Merge pull request #843 from gobuffalo/dev-node-modules

Make sure node deps are installed when running in dev fixes #839

buffalo/cmd/dev.go

@@ -4,11 +4,13 @@ import (
 	"context"
 	"os"
 	"os/exec"
+	"path/filepath"
 	"runtime"
 
 	"github.com/fatih/color"
 	"github.com/gobuffalo/buffalo/generators/assets/webpack"
 	rg "github.com/gobuffalo/buffalo/generators/refresh"
+	"github.com/gobuffalo/buffalo/meta"
 	"github.com/markbates/refresh/refresh"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -65,12 +67,29 @@ This behavior can be changed in your .buffalo.dev.yml file.`,
 }
 
 func startWebpack(ctx context.Context) error {
-	cfgFile := "./webpack.config.js"
-	_, err := os.Stat(cfgFile)
-	if err != nil {
+	app := meta.New(".")
+	if !app.WithWebpack {
 		// there's no webpack, so don't do anything
 		return nil
 	}
+
+	if _, err := os.Stat(filepath.Join(app.Root, "node_modules")); err != nil {
+		tool := "yarn"
+		if !app.WithYarn {
+			tool = "npm"
+		}
+		if _, err := exec.LookPath(tool); err != nil {
+			return errors.Errorf("no node_modules directory found, and couldn't find %s to install it with", tool)
+		}
+		cmd := exec.CommandContext(ctx, tool, "install")
+		cmd.Stdin = os.Stdin
+		cmd.Stderr = os.Stderr
+		cmd.Stdout = os.Stdout
+		if err := cmd.Run(); err != nil {
+			return errors.WithStack(err)
+		}
+	}
+
 	cmd := exec.CommandContext(ctx, webpack.BinPath, "--watch")
 	cmd.Stdin = os.Stdin
 	cmd.Stderr = os.Stderr