ildkule/gatus: add healthcheck for mariadb

hosts/ildkule/services/monitoring/gatus/default.nix

@@ -6,6 +6,7 @@ in
   imports = [
     ./minecraft-checker.nix
     ./postgres-checker.nix
+    ./mariadb-checker.nix
   ];
 
   services.gatus = {
@@ -140,6 +141,12 @@ in
             "[BODY].ok == true"
           ];
         })
+        (mkService "MariaDB" "http://localhost:1339" // {
+          conditions = [
+            "[STATUS] == 200"
+            "[BODY].ok == true"
+          ];
+        })
         (mkService "Email (SMTP)" "starttls://mail.pvv.ntnu.no:587")
         (mkService "Email (POP3)" "tls://mail.pvv.ntnu.no:995")
         (mkService "Email (IMAP)" "tls://mail.pvv.ntnu.no:993")

hosts/ildkule/services/monitoring/gatus/mariadb-checker.nix

@@ -0,0 +1,79 @@
+{ config, pkgs, ... }:
+{
+  sops.secrets."keys/gatus/mariadb" = {
+    restartUnits = [ "phh-gatus-mariadb-checker.service" ];
+  };
+
+  sops.templates."gatus-mariadb-checker.env" = {
+    restartUnits = [ "phh-gatus-mariadb-checker.service" ];
+    content = ''
+      MYSQL_HOST=mysql.pvv.ntnu.no
+      MYSQL_PORT=3306
+      MYSQL_DATABASE=mysql
+      MYSQL_USER=gatus_healthcheck
+      MYSQL_PASSWORD=${config.sops.placeholder."keys/gatus/mariadb"}
+    '';
+  };
+
+  services.python-http-handlers."gatus-mariadb-checker" = {
+    listenStreams = [ "127.0.0.1:1339" ];
+    libraries = with pkgs.python3Packages; [
+      pymysql
+    ];
+    serviceConfig = {
+      EnvironmentFile = config.sops.templates."gatus-mariadb-checker.env".path;
+    };
+    handler = ''
+      import os
+      import json
+      import pymysql
+
+      class Handler(BaseHTTPRequestHandler):
+          def do_GET(self):
+              try:
+                  conn = pymysql.connect(
+                      host=os.environ["MYSQL_HOST"],
+                      port=int(os.environ.get("MYSQL_PORT", "3306")),
+                      user=os.environ["MYSQL_USER"],
+                      password=os.environ["MYSQL_PASSWORD"],
+                      database=os.environ.get("MYSQL_DATABASE", "mysql"),
+                      connect_timeout=5,
+                  )
+
+                  try:
+                      with conn.cursor() as cur:
+                          cur.execute("SELECT VERSION();")
+                          (version,) = cur.fetchone()
+
+                          cur.execute("SHOW STATUS LIKE 'Threads_connected';")
+                          (_, connections) = cur.fetchone()
+
+                          cur.execute("SHOW DATABASES;")
+                          databases = cur.fetchall()
+                  finally:
+                      conn.close()
+
+                  body = {
+                      "ok": True,
+                      "version": version,
+                      "connections": int(connections),
+                      "databases": len(databases),
+                  }
+                  data = json.dumps(body).encode()
+
+                  self.send_response(200)
+                  self.send_header("Content-Type", "application/json")
+                  self.send_header("Content-Length", str(len(data)))
+                  self.end_headers()
+                  self.wfile.write(data)
+
+              except Exception as e:
+                  data = json.dumps({"ok": False, "error": str(e)}).encode()
+                  self.send_response(500)
+                  self.send_header("Content-Type", "application/json")
+                  self.send_header("Content-Length", str(len(data)))
+                  self.end_headers()
+                  self.wfile.write(data)
+    '';
+  };
+}