Add "exec" action

Signed-off-by: Knut Ahlers <knut@ahlers.me>

cmd/streamdeck/action_exec.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"os/exec"
+
+	"github.com/pkg/errors"
+)
+
+func init() {
+	registerAction("exec", actionExec{})
+}
+
+type actionExec struct{}
+
+func (actionExec) Execute(attributes map[string]interface{}) error {
+	cmd, ok := attributes["command"].([]interface{})
+	if !ok {
+		return errors.New("No command supplied")
+	}
+
+	var args []string
+	for _, c := range cmd {
+		if v, ok := c.(string); ok {
+			args = append(args, v)
+			continue
+		}
+		return errors.New("Command conatins non-string argument")
+	}
+
+	command := exec.Command(args[0], args[1:]...)
+	if err := command.Start(); err != nil {
+		return errors.Wrap(err, "Unable to start command")
+	}
+
+	return errors.Wrap(command.Process.Release(), "Unable to release process")
+}