Skip setup-uv if uv is already installed (#53)

* Skip setup-uv if uv is already installed

Signed-off-by: William Woodruff <william@astral.sh>

* Bump Dependabot intervals

Signed-off-by: William Woodruff <william@astral.sh>

* Document existing behavior

Signed-off-by: William Woodruff <william@astral.sh>

---------

Signed-off-by: William Woodruff <william@astral.sh>

Author: woodruffw

.github/dependabot.yml

@@ -3,7 +3,7 @@ updates:
   - package-ecosystem: github-actions
     directory: /
     schedule:
-      interval: weekly
+      interval: monthly
     cooldown:
       default-days: 7
     groups:
@@ -13,7 +13,7 @@ updates:
   - package-ecosystem: "uv"
     directory: "/"
     schedule:
-      interval: "weekly"
+      interval: "monthly"
     cooldown:
       default-days: 7
     groups:

README.md

@@ -71,6 +71,10 @@ a publishing tool that supports PEP 740 attestations. Such tools include:
 > We recommend using `uv publish` with this action, as it does not require
 > any additional installation or configuration.
 
+> [!TIP]
+> This action will attempt to install `uv` if it is not already installed
+> and available on the `PATH`.
+
 ### Quickstart
 
 Add `astral-sh/attest-action` directly above your publishing step in your

action.yml

@@ -1,14 +1,19 @@
 name: astral-sh/attest-action
 
-description: A GitHub Action that generates PEP 740 publish attestations for your Python packages.
+description: |
+  A GitHub Action that generates PEP 740 publish attestations for
+  your Python packages.
 
 inputs:
   paths:
-    description: One or more whitespace-separated directories or glob patterns to search for Python distributions to generate attestations for.
+    description: |
+      One or more whitespace-separated directories or glob patterns to
+      search for Python distributions to generate attestations for.
     required: false
     default: dist/*
   overwrite:
-    description: Whether to overwrite existing attestations if they already exist.
+    description: |
+      Whether to overwrite existing attestations if they already exist.
     required: false
     default: "false"
 
@@ -17,8 +22,21 @@ outputs: {}
 runs:
   using: composite
   steps:
+    - name: check if uv is already installed
+      id: check-uv
+      run: |
+        if ! command -v uv > /dev/null; then
+          echo "::notice::uv is not installed, this action will install it"
+          echo "install_needed=true" >> $GITHUB_OUTPUT
+        else
+          echo "::debug::uv is already installed"
+          echo "install_needed=false" >> $GITHUB_OUTPUT
+        fi
+      shell: bash
+
     - name: setup uv
       uses: astral-sh/setup-uv@cec208311dfd045dd5311c1add060b2062131d57 # v8.0.0
+      if: steps.check-uv.outputs.install_needed == 'true'
       with:
         version: ">=0.9.12"
         cache-dependency-glob: ${{ github.action_path }}/uv.lock