restarting.md

Restarting Commands

Sometimes it's useful to have commands that exited with a non-zero status to restart automatically.
concurrently lets you configure how many times you wish for such a command to restart through the --restart-tries flag:

$ concurrently --restart-tries 2 "exit 1"
[0] exit 1 exited with code 1
[0] exit 1 restarted
[0] exit 1 exited with code 1
[0] exit 1 restarted
[0] exit 1 exited with code 1

Sometimes, it might be interesting to have commands wait before restarting.
To do this, simply set --restart-after to a the number of milliseconds you'd like to delay restarting.

$ concurrently -p time --restart-tries 1 --restart-after 3000 "exit 1"
[2024-09-01 23:43:55.871] exit 1 exited with code 1
[2024-09-01 23:43:58.874] exit 1 restarted
[2024-09-01 23:43:58.891] exit 1 exited with code 1

If a command is not having success spawning, you might want to instead apply an exponential back-off.
Set --restart-after exponential to have commands respawn with a 2^N seconds delay.

$ concurrently -p time --restart-tries 3 --restart-after exponential "exit 1"

[2024-09-01 23:49:01.124] exit 1 exited with code 1
[2024-09-01 23:49:02.127] exit 1 restarted
[2024-09-01 23:49:02.139] exit 1 exited with code 1
[2024-09-01 23:49:04.141] exit 1 restarted
[2024-09-01 23:49:04.157] exit 1 exited with code 1
[2024-09-01 23:49:08.158] exit 1 restarted
[2024-09-01 23:49:08.174] exit 1 exited with code 1