p/nix-top: import last version from nixpkgs

overlays/nibylandia.nix

@@ -3,6 +3,7 @@ let inherit (self) lib;
 in {
   cass = super.callPackage ../pkgs/cass.nix { };
   notbot = super.callPackage ../pkgs/notbot.nix { };
+  nix-top = super.callPackage ../pkgs/nix-top { };
   glitch-soc = let
     emoji-reactions = import ../pkgs/glitch-soc/emoji.nix {
       inherit (super) fetchpatch fetchurl;

pkgs/nix-top/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 Samuel Dionne-Riel
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

pkgs/nix-top/default.nix

@@ -0,0 +1,46 @@
+{ stdenv
+, lib
+, fetchFromGitHub
+, ruby
+, makeWrapper
+, getent               # /etc/passwd
+, ncurses              # tput
+, binutils-unwrapped   # strings
+, coreutils
+, findutils
+}:
+
+# No gems used, so mkDerivation is fine.
+let
+  additionalPath = lib.makeBinPath [ getent ncurses binutils-unwrapped coreutils findutils ];
+in
+stdenv.mkDerivation rec {
+  pname = "nix-top";
+  version = "0.3.0";
+
+  src = ./.;
+
+  nativeBuildInputs = [
+    makeWrapper
+  ];
+
+  buildInputs = [
+    ruby
+  ];
+
+  installPhase = ''
+    mkdir -p $out/libexec/nix-top
+    install -D -m755 ./nix-top $out/bin/nix-top
+    wrapProgram $out/bin/nix-top \
+      --prefix PATH : "$out/libexec/nix-top:${additionalPath}"
+  '' + lib.optionalString stdenv.isDarwin ''
+    ln -s /bin/stty $out/libexec/nix-top
+  '';
+
+  meta = with lib; {
+    description = "Tracks what nix is building";
+    license = licenses.mit;
+    platforms = platforms.linux ++ platforms.darwin ++ platforms.freebsd;
+    mainProgram = "nix-top";
+  };
+}

pkgs/nix-top/nix-top

@@ -0,0 +1,166 @@
+#!/nix/store/c4bdx4dja3h06xg1ksv3f51alp5a44li-ruby-3.1.5/bin/ruby
+
+require "shellwords"
+require "optparse"
+require "io/wait"
+
+DEFAULTS = {
+  delay: 0.5,
+  once: false,
+}.freeze
+
+options = DEFAULTS.dup
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: nix-top [options]"
+
+  opts.on("-d", "--delay [seconds]", Numeric, "In seconds (default: #{DEFAULTS[:delay]})") do |v|
+    options[:delay] = v
+  end
+  opts.on("-1", "--once", "Only run once (generates one screen)") do |v|
+    options[:once] = v;
+  end
+end.parse!
+
+VT_CLEAR_LINE=`tput el`
+VT_CLEAR_REST=`tput ed`
+VT_HOME=`tput cup 0 0`
+
+def stty(*flags)
+  `#{["stty", *flags].shelljoin}`
+end
+
+# Returns [width, height] of the terminal.
+def size
+  `echo 'cols\nlines' | tput -S`.strip.split("\n").map(&:to_i)
+end
+
+def build_users
+  `getent group nixbld`.strip.split(":").last.split(",")
+end
+
+def active_build_users()
+  build_users.select do |name|
+    `pgrep -fu #{name.shellescape}`
+    $? == 0
+  end
+end
+
+# Returns a mostly correct snapshot of the PIDs for processes building
+# things, in a Hash indexed by build user.
+def get_processes()
+  active_build_users.map do |user|
+    pids = `pgrep -u #{user.shellescape}`
+        .strip.split("\n")
+        .map(&:to_i)
+        .sort
+    path = get_out_path(user, pids.first)
+
+    [
+      user,
+      [path, pids]
+    ]
+  end
+end
+
+# Gets either the out path, or an approximation, depending whether
+# or not it can peek into processes.
+def get_out_path(user, pid)
+  begin
+  # whew!
+  build_dir = `find -L /tmp -maxdepth 1 -user #{user.shellescape} -exec stat --printf '%Z:%n\\n' '{}' ';' | sort -n`
+    .strip
+    .split("\n")
+    .last
+    .split(":")
+    .last
+  rescue
+    "(unknown)"
+  end
+  begin
+    file = "#{build_dir}/env-vars"
+    # This can fail if the process disappears while trying to read.
+    # This is why we rescue everything
+    # (This also could fail due to missing `out=` and we get free rescue)
+    File.read(file)                          # Reads process' environment
+      .split("\n")                           # (which is a null-delimited list)
+      .grep(/^declare -x out=/)              # Keep out paths
+      .first                                 # Keep the only result
+      .split("\"").last                      # Keep only the value
+  rescue
+    build_dir
+  end
+end
+
+def per_output_infos(user, pids, path)
+  [
+    ":: (%s) → %s" % [user, path],
+    `ps -o uid,pid,ppid,stime,time,command -U "#{user.shellescape}"`
+  ]
+end
+
+# A "screenful" of information
+# Does not trim output to fit in one terminal screen.
+def print_screen()
+  processes = get_processes()
+
+  lines = []
+  sep = [
+    "",
+    " * * * ",
+    "",
+  ]
+
+  lines << "Summary per output"
+  lines.concat(processes.map do |user, (path, pids)|
+    "    %4d → %s" % [pids.length, path]
+  end)
+  lines.concat(sep)
+  lines.concat(processes.map do |user, (path, pids)|
+    per_output_infos(user, pids, path)
+  end)
+
+  # This is hacky and round-about...
+  # but the consumers will assume this gives *lines*.
+  # I don't want to ensure everything is already a line.
+  # So, uh, joining everything and re-splitting is done for now.
+  # TODO : better API for writing a screen.
+  lines.flatten.join("\n").split("\n")
+end
+
+# Trims the "screenful" to fit into the screen.
+def display(screen)
+  width, height = size
+  screen = screen[0...height].map do |line|
+    line[0...width] + VT_CLEAR_LINE
+  end.join("\n").strip
+
+  print VT_HOME + screen + VT_CLEAR_REST
+end
+
+# ------------------------------------------------------------------------------
+
+# Ensures no backtrace on ^C
+Signal.trap("INT") do
+  exit
+end
+
+at_exit {
+  stty($saved_stty)
+  puts ""
+  exit
+}
+$saved_stty = stty("-g").strip
+stty("-echo", "-icanon")
+
+display(print_screen)
+
+exit if options[:once]
+
+while true do
+  if $stdin.wait_readable(options[:delay]) then
+    exit if $stdin.readpartial(4096).include? "q"
+  end
+
+  display(print_screen)
+end