feat(adapters): add SSH and database adapters

backend/backup/adapters/ssh.py

@@ -0,0 +1,92 @@
+import os
+import tempfile
+from pathlib import Path
+from typing import List, AsyncIterator, Dict, Any
+import paramiko
+from .base import SourceAdapter, FileInfo
+
+
+class SSHAdapter(SourceAdapter):
+    def __init__(self, config: Dict[str, Any]):
+        super().__init__(config)
+        self.client = None
+        self.sftp = None
+
+    async def connect(self) -> None:
+        self.client = paramiko.SSHClient()
+        self.client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+
+        host = self.config.get("host", "localhost")
+        port = self.config.get("port", 22)
+        username = self.config.get("username")
+        password = self.config.get("password")
+        key_path = self.config.get("key_path")
+
+        connect_kwargs = {
+            "hostname": host,
+            "port": port,
+            "username": username,
+        }
+
+        if password:
+            connect_kwargs["password"] = password
+        elif key_path and os.path.exists(key_path):
+            connect_kwargs["key_filename"] = key_path
+
+        self.client.connect(**connect_kwargs)
+        self.sftp = self.client.open_sftp()
+
+    async def disconnect(self) -> None:
+        if self.sftp:
+            self.sftp.close()
+            self.sftp = None
+        if self.client:
+            self.client.close()
+            self.client = None
+
+    async def list_files(self, path: str = "") -> List[FileInfo]:
+        remote_path = self.config.get("path", ".")
+        target_path = f"{remote_path}/{path}" if path else remote_path
+
+        files = []
+        exclude_patterns = self.config.get("exclude", [])
+
+        try:
+            for entry in self.sftp.listdir_attr(target_path):
+                entry_path = f"{target_path}/{entry.filename}"
+                rel_path = entry_path.replace(remote_path + "/", "", 1) if remote_path != "." else entry_path
+
+                if any(pattern in rel_path for pattern in exclude_patterns):
+                    continue
+
+                is_dir = entry.st_mode & 0o40000 == 0o40000 if hasattr(entry, 'st_mode') else False
+
+                files.append(FileInfo(
+                    path=rel_path,
+                    size=entry.st_size,
+                    modified_time=entry.st_mtime,
+                    is_directory=is_dir
+                ))
+        except IOError:
+            pass
+
+        return files
+
+    async def read_file(self, path: str) -> AsyncIterator[bytes]:
+        remote_path = self.config.get("path", ".")
+        file_path = f"{remote_path}/{path}" if not path.startswith("/") else path
+
+        with tempfile.NamedTemporaryFile(delete=False) as tmp:
+            tmp_path = tmp.name
+
+        try:
+            self.sftp.get(file_path, tmp_path)
+            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)
+
+    async def get_database_dump(self, config: Dict[str, Any]) -> AsyncIterator[bytes]:
+        raise NotImplementedError("SSH adapter does not support database dumps directly")