Watch not reacting inside of docker, but run_process does

[Jim-Holmstroem]

Description

Having issue with the watch/awatch examples not generating changes inside of docker.
Tried with mounted file, mounted folder and a file inside of the container.
In the same environment watchfiles and run_process triggers as expected.
A raw-event is still logged (with debug=True) for watch/awatch, but nothing more happens

raw-event: Event { kind: Modify(Metadata(WriteTime)), paths: ["watch-this-folder/file"], attr:tracker: None, attr:flag: None, attr:info: None, attr:source: None }

Outside of docker all versions (see below) works as expected and all versions trigger on changes.

The same behavior is observed with both PollWatcher and INotifyWatcher (via WATCHFILES_FORCE_POLLING=1).

Example Code

The different examples and some docker to set up the environment:
https://github.com/Jim-Holmstroem/watch-issue

Run with

WATCH_THIS=watch-this-folder WATCHFILES_FORCE_POLLING=1 docker-compose up --build

Watchfiles Output

$ WATCH_THIS=watch-this-folder WATCHFILES_FORCE_POLLING=1 docker-compose up --build

watch-issue-watchfiles-1    | [18:34:31] watchfiles v0.19.0 __  path="/test/watch-this-folder" target="echo reloaded" (command) filter=DefaultFilter...
watch-issue-watchfiles-1    | [18:34:31] running "echo reloaded" as command
watch-issue-watchfiles-1    | watcher: PollWatcher { watches: Mutex { data: <locked>, poisoned: false, .. }, data_builder: Mutex { data: <locked>, poisoned: false, .. }, want_to_stop: false, delay: 300ms }
watch-issue-watchfiles-1    | reloaded
watch-issue-test-1          | watcher: PollWatcher { watches: Mutex { data: {"watch-this-folder": WatchData { root: "watch-this-folder", is_recursive: true, all_path_data: {"watch-this-folder/file": PathData { mtime: 1681929146, hash: None, last_check: Instant { tv_sec: 258857, tv_nsec: 375153812 } }, "watch-this-folder": PathData { mtime: 1681924805, hash: None, last_check: Instant { tv_sec: 258857, tv_nsec: 375153812 } }} }}, poisoned: false, .. }, data_builder: Mutex { data: DataBuilder { build_hasher: None, now: Instant { tv_sec: 258857, tv_nsec: 375153812 } }, poisoned: false, .. }, want_to_stop: false, delay: 300ms }
watch-issue-process-test-1  | watcher: PollWatcher { watches: Mutex { data: <locked>, poisoned: false, .. }, data_builder: Mutex { data: <locked>, poisoned: false, .. }, want_to_stop: false, delay: 300ms }
watch-issue-process-test-1  | changed
watch-issue-async-test-1    | watcher: PollWatcher { watches: Mutex { data: {"watch-this-folder": WatchData { root: "watch-this-folder", is_recursive: true, all_path_data: {"watch-this-folder": PathData { mtime: 1681924805, hash: None, last_check: Instant { tv_sec: 258857, tv_nsec: 424468683 } }, "watch-this-folder/file": PathData { mtime: 1681929146, hash: None, last_check: Instant { tv_sec: 258857, tv_nsec: 424468683 } }} }}, poisoned: false, .. }, data_builder: Mutex { data: <locked>, poisoned: false, .. }, want_to_stop: false, delay: 300ms }
watch-issue-watchfiles-1    | [18:34:36] rust notify timeout, continuing
watch-issue-watchfiles-1    | [18:34:41] rust notify timeout, continuing

...

$ echo "line" >> watch-this-folder/file

...

watch-issue-test-1          | raw-event: Event { kind: Modify(Metadata(WriteTime)), paths: ["watch-this-folder/file"], attr:tracker: None, attr:flag: None, attr:info: None, attr:source: None }
watch-issue-process-test-1  | raw-event: Event { kind: Modify(Metadata(WriteTime)), paths: ["watch-this-folder/file"], attr:tracker: None, attr:flag: None, attr:info: None, attr:source: None }
watch-issue-watchfiles-1    | raw-event: Event { kind: Modify(Metadata(WriteTime)), paths: ["/test/watch-this-folder/file"], attr:tracker: None, attr:flag: None, attr:info: None, attr:source: None }
watch-issue-async-test-1    | raw-event: Event { kind: Modify(Metadata(WriteTime)), paths: ["watch-this-folder/file"], attr:tracker: None, attr:flag: None, attr:info: None, attr:source: None }
watch-issue-process-test-1  | process already dead, exit code: 0
watch-issue-watchfiles-1    | [18:35:02] 1 change detected: {(<Change.modified: 2>, '/test/watch-this-folder/file')}
watch-issue-watchfiles-1    | [18:35:02] process already dead, exit code: 0
watch-issue-watchfiles-1    | reloaded
watch-issue-process-test-1  | changed

Operating System & Architecture

Linux-6.2.10-arch1-1-x86_64-with-glibc2.37
#1 SMP PREEMPT_DYNAMIC Fri, 07 Apr 2023 02:10:43 +0000

Environment

Docker version 23.0.3, build 3e7cbfdee1; Docker Compose version 2.17.2

Python & Watchfiles Version

python: 3.10.10 (main, Mar 5 2023, 22:26:53) [GCC 12.2.1 20230201], watchfiles: 0.19.0

Rust & Cargo Version

No response

[Jim-Holmstroem]

Forgot that you have to print(..., flush=True) if you run inside of docker, so not a bug.
Tested it with print(..., flush=True) and everything works as expected.

Closing