How do I build/run locally with nix?

[wch]

I'm completely new to teslamate and want to try it out, but without using Docker, if that's possible. I use nix on my Mac. I saw that there's a flake.nix file in the repository, and I searched for issues and discussions around nix but only found a few mentions here and there.

I think this is working for me, with the main branch checked out:

In one terminal, I ran the following, and this appeared to start mqtt and postgres:

nix develop --no-pure-eval
devenv up

And then in another terminal, I ran some commands from https://docs.teslamate.org/docs/development:

nix develop --no-pure-eval
mix setup
MIX_ENV=test mix ecto.setup

iex -S mix phx.server

This got me to the point where I can connect to localhost:4000 and sign in with Tesla tokens. But at this point I'm not sure where to go next: How do I get enough grafana running so I can connect to localhost:3000? Am I trying to do something that teslamate just isn't designed to do?

[brianmay]

Sorry, somehow I completely missed this.

What are you trying to do?

Generally speaking Teslamate needs to be running as a background task all the time. Doing so as above may not be so great, as you need to make sure you start it after every reboot. And only useful if the computer is a server and left on all the time.

We have a nixos module to setup Teslamate as a background process. You need to be running nixos on the computer not OSX though to use this module.

If you really want to use OSX, you would need a module that uses nix-darwin or home-manager to automatically start the daemon on reboot. This is not something I have had personal experience in, so I cannot actually comment any further. Somebody once told me that home-manager supports OSX launchd process to start processes but I forget the details, so might have this wrong.

[IngmarStein]

I'm trying to move all my homelab services out of containers and Teslamate is the last remaining service on Docker. The homelab is a Mac Studio, so I'm also using nix-darwin and have added the teslamate flake to my imports:

    teslamate = {
      url = "github:teslamate-org/teslamate/main";
      inputs.nixpkgs.follows = "nixpkgs";
    };

nix flake show github:teslamate-org/teslamate --impure shows a package for aarch64-darwin:

└───packages
    ├───aarch64-darwin
    │   ├───default: package 'teslamate-2.0.1-dev'
    │   ├───devenv-test: package 'devenv-test'
    │   └───devenv-up: package 'devenv-up'

However, when I add teslamate.packages.aarch64-darwin.default to environment.systemPackages and run darwin-rebuild build, I get the following error:

error: builder for '/nix/store/bbbm5jnz4if25yprdz9jbi792x4vqc70-teslamate-2.0.1-dev.drv' failed with exit code 1;
       last 25 log lines:
       > ==> phoenix
       > Compiling 71 files (.ex)
       > Generated phoenix app
       > ==> phoenix_live_view
       > Compiling 39 files (.ex)
       > Generated phoenix_live_view app
       > ==> phoenix_ecto
       > Compiling 7 files (.ex)
       > Generated phoenix_ecto app
       > ==> cloak_ecto
       > Compiling 22 files (.ex)
       > Generated cloak_ecto app
       > configurePhase completed in 32 seconds
       > Running phase: buildPhase
       > Compiling 78 files (.ex)
       >
       > == Compilation error in file lib/teslamate_web/cldr.ex ==
       > ** (File.Error) could not write to file "/nix/store/xrh3fjc2cv9rfi30gp3050p64yz0cc47-source/priv/cldr/locales/da.json": permission denied
       >     (elixir 1.17.3) lib/file.ex:1144: File.write!/3
       >     (ex_cldr 2.42.0) lib/cldr/install.ex:107: Cldr.Install.do_install_locale_name/3
       >     (elixir 1.17.3) lib/enum.ex:987: Enum."-each/2-lists^foreach/1-0-"/2
       >     (ex_cldr 2.42.0) lib/cldr/install.ex:29: Cldr.Install.install_known_locale_names/1
       >     (ex_cldr 2.42.0) lib/cldr.ex:102: Cldr.install_locales/1
       >     (ex_cldr 2.42.0) expanding macro: Cldr.Backend.Compiler.__before_compile__/1
       >     lib/teslamate_web/cldr.ex:1: TeslaMateWeb.Cldr (module)

I think I know how to create a launchd service later, but I'd need the package to build first :) Any idea what the issue could be?

