nixos/prometheus: add configText option for alertmanager

The reason being less mental overhead when reading upstream
documentation. Examples can be pasted right into the configuration
instead of translating to Nix attrset first.

1 files changed, 16 insertions, 1 deletions

diff --git a/nixos/modules/services/monitoring/prometheus/alertmanager.nix b/nixos/modules/services/monitoring/prometheus/alertmanager.nix
index da2cd02eaa3b..cf761edad926 100644
--- a/nixos/modules/services/monitoring/prometheus/alertmanager.nix
+++ b/nixos/modules/services/monitoring/prometheus/alertmanager.nix
@@ -5,6 +5,10 @@ with lib;
 let
   cfg = config.services.prometheus.alertmanager;
   mkConfigFile = pkgs.writeText "alertmanager.yml" (builtins.toJSON cfg.configuration);
+  alertmanagerYml =
+    if cfg.configText != null then
+      pkgs.writeText "alertmanager.yml" cfg.configText
+    else mkConfigFile;
 in {
   options = {
     services.prometheus.alertmanager = {
@@ -34,6 +38,17 @@ in {
         '';
       };
 
+      configText = mkOption {
+        type = types.nullOr types.lines;
+        default = null;
+        description = ''
+          Alertmanager configuration as YAML text. If non-null, this option
+          defines the text that is written to alertmanager.yml. If null, the
+          contents of alertmanager.yml is generated from the structured config
+          options.
+        '';
+      };
+
       logFormat = mkOption {
         type = types.nullOr types.str;
         default = null;
@@ -96,7 +111,7 @@ in {
       after    = [ "network.target" ];
       script = ''
         ${pkgs.prometheus-alertmanager.bin}/bin/alertmanager \
-        -config.file ${mkConfigFile} \
+        -config.file ${alertmanagerYml} \
         -web.listen-address ${cfg.listenAddress}:${toString cfg.port} \
         -log.level ${cfg.logLevel} \
         ${optionalString (cfg.webExternalUrl != null) ''-web.external-url ${cfg.webExternalUrl} \''}