krebs buildbot: add treeStableTimer as option

krebs/2configs/buildbot-all.nix

@@ -6,6 +6,7 @@
 
   networking.firewall.allowedTCPPorts = [ 80 8010 9989 ];
   krebs.ci.enable = true;
+  krebs.ci.treeStableTimer = 1;
   krebs.ci.users.krebs.all = true;
   krebs.ci.users.lass.all = true;
   krebs.ci.users.makefu.all = true;

krebs/2configs/buildbot-krebs.nix

@@ -6,6 +6,7 @@
 
   networking.firewall.allowedTCPPorts = [ 80 8010 9989 ];
   krebs.ci.enable = true;
+  krebs.ci.treeStableTimer = 120;
   krebs.ci.users.krebs.hosts = [
     config.networking.hostName
   ];

krebs/3modules/ci.nix

@@ -8,6 +8,11 @@ in
 {
   options.krebs.ci = {
     enable = mkEnableOption "krebs continous integration";
+    treeStableTimer = mkOption {
+      type = types.int;
+      default = 10;
+      description = "how long to wait until we test changes (in minutes)";
+    };
     users = mkOption {
       type = with types; attrsOf (submodule {
         options = {
@@ -69,7 +74,7 @@ in
           sched.append(
                 schedulers.SingleBranchScheduler(
                     change_filter=util.ChangeFilter(branch_re=".*"),
-                    treeStableTimer=10,
+                    treeStableTimer=${toString cfg.treeStableTimer}*60,
                     name="build-all-branches",
                     builderNames=[
                         "build-hosts"