feat(adapters): add SSH and database adapters

backend/backup/adapters/database.py

@@ -0,0 +1,74 @@
+import os
+import subprocess
+import tempfile
+from typing import List, AsyncIterator, Dict, Any
+from .base import SourceAdapter, FileInfo
+
+
+class DatabaseAdapter(SourceAdapter):
+    async def connect(self) -> None:
+        pass
+
+    async def disconnect(self) -> None:
+        pass
+
+    async def list_files(self, path: str = "") -> List[FileInfo]:
+        return []
+
+    async def read_file(self, path: str) -> AsyncIterator[bytes]:
+        raise NotImplementedError("Database adapter does not support file reading")
+
+    async def get_database_dump(self, config: Dict[str, Any]) -> AsyncIterator[bytes]:
+        db_type = config.get("db_type", "postgresql")
+        host = config.get("host", "localhost")
+        port = config.get("port", 5432 if db_type == "postgresql" else 3306)
+        database = config.get("database")
+        username = config.get("username")
+        password = config.get("password")
+
+        if not database:
+            raise ValueError("Database name is required")
+
+        with tempfile.NamedTemporaryFile(suffix=".sql", delete=False) as tmp:
+            tmp_path = tmp.name
+
+        try:
+            if db_type == "postgresql":
+                env = os.environ.copy()
+                if password:
+                    env["PGPASSWORD"] = password
+
+                cmd = [
+                    "pg_dump",
+                    "-h", host,
+                    "-p", str(port),
+                    "-U", username or "postgres",
+                    "-f", tmp_path,
+                    database
+                ]
+            elif db_type == "mysql":
+                env = os.environ.copy()
+                if password:
+                    env["MYSQL_PWD"] = password
+
+                cmd = [
+                    "mysqldump",
+                    "-h", host,
+                    "-P", str(port),
+                    "-u", username or "root",
+                    "--result-file", tmp_path,
+                    database
+                ]
+            else:
+                raise ValueError(f"Unsupported database type: {db_type}")
+
+            result = subprocess.run(cmd, env=env, capture_output=True, text=True)
+            if result.returncode != 0:
+                raise RuntimeError(f"Database dump failed: {result.stderr}")
+
+            with open(tmp_path, "rb") as f:
+                while chunk := f.read(8192):
+                    yield chunk
+        finally:
+            if os.path.exists(tmp_path):
+                os.unlink(tmp_path)