confirmed haskell.nix didn't work.

{

  description = "download large files across unreliable network via HTTP";

  inputs.haskellNix.url = "github:input-output-hk/haskell.nix";

  inputs.nixpkgs.follows = "haskellNix/nixpkgs-2311";

  # always check which channel and which ghc is supported (cached) by ci.nix

  # https://github.com/input-output-hk/haskell.nix/blob/master/ci.nix

  # for more information, see Why am I building GHC?

  # https://input-output-hk.github.io/haskell.nix/troubleshooting.html#why-am-i-building-ghc

  inputs.nixpkgs.follows = "haskellNix/nixpkgs-unstable";

  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils, haskellNix }:

    flake-utils.lib.eachSystem [ "x86_64-linux" ] (system:

          rdProject =

            final.haskell-nix.project' {

              src = ./.;

              compiler-nix-name = "ghc928";

              compiler-nix-name = "ghc948";

              # This is used by `nix develop .` to open a shell for use with

              # `cabal`, `hlint` and `haskell-language-server`

              shell.tools = {

      flake = pkgs.rdProject.flake {};

    in flake // {

      # Built by `nix build .`

      legacyPackages = pkgs;

      packages.default = flake.packages."reliable-download:exe:rd-api";

    });

* COMMENT -*- mode: org -*-

#+Date: 2018-05-04

Time-stamp: <2024-08-24>

Time-stamp: <2024-08-25>

#+STARTUP: content

* notes                                                               :entry:

** 2022-03-14 project dir structure

  should use a free CI tool to build the artifact and upload it to pypi.

  check whether this can be done using github or another CI tool.

- 2024-08-24 does haskell support cross-compiling? I would like to build arm64

  binary from x86_64 PC.

  does nix made that easy? I can try nix on de06, with a older glibc. that

  way, cross-compile will not be needed.

- search: ghc cross compile for aarch64

- How to build application in arm64 arch with a x86_64 host - Haskell Community

  https://discourse.haskell.org/t/how-to-build-application-in-arm64-arch-with-a-x86-64-host/7456/6

  it is possible. but you have to build a ghc yourself.

- State of Haskell Cross Compilation : r/haskell

  https://www.reddit.com/r/haskell/comments/h0e5ui/state_of_haskell_cross_compilation/

  #+begin_quote

  We have been using haskell cross compilation (to windows) at work in

  production for quite a while now. And this was the reason why haskell.nix

  was conceived.

  #+end_quote

  nix can do it, with haskell.nix.

  the problem with nix is, it needs to DL lots of things and network is slow

  when accessed from China.

  input-output-hk/haskell.nix: Alternative Haskell Infrastructure for Nixpkgs

  https://github.com/input-output-hk/haskell.nix

  it's maintained.

  Introduction - Alternative Haskell Infrastructure for Nixpkgs

  https://input-output-hk.github.io/haskell.nix/index.html

  has extensive document.

  I should try it.

- Cross-compiling Haskell to ARM. : r/haskell

  https://www.reddit.com/r/haskell/comments/a15hfv/crosscompiling_haskell_to_arm/

- 

** 2024-03-12 rd-api, if file is already transferred block by block, I can support

live compress easily. If the client request compress as param such as

?compress=zstd. default is no compress.

yes. see Route Patterns.

* wontfix                                                             :entry:

** 2024-08-24 try build this project using haskell.nix

- Getting started with Flakes - Alternative Haskell Infrastructure for Nixpkgs

  https://input-output-hk.github.io/haskell.nix/tutorials/getting-started-flakes.html

- I already have a not working file at ./flake.nix.not-working

- try it.

  nix --allow-import-from-derivation flake metadata .

  withproxy nix --allow-import-from-derivation flake show .

  tmake withproxy nix run .#reliable-download:exe:rd-api

  tmake withproxy nix run .#reliable-download:exe:rd

  //withproxy is needed, many pkg requires access to github to fetch and build.

  tmake withproxy nix build .#reliable-download:lib:reliable-download

  tmake withproxy nix build .#reliable-download:exe:rd-api

  tmake withproxy nix build .#reliable-download:exe:rd

  to run dev shell

  nix develop .

  cabal build reliable-download

- problems

  - 30m DL actually finished. cool.

  - a build error.

    nix build .#reliable-download:lib:reliable-download

    #+begin_quote

    error: flake 'git+file:///home/sylecn/projects/reliable-download' does not provide attribute 'packages.x86_64-linux.reliable-download:lib:reliable-download', 'legacyPackages.x86_64-linux.reliable-download:lib:reliable-download' or 'reliable-download:lib:reliable-download'

    #+end_quote

    try list packages, flake metadata.

    nix flake metadata .

    only has input. no output?

    nix flake show .

    error in other people's nix code.

