[Agent] Replace dockerapi container with Redis-based control bus

data/Dockerfiles/agent/internal/envelope/envelope.go

@@ -0,0 +1,34 @@
+// Package envelope defines the wire format for the mailcow-agent control bus.
+package envelope
+
+import "time"
+
+// Request is what the backend publishes on mailcow.control.<service>.
+type Request struct {
+	Cmd       string         `json:"cmd"`
+	RequestID string         `json:"request_id"`
+	Args      map[string]any `json:"args,omitempty"`
+	ReplyTo   string         `json:"reply_to,omitempty"`
+	Deadline  time.Time      `json:"deadline,omitempty"`
+	IssuedBy  string         `json:"issued_by,omitempty"`
+}
+
+// Response is what the agent publishes on the reply_to channel.
+type Response struct {
+	RequestID  string `json:"request_id"`
+	OK         bool   `json:"ok"`
+	Result     any    `json:"result,omitempty"`
+	Error      string `json:"error,omitempty"`
+	ErrorCode  string `json:"error_code,omitempty"`
+	DurationMS int64  `json:"duration_ms"`
+	Node       string `json:"node,omitempty"`
+}
+
+// Error codes returned in Response.ErrorCode. Keep in sync with the V2 schema.
+const (
+	ErrCodeValidation         = "validation"
+	ErrCodeNotFound           = "not_found"
+	ErrCodeTimeout            = "timeout"
+	ErrCodeUnsupportedCommand = "unsupported_command"
+	ErrCodeInternal           = "internal"
+)