refactoring plugin generating code

pkg/plugin/manager/manager.go

@@ -0,0 +1,134 @@
+// VulcanizeDB
+// Copyright © 2018 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package manager
+
+import (
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+
+	"github.com/vulcanize/vulcanizedb/pkg/config"
+	"github.com/vulcanize/vulcanizedb/pkg/plugin/helpers"
+)
+
+type MigrationManager interface {
+	RunMigrations() error
+}
+
+type manager struct {
+	GenConfig config.Plugin
+	DBConfig  config.Database
+	tmpMigDir string
+}
+
+func NewMigrationManager(gc config.Plugin, dbc config.Database) *manager {
+	return &manager{
+		GenConfig: gc,
+		DBConfig:  dbc,
+	}
+}
+
+func (m *manager) RunMigrations() error {
+	// Get paths to db migrations
+	paths, err := m.GenConfig.GetMigrationsPaths()
+	if err != nil {
+		return err
+	}
+	if len(paths) < 1 {
+		return nil
+	}
+
+	// Init directory for temporary copies
+	err = m.setupMigrationEnv()
+	if err != nil {
+		return err
+	}
+	defer m.cleanUp()
+
+	// Create temporary copies of migrations to the temporary migrationDir
+	// These tmps are identical except they have had `1` added in front of their unix_timestamps
+	// As such, they will be ran on top of all core migrations (at least, for the next ~317 years)
+	// But will still be ran in the same order relative to one another
+	// TODO: Less hacky way of handing migrations
+	err = m.createMigrationCopies(paths)
+	if err != nil {
+		return err
+	}
+
+	// Run the copied migrations
+	pgStr := fmt.Sprintf("postgres://%s:%d/%s?sslmode=disable", m.DBConfig.Hostname, m.DBConfig.Port, m.DBConfig.Name)
+	err = exec.Command("migrate", "-path", m.tmpMigDir, "-database", pgStr, "up").Run()
+	if err != nil {
+		return errors.New(fmt.Sprintf("db migrations for plugin transformers failed: %s", err.Error()))
+	}
+
+	return nil
+}
+
+func (m *manager) setupMigrationEnv() error {
+	// Initialize temp directory for transformer migrations
+	var err error
+	m.tmpMigDir, err = helpers.CleanPath("$GOPATH/src/github.com/vulcanize/vulcanizedb/db/plugin_migrations")
+	if err != nil {
+		return err
+	}
+	err = os.RemoveAll(m.tmpMigDir)
+	if err != nil {
+		return errors.New(fmt.Sprintf("unable to remove file found at %s where tmp directory needs to be written", m.tmpMigDir))
+	}
+	err = os.Mkdir(m.tmpMigDir, os.FileMode(0777))
+	if err != nil {
+		return errors.New(fmt.Sprintf("unable to create temporary migration directory %s", m.tmpMigDir))
+	}
+
+	return nil
+}
+
+func (m *manager) createMigrationCopies(paths []string) error {
+	for _, path := range paths {
+		dir, err := ioutil.ReadDir(path)
+		if err != nil {
+			return err
+		}
+		for _, file := range dir {
+			if file.IsDir() || len(file.Name()) < 15 || filepath.Ext(file.Name()) != ".sql" { // (10 digit unix time stamp + x + .sql) is bare minimum
+				continue
+			}
+			_, err := strconv.Atoi(file.Name()[:10])
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "migration file name %s does not posses 10 digit timestamp prefix\r\n", file.Name())
+				continue
+			}
+			src := filepath.Join(path, file.Name())
+			dst := filepath.Join(m.tmpMigDir, "1"+file.Name())
+			err = helpers.CopyFile(src, dst)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func (m *manager) cleanUp() error {
+	return os.RemoveAll(m.tmpMigDir)
+}