Add --secret parameter to support docker build --secret

file/file.go

@@ -40,6 +40,7 @@ type Dapperfile struct {
 	NoContext   bool
 	MountSuffix string
 	Target      string
+	Secret      string
 }
 
 func Lookup(file string) (*Dapperfile, error) {
@@ -249,6 +250,10 @@ func (d *Dapperfile) build(args []string, copy bool) (string, error) {
 		buildArgs = append(buildArgs, "--target", d.Target)
 	}
 
+	if d.Secret != "" {
+		buildArgs = append(buildArgs, "--secret", d.Secret)
+	}
+
 	for _, v := range d.Args {
 		buildArgs = append(buildArgs, "--build-arg", v)
 	}

main.go

@@ -97,6 +97,10 @@ func main() {
 			Name:  "target",
 			Usage: "The multistage build target to use",
 		},
+		cli.StringFlag{
+			Name:  "secret",
+			Usage: " Secret to expose to the build (format: id=mysecret[,src=/local/secret])",
+		},
 	}
 	app.Action = func(c *cli.Context) {
 		exit(run(c))
@@ -131,6 +135,7 @@ func run(c *cli.Context) error {
 	dapperFile.NoContext = c.Bool("no-context")
 	dapperFile.MountSuffix = c.String("mount-suffix")
 	dapperFile.Target = c.String("target")
+	dapperFile.Secret = c.String("secret")
 
 	if shell {
 		return dapperFile.Shell(c.Args())