58 lines
1.4 KiB
Markdown
58 lines
1.4 KiB
Markdown
|
# Local Path Inputs
|
||
|
|
|
||
|
|
This note covers `40-path-inputs/`, which uses `inputs.catalog.url = "path:./catalog";` to pull another local flake into the parent flake.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## 1. What a Local Path Input Looks Like
|
||
|
|
|
||
|
|
A local input is declared with a `path:` flake reference:
|
||
|
|
|
||
|
|
```nix
|
||
|
|
inputs.catalog.url = "path:./catalog";
|
||
|
|
```
|
||
|
|
|
||
|
|
The target directory must itself be a flake, so `catalog/` contains its own `flake.nix`.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## 2. What the Child Flake Exposes
|
||
|
|
|
||
|
|
The child flake in this example does not build packages. It exports pure data through `lib`:
|
||
|
|
|
||
|
|
- one release name,
|
||
|
|
- one service-owner map, and
|
||
|
|
- one rollout plan.
|
||
|
|
|
||
|
|
The parent flake reads those values and turns them into a runnable script.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## 3. Why This Example Uses `lib`
|
||
|
|
|
||
|
|
Using `lib` keeps the focus on the input boundary, not on packaging details in both flakes.
|
||
|
|
|
||
|
|
That is the important part of `path:` inputs: once the child is a flake, its outputs are consumed the same way as any other flake input.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## 4. The Git-Tracked File Rule Still Applies
|
||
|
|
|
||
|
|
This is still a flake input, so Nix reads it from the flake source tree. Files inside `catalog/` must be tracked, or the parent flake will not see
|
||
|
|
them during pure evaluation.
|
||
|
|
|
||
|
|
That rule is easy to miss when the child flake lives in the same repository.
|
||
|
|
|
||
|
|
---
|
||
|
|
|
||
|
|
## 5. Commands to Try
|
||
|
|
|
||
|
|
```bash
|
||
|
|
cd 40-path-inputs
|
||
|
|
|
||
|
|
nix flake metadata
|
||
|
|
nix build
|
||
|
|
./result/bin/show-local-plan
|
||
|
|
nix flake check
|
||
|
|
```
|