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

data/Dockerfiles/agent/internal/services/services.go

@@ -0,0 +1,87 @@
+// Package services registers per-service command tables. The agent selects
+// the right table at startup via MAILCOW_AGENT_SERVICE.
+//
+// A service "builder" receives a Supervisor for lifecycle commands; services
+// that don't supervise a main process (currently just "host") pass nil and
+// the generic lifecycle commands are skipped.
+package services
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/mailcow/mailcow-dockerized/agent/internal/commands"
+	"github.com/mailcow/mailcow-dockerized/agent/internal/proc"
+)
+
+// Builder constructs a command table for a service. sup may be nil for
+// services without a supervised main process.
+type Builder func(sup *proc.Supervisor) *commands.Table
+
+var registry = map[string]Builder{}
+
+// Register installs a builder for a service name. Called from init() in each
+// per-service file.
+func Register(service string, b Builder) {
+	if _, dup := registry[service]; dup {
+		panic("services: duplicate registration for " + service)
+	}
+	registry[service] = b
+}
+
+// Build returns the table for service, or an error if no builder exists.
+func Build(service string, sup *proc.Supervisor) (*commands.Table, error) {
+	b, ok := registry[service]
+	if !ok {
+		return nil, fmt.Errorf("services: unknown service %q (set MAILCOW_AGENT_SERVICE correctly)", service)
+	}
+	return b(sup), nil
+}
+
+// Known returns the list of registered service names (sorted-ish, depends on
+// map iteration — for help output only).
+func Known() []string {
+	out := make([]string, 0, len(registry))
+	for k := range registry {
+		out = append(out, k)
+	}
+	return out
+}
+
+// restartSettle is how long we wait after a Start to verify the new child
+// didn't immediately crash. Gives the operator real "did the service come
+// back up?" feedback instead of an instant OK that hides flapping services.
+const restartSettle = 3 * time.Second
+
+// addLifecycle wires reload/restart/stop/start onto t backed by sup. Services
+// override these (e.g. postfix overrides reload to run `postfix reload`).
+func addLifecycle(t *commands.Table, sup *proc.Supervisor) {
+	if sup == nil {
+		return
+	}
+	t.Register("reload", func(ctx context.Context, _ map[string]any) (any, error) {
+		return nil, sup.Reload()
+	})
+	t.Register("restart", func(ctx context.Context, _ map[string]any) (any, error) {
+		if err := sup.Restart(ctx); err != nil {
+			return nil, err
+		}
+		if err := sup.WaitStable(ctx, restartSettle); err != nil {
+			return nil, err
+		}
+		return map[string]any{"status": "restarted", "settled_ms": int(restartSettle / time.Millisecond)}, nil
+	})
+	t.Register("stop", func(ctx context.Context, _ map[string]any) (any, error) {
+		return nil, sup.Stop(ctx)
+	})
+	t.Register("start", func(ctx context.Context, _ map[string]any) (any, error) {
+		if err := sup.Start(); err != nil {
+			return nil, err
+		}
+		if err := sup.WaitStable(ctx, restartSettle); err != nil {
+			return nil, err
+		}
+		return map[string]any{"status": "started", "settled_ms": int(restartSettle / time.Millisecond)}, nil
+	})
+}