about summary refs log tree commit diff
path: root/modules/nixos/promtail.nix
blob: 157eb729cd1d06ede0547384c8888bca5367216e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
{
  config,
  lib,
  this,
  ...
}:
with lib; let
  cfg = config.nixfiles.modules.promtail;
in {
  options.nixfiles.modules.promtail = {
    enable = mkEnableOption "Promtail";

    port = mkOption {
      description = "Port.";
      type = with types; port;
      default = 30181;
    };

    loki.url = mkOption {
      description = "Address of a listening Loki service.";
      type = with types; str;
      default = "https://${config.nixfiles.modules.loki.domain}";
    };

    filters = mkOption {
      description = ''Filters to use with "scrape_config.pipeline_stages".'';
      type = with types; listOf attrs;
      default = [];
    };
  };

  config = mkIf cfg.enable {
    services.promtail = {
      enable = true;

      configuration = {
        server = rec {
          http_listen_address = this.wireguard.ipv4.address;
          http_listen_port = cfg.port;

          grpc_listen_address = this.wireguard.ipv4.address;
          grpc_listen_port = http_listen_port + 1;

          log_level = "warn";
        };

        clients = [
          {
            url = "${cfg.loki.url}/loki/api/v1/push";
            batchwait = "15s";
            batchsize = 1000000;
            external_labels.host_id = config.networking.hostId;
          }
        ];

        positions = {
          filename = "/tmp/positions.yaml";
          sync_period = "15s";
          ignore_invalid_yaml = true;
        };

        scrape_configs = [
          {
            job_name = "journal";
            journal.max_age = "24h";
            relabel_configs =
              map (n: let
                label = toLower n;
              in {
                source_labels = ["__journal_${label}"];
                target_label =
                  if hasPrefix "_" label
                  then substring 1 (stringLength label - 1) label
                  else label;
              }) [
                # Derived from systemd.journal fields[1][2].
                #
                # [1]: https://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html
                # [2]: https://github.com/coreos/go-systemd/blob/main/sdjournal/journal.go#L335

                "MESSAGE"
                # "MESSAGE_ID"
                "PRIORITY"
                # "CODE_FILE"
                # "CODE_LINE"
                # "CODE_FUNC"
                # "ERRNO"
                "SYSLOG_FACILITY"
                "SYSLOG_IDENTIFIER"
                # "SYSLOG_PID"
                # "_PID"
                # "_UID"
                # "_GID"
                # "_COMM"
                # "_EXE"
                "_CMDLINE"
                # "_CAP_EFFECTIVE"
                # "_AUDIT_SESSION"
                # "_AUDIT_LOGINUID"
                # "_SYSTEMD_CGROUP"
                # "_SYSTEMD_SESSION"
                # "_SYSTEMD_UNIT"
                # "_SYSTEMD_USER_UNIT"
                # "_SYSTEMD_OWNER_UID"
                # "_SYSTEMD_SLICE"
                # "_SELINUX_CONTEXT"
                # "_SOURCE_REALTIME_TIMESTAMP"
                # "_BOOT_ID"
                # "_MACHINE_ID"
                "_HOSTNAME"
                # "_TRANSPORT"
                # "__CURSOR"
                # "__REALTIME_TIMESTAMP"
                # "__MONOTONIC_TIMESTAMP"
              ]
              ++ [
                {
                  # This is weird. I can't find where is this defined in the
                  # source code but apparently it exists.
                  source_labels = ["__journal_priority_keyword"];
                  target_label = "level";
                }
              ];
            pipeline_stages = cfg.filters;
          }
        ];
      };
    };
  };
}

Consider giving Nix/NixOS a try! <3