Add meteocat exporter

Allows us to track ambient temperature changes and estimate the
temperature delta between the server room and exterior temperature.
We should be able to predict when we would need to stop the machines due
to excesive temperature as summer approaches.

m/hut/monitoring.nix

@@ -3,7 +3,9 @@
 {
   imports = [
     ../module/slurm-exporter.nix
+    ../module/meteocat-exporter.nix
     ./gpfs-probe.nix
+    ./nix-daemon-exporter.nix
   ];
 
   age.secrets.grafanaJungleRobotPassword = {
@@ -108,6 +110,8 @@
             "127.0.0.1:${toString config.services.prometheus.exporters.smartctl.port}"
             "127.0.0.1:9341" # Slurm exporter
             "127.0.0.1:9966" # GPFS custom exporter
+            "127.0.0.1:9999" # Nix-daemon custom exporter
+            "127.0.0.1:9929" # Meteocat custom exporter
             "127.0.0.1:${toString config.services.prometheus.exporters.blackbox.port}"
           ];
         }];

m/hut/nix-daemon-builds.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+# Locate nix daemon pid
+nd=$(pgrep -o nix-daemon)
+
+# Locate children of nix-daemon
+pids1=$(tr ' ' '\n' < "/proc/$nd/task/$nd/children")
+
+# For each children, locate 2nd level children
+pids2=$(echo "$pids1" | xargs -I @ /bin/sh -c 'cat /proc/@/task/*/children' | tr ' ' '\n')
+
+cat <<EOF
+HTTP/1.1 200 OK
+Content-Type: text/plain; version=0.0.4; charset=utf-8; escaping=values
+
+# HELP nix_daemon_build Nix daemon derivation build state.
+# TYPE nix_daemon_build gauge
+EOF
+
+for pid in $pids2; do
+  name=$(cat /proc/$pid/environ 2>/dev/null | tr '\0' '\n' | rg "^name=(.+)" - --replace '$1')
+  user=$(ps -o uname= -p "$pid")
+  if [ -n "$name" -a -n "$user" ]; then
+    printf 'nix_daemon_build{user="%s",name="%s"} 1\n' "$user" "$name"
+  fi
+done

m/hut/nix-daemon-exporter.nix

@@ -0,0 +1,23 @@
+{ pkgs, config, lib, ... }:
+let
+  script = pkgs.runCommand "nix-daemon-exporter.sh" { }
+    ''
+      cp ${./nix-daemon-builds.sh} $out;
+      chmod +x $out
+    ''
+  ;
+in
+{
+  systemd.services.nix-daemon-exporter = {
+    description = "Daemon to export nix-daemon metrics";
+    path = [ pkgs.procps pkgs.ripgrep ];
+    wantedBy = [ "default.target" ];
+    serviceConfig = {
+      Type = "simple";
+      ExecStart = "${pkgs.socat}/bin/socat TCP4-LISTEN:9999,fork EXEC:${script}";
+      # Needed root to read the environment, potentially unsafe
+      User = "root";
+      Group = "root";
+    };
+  };
+}

m/module/meteocat-exporter.nix

@@ -0,0 +1,17 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+{
+  systemd.services."prometheus-meteocat-exporter" = {
+    wantedBy = [ "multi-user.target" ];
+    after = [ "network.target" ];
+    serviceConfig = {
+      Restart = mkDefault "always";
+      PrivateTmp = mkDefault true;
+      WorkingDirectory = mkDefault "/tmp";
+      DynamicUser = mkDefault true;
+      ExecStart = "${pkgs.meteocat-exporter}/bin/meteocat-exporter";
+    };
+  };
+}

pkgs/meteocat-exporter/default.nix

@@ -0,0 +1,25 @@
+{ python3Packages, lib }:
+
+python3Packages.buildPythonApplication rec {
+  pname = "meteocat-exporter";
+  version = "1.0";
+
+  src = ./.;
+
+  doCheck = false;
+
+  build-system = with python3Packages; [
+    setuptools
+  ];
+
+  dependencies = with python3Packages; [
+    beautifulsoup4
+    lxml
+    prometheus-client
+  ];
+
+  meta = with lib; {
+    description = "MeteoCat Prometheus Exporter";
+    platforms = platforms.linux;
+  };
+}

pkgs/meteocat-exporter/meteocat-exporter

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+
+import time
+from prometheus_client import start_http_server, Gauge
+from bs4 import BeautifulSoup
+from urllib import request
+
+# Configuration -------------------------------------------
+meteo_station = "X8" # Barcelona - Zona Universitària
+listening_port = 9929
+update_period = 60 * 10 # Each 10 min
+# ---------------------------------------------------------
+
+metric_tmin = Gauge('meteocat_temp_min', 'Min temperature')
+metric_tmax = Gauge('meteocat_temp_max', 'Max temperature')
+metric_tavg = Gauge('meteocat_temp_avg', 'Average temperature')
+metric_srad = Gauge('meteocat_solar_radiation', 'Solar radiation')
+
+def update(st):
+    url = 'http://www.meteo.cat/observacions/xema/dades?codi=' + st
+    response = request.urlopen(url)
+    data = response.read()
+    soup = BeautifulSoup(data, 'lxml')
+    table = soup.find("table", {"class" : "tblperiode"})
+    rows = table.find_all('tr')
+    row = rows[-1] # Take the last row
+    row_data = []
+    header = row.find('th')
+    header_text = header.text.strip()
+    row_data.append(header_text)
+    for col in row.find_all('td'):
+        row_data.append(col.text)
+    try:
+        # Sometimes it will return '(s/d)' and fail to parse
+        metric_tavg.set(float(row_data[1]))
+        metric_tmax.set(float(row_data[2]))
+        metric_tmin.set(float(row_data[3]))
+        metric_srad.set(float(row_data[10]))
+    except:
+        pass
+
+if __name__ == '__main__':
+    start_http_server(port=listening_port, addr="localhost")
+    while True:
+        update(meteo_station)
+        time.sleep(update_period)

pkgs/meteocat-exporter/setup.py

@@ -0,0 +1,11 @@
+#!/usr/bin/env python
+
+from setuptools import setup, find_packages
+
+setup(name='meteocat-exporter',
+      version='1.0',
+      # Modules to import from other scripts:
+      packages=find_packages(),
+      # Executables
+      scripts=["meteocat-exporter"],
+     )

pkgs/overlay.nix

@@ -54,4 +54,5 @@ final: prev:
   });
 
   prometheus-slurm-exporter = prev.callPackage ./slurm-exporter.nix { };
+  meteocat-exporter = prev.callPackage ./meteocat-exporter/default.nix { };
 }