Implement simple pipe-based event handlers

solvable/src/pipe_io_auxlib.py

@@ -0,0 +1,154 @@
+from json import dumps, loads
+from tfw.crypto import KeyManager, sign_message, verify_message
+from tfw.components import PipeIOEventHandlerBase
+from tfw.components.pipe_io_event_handler import DEFAULT_PERMISSIONS
+
+class DeployPipeIOEventHandler(PipeIOEventHandlerBase):
+    # pylint: disable=too-many-arguments
+    def __init__(
+            self, in_pipe_path, out_pipe_path, process,
+            permissions=DEFAULT_PERMISSIONS
+    ):
+        self.expected = False
+        self.process = process
+
+        self.onsuccess = {
+            'key': 'processmanager',
+            'data': {
+                'process_name': process,
+                'command': 'restart'
+            }
+        }
+        self.onerror = {
+            'key': 'processmanager',
+            'data': {
+                'process_name': process,
+                'error': True
+            }
+        }
+
+        super().__init__('processmanager', in_pipe_path, out_pipe_path, permissions)
+
+    def handle_event(self, message):
+        if message == self.onsuccess:
+            self.expected = True
+            self.pipe_io.send_message(b'deploy')
+
+    def handle_pipe_event(self, message_bytes):
+        if not self.expected:
+            raise ValueError(
+                f'{self.pipe_io.in_pipe}: There is nothing to deploy.'
+            )
+
+        self.expected = False
+        if message_bytes == b'true':
+            self.server_connector.send(self.onsuccess)
+        elif message_bytes == b'false':
+            self.server_connector.send(self.onerror)
+        else:
+            raise ValueError(
+                f'{self.pipe_io.in_pipe}: Expected "true" or "false".'
+            )
+
+class IdePipeIOEventHandler(PipeIOEventHandlerBase):
+    # pylint: disable=too-many-arguments
+    def __init__(
+            self, in_pipe_path, out_pipe_path, filename,
+            permissions=DEFAULT_PERMISSIONS,
+            selected=True
+    ):
+        self.selected = selected
+        self.filename = filename
+        super().__init__('ide', in_pipe_path, out_pipe_path, permissions)
+
+    def handle_event(self, message):
+        data = message['data']
+
+        if data['command'] == 'select':
+            self.selected = data['filename'] == self.filename
+        elif data['command'] == 'write' and self.selected:
+            clean = data['content'].replace('\n', '\\n')
+            self.pipe_io.send_message(clean.encode())
+
+    def handle_pipe_event(self, message_bytes):
+        if not self.selected:
+            self.server_connector.send({
+                'key': 'mirror',
+                'data': {
+                    'key': 'ide',
+                    'data': {
+                        'command': 'select',
+                        'filename': self.filename
+                    }
+                }
+            })
+
+        self.server_connector.send({
+            'key': 'mirror',
+            'data': {
+                'key': 'ide',
+                'data': {
+                    'command': 'write',
+                    'content': message_bytes.decode().replace('\\n', '\n')
+                }
+            }
+        })
+        self.server_connector.send({
+            'key': 'mirror',
+            'data': {
+                'key': 'ide',
+                'data': {
+                    'command': 'read'
+                }
+            }
+        })
+
+class FSMPipeIOEventHandler(PipeIOEventHandlerBase):
+    def __init__(self, in_pipe_path, out_pipe_path, permissions=DEFAULT_PERMISSIONS):
+        super().__init__(
+            ['fsm', 'fsm_update'],
+            in_pipe_path, out_pipe_path, permissions
+        )
+
+    def handle_event(self, message):
+        if 'current_state' in message['data']:
+            self.pipe_io.send_message(message['data']['current_state'].encode())
+
+    def handle_pipe_event(self, message_bytes):
+        self.server_connector.send({
+            'key': '',
+            'trigger': message_bytes.decode()
+        })
+
+class MsgSignPipeIOEventHandler(PipeIOEventHandlerBase):
+    def __init__(
+            self, in_pipe_path, out_pipe_path,
+            permissions=DEFAULT_PERMISSIONS,
+            forwarding=True
+    ):
+        self.forwarding = forwarding
+        self.auth_key = KeyManager().auth_key
+        super().__init__(None, in_pipe_path, out_pipe_path, permissions)
+
+    def handle_event(self, message):
+        return
+
+    def handle_pipe_event(self, message_bytes):
+        message = loads(message_bytes)
+        sign_message(self.auth_key, message)
+        if self.forwarding:
+            self.server_connector.send(message)
+        self.pipe_io.send_message(dumps(message).encode())
+
+class MsgVerifyPipeIOEventHandler(PipeIOEventHandlerBase):
+    def __init__(self, in_pipe_path, out_pipe_path, permissions=DEFAULT_PERMISSIONS):
+        self.auth_key = KeyManager().auth_key
+        super().__init__(None, in_pipe_path, out_pipe_path, permissions)
+
+    def handle_event(self, message):
+        return
+
+    def handle_pipe_event(self, message_bytes):
+        message = loads(message_bytes)
+        validity = verify_message(self.auth_key, message)
+        self.pipe_io.send_message(str(validity).lower().encode())

