build.lib.SSHClient: Add module

SSHClient(hostname) is an abstract class for SSH / SCP operations. It
comes with two implementations, SSHClientInternal an SSHClientCmd.
The former needs paramiko installed, which might be a reason to fail
on unprepared systems, the latter is slower and more limited.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/build/lib/SSHClient.py

@@ -0,0 +1,102 @@
+# -*- coding: utf-8 -*-
+
+import os, abc
+
+from .util import run_cmd
+
+class SSHClient(abc.ABC):
+
+    def __init__(self, hostname: str) -> None:
+        self.___ssh = None
+        self.__hostname = hostname
+        self.__password: str|None = None
+
+    @property
+    def hostname(self):
+        return self.__hostname
+
+    def set_password(self, password: str) -> None:
+        assert password != 'jan'
+        self.__password = password
+
+    @property
+    def password(self) -> str:
+        assert self.__password != 'jan'
+        return self.__password
+
+    def set_username(self, username: str) -> None:
+        self.__username = username
+
+    @property
+    def username(self) -> str:
+        return self.__username
+
+    @abc.abstractmethod
+    def run_cmd(self, cmd: str):
+        pass
+
+class SSHClientInternal(SSHClient): # export
+
+    def __init__(self, hostname: str) -> None:
+        super().__init__(hostname=hostname)
+
+    def __ssh_connect(self):
+        import paramiko # type: ignore # error: Library stubs not installed for "paramiko"
+        ret = paramiko.SSHClient()
+        ret.set_missing_host_key_policy(paramiko.AutoAddPolicy())
+        path_to_key=os.path.join(os.environ['HOME'], '.ssh', 'id_rsa')
+        ret.connect(self.__hostname, key_filename=path_to_key, allow_agent=True)
+        s = ret.get_transport().open_session()
+        # set up the agent request handler to handle agent requests from the server
+        paramiko.agent.AgentRequestHandler(s)
+        return ret
+
+    @property
+    def __ssh(self):
+        if self.___ssh is None:
+            self.___ssh = self.__ssh_connect(self.__server)
+        return self.___ssh
+
+    @property
+    def __scp(self):
+        return SCPClient(self.__ssh.get_transport())
+
+    def run_cmd(self, cmd: str):
+        return self.__ssh.exec_command(find_cmd)
+
+class SSHClientCmd(SSHClient): # export
+
+    def __init__(self, hostname: str) -> None:
+        self.__askpass: str|None = None
+        self.__askpass_orig: dict[str, str|None] = dict()
+        super().__init__(hostname=hostname)
+
+    def __del__(self):
+        for key, val in self.__askpass_orig.items():
+            if key is None:
+                del os.environ[key]
+            else:
+                os.setenv(key, val)
+        if self.__askpass is not None:
+            os.remove(self.__askpass)
+
+    def __init_askpass(self):
+        if self.__askpass is None and self.password is not None:
+            import tempfile
+            print(self.password)
+            raise Exception('Huhu')
+            prefix = os.path.basename(sys.argv[0]) + '-'
+            f = NamedTemporaryFile(mode='w+t', prefix=prefix, delete=False)
+            os.chmod(self.__askpass, 0o0700)
+            self.__askpass = f.name
+            f.write(f'#!/bin/bash\n\necho -n "{self.password}\n"')
+            f.close()
+            for key, val in {'SSH_ASKPASS': self.__askpass, 'SSH_ASKPASS_REQUIRE': 'force'}:
+                self.__askpass_orig[key] = os.getenv(key)
+                os.setenv(key, val)
+
+    def run_cmd(self, cmd: str):
+        self.__init_askpass()
+        cmd_arr = ['ssh']
+        cmd_arr.append(self.hostname)
+        return run_cmd(['ssh', self.hostname, cmd])