nixos/promtail: Add a promtail module

2020-11-03 14:36:56 +01:00
parent 43b99f23b3
commit 54217cac69
3 changed files with 118 additions and 9 deletions
@@ -0,0 +1,95 @@
+{ config, lib, pkgs, ... }: with lib;
+let
+  cfg = config.services.promtail;
+
+  prettyJSON = conf: pkgs.runCommandLocal "promtail-config.json" {} ''
+    echo '${builtins.toJSON conf}' | ${pkgs.buildPackages.jq}/bin/jq 'del(._module)' > $out
+  '';
+
+in {
+  options.services.promtail = with types; {
+    enable = mkEnableOption "the Promtail ingresser";
+
+    configuration = mkOption {
+      type = with lib.types; let
+        valueType = nullOr (oneOf [
+          bool
+          int
+          float
+          str
+          (lazyAttrsOf valueType)
+          (listOf valueType)
+        ]) // {
+          description = "JSON value";
+          emptyValue.value = {};
+          deprecationMessage = null;
+        };
+      in valueType;
+      description = ''
+        Specify the configuration for Promtail in Nix.
+      '';
+    };
+
+    extraFlags = mkOption {
+      type = listOf str;
+      default = [];
+      example = [ "--server.http-listen-port=3101" ];
+      description = ''
+        Specify a list of additional command line flags,
+        which get escaped and are then passed to Loki.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.promtail.configuration.positions.filename = mkDefault "/var/cache/promtail/positions.yaml";
+
+    systemd.services.promtail = {
+      description = "Promtail log ingress";
+      wantedBy = [ "multi-user.target" ];
+      stopIfChanged = false;
+
+      serviceConfig = {
+        Restart = "on-failure";
+
+        ExecStart = "${pkgs.grafana-loki}/bin/promtail -config.file=${prettyJSON cfg.configuration} ${escapeShellArgs cfg.extraFlags}";
+
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectKernelTunables = true;
+        ProtectControlGroups = true;
+        RestrictSUIDSGID = true;
+        PrivateMounts = true;
+        CacheDirectory = "promtail";
+
+        User = "promtail";
+        Group = "promtail";
+
+        CapabilityBoundingSet = "";
+        NoNewPrivileges = true;
+
+        ProtectKernelModules = true;
+        SystemCallArchitectures = "native";
+        ProtectKernelLogs = true;
+        ProtectClock = true;
+
+        LockPersonality = true;
+        ProtectHostname = true;
+        RestrictRealtime = true;
+        MemoryDenyWriteExecute = true;
+        PrivateUsers = true;
+      } // (optionalAttrs (!pkgs.stdenv.isAarch64) { # FIXME: figure out why this breaks on aarch64
+        SystemCallFilter = "@system-service";
+      });
+    };
+
+    users.groups.promtail = {};
+    users.users.promtail = {
+      description = "Promtail service user";
+      isSystemUser = true;
+      group = "promtail";
+    };
+  };
+}