Add a script for updating the Stackage rev

default.nix

@@ -90,6 +90,7 @@ let
     # Scripts for keeping Hackage and Stackage up to date.
     maintainer-scripts = {
       update-hackage = self.callPackage ./scripts/update-hackage.nix {};
+      update-stackage = self.callPackage ./scripts/update-stackage.nix {};
     };
   });
 

scripts/update-external.nix

@@ -0,0 +1,26 @@
+{ stdenv, writeScript, glibc, coreutils, git, nix-tools, cabal-install, nix-prefetch-git }:
+
+{ name, script }:
+
+with stdenv.lib;
+
+writeScript "update-${name}-nix.sh" ''
+  #!${stdenv.shell}
+
+  set -euo pipefail
+
+  export PATH="${makeBinPath [ coreutils glibc git nix-tools cabal-install nix-prefetch-git ]}"
+
+  ${script}
+
+  git add .
+  git commit --allow-empty -m "Automatic update for $(date)"
+
+  rev=$(git rev-parse HEAD)
+
+  git push
+
+  cd ..
+
+  nix-prefetch-git https://github.com/input-output-hk/${name}.nix.git --rev "$rev" | tee ${name}-src.json
+''

scripts/update-hackage.nix

@@ -1,36 +1,24 @@
-{ stdenv, writeScriptBin, coreutils, git, nix-tools, cabal-install, nix-prefetch-git }:
+{ stdenv, writeScript, coreutils, glibc, git, nix-tools, cabal-install, nix-prefetch-git }@args:
 
-with stdenv.lib;
+import ./update-external.nix args {
+  name = "hackage";
+  script = ''
+    # Make sure the hackage index is recent.
+    cabal new-update
 
-writeScriptBin "update-hackage-nix" ''
-  #!${stdenv.shell}
+    # Clone or update the Hackage Nix expressions repo.
+    if [ -d hackage.nix ]; then
+      cd hackage.nix
+      git pull --ff-only
+      cd ..
+    else
+      git clone git@github.com:input-output-hk/hackage.nix.git
+    fi
 
-  set -euo pipefail
+    echo "Running hackage-to-nix..."
 
-  export PATH="${makeBinPath [ coreutils git nix-tools cabal-install nix-prefetch-git ]}"
+    hackage-to-nix hackage.nix
 
-  # Make sure the hackage index is recent.
-  cabal new-update
-
-  if [ -d hackage.nix ]; then
     cd hackage.nix
-    git pull --ff-only
-    cd ..
-  else
-    git clone git@github.com:input-output-hk/hackage.nix.git
-  fi
-
-  hackage-to-nix hackage.nix
-
-  cd hackage.nix
-  git add .
-  git commit --allow-empty -m "Automatic update for $(date)"
-
-  rev=$(git rev-parse HEAD)
-
-  git push
-
-  cd ..
-
-  nix-prefetch-git https://github.com/input-output-hk/hackage.nix.git --rev "$rev" | tee hackage-src.json
-''
+  '';
+}

scripts/update-stackage.nix

@@ -0,0 +1,44 @@
+{ stdenv, writeScript, coreutils, glibc, git, nix-tools, cabal-install, nix-prefetch-git }@args:
+
+import ./update-external.nix args {
+  name = "stackage";
+  script = ''
+    # Clone or update the main Stackage Nix expressions repo.
+    # The upstream LTS and Nightly package sets are in submodules, which
+    # should also be updated.
+    if [ -d stackage.nix ]; then
+      cd stackage.nix
+      git pull --ff-only
+      git submodule update --init
+      git submodule foreach git pull origin master
+    else
+      git clone git@github.com:input-output-hk/stackage.nix.git
+      cd stackage.nix
+      git submodule update --init
+    fi
+
+    echo "Running lts-to-nix for all snapshots..."
+
+    # update them all in parallel...
+    N=$(getconf _NPROCESSORS_ONLN)
+    for lts in {lts-haskell,stackage-nightly}/*.yaml
+    do
+        lts-to-nix $lts > $(basename ''${lts%.yaml}.nix) &
+        while [[ $(jobs -r -p | wc -l) -gt $N ]]; do
+        # can't use `wait -n` on older bash versions.
+        # e.g. what ships with macOS High Sierra
+        sleep 1;
+        done
+    done
+    wait
+
+    # update nightlies
+    echo "{" > nightlies.nix;
+    for a in nightly-*.nix; do echo "  \"''${a%%.nix}\" = import ./$a;" >> nightlies.nix; done;
+    echo "}" >> nightlies.nix
+    # update lts
+    echo "{" > ltss.nix;
+    for a in lts-*.nix; do echo "  \"''${a%%.nix}\" = import ./$a;" >> ltss.nix; done;
+    echo "}" >> ltss.nix
+  '';
+}