devices.srv2: add node2, swap node0/1

devices/jykang.xmuhpc/default.nix

@@ -2,15 +2,23 @@
 # sudo nix-store --store 'local?store=/data/gpfs01/jykang/.nix/store&state=/data/gpfs01/jykang/.nix/state&log=/data/gpfs01/jykang/.nix/log' -qR ./result | grep -Fxv -f <(ssh jykang find .nix/store -maxdepth 1 -exec realpath '{}' '\;') | sudo xargs nix-store --store 'local?store=/data/gpfs01/jykang/.nix/store&state=/data/gpfs01/jykang/.nix/state&log=/data/gpfs01/jykang/.nix/log' --export | xz -T0 | pv > jykang.nar.xz
 # cat data.nar | nix-store --import
 { inputs, localLib }:
-let pkgs = import inputs.nixpkgs (localLib.buildNixpkgsConfig
-{
-  inputs = { inherit (inputs.nixpkgs) lib; topInputs = inputs; };
-  nixpkgs = { march = "haswell"; cuda = null; nixRoot = "/data/gpfs01/jykang/.nix"; nixos = false; };
-});
+let
+  pkgs = import inputs.nixpkgs (localLib.buildNixpkgsConfig
+  {
+    inputs = { inherit (inputs.nixpkgs) lib; topInputs = inputs; };
+    nixpkgs = { march = "haswell"; cuda = null; nixRoot = "/data/gpfs01/jykang/.nix"; nixos = false; };
+  });
+  python-lyj =
+    let python = pkgs.pkgs-2411.python310.withPackages (_: [ pkgs.localPackages.pybinding ]);
+    in pkgs.runCommand "python-lyj" { }
+    ''
+      mkdir -p $out/bin
+      ln -s ${python}/bin/python3 $out/bin/python-lyj
+    '';
 in pkgs.symlinkJoin
 {
   name = "jykang";
-  paths = with pkgs; [ hello iotop gnuplot localPackages.vaspkit pv btop ];
+  paths = with pkgs; [ gnuplot localPackages.vaspkit pv python-lyj ];
   postBuild = "echo ${inputs.self.rev or "dirty"} > $out/.version";
   passthru = { inherit pkgs; };
 }

devices/srv2/default.nix

@@ -19,6 +19,8 @@ inputs:
           "6.1"
           # 2080 Ti
           "7.5"
+          # A30
+          "8.0"
           # 3090
           "8.6"
           # 4090

devices/srv2/node0/default.nix

@@ -7,7 +7,7 @@ inputs:
       model.cluster.nodeType = "master";
       system =
       {
-        nixpkgs.march = "skylake";
+        nixpkgs.march = "icelake-server";
         network =
         {
           static.eno2 = { ip = "192.168.178.1"; mask = 24; };

devices/srv2/node2/default.nix

@@ -0,0 +1,43 @@
+inputs:
+{
+  config =
+  {
+    nixos =
+    {
+      model.cluster.nodeType = "master";
+      system =
+      {
+        nixpkgs.march = "skylake";
+        network =
+        {
+          static.eno2 = { ip = "192.168.178.1"; mask = 24; };
+          masquerade = [ "eno2" ];
+          trust = [ "eno2" ];
+        };
+        nix.remote.slave = {};
+        fileSystems =
+        {
+          swap = [ "/dev/disk/by-partlabel/srv2-node2-swap" ];
+          mount.btrfs."/dev/disk/by-partlabel/srv2-node2-root1" =
+          {
+            "/nix/remote/jykang.xmuhpc" = "/data/gpfs01/jykang/.nix";
+            "/nix/remote/xmuhk" = "/public/home/xmuhk/.nix";
+          };
+        };
+      };
+      services =
+      {
+        xray.client.dnsmasq = { extraInterfaces = [ "eno1" "eno2" ]; hosts."hpc.xmu.edu.cn" = "121.192.191.11"; };
+        beesd."/" = { hashTableSizeMB = 16 * 128; loadAverage = 8; };
+        xrdp = { enable = true; hostname = [ "srv2.chn.moe" ]; };
+        samba = { hostsAllowed = ""; shares = { home.path = "/home"; root.path = "/"; }; };
+        groupshare = {};
+        hpcstat = {};
+        ollama = {};
+        sshd = { groupBanner = true; motd = true; };
+        speedtest = {};
+        lumericalLicenseManager.macAddress = "70:20:84:09:a3:52";
+      };
+    };
+  };
+}

