common/config: config filter function [GH-521]

Fixes #521

builder/amazon/chroot/builder.go

@@ -143,7 +143,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		return errs
 	}
 
-	log.Printf("Config: %+v", b.config)
+	log.Println(common.ScrubConfig(b.config), b.config.AccessKey, b.config.SecretKey)
 	return nil
 }
 

builder/amazon/ebs/builder.go

@@ -56,7 +56,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		return errs
 	}
 
-	log.Printf("Config: %+v", b.config)
+	log.Println(common.ScrubConfig(b.config), b.config.AccessKey, b.config.SecretKey)
 	return nil
 }
 

builder/amazon/instance/builder.go

@@ -159,7 +159,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		return errs
 	}
 
-	log.Printf("Config: %+v", b.config)
+	log.Println(common.ScrubConfig(b.config), b.config.AccessKey, b.config.SecretKey)
 	return nil
 }
 

builder/digitalocean/builder.go

@@ -11,7 +11,6 @@ import (
 	"github.com/mitchellh/packer/packer"
 	"log"
 	"os"
-	"strings"
 	"time"
 )
 
@@ -165,10 +164,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		return errs
 	}
 
-	configRepr := fmt.Sprintf("Config: %+v", b.config)
-	scrubbedConfig := strings.Replace(configRepr, b.config.ClientID, "CLIENT_ID", -1)
-	scrubbedConfig = strings.Replace(scrubbedConfig, b.config.APIKey, "API_KEY", -1)
-	log.Println(scrubbedConfig)
+	common.ScrubConfig(b.config, b.config.ClientID, b.config.APIKey)
 	return nil
 }
 

builder/openstack/builder.go

@@ -51,7 +51,7 @@ func (b *Builder) Prepare(raws ...interface{}) error {
 		return errs
 	}
 
-	log.Printf("Config: %+v", b.config)
+	log.Println(common.ScrubConfig(b.config), b.config.AccessKey, b.config.SecretKey)
 	return nil
 }
 

common/config.go

@@ -12,6 +12,16 @@ import (
 	"strings"
 )
 
+// ScrubConfig is a helper that returns a string representation of
+// any struct with the given values stripped out.
+func ScrubConfig(target interface{}, values ...string) string {
+	conf := fmt.Sprintf("Config: %+v", target)
+	for _, value := range values {
+		conf = strings.Replace(conf, value, "<Filtered>", -1)
+	}
+	return conf
+}
+
 // CheckUnusedConfig is a helper that makes sure that the there are no
 // unused configuration keys, properly ignoring keys that don't matter.
 func CheckUnusedConfig(md *mapstructure.Metadata) *packer.MultiError {

common/config_test.go

@@ -159,3 +159,20 @@ func TestDownloadableURL_FilePaths(t *testing.T) {
 		}
 	}
 }
+
+func TestScrubConfig(t *testing.T) {
+	type Inner struct {
+		Baz string
+	}
+	type Local struct {
+		Foo string
+		Bar string
+		Inner
+	}
+	c := Local{"foo", "bar", Inner{"bar"}}
+	expect := "Config: {Foo:foo Bar:<Filtered> Inner:{Baz:<Filtered>}}"
+	conf := ScrubConfig(c, c.Bar)
+	if conf != expect {
+		t.Fatalf("got %s, expected %s", conf, expect)
+	}
+}