From 0bb268054c6b70d89a02044f278d703341324a08 Mon Sep 17 00:00:00 2001
From: Rene Cannao <rene@proxysql.com>
Date: Tue, 24 Mar 2026 00:59:44 +0000
Subject: [PATCH] feat: add Provider interface and ProviderRegistry

---
 providers/provider.go      | 57 ++++++++++++++++++++++++++++++++++++++
 providers/provider_test.go | 53 +++++++++++++++++++++++++++++++++++
 2 files changed, 110 insertions(+)
 create mode 100644 providers/provider.go
 create mode 100644 providers/provider_test.go

diff --git a/providers/provider.go b/providers/provider.go
new file mode 100644
index 0000000..4249bff
--- /dev/null
+++ b/providers/provider.go
@@ -0,0 +1,57 @@
+package providers
+
+import (
+	"fmt"
+	"sort"
+)
+
+// Provider is the core abstraction for deploying database infrastructure.
+// Phase 2a defines a minimal interface (Name, ValidateVersion, DefaultPorts).
+// Phase 2b will add CreateSandbox, Start, Stop, Destroy, HealthCheck when
+// ProxySQL and other providers need them.
+type Provider interface {
+	Name() string
+	ValidateVersion(version string) error
+	DefaultPorts() PortRange
+}
+
+type PortRange struct {
+	BasePort         int
+	PortsPerInstance int
+}
+
+type Registry struct {
+	providers map[string]Provider
+}
+
+func NewRegistry() *Registry {
+	return &Registry{providers: make(map[string]Provider)}
+}
+
+func (r *Registry) Register(p Provider) error {
+	name := p.Name()
+	if _, exists := r.providers[name]; exists {
+		return fmt.Errorf("provider %q already registered", name)
+	}
+	r.providers[name] = p
+	return nil
+}
+
+func (r *Registry) Get(name string) (Provider, error) {
+	p, exists := r.providers[name]
+	if !exists {
+		return nil, fmt.Errorf("provider %q not found", name)
+	}
+	return p, nil
+}
+
+func (r *Registry) List() []string {
+	names := make([]string, 0, len(r.providers))
+	for name := range r.providers {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return names
+}
+
+var DefaultRegistry = NewRegistry()
diff --git a/providers/provider_test.go b/providers/provider_test.go
new file mode 100644
index 0000000..d1ca46a
--- /dev/null
+++ b/providers/provider_test.go
@@ -0,0 +1,53 @@
+package providers
+
+import "testing"
+
+type mockProvider struct{ name string }
+
+func (m *mockProvider) Name() string                         { return m.name }
+func (m *mockProvider) ValidateVersion(version string) error { return nil }
+func (m *mockProvider) DefaultPorts() PortRange              { return PortRange{BasePort: 9999, PortsPerInstance: 1} }
+
+func TestRegistryRegisterAndGet(t *testing.T) {
+	reg := NewRegistry()
+	mock := &mockProvider{name: "test"}
+	if err := reg.Register(mock); err != nil {
+		t.Fatalf("Register failed: %v", err)
+	}
+	p, err := reg.Get("test")
+	if err != nil {
+		t.Fatalf("Get failed: %v", err)
+	}
+	if p.Name() != "test" {
+		t.Errorf("expected name 'test', got %q", p.Name())
+	}
+}
+
+func TestRegistryDuplicateRegister(t *testing.T) {
+	reg := NewRegistry()
+	mock := &mockProvider{name: "test"}
+	_ = reg.Register(mock)
+	if err := reg.Register(mock); err == nil {
+		t.Fatal("expected error on duplicate register")
+	}
+}
+
+func TestRegistryGetNotFound(t *testing.T) {
+	reg := NewRegistry()
+	if _, err := reg.Get("nonexistent"); err == nil {
+		t.Fatal("expected error on missing provider")
+	}
+}
+
+func TestRegistryList(t *testing.T) {
+	reg := NewRegistry()
+	_ = reg.Register(&mockProvider{name: "b"})
+	_ = reg.Register(&mockProvider{name: "a"})
+	names := reg.List()
+	if len(names) != 2 {
+		t.Errorf("expected 2 providers, got %d", len(names))
+	}
+	if names[0] != "a" || names[1] != "b" {
+		t.Errorf("expected sorted [a b], got %v", names)
+	}
+}