refactoring plugin generating code

pkg/plugin/builder/builder.go

@@ -0,0 +1,118 @@
+// 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 builder
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/vulcanize/vulcanizedb/pkg/config"
+	"github.com/vulcanize/vulcanizedb/pkg/plugin/helpers"
+)
+
+type PluginBuilder interface {
+	BuildPlugin() error
+	CleanUp() error
+}
+
+type builder struct {
+	GenConfig  config.Plugin
+	tmpVenDirs []string
+	goFile     string
+}
+
+func NewPluginBuilder(gc config.Plugin, dbc config.Database) *builder {
+	return &builder{
+		GenConfig:  gc,
+		tmpVenDirs: make([]string, 0, len(gc.Dependencies)),
+	}
+}
+
+func (b *builder) BuildPlugin() error {
+	// Get plugin .go and .so file paths
+	var err error
+	var soFile string
+	b.goFile, soFile, err = b.GenConfig.GetPluginPaths()
+	if err != nil {
+		return err
+	}
+
+	// setup env to build plugin
+	err = b.setupBuildEnv()
+	if err != nil {
+		return err
+	}
+
+	// Build the .go file into a .so plugin
+	err = exec.Command("go", "build", "-buildmode=plugin", "-o", soFile, b.goFile).Run()
+	if err != nil {
+		return errors.New(fmt.Sprintf("unable to build .so file: %s", err.Error()))
+	}
+	return nil
+}
+
+// Sets up temporary vendor libs needed for plugin build
+func (b *builder) setupBuildEnv() error {
+	// TODO: Less hacky way of handling plugin build deps
+	vendorPath, err := helpers.CleanPath("$GOPATH/src/github.com/vulcanize/vulcanizedb/vendor")
+	if err != nil {
+		return err
+	}
+
+	// Import transformer dependencies so that we can build our plugin
+	for name, importPath := range b.GenConfig.Dependencies {
+		index := strings.Index(importPath, "/")
+		gitPath := importPath[:index] + ":" + importPath[index+1:]
+		importURL := "git@" + gitPath + ".git"
+		depPath := filepath.Join(vendorPath, importPath)
+		err = exec.Command("git", "clone", importURL, depPath).Run()
+		if err != nil {
+			return errors.New(fmt.Sprintf("unable to clone %s transformer dependency: %s", name, err.Error()))
+		}
+
+		err := os.RemoveAll(filepath.Join(depPath, "vendor/"))
+		if err != nil {
+			return err
+		}
+
+		b.tmpVenDirs = append(b.tmpVenDirs, depPath)
+	}
+
+	return nil
+}
+
+func (b *builder) CleanUp() error {
+	if !b.GenConfig.Save {
+		err := helpers.ClearFiles(b.goFile)
+		if err != nil {
+			return err
+		}
+	}
+
+	for _, venDir := range b.tmpVenDirs {
+		err := os.RemoveAll(venDir)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}