1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
"""
Some light wrappers around Python's multiprocessing, to deal with cleanly
starting child processes.
"""
from __future__ import annotations
import multiprocessing
import os
import sys
from multiprocessing.context import SpawnProcess
from socket import socket
from typing import Callable, Optional
from uvicorn.config import Config
multiprocessing.allow_connection_pickling()
spawn = multiprocessing.get_context("spawn")
def get_subprocess(
config: Config,
target: Callable[..., None],
sockets: list[socket],
) -> SpawnProcess:
"""
Called in the parent process, to instantiate a new child process instance.
The child is not yet started at this point.
* config - The Uvicorn configuration instance.
* target - A callable that accepts a list of sockets. In practice this will
be the `Server.run()` method.
* sockets - A list of sockets to pass to the server. Sockets are bound once
by the parent process, and then passed to the child processes.
"""
# We pass across the stdin fileno, and reopen it in the child process.
# This is required for some debugging environments.
stdin_fileno: Optional[int]
try:
stdin_fileno = sys.stdin.fileno()
except OSError:
stdin_fileno = None
kwargs = {
"config": config,
"target": target,
"sockets": sockets,
"stdin_fileno": stdin_fileno,
}
return spawn.Process(target=subprocess_started, kwargs=kwargs)
def subprocess_started(
config: Config,
target: Callable[..., None],
sockets: list[socket],
stdin_fileno: int | None,
) -> None:
"""
Called when the child process starts.
* config - The Uvicorn configuration instance.
* target - A callable that accepts a list of sockets. In practice this will
be the `Server.run()` method.
* sockets - A list of sockets to pass to the server. Sockets are bound once
by the parent process, and then passed to the child processes.
* stdin_fileno - The file number of sys.stdin, so that it can be reattached
to the child process.
"""
# Re-open stdin.
if stdin_fileno is not None:
sys.stdin = os.fdopen(stdin_fileno)
# Logging needs to be setup again for each child.
config.configure_logging()
# Now we can call into `Server.run(sockets=sockets)`
target(sockets=sockets)
|
