namespace: rules
groups:
    - name: postgresql
      rules:
        - alert: PostgresqlCollationMismatch
          expr: |-
            {unit="postgresql.service"} |~ "WARNING:  database \"[^\"]+\" has a collation version mismatch" | regexp "database \"(?<database>[^\"]+)\""
          for: 1m
          labels:
            severity: warning
          annotations:
            summary: PostgreSQL database on {{ $labels.machine }} reports database collations mismatches

  yaml = pkgs.formats.yaml { };
  rulesFile = pkgs.runCommand "rules.yaml" {
    preferLocalBuild = true;
  } ''
    install -m0700 ${yaml.generate "rules.tmp" rulerConfig} $out
    ${lib.getExe' config.services.loki.package "lokitool"} rules lint $out
  '';

      name = "housekeeping";
      rules = [ {
        alert = "LokiAlwaysFiring";
        expr = "vector(1)";
        annotations.summary = "Rule that always fires to test alert propagation";
      } ];

      ruler = {
        storage = {
          type = "local";
          local.directory = "/etc/loki/rules/";
        };
        rule_path = "/tmp/loki-rules-scratch";
        alertmanager_url = "http://127.0.0.1:9093";
        ring.kvstore.store = "inmemory";
      };

# lokitool rules print --address https://loki.lossy.network --id=1
INFO[0000] no rule groups currently exist for this user 

When configured with auth_enabled: false, Loki uses a single tenant. [...] The single tenant ID will be the string fake.

# lokitool rules print --address https://loki.lossy.network --id=fake
INFO[0000] no rule groups currently exist for this user 

caller=ruler.go:576 msg="unable to list rules" err="failed to list rule groups for user fake: failed to list rule group for user fake and namespace rules.yaml: error parsing /etc/loki/rules/fake/rules.yaml: /etc/loki/rules/fake/rules.yaml: yaml: unmarshal errors:\n line 1: field namespace not found in type rulefmt.RuleGroups"