    #+begin_quote

    error: cannot build '/nix/store/825d0r20hz3l3m1k29iw8z55sqf63xca-stack-repos.drv^out' during evaluation because the option 'allow-import-from-derivation' is disabled

    #+end_quote

    check this option

    allow-import-from-derivation

    not documented in haskell.nix doc.

    try google

    search: haskell.nix cannot build during evaluation because the option 'allow-import-from-derivation' is disabled

    "'allow-import-from-derivation' is disabled" error · Issue #34 · purenix-org/purenix

    https://github.com/purenix-org/purenix/issues/34

    IFD (import from derivation)

    Native support for import-from-derivation – Hercules CI blog

    https://blog.hercules-ci.com/2019/08/30/native-support-for-import-for-derivation/

    Don't allow IFD in flakes by default by edolstra · Pull Request #5253 · NixOS/nix

    https://github.com/NixOS/nix/pull/5253

    try enable IFD

    nix --allow-import-from-derivation flake show .

    it's said it can work if you only enable your host's arch in eachSystem call.

    yes. this works.

  - has HTTP 524 error from cache.iog.io

    auto retry okay.

  - lots of DL, again, for

    tmake withproxy nix run .#reliable-download:exe:rd-api

    including python3-3.11.8

    780MiB DL, 9312.6MiB unpacked

    fetching ghc-9.0.2 why?

    now shows

    947MiB DL, 11093MiB unpacked.

    //11GiB to build a haskell project. that's more than flutter + android sdk combined.

    2024-08-25 01:28:54

    before build

    33G used on /

    now 43G used on /

    2024-08-25 01:30:15

    building ghc-9.4.8.

    no. maybe I should not specify a version.

    compiler-nix-name = "ghc948";

    what should I put here?

    try search in nixpkgs-2311

    which ghc is there.

    no. website can only search 24.05 and unstable.

    should I use unstable?

    try ghc94

    nope.

    #+begin_quote

    error: This version of Nixpkgs does not contain GHC 9.4.8

    (or it is not present at attribute 'ghc94)').

    Either switch to a version of Nixpkgs which does have this version, or use a version

    of GHC which the current version of Nixpkgs contains.

    #+end_quote

    how to search pkg in nixpkgs-2311?

    nix search nixpkgs ghc94

    nix search nixpkgs#nixos-23.11 ghc94

    none of these work.

    search: haskell.nix flake what should I put in compiler-nix-name?

    check haskell.nix source code

    https://github.com/input-output-hk/haskell.nix/blob/master/compiler/ghc/default.nix

    compiler-nix-name

    can I omit it?

    try ghc928

    now it tries to build ghc 8.10.7.

    WTF.

    Why am I building GHC?

    https://input-output-hk.github.io/haskell.nix/troubleshooting.html#why-am-i-building-ghc

    supported ghc version is mentioned in ci.nix

    haskell.nix/ci.nix at master · input-output-hk/haskell.nix

    https://github.com/input-output-hk/haskell.nix/blob/master/ci.nix

    for R2311

    unstable + ghc948

    this should work.

    no more ghc builds.

  - make https://cache.iog.io faster

    https://ping.chinaz.com/

    cache.iog.io

    cache.iog.io.		23	IN	A	104.21.38.77

    cache.iog.io.		23	IN	A	172.67.220.22

    可以直接访问，不要翻墙。cloudflare.

    都可以。翻墙也可以，不翻也可以。

  - use unstable channel

    6GiB unpack, 830M DL.

    need to build 169 pkgs, copy 201 artifacts.

    fetching ghc-9.6.4 from cache.iog.io

    no build ghc this time.

    this is used to build some tools.

    also fetching ghc-9.4.8 from sjtu.edu.cn

    this is used to build my project.

    sjtu.edu.cn is slower than cache.iog.io.

    I have no direct rule for it.

    DOMAIN-SUFFIX,sjtu.edu.cn,DIRECT

    with DIRECT rule, it's still slow.

    https://mirrors.sjtug.sjtu.edu.cn/nix-channels/store

    https://mirrors.sjtug.sjtu.edu.cn/

    tmake curl -v -o /dev/null https://mirrors.sjtug.sjtu.edu.cn/

    不慢的啊。

    drop withproxy. since both repo is DIRECT access.

    only have 100KiB/s bandwidth.

    try this:

    curl -OL https://mirror.sjtu.edu.cn/debian-cd/12.6.0-live/amd64/iso-hybrid/debian-live-12.6.0-amd64-kde.iso

    17MiB/s

    2024-08-25 02:16:31

    build ghc-9.4.8 again!!

    I thought the binary is DL, did it just DL the source code?

    noooooooooooooo.

    now 51G used on /

    it's crazy and not working.

    canceled.

    maybe it's ghc94, not ghc948.

    nope. ghc94 nix error.

    try ghc924.

    that is in the md file.

    https://github.com/input-output-hk/haskell.nix/blob/master/docs/reference/supported-ghc-versions.md

    now it wants to build

    ghc-a54827e

    wtf.

    yeah, nothing works.

    nix is a total PITA.

  - WONTFIX try search in github see whether any open source project is using

    haskell.nix

** 2024-08-24 when DL more than 1 URL, one thread is combining blocks, other thread can continue DL. :invalid:

-w,--worker INT          concurrent HTTP download worker (default: 5)