devices/srv2/node2/secrets.yaml

@@ -0,0 +1,34 @@
+xray-client:
+    uuid: ENC[AES256_GCM,data:j2R0UtfS/es2A+Ic+Kq6FZJSqXlA/Q8tGkuAIX0ZdTsV4hGk,iv:Ovpr49isIJRdUyM3jxgiT+9Sc+qTF6ZnkKUwxIq6KUs=,tag:2VRSkiPNWaOmCqLJti8Bzw==,type:str]
+wireguard: ENC[AES256_GCM,data:TEi3LAZA0BaPxeXA1yFMD6fQPRKSndVyAzNycCD/5CYXmNVyO7zv4o23ahg=,iv:tEKFPyuqmpsWf0vDoSaw4Ai6S5DzacZFA4otNgnknxY=,tag:qZJzr/Yyoex2hDfVtT6nYA==,type:str]
+mariadb:
+    slurm: ENC[AES256_GCM,data:9wLQ1zF/kDaiw0s3UaRpiHgmngU7u6hwyqpddSjev0+Z0v58Q2oiJtK8vn+2VlSxx5ACfqEFbzp0PZYAxd575w==,iv:q9JTkgDymOwkbZ/PaxRAAQrtO96QmGgZcQuLTFCMoS4=,tag:dwOHlOTgZqT/1jQ+oGf7UQ==,type:str]
+hpcstat:
+    key: ENC[AES256_GCM,data:+Z7MRDkLLdUqDwMrkafFKkBjeCkw+zgRoAoiVEwrr+LY0uMeW8nNYoaYrfz6Ig8CMCDgX3n/DMb0ibUeN32j3HShQIStbtUxRPGpQMyH+ealbvgskGriTFpST4VPyQxNACkUpq/e+sh2CmLbKkSxhamkjKOXwsfqrBlgVbEkp7u7HkWGuAaYL1oPGt0Q94fWXwH0UVhRYZYQ2iFA/S6SEZY8gxaTIGDKUdWU9+fOHzPQ5WfhxtKYU4p4ydyfYsAt6ffqnPSx/SI72GsUCOJ4981JX8TuvnEzx3gQLVFYheK6NibTWCy6eODbvguieVOTHSvCPTrHmoP12lHVWU2kKzLwv70Jl7sXyzKHYROG0D+/z/4DKlNeotKM/IA0q2cST08/lwSKN7WDDmrt+O6xXhvwby28ZYKEsSvvrfV+VIKzHPl84ZKbUEX5xv/GHc3THfznUvKKz5PzDiqrkjCkEt5PRMsVW9A6MU1+QEUr+sXLLtcUd2CCL87c8CpwNHJx1us6vJ4ji1gu0PGoT+60,iv:yU6j9W2Hs2D34uHMJqqPFbNy2pNEZY2kzXoNdhPMSmA=,tag:TNvEfMVrhu7HrNxY8qe5mg==,type:str]
+wireless:
+    #ENC[AES256_GCM,data:n9OPSJsB7yNk,iv:xQzKJxqPB7uT83m/B4UoOje6NQbPLhuHR7Hp93oNz8A=,tag:gtsTx6ALnS/7fIDd7VimOg==,type:comment]
+    409的5G: ENC[AES256_GCM,data:K9wm3zedoil7jHgTcb+VmbdbkG2dgrMdr3BmDRUHDVADqLANMvnUMSecggYTO4HaiI9q6uv2/BSkluanD5K4Dw==,iv:7dGET3ULKlnaDMVmkuXDek+hQPLZ2VUbPqvEOX+5jlQ=,tag:MBGmQ0NNNqX+T9EsBiWCaw==,type:str]
+sops:
+    age:
+        - recipient: age19ax6vm3pv8rph5tq3mmehd9sy9jk823tw8svsd790r0lkslycquqvlwz9m
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSA0Rmc2Ull1WFB4Smh3c0Zl
+            emlTNGJKZkpIK2JFeUNVeUcrR2FzRXRQZHlvCkhzMHpzYmZRZ0M0cXdRVi8wZmp6
+            ZDRZQ2FkOWt6M0lrdjBHa3VTWXBDKzgKLS0tIGtJbTRRelg1VVk2QStwdzlFM1g4
+            M1JOd1g3cVdjUFRhZ0FxcWphZXZJbkkKFXDtJVoi+qIrXp6cznevuZ+peBiRRITP
+            rrplqLiYsNIGKmKYtRIUu8WXDZ2q2CJ8Z+pka3W3H/U+m957hBDWyw==
+            -----END AGE ENCRYPTED FILE-----
+        - recipient: age1l4stuz0vr7gs7pqwjrmezam44702jp2vmqaqyxw0l0r42kf9updq4dfhrw
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBsSHdka3FPQUYrcXQzcTFo
+            a000TUllT0MvUzk5ZzVFbXZheG9ZVTM2S253CkE5VW9tQktvL2pMWFoxcnFjTGpr
+            Z0p1RjZWRGpSZ01TdTZRcEJXM2NOUkUKLS0tIC9rNmNzWitMdEd5dXQvdWlELzhM
+            M0xoL1dQR0kvMWpzN0RMNWVCTFQxNFUKj9LPjBo5NGOrGYNvu8qZ13PLYjLEWllU
+            LARzEn4XgkeHckouwvxZYMCx7WxmAruRWaOvnxTIczzSNP7wIrqnkA==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2025-07-12T04:13:47Z"
+    mac: ENC[AES256_GCM,data:W+e5d1scvV24AdVdl7Pisp9HxsXQ/tPjN2NV/Bd0RXZNBRB7LNQrSfk1GadboBnihW0ctAQOFk66PZsxwE2czfFL2/yzFxm9Cf11Mc822ZL3BwjnQBK4uR9LJrbjL7x1lFUk9v0AIPhjrir8F6dcX8mq6++hHNN0wjGaH3J9E0Y=,iv:RK7e4Dxog+Qsgk6gxK0f8PN8oF9bjWIrTyYK67Cdras=,tag:QSKsETYXbhnvhhjavP4UiA==,type:str]
+    unencrypted_suffix: _unencrypted
+    version: 3.10.2

