feat: 接入 Instance 版本与扩展可用性观测

internal/database/adapter/postgresql/connector.go

@@ -47,14 +47,6 @@ func (d *database) Close() {
 	d.pool.Close()
 }
 
-func (d *database) Version(ctx context.Context) (string, error) {
-	var version string
-	if err := d.pool.QueryRow(ctx, "SHOW server_version").Scan(&version); err != nil {
-		return "", safeError(err, application.ErrObservation)
-	}
-	return version, nil
-}
-
 func (c Connector) Connect(ctx context.Context, endpoint instance.Endpoint, credentials application.Credentials) (application.Database, error) {
 	if err := endpoint.Validate(); err != nil {
 		return nil, err

internal/database/adapter/postgresql/credentials_integration_test.go

@@ -131,13 +131,17 @@ func TestObservationDiscardsResultWhenCredentialsChange(t *testing.T) {
 		}
 	}
 
-	version, err := fixture.service.ObserveVersion(fixture.ctx, fixture.target)
+	observation, err := fixture.service.ObserveMetadata(fixture.ctx, fixture.target)
 	if !errors.Is(err, application.ErrCredentialsChanged) {
 		t.Fatal("in-flight rotation was not detected")
 	}
-	if version != "" {
+	if observation.Version() != "" {
 		t.Fatal("observation returned data obtained with stale credentials")
 	}
+	requested := instance.NewExtensionSet([]string{fixtureExtension})
+	if observation.Extensions().Check(requested).Decision != instance.ExtensionSupportUnobserved {
+		t.Fatal("observation returned extension support obtained with stale credentials")
+	}
 	if fixture.backendIDs(t) != "" {
 		t.Fatal("stale connection was retained after rotation")
 	}

internal/database/adapter/postgresql/fixture_integration_test.go

@@ -42,6 +42,7 @@ import (
 const (
 	fixtureHost         = "fixture.invalid"
 	fixtureUser         = "postgres"
+	fixtureExtension    = "plpgsql"
 	dockerExec          = "exec"
 	fixtureImage        = "postgres@sha256:18cfe3ef5e6815560c98237d6216d1e5119702fb0f3894c8785dd58b8bbe5d73"
 	fixturePassword     = "AYATORI-TEST-ONLY-initial-password"

internal/database/adapter/postgresql/metadata.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2026.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package postgresql
+
+import (
+	"context"
+
+	"git.ddupan.top/panxiao81/ayatori/internal/database/application"
+)
+
+// 使用 pg_catalog 限定名称，避免管理账号的 search_path 改变查询来源。
+// 一个语句读取版本和可用列表；ARRAY 子查询在无行时返回空数组，而非 NULL。
+// 不查询 pg_extension：已安装集合不能代表服务器提供的全部扩展。
+const inspectMetadataStatement = `
+SELECT
+    pg_catalog.current_setting('server_version'),
+    ARRAY(
+        SELECT name::text
+        FROM pg_catalog.pg_available_extensions
+        ORDER BY name
+    )`
+
+func (d *database) InspectMetadata(ctx context.Context) (application.DatabaseMetadata, error) {
+	var metadata application.DatabaseMetadata
+	err := d.pool.QueryRow(ctx, inspectMetadataStatement).Scan(
+		&metadata.Version,
+		&metadata.AvailableExtensions,
+	)
+	if err != nil {
+		// 不返回部分结果，也不把查询失败转换为“成功观察到空列表”。
+		return application.DatabaseMetadata{}, safeError(err, application.ErrObservation)
+	}
+	return metadata, nil
+}

