ci: Create GitHub Action to generate types.py from specification JSON

.github/workflows/update-a2a-types.yml

@@ -0,0 +1,81 @@
+name: Update A2A Schema from Specification
+
+on:
+  schedule:
+    - cron: "0 0 * * *" # Runs daily at 00:00 UTC
+  workflow_dispatch:
+
+jobs:
+  check_and_update:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.13"
+
+      - name: Install uv
+        run: curl -LsSf https://astral.sh/uv/install.sh | sh
+
+      - name: Configure uv shell
+        run: echo "$HOME/.cargo/bin" >> $GITHUB_PATH
+
+      - name: Install dependencies (datamodel-code-generator)
+        run: uv sync
+
+      - name: Define output file variable
+        id: vars
+        run: |
+          GENERATED_FILE="./src/a2a/types.py"
+          echo "GENERATED_FILE=$GENERATED_FILE" >> "$GITHUB_OUTPUT"
+
+      - name: Run datamodel-codegen
+        run: |
+          set -euo pipefail # Exit immediately if a command exits with a non-zero status
+
+          REMOTE_URL="https://raw.githubusercontent.com/google/A2A/refs/heads/main/specification/json/a2a.json"
+          GENERATED_FILE="${{ steps.vars.outputs.GENERATED_FILE }}"
+
+          echo "Running datamodel-codegen..."
+          uv run datamodel-codegen \
+            --url "$REMOTE_URL" \
+            --input-file-type jsonschema \
+            --output "$GENERATED_FILE" \
+            --target-python-version 3.10 \
+            --output-model-type pydantic_v2.BaseModel \
+            --disable-timestamp \
+            --use-schema-description \
+            --use-union-operator \
+            --use-field-description \
+            --use-default \
+            --use-default-kwarg \
+            --use-one-literal-as-default \
+            --class-name A2A \
+            --use-standard-collections
+          echo "Codegen finished."
+
+      - name: Create Pull Request if generated file changed
+        uses: peter-evans/create-pull-request@v6
+        with:
+          committer: a2a-bot <a2a-bot@google.com>
+          author: a2a-bot <a2a-bot@google.com>
+          commit-message: "chore: 🤖 Auto-update A2A schema from specification"
+          title: "chore: 🤖 Auto-update A2A Schema from Specification"
+          body: |
+            This PR automatically updates the A2A schema types based on the latest specification.
+
+            This update was triggered by the scheduled workflow run.
+            See the workflow run details: [${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}](https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }})
+          branch: "a2a-schema-update"
+          base: main
+          labels: |
+            automated
+            dependencies
+          add-paths: ${{ steps.vars.outputs.GENERATED_FILE }}