ildkule: add config for prometheus_mysqld_exporter

There's a PR waiting to add this module to nixpkgs,
so we should enable this once it gets merged.

hosts/ildkule/services/metrics/grafana.nix

@@ -64,6 +64,13 @@ in {
           url = "https://raw.githubusercontent.com/matrix-org/synapse/develop/contrib/grafana/synapse.json";
           options.path = dashboards/synapse.json;
         }
+	# TODO: enable once https://github.com/NixOS/nixpkgs/pull/242365 gets merged
+	# {
+	#   name = "MySQL";
+	#   type = "file";
+	#   url = "https://raw.githubusercontent.com/prometheus/mysqld_exporter/main/mysqld-mixin/dashboards/mysql-overview.json";
+	#   options.path = dashboards/mysql.json;
+	# }
         {
           name = "Postgresql";
           type = "file";

hosts/ildkule/services/metrics/prometheus/default.nix

@@ -1,9 +1,11 @@
 { config, ... }: {
   imports = [
-    ./node.nix
-    ./matrix-synapse.nix
-    ./postgres.nix
     ./gogs.nix
+    ./matrix-synapse.nix
+    # TODO: enable once https://github.com/NixOS/nixpkgs/pull/242365 gets merged
+    # ./mysqld.nix
+    ./node.nix
+    ./postgres.nix
   ];
 
   services.prometheus = {

hosts/ildkule/services/metrics/prometheus/mysqld.nix

@@ -0,0 +1,25 @@
+{ config, unstable, ... }: let
+  cfg = config.services.prometheus;
+in {
+  sops.secrets."config/mysqld_exporter" = { };
+
+  services.prometheus = {
+    scrapeConfigs = [{
+      job_name = "mysql";
+      scheme = "http";
+      metrics_path = cfg.exporters.mysqld.telemetryPath;
+      static_configs = [
+        {
+          targets = [
+            "localhost:${toString cfg.exporters.mysqld.port}"
+          ];
+        }
+      ];
+    }];
+
+    exporters.mysqld = {
+      enable = true;
+      configFilePath = config.sops.secrets."config/mysqld_exporter".path;
+    };
+  };
+}

secrets/ildkule/ildkule.yaml

@@ -8,6 +8,8 @@
 #ENC[AES256_GCM,data:IVFSM6VOWnR0YDRfecsDPlYr,iv:Jxe8pq3lxw5QUGKyspB8tWSquDSMo3mAJBAsQGKxSec=,tag:7bffwY98iTX4/De0coUIxA==,type:comment]
 #ENC[AES256_GCM,data:pHSDnojWTLYXIKk=,iv:ph2xCpxbP3OiWm+B/MDboykPa2gtCWpP0b3j96YCDh4=,tag:u5hmvxHaa/m8GaSeYvONmg==,type:comment]
 #ENC[AES256_GCM,data:Q0fCyyP0DJqUyJPo,iv:qwBE3c2VqF52Yq8POXhy2Qv2xJd82wL1aX4eVY6wL1w=,tag:IwmbD7XqIkemOTODBKpS0g==,type:comment]
+config:
+    mysqld_exporter: ENC[AES256_GCM,data:w4muNsWmsW1fPx9nqtDGPCZ9faO3W5Pagn/DfWrb5yf88GQOzOsN4z7TH3QeW0Xs6I5jDIktGmFml6RDxCjD8UX9eer1pvC7Kxyl2DQKLHwmsgx1DUFNTRUzE1Sgx8rZAJ8HM7DO7L/6aXS0ndY4J+huyhDDVd+cIetgiQ==,iv:Q4cZD9CKd/EDOm4bjAE2EOstwKpwexF2pxhMEF0/5/k=,tag:S0rOLJS+b9ualtxcHKdHlw==,type:str]
 keys:
     grafana:
         secret_key: ENC[AES256_GCM,data:+WoAJbDBEgKs0RoHT+7oEELAVQ+/2Xt+5RTMSXg23moCqVRx+Gzll9P5Drw=,iv:AkRn/Y20iEe5i1T+84wAgLCTFtAox2G3giyawAkltAw=,tag:BZbt5Wb5lYLIJBm/pfP4GQ==,type:str]
@@ -49,8 +51,8 @@ sops:
             a2hQVVprakt5NURpNXdQUjREczJKWTgKn60yrLqco9brlqigAolO8rEkww9z3y3u
             KmefLVZCGfoko+fnKLVE9UKFS/tAowqgPS1qE76u1Mmkk6yqZoG9rg==
             -----END AGE ENCRYPTED FILE-----
-    lastmodified: "2023-01-26T00:16:54Z"
+    lastmodified: "2023-07-08T12:46:19Z"
-    mac: ENC[AES256_GCM,data:T13TG5fwXgAXUD4I8yIsdUQTA4MKZdEWkpVP1H734YBt5c0J0FJ5Ppxvf1n3hPcC6dcyCJ1NonbmmDBeKn0JUlxTlrK645O33RHLHlsMZGVijYyLyvxCxGo22SfdT2OdPv7tggyat9Cpd9bVLd7YdhPxTYDnZ3eNbIwx+5Fnw48=,iv:bYz6k1f30nlCjOuTRu3F2OE9iQIMd2eBGezXQx901zE=,tag:GHGGNlNg+huP6F3uyrbncQ==,type:str]
+    mac: ENC[AES256_GCM,data:bQWG/GgSIv5LdhGTsyx3ENOAywtYVKjzK6nxOnUEZvD+RSi6jxj9Wze7qOhXvgjKWCz/cZj5oSuMQNRyoI8p8xJdxf0+UNdX8uPT05HiKuF7CBcXzprjKri/H6yFp87epOM9fMdn7ZUACn/iT1IZBo+5OuMtDnqVUm/GEmMcsog=,iv:ll/vEeiXsD3crbbxEFsJlxGbm9dZDUPC4GeO95RZZX4=,tag:TGCA721vK9EY3xlY6zIeIg==,type:str]
     pgp:
         - created_at: "2023-01-21T19:52:08Z"
           enc: |