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Merged
erictapen merged 2 commits into from
Jun 6, 2025
Merged

overview: modularize NIX_CONFIG #1097

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47e279e
modularize NIX_CONFIG
themadbit Jun 5, 2025
36ec0b1
Merge branch 'main' into modularize-overview
erictapen Jun 6, 2025
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20 changes: 20 additions & 0 deletions overview/content-types/config-item.nix
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
{
name,
config,
lib,
...
}:
let
inherit (lib) mkOption types;
in
{
options = {
name = mkOption {
type = types.str;
default = name;
};
value = mkOption {
type = with types; either str (listOf str);
};
};
Comment on lines +11 to +19
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@fricklerhandwerk fricklerhandwerk Jun 6, 2025 •
edited
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The NIX_CONFIG thing is a bit tricky. In the instructions what we really want to show is how to set the environment variable to the right value. This is challenging here because NIX_CONFIG is multiline. A convenient rendering will look differently for different shells. So what this change should really be about is

  • adding a shell-code snippet the modular way
  • encoding how to cleverly render setting a multi-line shell variable for bash

the nix configuration we don't need to re-invent -- it's already a NixOS module option, and we should even be able to re-use its rendering logic to produce a string that Nix will accept (not sure though, haven't looked).

then plug it all together such that it displays correctly in the project detail view.

}
29 changes: 29 additions & 0 deletions overview/content-types/nix-config.nix
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@@ -0,0 +1,29 @@
{
name,
config,
lib,
...
}:
let
inherit (lib) mkOption types;
in
{
options = {
__toString = mkOption {
type = with types; functionTo str;
readOnly = true;
default =
self:
let
separator = "'$'\\n''";
concatSettings = lib.concatStringsSep separator (
lib.map (attrs: "${attrs.name} = ${toString attrs.value}") self.settings
);
in
"NIX_CONFIG='${concatSettings}'";
};
settings = mkOption {
type = with types; listOf (submodule ./config-item.nix);
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@erictapen erictapen Jun 6, 2025

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I think the submodule definition could be inlined here. I think file granularity still needs to be figured out but for now as a rule of thumb stuff that doesn't have a __toString attr shouldn't live in its own file.

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@erictapen erictapen Jun 6, 2025

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Actually nevermind, just saw what @fricklerhandwerk did in #1092 and it was his idea in the first place, so let's roll with this granularity.

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@fricklerhandwerk fricklerhandwerk Jun 6, 2025 •
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__toString attr shouldn't live in its own file.

It doesn't, but arguably we could have collapsed ./config-item into this module.

};
};
}
21 changes: 20 additions & 1 deletion overview/default.nix
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Expand Up @@ -268,6 +268,25 @@ let
openPorts = demoSystem.config.networking.firewall.allowedTCPPorts;
# The port that is forwarded to the host so that the user can access the demo service.
servicePort = (builtins.head openPorts);
nix-config = eval {
imports = [ ./content-types/nix-config.nix ];
settings = [
{
name = "substituters";
value = [
"https://cache.nixos.org/"
"https://ngi.cachix.org/"
];
}
{
name = "trusted-public-keys";
value = [
"cache.nixos.org-1:6nchdd59x431o0gwypbmraurkbj16zpmqfgspcdshjy="
"ngi.cachix.org-1:n+cal72roc3qqulxihpv+tw5t42whxmmhpragkrsrow="
];
}
];
};
in
''
${heading 2 "demo" "Try the service in a VM"}
Expand All @@ -291,7 +310,7 @@ let
</li>
<li>
<strong>Enable binary substituters</strong>
<pre><code>NIX_CONFIG='substituters = https://cache.nixos.org/ https://ngi.cachix.org/'$'\n'''trusted-public-keys = cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY= ngi.cachix.org-1:n+CAL72ROC3qQuLxIHpV+Tw5t42WhXmMhprAGkRSrOw='</code></pre>
<pre><code>${nix-config}</code></pre>
<pre><code>export NIX_CONFIG</code></pre>
</li>
<li>
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