1 files changed, 115 insertions, 0 deletions
diff --git a/krebs/populate.nix b/krebs/populate.nix
new file mode 100644
index 00000000..9994fda8
--- /dev/null
+++ b/krebs/populate.nix
@@ -0,0 +1,115 @@
+{ source
+, target-user ? "root"
+, target-host
+, target-path ? "/var/src"
+}:
+with import <nixpkgs/lib>;
+with import ~/stockholm/krebs/4lib {
+  lib = import <nixpkgs/lib>;
+};
+with builtins;
+let
+  out = ''
+    #! /bin/sh
+    set -efu
+
+    echo ${shell.escape git-script} \
+      | ssh ${shell.escape "${target-user}@${target-host}"} -T
+
+    tmpdir=$(mktemp -dt stockholm.XXXXXXXX)
+    trap '
+      set +f
+      rm "$tmpdir"/*
+      rmdir "$tmpdir"
+      trap - EXIT INT QUIT
+    '        EXIT INT QUIT
+    ${concatStringsSep "\n"
+      (mapAttrsToList
+        (name: spec: let dst = removePrefix "symlink:" (get-url spec); in
+          "ln -s ${shell.escape dst} $tmpdir/${shell.escape name}")
+        symlink-specs)}
+
+    proot \
+        -b $tmpdir:${shell.escape target-path} \
+        ${concatStringsSep " \\\n    "
+          (mapAttrsToList
+            (name: spec:
+              "-b ${shell.escape "${get-url spec}:${target-path}/${name}"}")
+            file-specs)} \
+        rsync \
+            -f ${shell.escape "P /*"} \
+            ${concatMapStringsSep " \\\n        "
+              (name: "-f ${shell.escape "R /${name}"}")
+              (attrNames file-specs)} \
+            --delete \
+            -vFrlptD \
+            ${shell.escape target-path}/ \
+            ${shell.escape "${target-user}@${target-host}:${target-path}"}
+  '';
+
+  get-schema = uri:
+    if substring 0 1 uri == "/"
+      then "file"
+      else head (splitString ":" uri);
+
+  has-schema = schema: uri: get-schema uri == schema;
+
+  get-url = spec: {
+    string = spec;
+    path = toString spec;
+    set = get-url spec.url;
+  }.${typeOf spec};
+
+  git-specs =
+    filterAttrs (_: spec: has-schema "https" (get-url spec)) source //
+    filterAttrs (_: spec: has-schema "http" (get-url spec)) source //
+    filterAttrs (_: spec: has-schema "git" (get-url spec)) source;
+
+  file-specs =
+    filterAttrs (_: spec: has-schema "file" (get-url spec)) source;
+
+  symlink-specs =
+    filterAttrs (_: spec: has-schema "symlink" (get-url spec)) source;
+
+  git-script = ''
+    fetch_git() {(
+      dst_dir=$1
+      src_url=$2
+      src_ref=$3
+
+      if ! test -e "$dst_dir"; then
+        git clone "$src_url" "$dst_dir"
+      fi
+
+      cd "$dst_dir"
+
+      if ! url=$(git config remote.origin.url); then
+        git remote add origin "$src_url"
+      elif test "$url" != "$src_url"; then
+        git remote set-url origin "$src_url"
+      fi
+
+      # TODO resolve src_ref to commit hash
+      hash=$src_ref
+
+      if ! test "$(git log --format=%H -1)" = "$hash"; then
+        git fetch origin
+        git checkout "$hash" -- "$dst_dir"
+        git checkout "$hash"
+      fi
+
+      git clean -dxf
+    )}
+
+    ${concatStringsSep "\n"
+      (mapAttrsToList
+        (name: spec: toString (map shell.escape [
+          "fetch_git"
+          "${target-path}/${name}"
+          spec.url
+          spec.rev
+        ]))
+        git-specs)}
+  '';
+
+in out