flake.lock

@@ -25,12 +25,12 @@
     "blog": {
       "flake": false,
       "locked": {
-        "lastModified": 1757155808,
+        "lastModified": 1759333393,
         "lfs": true,
-        "narHash": "sha256-dngkmShADPQOziASLZmwXNop0R6O4PlbHYOUAXfaoxs=",
+        "narHash": "sha256-0ruJ4kw82hQZDLp5oIBG2Kq+SBeOUoTSMJzFofOz4Sg=",
         "ref": "refs/heads/public",
-        "rev": "0b2cb19d9f9da2a8cab440c0053029ec93d263b7",
-        "revCount": 36,
+        "rev": "e6d2bc75a815a8ea73eea24091af10b4eb595b95",
+        "revCount": 37,
         "type": "git",
         "url": "https://git.chn.moe/chn/blog-public.git"
       },
@@ -851,11 +851,11 @@
     },
     "nixpkgs-2311": {
       "locked": {
-        "lastModified": 1735377590,
-        "narHash": "sha256-U9W9H/HYoaKa5wzSL2IBmnFDhxlesuKAcKi/hl5xPvE=",
+        "lastModified": 1760234929,
+        "narHash": "sha256-4W0o4O8ANykPCOQD2Jb6pdGerDSLNzIVNF7AoVNMZvM=",
         "owner": "CHN-beta",
         "repo": "nixpkgs",
-        "rev": "0c3e74a65634ae3f43be7d0f6c3b5156ac54747b",
+        "rev": "66170f3c82eecdee7dcd29a7e72ed87965bde4fc",
         "type": "github"
       },
       "original": {
@@ -1213,6 +1213,24 @@
         "type": "github"
       }
     },
+    "pybinding": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1598796477,
+        "narHash": "sha256-4DtGtQ40TEaM6qSydwsj9gD3JqpaCFpcvWJISwn69Zk=",
+        "ref": "refs/heads/master",
+        "rev": "ec1128aaa84a1b43a74fb970479ce4544bd63179",
+        "revCount": 774,
+        "submodules": true,
+        "type": "git",
+        "url": "https://github.com/dean0x7d/pybinding"
+      },
+      "original": {
+        "submodules": true,
+        "type": "git",
+        "url": "https://github.com/dean0x7d/pybinding"
+      }
+    },
     "root": {
       "inputs": {
         "aagl": "aagl",
@@ -1254,6 +1272,7 @@
         "plasma-manager": "plasma-manager",
         "pocketfft": "pocketfft",
         "py4vasp": "py4vasp",
+        "pybinding": "pybinding",
         "rsshub": "rsshub",
         "rycee": "rycee",
         "sops-nix": "sops-nix",

flake.nix

@@ -64,6 +64,7 @@
     phono3py = { url = "github:phonopy/phono3py"; flake = false; };
     sticker = { url = "git+https://git.chn.moe/chn/sticker.git?lfs=1"; flake = false; };
     speedtest = { url = "github:librespeed/speedtest"; flake = false; };
+    pybinding = { url = "git+https://github.com/dean0x7d/pybinding?submodules=1"; flake = false; };
   };
 
