Some additional logging

builder/amazonebs/builder.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"github.com/mitchellh/packer/packer"
+	"log"
 )
 
 type config struct {
@@ -34,6 +35,7 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 		return
 	}
 
+	log.Printf("Config: %+v\n", b.config)
 	return
 }
 

packer/build.go

 package packer
 
+import "log"
+
 // A Build represents a single job within Packer that is responsible for
 // building some machine image artifact. Builds are meant to be parallelized.
 type Build interface {
@@ -41,9 +43,14 @@ func (b *coreBuild) Name() string {
 
 // Prepare prepares the build by doing some initialization for the builder
 // and any hooks. This _must_ be called prior to Run.
-func (b *coreBuild) Prepare() error {
+func (b *coreBuild) Prepare() (err error) {
 	b.prepareCalled = true
-	return b.builder.Prepare(b.rawConfig)
+	err = b.builder.Prepare(b.rawConfig)
+	if err != nil {
+		log.Printf("Build '%s' prepare failure: %s\n", b.name, err)
+	}
+
+	return
 }
 
 // Runs the actual build. Prepare must be called prior to running this.