app_scheduler was a process group manager, launch and monitor mutiple processes' stopped state, cpu, mem usage.

process was describe as app job, started from Lua's os.execute() in background, so every process has its own working dir, shell env.

with processes' PID, we can monitor the them with 'ps u -p PID1 -p PID2', get every processes' CPU, MEM usage, detect stopped state, then restart them.

all these defined in job_spec.lua, with pre-defined variables, launcher and monitor functions.

support Linux/FreeBSD/macOS, Lua 5.2/5.3, LuaJIT-2.0.5, other version and environment not test.

• launch, monitor processes in group
• independent working dir, shell env
• start/stop process dynamically
• monitor processes' CPU, MEM, running or stopped state
• pure Lua/shell command

1. first compile busy_app_demo.c, then start from jobs

# gcc -Wall -O2 busy_app_demo.c -o busy_app.out # cc in FreeBSD
# lua app_scheduler.lua start job_spec.lua &

2. try kill one of them with PID, cause all jobs stop

# kill [one PID of busy_app.out]

or, to stop all 3 app jobs with

# lua app_scheduler.lua stop job_spec.lua

more in job_spec.lua.