internal/database/adapter/postgresql/metadata_integration_test.go

@@ -0,0 +1,115 @@
+//go:build integration
+
+/*
+Copyright 2026.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package postgresql_test
+
+import (
+	"errors"
+	"testing"
+
+	corev1 "k8s.io/api/core/v1"
+
+	"git.ddupan.top/panxiao81/ayatori/internal/database/application"
+	"git.ddupan.top/panxiao81/ayatori/internal/database/domain/instance"
+)
+
+func TestMetadataObservesAvailableExtensionsWithoutInstalling(t *testing.T) {
+	f := newCredentialFixture(t)
+	f.createSecret(t, controllerNamespace)
+	if installed := f.queryPostgres(t, "SELECT count(*) FROM pg_catalog.pg_extension WHERE extname = 'hstore'"); installed != "0" {
+		t.Fatal("fixture unexpectedly has hstore installed")
+	}
+	// 提供同名遮蔽对象，验证 adapter 不依赖管理账号可修改的 search_path。
+	f.queryPostgres(t, "CREATE VIEW public.pg_available_extensions AS SELECT 'fake_extension'::name AS name")
+	f.queryPostgres(t, "ALTER ROLE postgres SET search_path = public, pg_catalog")
+	observed, err := f.service.ObserveMetadata(f.ctx, f.target)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !observed.Target().Matches(f.target) || observed.Version() == "" {
+		t.Fatal("metadata was not bound to the current target")
+	}
+	requested := instance.NewExtensionSet([]string{"hstore", fixtureExtension})
+	if observed.Extensions().Check(requested).Decision != instance.ExtensionsAccepted {
+		t.Fatal("available but uninstalled extension was omitted")
+	}
+	unsupported := instance.NewExtensionSet([]string{"fake_extension", "HSTORE"})
+	check := observed.Extensions().Check(unsupported)
+	if check.Decision != instance.ExtensionsUnsupported || len(check.Unsupported) != 2 {
+		t.Fatal("metadata accepted shadowed or case-normalized extension names")
+	}
+	if installed := f.queryPostgres(t, "SELECT count(*) FROM pg_catalog.pg_extension WHERE extname = 'hstore'"); installed != "0" {
+		t.Fatal("metadata observation installed an extension")
+	}
+	if schemas := f.queryPostgres(t, "SELECT count(*) FROM pg_catalog.pg_namespace WHERE nspname = 'postgresql_tenant_operator'"); schemas != "0" {
+		t.Fatal("metadata observation initialized the registry")
+	}
+
+	aggregate, err := instance.Reconstitute(f.target, instance.Snapshot{}, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := aggregate.ObserveExtensions(observed.Target(), observed.Extensions()); err != nil {
+		t.Fatal(err)
+	}
+	if aggregate.CheckExtensions(requested).Decision != instance.ExtensionsAccepted {
+		t.Fatal("domain rejected observed extension availability")
+	}
+	if err := aggregate.RequireProvisioningReady(); err == nil {
+		t.Fatal("extension availability incorrectly authorized provisioning")
+	}
+}
+
+func TestMetadataPermissionFailureAndRecovery(t *testing.T) {
+	f := newCredentialFixture(t)
+	f.createSecret(t, controllerNamespace)
+	// 低权限账号也能读取可用列表；这不能证明具备 role/database/extension 管理权限。
+	f.queryPostgres(t, "CREATE ROLE metadata_reader LOGIN PASSWORD '"+fixturePassword+"'")
+	f.updateSecret(t, func(secret *corev1.Secret) {
+		secret.Data["login"] = []byte("metadata_reader")
+	})
+	if flags := f.queryPostgres(t, "SELECT rolsuper, rolcreaterole, rolcreatedb FROM pg_catalog.pg_roles WHERE rolname = 'metadata_reader'"); flags != "f|f|f" {
+		t.Fatal("metadata reader unexpectedly has management privileges")
+	}
+	requested := instance.NewExtensionSet([]string{fixtureExtension})
+	observed, err := f.service.ObserveMetadata(f.ctx, f.target)
+	if err != nil || observed.Extensions().Check(requested).Decision != instance.ExtensionsAccepted {
+		t.Fatalf("read-only account could not observe metadata: %v", err)
+	}
+
+	// 仅操作本测试独占容器的 catalog ACL；失败不能转换成“不支持任何扩展”。
+	f.queryPostgres(t, "REVOKE SELECT ON pg_catalog.pg_available_extensions FROM PUBLIC")
+	failed, err := f.service.ObserveMetadata(f.ctx, f.target)
+	if !errors.Is(err, application.ErrObservation) {
+		t.Fatalf("metadata permission failure was not reported safely: %v", err)
+	}
+	if failed.Version() != "" || failed.Target().Validate() == nil {
+		t.Fatal("permission failure returned partial metadata")
+	}
+	if failed.Extensions().Check(requested).Decision != instance.ExtensionSupportUnobserved {
+		t.Fatal("permission failure returned an observed empty set")
+	}
+	if f.backendIDs(t) != "" {
+		t.Fatal("failed metadata connection was retained")
+	}
+	f.queryPostgres(t, "GRANT SELECT ON pg_catalog.pg_available_extensions TO PUBLIC")
+	recovered, err := f.service.ObserveMetadata(f.ctx, f.target)
+	if err != nil || recovered.Extensions().Check(requested).Decision != instance.ExtensionsAccepted {
+		t.Fatalf("metadata observation did not recover: %v", err)
+	}
+}

internal/database/adapter/postgresql/tls_integration_test.go

@@ -107,7 +107,7 @@ func TestPostgreSQLTLSHostIdentity(t *testing.T) {
 	if err != nil {
 		t.Fatal("trusted DNS SAN connection failed", err)
 	}
-	if version, err := db.Version(ctx); err != nil || version == "" {
+	if metadata, err := db.InspectMetadata(ctx); err != nil || metadata.Version == "" {
 		db.Close()
 		t.Fatal("TLS metadata read failed", err)
 	}