add binfmt switch

cmd/drone-docker-buildx/config.go

@@ -99,6 +99,12 @@ func settingsFlags(settings *plugin.Settings) []cli.Flag {
 			EnvVars:     []string{"PLUGIN_BUILDKIT_CONFIG"},
 			Destination: &settings.Daemon.BuildkitConfig,
 		},
+		&cli.BoolFlag{
+			Name:        "daemon.install-binfmt",
+			Usage:       "run bimfmt binaries installer",
+			EnvVars:     []string{"PLUGIN_INSTALL_BINFMT"},
+			Destination: &settings.Daemon.InstallBinfmt,
+		},
 		&cli.StringFlag{
 			Name:        "dockerfile",
 			Usage:       "build dockerfile",

plugin/docker.go

@@ -52,6 +52,14 @@ func commandInfo() *exec.Cmd {
 	return exec.Command(dockerExe, "info")
 }
 
+func commandInstallBinfmt() *exec.Cmd {
+	return exec.Command(
+		dockerExe, "run",
+		"--privileged", "--rm",
+		"tonistiigi/binfmt", "--install all"
+	)
+}
+
 func commandBuilder(daemon Daemon) *exec.Cmd {
 	args := []string{
 		"buildx",

plugin/impl.go

@@ -27,6 +27,7 @@ type Daemon struct {
 	IPv6           bool            // Docker daemon IPv6 networking
 	Experimental   bool            // Docker daemon enable experimental mode
 	BuildkitConfig string          // Docker buildkit config
+	InstallBinfmt  bool            // Install binfmt binaries for better emulation support
 }
 
 // Login defines Docker login parameters.
@@ -160,6 +161,11 @@ func (p *Plugin) Execute() error {
 		p.settings.Build.Squash = false
 	}
 
+	// run the binfmt docker image if requested
+	if p.settings.Daemon.InstallBinfmt {
+		commandInstallBinfmt()
+	}
+
 	// add proxy build args
 	addProxyBuildArgs(&p.settings.Build)