Ensure mitmproxy uses /home/mitmproxy/.mitmproxy as the config directory
even if the mapped volume is owned by host root, preventing fallback to
/root/.mitmproxy and CA file regeneration on redeploy. Add `HOME` env confdir
in entrypoint to enforce this behavior.
Fixesmitmproxy/mitmproxy#7597
Current docker-entrypoint.sh [0][1] runs
gosu mitmproxy "$@"
for mitmproxy, mitmdump and mitmweb. There is a problem with this
approach: bash becomes a parent process for mitmproxy [2][3], but when
signals are sent by docker-compose to mitmproxy container they are sent
to bash, but they are not delivered to mitmproxy [4]. This leads to a
slow shutdown of the container, because by default docker sends SIGTERM,
waits for 10 seconds and then sends SIGKILL if the container is still
alive [5].
This patch solves the issue by replacing bash process with mitmproxy
entirely using "exec" - this way the signals are delivered to mitmproxy
directly.
To test the patch a Dockerfile [6] that applies the patch to the release
image from the dockerhub could be used along with slighly modified
compose.yml [7]. With the patch bash is no longer running inside the
container [8] and the `docker compose down` time on my machine drops
from 10.3s to 0.5s [9].
0. https://github.com/mitmproxy/mitmproxy/blob/main/release/docker/docker-entrypoint.sh
1. To confirm that this is what's actually in the image:
```
> docker run mitmproxy/mitmproxy grep gosu /usr/local/bin/docker-entrypoint.sh
gosu mitmproxy "$@"
```
2. compose.yaml
```
services:
mitmproxy-test:
image: mitmproxy/mitmproxy
command: ["mitmweb"]
# https://github.com/mitmproxy/mitmproxy/issues/5727
stdin_open: true
tty: true
```
3. We can see that the parent PID for mitmweb is the pid of bash.
```
> docker compose up -d
[+] Running 2/2
⠿ Network mitmproxy_default Created 0.1s
⠿ Container mitmproxy-mitmproxy-test-1 Started 0.5s
> docker compose top
mitmproxy-mitmproxy-test-1
UID PID PPID C STIME TTY TIME CMD
root 31227 31202 0 16:12 pts/0 00:00:00 /bin/bash /usr/local/bin/docker-entrypoint.sh mitmweb
root 31314 31227 1 16:12 pts/0 00:00:01 /usr/local/bin/python /usr/local/bin/mitmweb
```
4. https://unix.stackexchange.com/a/196053
5. https://docs.docker.com/compose/faq/#why-do-my-services-take-10-seconds-to-recreate-or-stop
6. Dockerfile:
```
FROM mitmproxy/mitmproxy
RUN sed -i 's/^ gosu mitmproxy/ exec gosu mitmproxy/' /usr/local/bin/docker-entrypoint.sh
```
7. compose.yaml to build an image from Dockerfile and use it:
```
services:
mitmproxy-test:
build:
dockerfile: Dockerfile
context: .
command: ["mitmweb"]
# https://github.com/mitmproxy/mitmproxy/issues/5727
stdin_open: true
tty: true
```
8. With the patch:
```
> docker compose top
mitmproxy-mitmproxy-test-1
UID PID PPID C STIME TTY TIME CMD
root 4994 4970 50 17:00 pts/0 00:00:02 /usr/local/bin/python /usr/local/bin/mitmweb
```
9. Without the patch:
```
> docker compose down
[+] Running 2/2
⠿ Container mitmproxy-mitmproxy-test-1 Removed 10.2s
⠿ Network mitmproxy_default Removed 0.1s
```
With the patch:
```
> docker compose down
[+] Running 2/2
⠿ Container mitmproxy-mitmproxy-test-1 Removed 0.4s
⠿ Network mitmproxy_default Removed 0.1s
```
