1 files changed, 191 insertions, 0 deletions
diff --git a/nixpkgs/nixos/modules/services/monitoring/apcupsd.nix b/nixpkgs/nixos/modules/services/monitoring/apcupsd.nix
new file mode 100644
index 00000000000..75218aa1d46
--- /dev/null
+++ b/nixpkgs/nixos/modules/services/monitoring/apcupsd.nix
@@ -0,0 +1,191 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.apcupsd;
+
+  configFile = pkgs.writeText "apcupsd.conf" ''
+    ## apcupsd.conf v1.1 ##
+    # apcupsd complains if the first line is not like above.
+    ${cfg.configText}
+    SCRIPTDIR ${toString scriptDir}
+  '';
+
+  # List of events from "man apccontrol"
+  eventList = [
+    "annoyme"
+    "battattach"
+    "battdetach"
+    "changeme"
+    "commfailure"
+    "commok"
+    "doreboot"
+    "doshutdown"
+    "emergency"
+    "failing"
+    "killpower"
+    "loadlimit"
+    "mainsback"
+    "onbattery"
+    "offbattery"
+    "powerout"
+    "remotedown"
+    "runlimit"
+    "timeout"
+    "startselftest"
+    "endselftest"
+  ];
+
+  shellCmdsForEventScript = eventname: commands: ''
+    echo "#!${pkgs.runtimeShell}" > "$out/${eventname}"
+    echo '${commands}' >> "$out/${eventname}"
+    chmod a+x "$out/${eventname}"
+  '';
+
+  eventToShellCmds = event: if builtins.hasAttr event cfg.hooks then (shellCmdsForEventScript event (builtins.getAttr event cfg.hooks)) else "";
+
+  scriptDir = pkgs.runCommand "apcupsd-scriptdir" { preferLocalBuild = true; } (''
+    mkdir "$out"
+    # Copy SCRIPTDIR from apcupsd package
+    cp -r ${pkgs.apcupsd}/etc/apcupsd/* "$out"/
+    # Make the files writeable (nix will unset the write bits afterwards)
+    chmod u+w "$out"/*
+    # Remove the sample event notification scripts, because they don't work
+    # anyways (they try to send mail to "root" with the "mail" command)
+    (cd "$out" && rm changeme commok commfailure onbattery offbattery)
+    # Remove the sample apcupsd.conf file (we're generating our own)
+    rm "$out/apcupsd.conf"
+    # Set the SCRIPTDIR= line in apccontrol to the dir we're creating now
+    sed -i -e "s|^SCRIPTDIR=.*|SCRIPTDIR=$out|" "$out/apccontrol"
+    '' + concatStringsSep "\n" (map eventToShellCmds eventList)
+
+  );
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.apcupsd = {
+
+      enable = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          Whether to enable the APC UPS daemon. apcupsd monitors your UPS and
+          permits orderly shutdown of your computer in the event of a power
+          failure. User manual: http://www.apcupsd.com/manual/manual.html.
+          Note that apcupsd runs as root (to allow shutdown of computer).
+          You can check the status of your UPS with the "apcaccess" command.
+        '';
+      };
+
+      configText = mkOption {
+        default = ''
+          UPSTYPE usb
+          NISIP 127.0.0.1
+          BATTERYLEVEL 50
+          MINUTES 5
+        '';
+        type = types.lines;
+        description = ''
+          Contents of the runtime configuration file, apcupsd.conf. The default
+          settings makes apcupsd autodetect USB UPSes, limit network access to
+          localhost and shutdown the system when the battery level is below 50
+          percent, or when the UPS has calculated that it has 5 minutes or less
+          of remaining power-on time. See man apcupsd.conf for details.
+        '';
+      };
+
+      hooks = mkOption {
+        default = {};
+        example = {
+          doshutdown = ''# shell commands to notify that the computer is shutting down'';
+        };
+        type = types.attrsOf types.lines;
+        description = ''
+          Each attribute in this option names an apcupsd event and the string
+          value it contains will be executed in a shell, in response to that
+          event (prior to the default action). See "man apccontrol" for the
+          list of events and what they represent.
+
+          A hook script can stop apccontrol from doing its default action by
+          exiting with value 99. Do not do this unless you know what you're
+          doing.
+        '';
+      };
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    assertions = [ {
+      assertion = let hooknames = builtins.attrNames cfg.hooks; in all (x: elem x eventList) hooknames;
+      message = ''
+        One (or more) attribute names in services.apcupsd.hooks are invalid.
+        Current attribute names: ${toString (builtins.attrNames cfg.hooks)}
+        Valid attribute names  : ${toString eventList}
+      '';
+    } ];
+
+    # Give users access to the "apcaccess" tool
+    environment.systemPackages = [ pkgs.apcupsd ];
+
+    # NOTE 1: apcupsd runs as root because it needs permission to run
+    # "shutdown"
+    #
+    # NOTE 2: When apcupsd calls "wall", it prints an error because stdout is
+    # not connected to a tty (it is connected to the journal):
+    #   wall: cannot get tty name: Inappropriate ioctl for device
+    # The message still gets through.
+    systemd.services.apcupsd = {
+      description = "APC UPS Daemon";
+      wantedBy = [ "multi-user.target" ];
+      preStart = "mkdir -p /run/apcupsd/";
+      serviceConfig = {
+        ExecStart = "${pkgs.apcupsd}/bin/apcupsd -b -f ${configFile} -d1";
+        # TODO: When apcupsd has initiated a shutdown, systemd always ends up
+        # waiting for it to stop ("A stop job is running for UPS daemon"). This
+        # is weird, because in the journal one can clearly see that apcupsd has
+        # received the SIGTERM signal and has already quit (or so it seems).
+        # This reduces the wait time from 90 seconds (default) to just 5. Then
+        # systemd kills it with SIGKILL.
+        TimeoutStopSec = 5;
+      };
+      unitConfig.Documentation = "man:apcupsd(8)";
+    };
+
+    # A special service to tell the UPS to power down/hibernate just before the
+    # computer shuts down. (The UPS has a built in delay before it actually
+    # shuts off power.) Copied from here:
+    # http://forums.opensuse.org/english/get-technical-help-here/applications/479499-apcupsd-systemd-killpower-issues.html
+    systemd.services.apcupsd-killpower = {
+      description = "APC UPS Kill Power";
+      after = [ "shutdown.target" ]; # append umount.target?
+      before = [ "final.target" ];
+      wantedBy = [ "shutdown.target" ];
+      unitConfig = {
+        ConditionPathExists = "/run/apcupsd/powerfail";
+        DefaultDependencies = "no";
+      };
+      serviceConfig = {
+        Type = "oneshot";
+        ExecStart = "${pkgs.apcupsd}/bin/apcupsd --killpower -f ${configFile}";
+        TimeoutSec = "infinity";
+        StandardOutput = "tty";
+        RemainAfterExit = "yes";
+      };
+    };
+
+  };
+
+}