Object store metadata schema

The object store will require tracking the underlying blobs of the
object store. To do this we need to keep track of the path, size
and hash. The path needs to be unique so multiple files are not
added, the hash is not unqiue as multiple metadata can point to
the same blob.

domain/schema/controller.go

@@ -46,6 +46,7 @@ func ControllerDDL() *schema.Schema {
 		changeLogTriggersForTable("upgrade_info", "uuid", tableUpgradeInfo),
 		changeLogTriggersForTable("upgrade_info_controller_node", "upgrade_info_uuid", tableUpgradeInfoControllerNode),
 		autocertCacheSchema,
+		objectStoreMetadataSchema,
 	}
 
 	schema := schema.New()

domain/schema/model.go

@@ -19,6 +19,7 @@ func ModelDDL() *schema.Schema {
 		modelConfig,
 		changeLogTriggersForTable("model_config", "key", tableModelConfig),
 		spacesSchema,
+		objectStoreMetadataSchema,
 	}
 
 	schema := schema.New()

domain/schema/objectstore.go

@@ -0,0 +1,48 @@
+// Copyright 2023 Canonical Ltd.
+// Licensed under the AGPLv3, see LICENCE file for details.
+
+package schema
+
+import "github.com/juju/juju/core/database/schema"
+
+// objectStoreMetadataSchema provides a helper function for generating a change_log ddl
+// for a schema.
+func objectStoreMetadataSchema() schema.Patch {
+	return schema.MakePatch(`
+CREATE TABLE object_store_metadata_hash_type (
+    id          INT PRIMARY KEY,
+    hash_type   TEXT NOT NULL
+);
+
+CREATE UNIQUE INDEX idx_object_store_metadata_hash_type_name
+ON object_store_metadata_hash_type (hash_type);
+
+INSERT INTO object_store_metadata_hash_type VALUES
+    (0, 'none'),
+    (1, 'sha-256');
+
+CREATE TABLE object_store_metadata (
+    uuid            TEXT PRIMARY KEY,
+    hash_type_id    INT NOT NULL,
+    hash            TEXT,
+    CONSTRAINT      fk_object_store_metadata_hash_type
+        FOREIGN KEY (hash_type_id)
+        REFERENCES  object_store_metadata_hash_type(id)
+);
+
+CREATE UNIQUE INDEX idx_object_store_metadata_hash ON object_store_metadata (hash);
+
+CREATE TABLE object_store_metadata_path (
+    uuid            TEXT PRIMARY KEY,
+    metadata_uuid   TEXT NOT NULL,
+    path            TEXT NOT NULL,
+    size            INT NOT NULL,
+    CONSTRAINT      fk_object_store_metadata_metadata_uuid
+        FOREIGN KEY (metadata_uuid)
+        REFERENCES  object_store_metadata(uuid)
+);
+
+CREATE UNIQUE INDEX idx_object_store_metadata_path ON object_store_metadata_path (path);
+
+`)
+}

domain/schema/schema_test.go

@@ -87,6 +87,11 @@ func (s *schemaSuite) TestControllerDDLApply(c *gc.C) {
 		"upgrade_info",
 		"upgrade_info_controller_node",
 		"upgrade_state_type",
+
+		// Object store metadata
+		"object_store_metadata",
+		"object_store_metadata_path",
+		"object_store_metadata_hash_type",
 	)
 	c.Assert(readTableNames(c, s.DB()), jc.SameContents, expected.Union(internalTableNames).SortedValues())
 }
@@ -112,6 +117,11 @@ func (s *schemaSuite) TestModelDDLApply(c *gc.C) {
 		// Spaces
 		"spaces",
 		"provider_spaces",
+
+		// Object store metadata
+		"object_store_metadata",
+		"object_store_metadata_path",
+		"object_store_metadata_hash_type",
 	)
 	c.Assert(readTableNames(c, s.DB()), jc.SameContents, expected.Union(internalTableNames).SortedValues())
 }