feat: provider interface + registry — factory pattern for multi-cloud

internal/provider/registry.go

@@ -0,0 +1,41 @@
+package provider
+
+import (
+	"fmt"
+	"sort"
+	"sync"
+)
+
+type Factory func(cfg ProviderConfig) (Provider, error)
+
+var (
+	registry   = map[string]Factory{}
+	registryMu sync.RWMutex
+)
+
+func Register(name string, factory Factory) {
+	registryMu.Lock()
+	defer registryMu.Unlock()
+	registry[name] = factory
+}
+
+func New(name string, cfg ProviderConfig) (Provider, error) {
+	registryMu.RLock()
+	factory, ok := registry[name]
+	registryMu.RUnlock()
+	if !ok {
+		return nil, fmt.Errorf("unknown provider: %s (run 'ry provider add %s' first)", name, name)
+	}
+	return factory(cfg)
+}
+
+func List() []string {
+	registryMu.RLock()
+	defer registryMu.RUnlock()
+	names := make([]string, 0, len(registry))
+	for name := range registry {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}