### Complete GitHub Actions Workflow with Magic Nix Cache

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

A full example of a GitHub Actions workflow demonstrating the integration of Magic Nix Cache for CI jobs on Linux and macOS. This setup automatically caches Nix builds.

```yaml
name: CI

on:
  push:
  pull_request:

jobs:
  check:
    runs-on: ubuntu-22.04
    permissions:
      contents: read
      id-token: write
    steps:
      - uses: actions/checkout@v4
      - uses: DeterminateSystems/nix-installer-action@main
      - uses: DeterminateSystems/magic-nix-cache-action@main
      - run: nix flake check
```

--------------------------------

### Local Development: Copy Bash to Local Cache

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Command to copy the 'bash' executable to a local Magic Nix Cache instance running at http://127.0.0.1:3000. This is part of the local development setup.

```shell
nix copy --to 'http://127.0.0.1:3000' $(which bash)
```

--------------------------------

### Integrate Magic Nix Cache Action in GitHub Workflow

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Add this action after installing Nix in your GitHub Actions workflow to enable automatic caching of Nix builds. Ensure necessary permissions are granted.

```yaml
permissions:
  contents: read
  id-token: write
steps:
  - uses: actions/checkout@v4
  - uses: DeterminateSystems/nix-installer-action@main
  - uses: DeterminateSystems/magic-nix-cache-action@main
  - run: nix flake check
```

--------------------------------

### Handle GitHub Actions Cache Rate Limit Error

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Example of an error message indicating that the GitHub Actions Cache API rate limit has been exceeded. The Magic Nix Cache and Nix handle this gracefully, preventing CI failures.

```text
error: unable to download 'http://127.0.0.1:37515/<...>': HTTP error 418
       response body:
       GitHub API error: API error (429 Too Many Requests): StructuredApiError { message: "Request was blocked due to exceeding usage of resource 'Count' in namespace ''." }
```

--------------------------------

### Local Development: Build Release Binaries for Nix Cache

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Commands to build the Magic Nix Cache release binaries for different architectures (x86_64-unknown-linux-gnu and aarch64-unknown-linux-gnu).

```shell
cargo build --release --target x86_64-unknown-linux-gnu
```

```shell
cargo build --release --target aarch64-unknown-linux-gnu
```

--------------------------------

### Local Development: Nix Store Operation with Local Cache

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Command to perform a Nix store operation, referencing a local cache at http://localhost:3000 and disabling signature requirements. Used for local testing.

```shell
nix-store --store $PWD/test-root --extra-substituters 'http://localhost:3000' --option require-sigs false -r $(which bash)
```

--------------------------------

### Local Development: Run Magic Nix Cache with Upstream Cache

Source: https://github.com/determinatesystems/magic-nix-cache/blob/main/README.md

Command to run the Magic Nix Cache locally for development, specifying credentials and an upstream cache. This is useful for testing and debugging.

```shell
cargo run -- -c creds.json --upstream https://cache.nixos.org
```

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