   outputs = inputs: let localLib = import ./flake/lib inputs.nixpkgs.lib; in

flake/lib/buildNixpkgsConfig/default.nix

@@ -81,7 +81,22 @@ in platformConfig //
           {
             pkgs-2305 = "nixpkgs-2305";
             pkgs-2311 = "nixpkgs-2311";
-            pkgs-2411 = { source = "nixpkgs-2411"; overlays = [ inputs.topInputs.bscpkgs.overlays.default ]; };
+            pkgs-2411 =
+            {
+              source = "nixpkgs-2411";
+              overlays =
+              [
+                inputs.topInputs.bscpkgs.overlays.default
+                (final: prev: inputs.lib.optionalAttrs (nixpkgs.march != null)
+                {
+                  pythonPackagesExtensions = prev.pythonPackagesExtensions or [] ++ [(final: prev:
+                  {
+                    sphinx = prev.sphinx.overridePythonAttrs (prev:
+                      { disabledTests = prev.disabledTests or [] ++ [ "test_xml_warnings" ]; });
+                  })];
+                })
+              ];
+            };
             pkgs-unstable =
             {
               source = "nixpkgs-unstable";

flake/nixos.nix

@@ -1,7 +1,7 @@
 { inputs, localLib }:
 let
   singles = [ "nas" "pc" "vps4" "vps6" "r2s" ];
-  cluster = { srv1 = 3; srv2 = 2; };
+  cluster = { srv1 = 3; srv2 = 3; };
   deviceModules = builtins.listToAttrs
   (
     (builtins.map

flake/src.nix

@@ -29,7 +29,7 @@
     netboot = pkgs.fetchurl
     {
       url = "https://boot.netboot.xyz/ipxe/netboot.xyz.iso";
-      sha256 = "01hlslbi2i3jkzjwn24drhd2lriaqiwr9hb83r0nib9y1jvr3k5p";
+      sha256 = "6GeOcugqElGPoPXeaWVpjcV5bCFxNLShGgN/sjsVzuI=";
     };
   };
   vasp =

modules/hardware/cpu.nix

@@ -5,8 +5,8 @@ inputs:
     type = types.nullOr (types.enum [ "intel" "amd" ]);
     default = let inherit (inputs.config.nixos.system.nixpkgs) march; in
       if march == null then null
-      else if inputs.lib.hasPrefix "znver" march then "amd"
-      else if (inputs.lib.hasSuffix "lake" march)
+      else if inputs.lib.hasInfix "znver" march then "amd"
+      else if (inputs.lib.hasInfix "lake" march)
         || (builtins.elem march [ "sandybridge" "silvermont" "haswell" "broadwell" ])
         then "intel"
       else null;

modules/system/nixpkgs.nix

@@ -20,23 +20,5 @@ inputs:
       inherit inputs;
       nixpkgs = nixpkgs // { nixRoot = null; nixos = true; inherit (inputs.config.nixos.model) arch; };
     };
-    boot.kernelPatches = inputs.lib.mkIf (nixpkgs.march != null)
-    (
-      let configName =
-        if inputs.config.nixos.system.kernel.variant == "xanmod-unstable" then "structuredExtraConfig"
-        else "extraStructuredConfig";
-      in
-      [{
-        name = "native kernel";
-        patch = null;
-        ${configName} =
-          let kernelConfig = { znver2 = "MZEN2"; znver3 = "MZEN3"; znver4 = "MZEN4"; znver5 = "MZEN5"; };
-          in
-          {
-            GENERIC_CPU = inputs.lib.kernel.no;
-            ${kernelConfig.${nixpkgs.march} or "M${inputs.lib.toUpper nixpkgs.march}"} = inputs.lib.kernel.yes;
-          };
-      }]
-    );
   };
 }

packages/default.nix

@@ -147,6 +147,11 @@ inputs: rec
   atomkit = inputs.pkgs.callPackage ./atomkit.nix { src = inputs.topInputs.self.src.atomkit; };
   xinli = inputs.pkgs.callPackage ./xinli
     { inherit biu; stdenv = inputs.pkgs.clang18Stdenv; inherit (inputs.pkgs.pkgs-unstable) httplib; };
+  pybinding = inputs.pkgs.pkgs-2411.python310Packages.callPackage ./pybinding
+  {
+    src = inputs.topInputs.pybinding;
+    buildProxy = inputs.pkgs.lib.mkBuildproxy ./pybinding/proxy.nix;
+  };
 
   fromYaml = content: builtins.fromJSON (builtins.readFile
     (inputs.pkgs.runCommand "toJSON" {}

