From ecf03368f8b624b8573f97f70387d6d14f7e32fe Mon Sep 17 00:00:00 2001
From: Bas van Dijk <v.dijk.bas@gmail.com>
Date: Sat, 8 Apr 2017 19:32:19 +0200
Subject: [PATCH] bepasty: add secretKeyFile option

This gives users the option to store secrets outside the
world-readable Nix store.
---
 nixos/modules/services/misc/bepasty.nix | 36 ++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 4 deletions(-)

diff --git a/nixos/modules/services/misc/bepasty.nix b/nixos/modules/services/misc/bepasty.nix
index 52719222db66..4d78cddcb54f 100644
--- a/nixos/modules/services/misc/bepasty.nix
+++ b/nixos/modules/services/misc/bepasty.nix
@@ -21,7 +21,7 @@ in
         configure a number of bepasty servers which will be started with
         gunicorn.
         '';
-      type = with types ; attrsOf (submodule ({
+      type = with types ; attrsOf (submodule ({ config, ... } : {
 
         options = {
 
@@ -34,7 +34,6 @@ in
             default = "127.0.0.1:8000";
           };
 
-
           dataDir = mkOption {
             type = types.str;
             description = ''
@@ -73,10 +72,28 @@ in
             type = types.str;
             description = ''
               server secret for safe session cookies, must be set.
+
+              Warning: this secret is stored in the WORLD-READABLE Nix store!
+
+              It's recommended to use <option>secretKeyFile</option>
+              which takes precedence over <option>secretKey</option>.
               '';
             default = "";
           };
 
+          secretKeyFile = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+            description = ''
+              A file that contains the server secret for safe session cookies, must be set.
+
+              <option>secretKeyFile</option> takes precedence over <option>secretKey</option>.
+
+              Warning: when <option>secretKey</option> is non-empty <option>secretKeyFile</option>
+              defaults to a file in the WORLD-READABLE Nix store containing that secret.
+              '';
+          };
+
           workDir = mkOption {
             type = types.str;
             description = ''
@@ -87,11 +104,22 @@ in
           };
 
         };
+        config = {
+          secretKeyFile = mkDefault (
+            if config.secretKey != ""
+            then toString (pkgs.writeTextFile {
+              name = "bepasty-secret-key";
+              text = config.secretKey;
+            })
+            else null
+          );
+        };
       }));
     };
   };
 
   config = mkIf cfg.enable {
+
     environment.systemPackages = [ bepasty ];
 
     # creates gunicorn systemd service for each configured server
@@ -115,7 +143,7 @@ in
           serviceConfig = {
             Type = "simple";
             PrivateTmp = true;
-            ExecStartPre = assert server.secretKey != ""; pkgs.writeScript "bepasty-server.${name}-init" ''
+            ExecStartPre = assert !isNull server.secretKeyFile; pkgs.writeScript "bepasty-server.${name}-init" ''
               #!/bin/sh
               mkdir -p "${server.workDir}"
               mkdir -p "${server.dataDir}"
@@ -123,7 +151,7 @@ in
               cat > ${server.workDir}/bepasty-${name}.conf <<EOF
               SITENAME="${name}"
               STORAGE_FILESYSTEM_DIRECTORY="${server.dataDir}"
-              SECRET_KEY="${server.secretKey}"
+              SECRET_KEY="$(cat "${server.secretKeyFile}")"
               DEFAULT_PERMISSIONS="${server.defaultPermissions}"
               ${server.extraConfig}
               EOF