigrator(c)
 

migrate/testdata/002_create_t2.sql

@@ -0,0 +1,7 @@
+create table t2(
+  id serial primary key
+);
+
+---- create above / drop below ----
+
+drop table t2;

migrate/testdata/sample/001_create_t1.sql

@@ -0,0 +1,7 @@
+create table t1(
+  id serial primary key
+);
+
+---- create above / drop below ----
+
+drop table t1;

migrate/testdata/sample/002_create_t2.sql

@@ -0,0 +1,7 @@
+create table t2(
+  id serial primary key
+);
+
+---- create above / drop below ----
+
+drop table t2;

migrate/testdata/sample/003_irreversible.sql

@@ -0,0 +1 @@
+drop table t2;