{ depot, pkgs, ... }: let bins = depot.nix.getBins pkgs.coreutils [ "printf" "echo" "cat" "printenv" "tee" ] // depot.nix.getBins pkgs.bash [ "bash" ] // depot.nix.getBins pkgs.fdtools [ "multitee" ] ; # Print `msg` and and argv to stderr, then execute into argv debugExec = msg: depot.nix.writeExecline "debug-exec" { } [ "if" [ "fdmove" "-c" "1" "2" "if" [ bins.printf "%s: " msg ] "if" [ bins.echo "$@" ] ] "$@" ]; # Print stdin to stderr and stdout eprint-stdin = depot.nix.writeExecline "eprint-stdin" { } [ "pipeline" [ bins.multitee "0-1,2" ] "$@" ]; # Assume the input on stdin is netencode, pretty print it to stderr and forward it to stdout eprint-stdin-netencode = depot.nix.writeExecline "eprint-stdin-netencode" { } [ "pipeline" [ # move stdout to 3 "fdmove" "3" "1" # the multitee copies stdin to 1 (the other pipeline end) and 3 (the stdout of the outer pipeline block) "pipeline" [ bins.multitee "0-1,3" ] # make stderr the stdout of pretty, merging with the stderr of pretty "fdmove" "-c" "1" "2" depot.users.Profpatsch.netencode.pretty ] "$@" ]; # print the given environment variable in $1 to stderr, then execute into the rest of argv eprintenv = depot.nix.writeExecline "eprintenv" { readNArgs = 1; } [ "ifelse" [ "fdmove" "-c" "1" "2" bins.printenv "$1" ] [ "$@" ] "if" [ depot.tools.eprintf "eprintenv: could not find \"\${1}\" in the environment\n" ] "$@" ]; # Split stdin into two commands, given by a block and the rest of argv # # Example (execline): # # pipeline [ echo foo ] # split-stdin [ fdmove 1 2 foreground [ cat ] echo "bar" ] cat # # stdout: foo\n # stderr: foo\nbar\n split-stdin = depot.nix.writeExecline "split-stdin" { argMode = "env"; } [ "pipeline" [ # this is horrible yes but the quickest way I knew how to implement it "runblock" "1" bins.bash "-c" ''${bins.tee} >("$@")'' "bash-split-stdin" ] "runblock" "-r" "1" ]; # remove everything but a few selected environment variables runInEmptyEnv = keepVars: let importas = pkgs.lib.concatMap (var: [ "importas" "-i" var var ]) keepVars; # we have to explicitely call export here, because PATH is probably empty export = pkgs.lib.concatMap (var: [ "${pkgs.execline}/bin/export" var ''''${${var}}'' ]) keepVars; in depot.nix.writeExecline "empty-env" { } (importas ++ [ "emptyenv" ] ++ export ++ [ "${pkgs.execline}/bin/exec" "$@" ]); in { inherit debugExec eprint-stdin eprint-stdin-netencode eprintenv split-stdin runInEmptyEnv ; }