Initial commit

commands.go

@@ -0,0 +1,242 @@
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"github.com/adrianmacneil/dbmate/driver"
+	"github.com/adrianmacneil/dbmate/driver/shared"
+	"github.com/codegangsta/cli"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"path/filepath"
+	"regexp"
+	"time"
+)
+
+// CreateCommand creates the current database
+func CreateCommand(ctx *cli.Context) error {
+	u, err := GetDatabaseURL()
+	if err != nil {
+		return err
+	}
+
+	drv, err := driver.Get(u.Scheme)
+	if err != nil {
+		return err
+	}
+
+	return drv.CreateDatabase(u)
+}
+
+// DropCommand drops the current database (if it exists)
+func DropCommand(ctx *cli.Context) error {
+	u, err := GetDatabaseURL()
+	if err != nil {
+		return err
+	}
+
+	drv, err := driver.Get(u.Scheme)
+	if err != nil {
+		return err
+	}
+
+	return drv.DropDatabase(u)
+}
+
+const migrationTemplate = "-- migrate:up\n\n\n-- migrate:down\n\n"
+
+// NewCommand creates a new migration file
+func NewCommand(ctx *cli.Context) error {
+	// new migration name
+	timestamp := time.Now().UTC().Format("20060102150405")
+	name := ctx.Args().First()
+	if name == "" {
+		return fmt.Errorf("Please specify a name for the new migration.")
+	}
+	name = fmt.Sprintf("%s_%s.sql", timestamp, name)
+
+	// create migrations dir if missing
+	migrationsDir := ctx.GlobalString("migrations-dir")
+	if err := os.MkdirAll(migrationsDir, 0755); err != nil {
+		return fmt.Errorf("Unable to create directory `%s`.", migrationsDir)
+	}
+
+	// check file does not already exist
+	path := filepath.Join(migrationsDir, name)
+	fmt.Printf("Creating migration: %s\n", path)
+
+	if _, err := os.Stat(path); !os.IsNotExist(err) {
+		return fmt.Errorf("File already exists")
+	}
+
+	// write new migration
+	file, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+	_, err = file.WriteString(migrationTemplate)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// GetDatabaseURL returns the current environment database url
+func GetDatabaseURL() (u *url.URL, err error) {
+	return url.Parse(os.Getenv("DATABASE_URL"))
+}
+
+func doTransaction(db *sql.DB, txFunc func(shared.Transaction) error) error {
+	tx, err := db.Begin()
+	if err != nil {
+		return err
+	}
+
+	if err := txFunc(tx); err != nil {
+		tx.Rollback()
+		return err
+	}
+
+	return tx.Commit()
+}
+
+// UpCommand migrates database to the latest version
+func UpCommand(ctx *cli.Context) error {
+	migrationsDir := ctx.GlobalString("migrations-dir")
+	available, err := findAvailableMigrations(migrationsDir)
+	if err != nil {
+		return err
+	}
+
+	if len(available) == 0 {
+		return fmt.Errorf("No migration files found.")
+	}
+
+	u, err := GetDatabaseURL()
+	if err != nil {
+		return err
+	}
+
+	drv, err := driver.Get(u.Scheme)
+	if err != nil {
+		return err
+	}
+
+	db, err := drv.Open(u)
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+
+	if err := drv.CreateMigrationsTable(db); err != nil {
+		return err
+	}
+
+	applied, err := drv.SelectMigrations(db)
+	if err != nil {
+		return err
+	}
+
+	for filename := range available {
+		ver := migrationVersion(filename)
+		if _, ok := applied[ver]; ok {
+			// migration already applied
+			continue
+		}
+
+		fmt.Printf("Applying: %s\n", filename)
+
+		migration, err := parseMigration(filepath.Join(migrationsDir, filename))
+		if err != nil {
+			return err
+		}
+
+		// begin transaction
+		doTransaction(db, func(tx shared.Transaction) error {
+			// run actual migration
+			if _, err := tx.Exec(migration["up"]); err != nil {
+				return err
+			}
+
+			// record migration
+			if err := drv.InsertMigration(tx, ver); err != nil {
+				return err
+			}
+
+			return nil
+		})
+
+	}
+
+	return nil
+}
+
+func findAvailableMigrations(dir string) (map[string]struct{}, error) {
+	files, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return nil, fmt.Errorf("Could not find migrations directory `%s`.", dir)
+	}
+
+	nameRegexp := regexp.MustCompile(`^\d.*\.sql$`)
+	migrations := map[string]struct{}{}
+
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+
+		name := file.Name()
+		if !nameRegexp.MatchString(name) {
+			continue
+		}
+
+		migrations[name] = struct{}{}
+	}
+
+	return migrations, nil
+}
+
+func migrationVersion(filename string) string {
+	return regexp.MustCompile(`^\d+`).FindString(filename)
+}
+
+// parseMigration reads a migration file into a map with up/down keys
+// implementation is similar to regexp.Split()
+func parseMigration(path string) (map[string]string, error) {
+	// read migration file into string
+	data, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	contents := string(data)
+
+	// split string on our trigger comment
+	separatorRegexp := regexp.MustCompile(`(?m)^-- migrate:(.*)$`)
+	matches := separatorRegexp.FindAllStringSubmatchIndex(contents, -1)
+
+	migrations := map[string]string{}
+	direction := ""
+	beg := 0
+	end := 0
+
+	for _, match := range matches {
+		end = match[0]
+		if direction != "" {
+			// write previous direction to output map
+			migrations[direction] = contents[beg:end]
+		}
+
+		// each match records the start of a new direction
+		direction = contents[match[2]:match[3]]
+		beg = match[1]
+	}
+
+	// write final direction to output map
+	migrations[direction] = contents[beg:]
+
+	return migrations, nil
+}