WIP: postprocessing pipeline

Now each run is executed in a independent folder

garlic/pp/fetch.nix

@@ -0,0 +1,58 @@
+{
+  stdenv
+, rsync
+, openssh
+, nix
+, curl
+, garlicTools
+}:
+
+{
+  sshHost
+, prefix
+, experimentStage
+, trebuchetStage
+, garlicTemp
+# We only fetch the config, stdout and stderr by default
+, fetchAll ? false
+}:
+
+with garlicTools;
+
+let
+  experimentName = baseNameOf (toString experimentStage);
+  rsyncFilter = if (fetchAll) then "" else ''
+    --include='*/*/garlic_config.json' \
+    --include='*/*/std*.log' \
+    --include='*/*/*/std*.log' \
+    --exclude='*/*/*/*' '';
+in
+  stdenv.mkDerivation {
+    name = "fetch";
+    preferLocalBuild = true;
+
+    buildInputs = [ rsync openssh curl ];
+    phases = [ "installPhase" ];
+
+    installPhase = ''
+      cat > $out << EOF
+      #!/bin/sh -e
+      mkdir -p ${garlicTemp}
+      export PATH=${rsync}/bin:${openssh}/bin:${nix}/bin
+      rsync -av \
+        --copy-links \
+        ${rsyncFilter} \
+        '${sshHost}:${prefix}/${experimentName}' ${garlicTemp}
+
+      res=\$(nix-build -E '(with import ./default.nix; garlic.pp.getExpResult { \
+        experimentStage = "${experimentStage}"; \
+        trebuchetStage = "${trebuchetStage}"; \
+        garlicTemp = "${garlicTemp}"; \
+      })')
+
+      echo "The results for experiment ${experimentName} are at:"
+      echo "  \$res"
+      EOF
+      chmod +x $out
+    '';
+  }