From 2a080ac4349899a9d1d103ba42b0c8ecba95dba0 Mon Sep 17 00:00:00 2001
From: Martin Milata <martin@martinmilata.cz>
Date: Fri, 6 Mar 2020 01:11:21 +0100
Subject: [PATCH] nixos/prometheus-snmp-exporter: fix assertion

The assertion was printed when user explicitly defined only the
configurationPath option.
---
 nixos/modules/services/monitoring/prometheus/exporters.nix    | 4 +++-
 .../modules/services/monitoring/prometheus/exporters/snmp.nix | 4 ++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/nixos/modules/services/monitoring/prometheus/exporters.nix b/nixos/modules/services/monitoring/prometheus/exporters.nix
index 36ebffa4463..e9845fc4bb8 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters.nix
@@ -197,7 +197,9 @@ in
 
   config = mkMerge ([{
     assertions = [ {
-      assertion = (cfg.snmp.configurationPath == null) != (cfg.snmp.configuration == null);
+      assertion = cfg.snmp.enable -> (
+        (cfg.snmp.configurationPath == null) != (cfg.snmp.configuration == null)
+      );
       message = ''
         Please ensure you have either `services.prometheus.exporters.snmp.configuration'
           or `services.prometheus.exporters.snmp.configurationPath' set!
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix b/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
index ddde3c10481..045e48a3d0f 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters/snmp.nix
@@ -19,7 +19,7 @@ in
 
     configuration = mkOption {
       type = types.nullOr types.attrs;
-      default = {};
+      default = null;
       description = ''
         Snmp exporter configuration as nix attribute set. Mutually exclusive with 'configurationPath' option.
       '';
@@ -54,7 +54,7 @@ in
   serviceOpts = let
     configFile = if cfg.configurationPath != null
                  then cfg.configurationPath
-                 else "${pkgs.writeText "snmp-eporter-conf.yml" (builtins.toJSON cfg.configuration)}";
+                 else "${pkgs.writeText "snmp-exporter-conf.yml" (builtins.toJSON cfg.configuration)}";
     in {
     serviceConfig = {
       ExecStart = ''