option to write the plugin .go file and run the plugin migrations without building the .so file so that it can be done from the shell instead to afford complete error messages

cmd/compose.go

@@ -188,5 +188,6 @@ func prepConfig() {
 		FileName:     viper.GetString("exporter.name"),
 		Save:         viper.GetBool("exporter.save"),
 		Home:         viper.GetString("exporter.home"),
+		WriteOnly:    viper.GetBool("exporter.writeOnly"),
 	}
 }

cmd/contractWatcher.go

@@ -18,13 +18,13 @@ package cmd
 
 import (
 	"fmt"
-	"github.com/vulcanize/vulcanizedb/pkg/config"
 	"time"
 
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 
 	st "github.com/vulcanize/vulcanizedb/libraries/shared/transformer"
+	"github.com/vulcanize/vulcanizedb/pkg/config"
 	ft "github.com/vulcanize/vulcanizedb/pkg/contract_watcher/full/transformer"
 	ht "github.com/vulcanize/vulcanizedb/pkg/contract_watcher/header/transformer"
 	"github.com/vulcanize/vulcanizedb/utils"

pkg/config/contract.go

@@ -17,10 +17,12 @@
 package config
 
 import (
+	"strings"
+
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
+
 	"github.com/vulcanize/vulcanizedb/pkg/geth"
-	"strings"
 )
 
 // Config struct for generic contract transformer

pkg/config/plugin.go

@@ -31,6 +31,7 @@ type Plugin struct {
 	FileName     string
 	Save         bool
 	Home         string
+	WriteOnly    bool
 }
 
 type Transformer struct {

pkg/config/plugin_test.go

@@ -17,11 +17,13 @@
 package config_test
 
 import (
-	. "github.com/onsi/ginkgo"
-	. "github.com/onsi/gomega"
-	"github.com/vulcanize/vulcanizedb/pkg/config"
 	"os"
 	"path/filepath"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"github.com/vulcanize/vulcanizedb/pkg/config"
 )
 
 var allDifferentPathsConfig = config.Plugin{

pkg/plugin/composer/composer.go

@@ -0,0 +1,100 @@
+// VulcanizeDB
+// Copyright © 2019 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 composer
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/vulcanize/vulcanizedb/pkg/config"
+	"github.com/vulcanize/vulcanizedb/pkg/plugin/helpers"
+)
+
+type composer struct {
+	GenConfig    config.Plugin
+	dependencies []string
+	tmpVenDirs   []string // Keep track of temp vendor directories
+	goFile       string   // Keep track of goFile name
+}
+
+// Requires populated plugin config
+func NewPluginComposer(gc config.Plugin) *composer {
+	return &composer{
+		GenConfig:  gc,
+		tmpVenDirs: make([]string, 0),
+	}
+}
+
+func (b *composer) BuildPlugin() error {
+	// Get plugin .go and .so file paths
+	var err error
+	b.goFile, _, err = b.GenConfig.GetPluginPaths()
+	if err != nil {
+		return err
+	}
+
+	// setup env to build plugin
+	return b.setupComposeEnv()
+}
+
+// Sets up temporary vendor libs needed for plugin build
+// This is to work around a conflict between plugins and vendoring (https://github.com/golang/go/issues/20481)
+func (b *composer) setupComposeEnv() error {
+	// TODO: Less hacky way of handling plugin build deps
+	vendorPath, err := helpers.CleanPath(filepath.Join("$GOPATH/src", b.GenConfig.Home, "vendor"))
+	if err != nil {
+		return err
+	}
+
+	repoPaths := b.GenConfig.GetRepoPaths()
+
+	// Import transformer dependencies so that we can build our plugin
+	for importPath := range repoPaths {
+		dst := filepath.Join(vendorPath, importPath)
+		src, cleanErr := helpers.CleanPath(filepath.Join("$GOPATH/src", importPath))
+		if cleanErr != nil {
+			return cleanErr
+		}
+
+		copyErr := helpers.CopyDir(src, dst, "vendor")
+		if copyErr != nil {
+			return errors.New(fmt.Sprintf("unable to copy transformer dependency from %s to %s: %v", src, dst, copyErr))
+		}
+
+		// Have to clear out the copied over vendor lib or plugin won't build (see issue above)
+		removeErr := os.RemoveAll(filepath.Join(dst, "vendor"))
+		if removeErr != nil {
+			return removeErr
+		}
+		// Keep track of this vendor directory to clear later
+		b.tmpVenDirs = append(b.tmpVenDirs, dst)
+	}
+
+	return nil
+}
+
+func (c *composer) CleanUp() error {
+	for _, venDir := range c.tmpVenDirs {
+		err := os.RemoveAll(venDir)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/plugin/generator.go

@@ -18,8 +18,10 @@ package plugin
 
 import (
 	"errors"
+
 	"github.com/vulcanize/vulcanizedb/pkg/config"
 	"github.com/vulcanize/vulcanizedb/pkg/plugin/builder"
+	"github.com/vulcanize/vulcanizedb/pkg/plugin/composer"
 	"github.com/vulcanize/vulcanizedb/pkg/plugin/manager"
 	"github.com/vulcanize/vulcanizedb/pkg/plugin/writer"
 )
@@ -40,11 +42,16 @@ func NewGenerator(gc config.Plugin, dbc config.Database) (*generator, error) {
 	if len(gc.Transformers) < 1 {
 		return nil, errors.New("plugin generator is not configured with any transformers")
 	}
-	return &generator{
+	gen := &generator{
 		PluginWriter:     writer.NewPluginWriter(gc),
-		PluginBuilder:    builder.NewPluginBuilder(gc),
 		MigrationManager: manager.NewMigrationManager(gc, dbc),
-	}, nil
+	}
+	if gc.WriteOnly {
+		gen.PluginBuilder = composer.NewPluginComposer(gc)
+	} else {
+		gen.PluginBuilder = builder.NewPluginBuilder(gc)
+	}
+	return gen, nil
 }
 
 // Generates plugin for the transformer initializers specified in the generator config

pkg/plugin/manager/manager.go

@@ -20,13 +20,14 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
 	"github.com/lib/pq"
 	"github.com/pressly/goose"
 	"github.com/vulcanize/vulcanizedb/pkg/config"
 	"github.com/vulcanize/vulcanizedb/pkg/plugin/helpers"
-	"io/ioutil"
-	"os"
-	"path/filepath"
 )
 
 // Interface for managing the db migrations for plugin transformers