diff --git a/ofborg/src/commentparser.rs b/ofborg/src/commentparser.rs
index 68f9ffe..70add03 100644
--- a/ofborg/src/commentparser.rs
+++ b/ofborg/src/commentparser.rs
@@ -21,7 +21,7 @@ pub fn parse(text: &str) -> Option<Vec<Instruction>> {
         let (left, right) = command.split_at(1);
         match left[0].as_ref() {
             "build" => {
-                instructions.push(Instruction::Build(right.to_vec()))
+                instructions.push(Instruction::Build(Subset::Nixpkgs, right.to_vec()))
             }
             "eval" => {
                 instructions.push(Instruction::Eval)
@@ -35,11 +35,17 @@ pub fn parse(text: &str) -> Option<Vec<Instruction>> {
 
 #[derive(PartialEq, Debug)]
 pub enum Instruction {
-    Build(Vec<String>),
+    Build(Subset, Vec<String>),
     Eval
 
 }
 
+#[derive(Serialize, Deserialize, Debug, PartialEq)]
+pub enum Subset {
+    Nixpkgs,
+    NixOS,
+}
+
 #[cfg(test)]
 mod tests {
 
diff --git a/ofborg/src/message/buildjob.rs b/ofborg/src/message/buildjob.rs
index f11ddb7..2cefb6f 100644
--- a/ofborg/src/message/buildjob.rs
+++ b/ofborg/src/message/buildjob.rs
@@ -1,5 +1,6 @@
 use ofborg::message::{Pr,Repo};
 use ofborg::message::buildresult;
+use ofborg::commentparser::Subset;
 use ofborg::worker;
 use serde_json;
 
@@ -11,12 +12,6 @@ pub struct BuildJob {
     pub attrs: Vec<String>,
 }
 
-#[derive(Serialize, Deserialize, Debug)]
-pub enum Subset {
-    Nixpkgs,
-    NixOS,
-}
-
 pub fn from(data: &Vec<u8>) -> Result<BuildJob, serde_json::error::Error> {
     return serde_json::from_slice(&data);
 }
diff --git a/ofborg/src/tasks/githubcommentfilter.rs b/ofborg/src/tasks/githubcommentfilter.rs
index 4348a84..098d7cd 100644
--- a/ofborg/src/tasks/githubcommentfilter.rs
+++ b/ofborg/src/tasks/githubcommentfilter.rs
@@ -99,11 +99,11 @@ impl worker::SimpleWorker for GitHubCommentWorker {
         if let Some(instructions) = instructions {
             for instruction in instructions {
                 match instruction {
-                    commentparser::Instruction::Build(attrs) => {
+                    commentparser::Instruction::Build(subset, attrs) => {
                         let msg = buildjob::BuildJob{
                             repo: repo_msg.clone(),
                             pr: pr_msg.clone(),
-                            subset: Some(buildjob::Subset::Nixpkgs),
+                            subset: Some(subset),
                             attrs: attrs,
                         };
 
diff --git a/ofborg/src/tasks/massrebuilder.rs b/ofborg/src/tasks/massrebuilder.rs
index 2fc37bb..049c8da 100644
--- a/ofborg/src/tasks/massrebuilder.rs
+++ b/ofborg/src/tasks/massrebuilder.rs
@@ -10,7 +10,7 @@ use std::path::Path;
 use std::path::PathBuf;
 use ofborg::checkout;
 use ofborg::message::massrebuildjob;
-use ofborg::nix;
+use ofborg::nix::Nix;
 
 use ofborg::worker;
 use ofborg::tagger::{StdenvTagger,RebuildTagger};
@@ -22,12 +22,12 @@ use hubcaps;
 
 pub struct MassRebuildWorker {
     cloner: checkout::CachedCloner,
-    nix: nix::Nix,
+    nix: Nix,
     github: hubcaps::Github,
 }
 
 impl MassRebuildWorker {
-    pub fn new(cloner: checkout::CachedCloner, nix: nix::Nix, github: hubcaps::Github) -> MassRebuildWorker {
+    pub fn new(cloner: checkout::CachedCloner, nix: Nix, github: hubcaps::Github) -> MassRebuildWorker {
         return MassRebuildWorker{
             cloner: cloner,
             nix: nix,
@@ -330,7 +330,7 @@ pub enum System {
 
 #[derive(Debug, PartialEq)]
 struct Stdenvs {
-    nix: nix::Nix,
+    nix: Nix,
     co: PathBuf,
 
     linux_stdenv_before: Option<String>,
@@ -341,7 +341,7 @@ struct Stdenvs {
 }
 
 impl Stdenvs {
-    fn new(nix: nix::Nix, co: PathBuf) -> Stdenvs {
+    fn new(nix: Nix, co: PathBuf) -> Stdenvs {
         return Stdenvs {
             nix: nix,
             co: co,
@@ -496,7 +496,7 @@ mod tests {
 
     #[test]
     fn stdenv_checking() {
-        let nix = nix::new(String::from("x86_64-linux"), String::from("daemon"));
+        let nix = Nix::new(String::from("x86_64-linux"), String::from("daemon"), 1200);
         let mut stdenv = Stdenvs::new(nix.clone(), PathBuf::from("/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs"));
         stdenv.identify(System::X8664Linux, StdenvFrom::Before);
         stdenv.identify(System::X8664Darwin, StdenvFrom::Before);