packages/pybinding/default.nix

@@ -0,0 +1,12 @@
+{ src, buildPythonPackage, setuptools, cmake, buildProxy, distutils, numpy, scipy, matplotlib, pytest }:
+buildPythonPackage
+{
+  name = "pybinding";
+  inherit src;
+  pyproject = true;
+  build-system = [ setuptools cmake distutils ];
+  dependencies = [ numpy scipy matplotlib pytest ];
+  dontUseCmakeConfigure = true;
+  preBuild = ''source ${buildProxy}'';
+  patches = [ ./fix.patch ];
+}

packages/pybinding/fix.patch

@@ -0,0 +1,24 @@
+diff --git a/cppcore/include/numeric/arrayref.hpp b/cppcore/include/numeric/arrayref.hpp
+index e1ef1ba..722ebdc 100644
+--- a/cppcore/include/numeric/arrayref.hpp
++++ b/cppcore/include/numeric/arrayref.hpp
+@@ -7,6 +7,7 @@
+ #include <numeric>
+ #include <stdexcept>
+ #include <array>
++#include <cstdint>
+ 
+ namespace cpb { namespace num {
+ 
+diff --git a/cppmodule/deps/pybind11/include/pybind11/attr.h b/cppmodule/deps/pybind11/include/pybind11/attr.h
+index 6962d6fc..f8261bc3 100644
+--- a/cppmodule/deps/pybind11/include/pybind11/attr.h
++++ b/cppmodule/deps/pybind11/include/pybind11/attr.h
+@@ -11,6 +11,7 @@
+ #pragma once
+ 
+ #include "cast.h"
++#include <cstdint>
+ 
+ NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
+ 

packages/pybinding/proxy.nix

@@ -0,0 +1,130 @@
+{ fetchurl }:
+[
+  {
+    url = "https://gitlab.com/libeigen/eigen/-/archive/3.3.3/eigen-3.3.3.tar.gz";
+    file = fetchurl
+    {
+      url = "https://gitlab.com/libeigen/eigen/-/archive/3.3.3/eigen-3.3.3.tar.gz";
+      hash = "sha256-/XJpQ5C9joFYYgVxfSz4I+cY9YS3eaFV23R9HmhIGi4=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "application/octet-stream";
+      "content-disposition" = "attachment; filename=eigen-3.3.3.tar.gz";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/variant.hpp";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/variant.hpp";
+      hash = "sha256-TsAoFQ3nrnXwS8cxg2RLiu6U7CxZGYHmIm7mHemTgSA=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "31575";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/recursive_wrapper.hpp";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/recursive_wrapper.hpp";
+      hash = "sha256-Su1xw27Ctf7TM8isDU8SGXiKg9rM9LvxEh8bUiaGnR0=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "2632";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/variant_visitor.hpp";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/mapbox/variant/v1.1.4/include/mapbox/variant_visitor.hpp";
+      hash = "sha256-JiPsMvUm0V8P/cXxM3BMHrCAk+cU2JGzWAoK5T2e9DI=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "743";
+    };
+  }
+  {
+    url = "https://github.com/p12tic/libsimdpp/archive//v2.0-rc2.tar.gz";
+    file = fetchurl
+    {
+      url = "https://github.com/p12tic/libsimdpp/archive//v2.0-rc2.tar.gz";
+      hash = "sha256-dLYHn29FfiMm8HGclKiB/XN4Xu71mpKGjGmTWcuXndg=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-disposition" = "attachment; filename=libsimdpp-2.0-rc2.tar.gz";
+      "content-type" = "application/x-gzip";
+      "content-length" = "287439";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/format.h";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/format.h";
+      hash = "sha256-7v0pfyt2c2KDtMhot68W9nt13pN+j2OswuuKeB/ZnBs=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "119800";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/format.cc";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/format.cc";
+      hash = "sha256-cwjmLJljDJ/iQbF5dD6PHnvUSGYfx1Elfq1kebFVzE0=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "28777";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/ostream.h";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/ostream.h";
+      hash = "sha256-is8VgEdM7FovPR6X3MuRGoPfd+Gm7vtHT+3r6rZasII=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "2830";
+    };
+  }
+  {
+    url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/ostream.cc";
+    file = fetchurl
+    {
+      url = "https://raw.githubusercontent.com/fmtlib/fmt/3.0.2/fmt/ostream.cc";
+      hash = "sha256-NKg67BJHmwd5YAIkOqjNEDjvqSspLFHN2+23W5XImSQ=";
+    };
+    status_code = 200;
+    headers =
+    {
+      "content-type" = "text/plain; charset=utf-8";
+      "content-length" = "1073";
+    };
+  }
+]