Remove start_rpc_server() and make Rpc a context manager

Rpc now has a start() method.
This way it is possible to use Rpc from IPython without calling __aenter__()

deltachat-rpc-client/README.md

@@ -30,11 +30,12 @@ from the REPL.
 $ pip install ipython
 $ PATH="../target/debug:$PATH" ipython
 ...
-In  [1]: from deltachat_rpc_client import *
-In  [2]: rpc_generator = start_rpc_server()
-In  [3]: rpc = await rpc_generator.__aenter__()
-In  [4]: dc = Deltachat(rpc)
-In  [5]: system_info = await dc.get_system_info()
-In  [6]: system_info["level"]
-Out [6]: 'awesome'
+In [1]: from deltachat_rpc_client import *
+In [2]: rpc = Rpc()
+In [3]: await rpc.start()
+In [4]: dc = Deltachat(rpc)
+In [5]: system_info = await dc.get_system_info()
+In [6]: system_info["level"]
+Out[6]: 'awesome'
+In [7]: await rpc.close()
 ```

deltachat-rpc-client/examples/echobot.py

@@ -7,7 +7,7 @@ import deltachat_rpc_client as dc
 
 
 async def main():
-    async with dc.start_rpc_server() as rpc:
+    async with dc.Rpc() as rpc:
         deltachat = dc.Deltachat(rpc)
         system_info = await deltachat.get_system_info()
         logging.info("Running deltachat core %s", system_info["deltachat_core_version"])

deltachat-rpc-client/src/deltachat_rpc_client/__init__.py

@@ -2,4 +2,4 @@ from .account import Account
 from .contact import Contact
 from .deltachat import Deltachat
 from .message import Message
-from .rpc import Rpc, start_rpc_server
+from .rpc import Rpc

deltachat-rpc-client/src/deltachat_rpc_client/pytestplugin.py

@@ -8,7 +8,7 @@ import pytest_asyncio
 
 from .account import Account
 from .deltachat import Deltachat
-from .rpc import start_rpc_server
+from .rpc import Rpc
 
 
 async def get_temp_credentials() -> dict:
@@ -42,7 +42,8 @@ class ACFactory:
 @pytest_asyncio.fixture
 async def rpc(tmp_path) -> AsyncGenerator:
     env = {**os.environ, "DC_ACCOUNTS_PATH": str(tmp_path / "accounts")}
-    async with start_rpc_server(env=env) as rpc:
+    rpc_server = Rpc(env=env)
+    async with rpc_server as rpc:
         yield rpc
 
 

deltachat-rpc-client/src/deltachat_rpc_client/rpc.py

@@ -1,6 +1,5 @@
 import asyncio
 import json
-from contextlib import asynccontextmanager
 from typing import Any, AsyncGenerator, Dict, Optional
 
 
@@ -9,8 +8,19 @@ class JsonRpcError(Exception):
 
 
 class Rpc:
-    def __init__(self, process: asyncio.subprocess.Process) -> None:
-        self.process = process
+    def __init__(self, *args, **kwargs):
+        """The given arguments will be passed to asyncio.create_subprocess_exec()"""
+        self.args = args
+        self.kwargs = kwargs
+
+    async def start(self) -> None:
+        self.process = await asyncio.create_subprocess_exec(
+            "deltachat-rpc-server",
+            stdin=asyncio.subprocess.PIPE,
+            stdout=asyncio.subprocess.PIPE,
+            *self.args,
+            **self.kwargs
+        )
         self.event_queues: Dict[int, asyncio.Queue] = {}
         self.id = 0
         self.reader_task = asyncio.create_task(self.reader_loop())
@@ -18,6 +28,18 @@ class Rpc:
         # Map from request ID to `asyncio.Future` returning the response.
         self.request_events: Dict[int, asyncio.Future] = {}
 
+    async def close(self) -> None:
+        """Terminate RPC server process and wait until the reader loop finishes."""
+        self.process.terminate()
+        await self.reader_task
+
+    async def __aenter__(self):
+        await self.start()
+        return self
+
+    async def __aexit__(self, exc_type, exc, tb):
+        await self.close()
+
     async def reader_loop(self) -> None:
         while True:
             line = await self.process.stdout.readline()
@@ -37,11 +59,6 @@ class Rpc:
             else:
                 print(response)
 
-    async def close(self) -> None:
-        """Terminate RPC server process and wait until the reader loop finishes."""
-        self.process.terminate()
-        await self.reader_task
-
     async def wait_for_event(self, account_id: int) -> Optional[dict]:
         """Waits for the next event from the given account and returns it."""
         if account_id in self.event_queues:
@@ -73,20 +90,3 @@ class Rpc:
                 return response["result"]
 
         return method
-
-
-@asynccontextmanager
-async def start_rpc_server(*args, **kwargs) -> AsyncGenerator:
-    """The given arguments will be passed to asyncio.create_subprocess_exec()"""
-    proc = await asyncio.create_subprocess_exec(
-        "deltachat-rpc-server",
-        stdin=asyncio.subprocess.PIPE,
-        stdout=asyncio.subprocess.PIPE,
-        *args,
-        **kwargs
-    )
-    rpc = Rpc(proc)
-    try:
-        yield rpc
-    finally:
-        await rpc.close()