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feat(users/Profpatsch): add shortcuttable

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Initial mockup for a tool which restarts its subprocess on SIGHUP, and
stops everything on SIGTERM and SIGINT.

Change-Id: Ie5260d73c2663d1821eb6623e2bc61d16f6c92cd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11168
Autosubmit: Profpatsch <mail@profpatsch.de>
Reviewed-by: Profpatsch <mail@profpatsch.de>
Tested-by: BuildkiteCI
This commit is contained in:
Profpatsch 2024-03-16 22:33:20 +01:00 committed by clbot
parent 16461c4100
commit 8335076173
1 changed files with 172 additions and 0 deletions
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172
users/Profpatsch/shortcuttable/default.nix Normal file
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{ depot, lib, pkgs, ... }:
let
# run prog... and restart whenever SIGHUP is received
#
# this is useful for binding to a shortcut.
#
# Unfortunately, this requires a bunch of workarounds around the semantics of `trap`,
# but the general idea of bundling subprocesses with `setsid` is somewhat sound.
runShortcuttable =
depot.nix.writeExecline "run-shortcuttable" { } [
"importas"
"-i"
"run"
"XDG_RUNTIME_DIR"
"if"
[ "mkdir" "-p" "\${run}/shortcuttable/test" ]
"getpid"
"-E"
"controlpid"
savePid
"\${run}/shortcuttable/test/control"
"$controlpid"
# start the program
"background"
[
startSaveSID
"\${run}/shortcuttable/test/running-sid"
"$@"
]
"trap"
[
"SIGHUP"
[
"if"
[ "echo" "got hup" ]
"if"
[
"if"
[ "echo" "killing our child processes" ]
"envfile"
"\${run}/shortcuttable/test/running-sid"
"importas"
"-ui"
"child_sid"
"pid"
"foreground"
[ "ps" "-f" "--sid" "$child_sid" ]
ctrlCCtrlDSid
"$child_sid"
]
"if"
[ "echo" "restarting into" "$@" ]
"background"
[
startSaveSID
"\${run}/shortcuttable/test/running-sid"
"$@"
]
]
"SIGTERM"
[
(killShortcuttable { signal = "TERM"; })
"\${run}/shortcuttable/test/running-sid"
"\${run}/shortcuttable/test/exit"
]
"SIGINT"
[
(killShortcuttable { signal = "INT"; })
"\${run}/shortcuttable/test/running-sid"
"\${run}/shortcuttable/test/exit"
]
]
depot.users.Profpatsch.execline.setsid
"child_sid"
"getpid"
"-E"
"exitpid"
savePid
"\${run}/shortcuttable/test/exit"
"$exitpid"
"sleep"
"infinity"
];
killShortcuttable = { signal }: depot.nix.writeExecline "kill-shortcuttable" { readNArgs = 2; } [
"if"
[ "echo" "got SIG${signal}, quitting" ]
"if"
[
"envfile"
"$1"
"importas"
"-ui"
"child_sid"
"pid"
"foreground"
[ "ps" "-f" "--sid" "$child_sid" ]
ctrlCCtrlDSid
"$child_sid"
]
"if"
[ "echo" "killing shortcuttable loop" ]
"envfile"
"$2"
"importas"
"-ui"
"trap_pid"
"pid"
"foreground"
[ "ps" "-fp" "$trap_pid" ]
"kill"
"--signal"
signal
"$trap_pid"
];
savePid = depot.nix.writeExecline "save-pid" { readNArgs = 2; } [
"if"
[ "echo" "saving process:" ]
"if"
[ "ps" "-fp" "$2" ]
"if"
[
"redirfd"
"-w"
"1"
"$1"
"printf"
"pid = %s\n"
"$2"
]
"$@"
];
# try to kill process, first with SIGTERM then SIGQUIT (in case it’s a repl)
ctrlCCtrlDSid = depot.nix.writeExecline "ctrl-c-ctrl-d" { readNArgs = 1; } [
"ifelse"
"-n"
[ "kill" "--signal" "TERM" "--" "-\${1}" ]
[
"if"
[ "echo" "could not kill via SIGTERM, trying SIGQUIT …" ]
"ifelse"
"-n"
[ "kill" "--signal" "QUIT" "--" "-\${1}" ]
[ "echo" "SIGQUIT failed as well, keeping it running" ]
"$@"
]
"$@"
];
startSaveSID = depot.nix.writeExecline "start-save-sid" { readNArgs = 1; } [
depot.users.Profpatsch.execline.setsid
"child_sid"
"importas"
"-ui"
"child_sid"
"child_sid"
"if"
[ "echo" "children sid:" "$child_sid" ]
savePid
"$1"
"$child_sid"
"$@"
];
in
runShortcuttable