feat: add working-directory option

Add option `working-directory` to execute the script inside the specified working directory instead of the repository root.

.github/workflows/test.yml

@@ -105,3 +105,22 @@ jobs:
           script: |
             hello
             command -v docker
+
+  test-local-flake-in-working-directory:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Nix
+        uses: cachix/install-nix-action@v18
+        with:
+          extra_nix_config: |
+            access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
+      - name: Test Bash Shell with Local and External Flakes
+        uses: ./
+        with:
+          flakes: .#cowsay,nixpkgs#docker
+          working-directory: test/working-directory
+          script: |
+            pwd
+            cowsay hello
+            command -v docker

README.md

@@ -79,10 +79,14 @@ jobs:
 
 - `interpreter`:  Interpreter to use in the nix shell shebang, defaults to `bash`. (This is passed to `nix run -c`, used to be `-i` in a nix shell shebang)
 
-- `packages`: Comma-separated list of packages to pre-install in your shell. Defaults to just `bash` 
+- `packages`: Comma-separated list of packages to pre-install in your shell. Defaults to just `bash`. Cannot be used together with the `flakes` option.
+
+- `flakes`: Comma-separated list of fully qualified flakes to pre-install in your shell. Use either `packages` or `flakes`. Cannot be used together with the `packages` option.
 
 - `script`: The actual script to execute in your shell. Will be passed to the `interpreter`, which defaults to `bash`
 
+- `working-directory`: Execute the script inside the specified working directory instead of the repository root. Example: `path/to/dir`
+
 ## FAQ: Passing a Github Token against Rate Limits
 
 ```yaml

src/main.ts

@@ -8,9 +8,14 @@ function run(): void {
     const packages: string = core.getInput('packages')
     const flakes: string = core.getInput('flakes')
     const script: string = core.getInput('script')
+    const workingDirectory: string = core.getInput('working-directory')
 
-    const nixWrapperPath = `${__dirname}/wrapper.sh`
-    const scriptPath = `${__dirname}/script.sh`
+    const nixWrapperPath = workingDirectory
+      ? `./wrapper.sh`
+      : `${__dirname}/wrapper.sh`
+    const scriptPath = workingDirectory
+      ? `./script.sh`
+      : `${__dirname}/script.sh`
 
     const wrappedPackages = packages
       .split(',')
@@ -53,10 +58,15 @@ set -euo pipefail
 ${script}
    `
 
-    writeFileSync(nixWrapperPath, nixWrapper, {mode: 0o755})
-    writeFileSync(scriptPath, wrappedScript, {mode: 0o755})
+    writeFileSync(`${workingDirectory}/${nixWrapperPath}`, nixWrapper, {
+      mode: 0o755
+    })
+    writeFileSync(`${workingDirectory}/${scriptPath}`, wrappedScript, {
+      mode: 0o755
+    })
 
     execFileSync(nixWrapperPath, {
+      cwd: workingDirectory || undefined,
       stdio: 'inherit',
       shell: 'bash'
     })

test/working-directory/flake.nix

@@ -0,0 +1,11 @@
+{
+  description = "A very basic flake";
+
+  outputs = { self, nixpkgs }: {
+
+    packages.x86_64-linux.cowsay = nixpkgs.legacyPackages.x86_64-linux.cowsay;
+
+    packages.x86_64-linux.default = self.packages.x86_64-linux.cowsay;
+
+  };
+}

test/working-directory/test.sh

@@ -0,0 +1 @@
+echo hello