solvable/src/pipe_io_main.py

@@ -5,12 +5,85 @@ from tornado.ioloop import IOLoop
 from tfw import EventHandlerBase
 from tfw.components import PipeIOEventHandler
 
+from pipe_io_auxlib import (
+        MsgSignPipeIOEventHandler, MsgVerifyPipeIOEventHandler,
+        DeployPipeIOEventHandler, IdePipeIOEventHandler,
+        FSMPipeIOEventHandler
+)
+
 
 if __name__ == '__main__':
-    pipe_io = PipeIOEventHandler(
+    '''
+    Creates general purpose pipes.
+    You can send/receive JSON messages to/from the TFW server as any user.
+    '''
+    json_pipe = PipeIOEventHandler(
         '',
-        '/tmp/tfw_send',
+        '/tmp/tfw_json_send',
-        '/tmp/tfw_recv'
+        '/tmp/tfw_json_recv',
+        permissions=0o666
+    )
+
+    '''
+    Signs a valid TFW message with HMAC.
+    Note that this process needs root permissions in order to read the
+    authentication key.
+    When forwarding is true, it will send the signed message to the TFW
+    server before writing it into the output pipe.
+    '''
+    sign_pipe = MsgSignPipeIOEventHandler(
+        '/tmp/tfw_sign_send',
+        '/tmp/tfw_sign_recv',
+        forwarding=True
+    )
+
+    '''
+    Verifies a signed TFW message.
+    This pipe also needs root permissions. Send the serialized JSON object
+    to the pipe, then wait for its boolean response.
+    '''
+    verify_pipe = MsgVerifyPipeIOEventHandler(
+        '/tmp/tfw_verify_send',
+        '/tmp/tfw_verify_recv'
+    )
+
+    '''
+    Manages deployment in the IDE.
+    When you receive "deploy", then you have to answer with a "true" or
+    "false" depending whether you are satisfied with the result or not.
+    The third parameter is the name of the supervised service.
+    '''
+    deploy_pipe = DeployPipeIOEventHandler(
+        '/tmp/tfw_deploy_send',
+        '/tmp/tfw_deploy_recv',
+        'webservice'
+    )
+
+    '''
+    Manipulates the content of the IDE.
+    You can observe a file, and when the user edits it, you will receive
+    the new contents where newlines are escaped as "\\n".
+    In order to overwrite the file, send an escaped text back to the pipe.
+    Since the pipe doesn't know if the file is selected initially in the IDE,
+    you have to provide this information by yourself, but it will track it
+    later on.
+    '''
+    ide_pipe = IdePipeIOEventHandler(
+        '/tmp/tfw_ide_send',
+        '/tmp/tfw_ide_recv',
+        'user_ops.py',
+        selected=True
+    )
+
+    '''
+    Handles FSM steps.
+    When the FSM enters the next state, you will receive a line containing
+    its name.
+    To trigger a state change, send the name of the transition to the pipe.
+    '''
+    fsm_pipe = FSMPipeIOEventHandler(
+        '/tmp/tfw_fsm_send',
+        '/tmp/tfw_fsm_recv'
     )
 
     event_handlers = EventHandlerBase.get_local_instances()