[brianmay]

I use the nixos module:

{
  config,
  teslamate,
  ...
}: {
  age.secrets.teslamate = {file = ../secrets/teslamate.age;};

  imports = [teslamate.nixosModules.default];

  services.teslamate = {
    enable = true;
    secretsFile = config.age.secrets.teslamate.path;
    listenAddress = "127.0.0.1";
    port = 4001;
    virtualHost = "[censored]";
    postgres = {
      user = "teslamate";
      database = "teslamate";
      host = "localhost";
    };
    mqtt = {
      enable = true;
      host = "[censored]";
      port = 8883;
    };
    grafana = {
      enable = true;
      listenAddress = "127.0.0.1";
      port = 3000;
    };
  };
}

Having said that, this just does the exact same thing you did:

teslamate = self.packages.${pkgs.system}.default;

Looks like maybe on Darwin it thinks the locales are wrong and need updating. Yuck.

In the past I have attempted to resolve problems by manually downloading the exact version locales required and setting LOCALES to this directory. I think this is because the cldr package really likes to download these files at build time.

teslamate/nix/flake-modules/package.nix

Lines 50 to 56 in a7d4e26

	cldr = pkgs.fetchFromGitHub {
	owner = "elixir-cldr";
	repo = "cldr";
	rev = "v2.40.0";
	sha256 = "sha256-B3kIJx684kg3uxdFaWWMn9SBktb1GUqCzSJwN1a0oNo=";
	# sha256 = pkgs.lib.fakeHash;
	};

I think this is working - /nix/store/xrh3fjc2cv9rfi30gp3050p64yz0cc47-source/priv/cldr/locales/da.json - looks correct.

Oh, wait, that refers to version 2.40.0 still, but mix.exs now has 2.42.0:

teslamate/mix.exs

Line 41 in a7d4e26

{:ex_cldr, "~> 2.42.0"},

So actually I am a bit surprised it works for me.

Possibly setting SKIP_LOCALE_DOWNLOAD to true during the build might help. It is set to true for the Docker build. Looking at the code though, I think it is going to decide that the version is wrong, and download them anyway.

The correct solution will be to update the reference in package.nix to use the correct version of cldr.

Only thing that confuses me now is - why is this working on my box? It should be failing also. Here "nix build" works fine.

Building manually without nix comes up with the expected error:

07:58:33.057 [info] Locale data for :da is stale. Cldr version is 47.0.0, locale version is 45.0.0. Updated locale data will be downloaded.

== Compilation error in file lib/teslamate_web/cldr.ex ==
** (File.Error) could not write to file "/nix/store/xrh3fjc2cv9rfi30gp3050p64yz0cc47-source/priv/cldr/locales/da.json": read-only file system
    (elixir 1.17.3) lib/file.ex:1144: File.write!/3
    (ex_cldr 2.42.0) lib/cldr/install.ex:107: Cldr.Install.do_install_locale_name/3
    (elixir 1.17.3) lib/enum.ex:987: Enum."-each/2-lists^foreach/1-0-"/2
    (ex_cldr 2.42.0) lib/cldr/install.ex:29: Cldr.Install.install_known_locale_names/1
    (ex_cldr 2.42.0) lib/cldr.ex:102: Cldr.install_locales/1
    (ex_cldr 2.42.0) expanding macro: Cldr.Backend.Compiler.__before_compile__/1
    lib/teslamate_web/cldr.ex:1: TeslaMateWeb.Cldr (module)

[IngmarStein]

I ended up writing a Homebrew formula instead: Homebrew/homebrew-core#222388. Maybe it gets accepted to the core repository where it may help other people install Teslamate on macOS (or Linux).

[IngmarStein]

I tried setting SKIP_LOCALE_DOWNLOAD=true and building with --impure but as you predicted, still got the same error. Thanks for spotting the version mismatch!

[brianmay]

I see the what is happening now.

Normally nix builds try to download, but thanks to containment, these fail but continue with the old file.

teslamate> 07:29:24.565 [error] Failed to connect to ~c"raw.githubusercontent.com" to download ~c"https://raw.githubusercontent.com/elixir-cldr/cldr/v2.42.0/priv/cldr/locales/da.json"
teslamate>
teslamate> 07:29:24.566 [error] Unable to downloaded locale :da version v2.42.0. nxdomain.

But you are building on darwin. And nix on darwin, I seem to recall doesn't have the same level of containment by default (although I can't find references to back this up right now). As a result, if this http requests are working that would explain why you got the error.

[JakobLichterfeld]

When switching to force_locale_download: false it seems to work on darwin, so your assumptions are totally right about the nix-darwin containment

[JakobLichterfeld]

moved to #4761