Awesome

Example in rust of the core part of foreman

It is an implementation example in rust of IO processing and signal processing in multithread as done by foreman of ruby.

IO process in multi thread
handle signlas in another thread
child wait in another thread

Since it is a sample, unlike foreman, it does not have the flexibility to define a process in Procfile.
The processes that can be executed are as follows.

process	concurrency	command
exit_0	1	`sleep 5 && echo 'success' && exit 0;`
exit_1	1	`sleep 5 && echo 'failed' && exit 1;`
loop	2	`while :; do sleep 1 && echo 'hello world'; done;`

The behavior is that when exit_0 or exit_1 exits after 5 seconds, the remaining child processes will be signaled with a SIGTERM and killed.

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.08s
     Running `target/debug/eg_foreman`
system    | exit_0.1  start at pid: 11350
system    | loop.1    start at pid: 11351
system    | exit_1.1  start at pid: 11352
system    | loop.2    start at pid: 11353
loop.2    | hello world
loop.1    | hello world
loop.1    | hello world
loop.2    | hello world
loop.2    | hello world
loop.1    | hello world
loop.1    | hello world
loop.2    | hello world
exit_1.1  | failed
exit_0.1  | success
system    | sending SIGTERM for loop.1    at pid 11351
system    | sending SIGTERM for exit_1.1  at pid 11352
system    | sending SIGTERM for loop.2    at pid 11353
system    | exit 0

</details>

If <kbd>ctrl-c</kbd> is detected within 5 seconds, SIGTERM will be sent to all child processes and the process will be killed.

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.09s
     Running `target/debug/eg_foreman`
system    | exit_0.1  start at pid: 43204
system    | loop.1    start at pid: 43205
system    | exit_1.1  start at pid: 43206
system    | loop.2    start at pid: 43207
loop.2    | hello world
loop.1    | hello world
loop.1    | hello world
loop.2    | hello world
^Csystem  | ctrl-c detected
system    | sending SIGTERM for children
system    | sending SIGTERM for exit_0.1  at pid 43204
system    | sending SIGTERM for loop.1    at pid 43205
system    | sending SIGTERM for exit_1.1  at pid 43206
system    | sending SIGTERM for loop.2    at pid 43207
system    | exit 0

</details>

If you generalize this, you can make a foreman. You did it. 🎉

Development

Executte Test

cargo test
# or
cargo test -- --nocapture

Environment

name	desc	defaul
COLOR	Color the output	true

Reference

I really referred to the implementation of the following repository.

fors
arpx