patch: Workflow to call airflow

.github/workflows/promote.yaml

@@ -0,0 +1,80 @@
+# Copyright 2026 Canonical Ltd.
+# See LICENSE file for licensing details.
+name: Release to candidate promotion train
+
+on:
+  workflow_dispatch:
+    inputs:
+      single-kernel-version:
+        description: "A pip package version of single kernel (eg: 1.8.42)"
+        required: true
+        type: string
+
+jobs:
+  trigger-release-ci:
+    # only on beta promotion
+    name: Trigger release CI (Airflow)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Validate input
+        id: validate-input
+        shell: python
+        env:
+          PIP_VERSION: ${{ inputs.single-kernel-version }}
+        run: |
+          import re
+          import os
+
+          pip_package_version = os.environ["PIP_VERSION"]
+          VERSION_REGEX = re.compile(r"\d.\d.\d+")
+
+          if not VERSION_REGEX.match(pip_package_version):
+              raise ValueError(f"Invalid version received: {pip_package_version}")
+      - name: Check version exists
+        id: check-version
+        env:
+          PIP_VERSION: ${{ inputs.single-kernel-version }}
+        run: |
+          set -euo pipefail
+          DEP_NAME="mongo-charms-single-kernel"
+          URL="https://pypi.org/pypi/${DEP_NAME}/${PIP_VERSION}/json"
+          for i in {1..30}; do
+            if curl -fsS "$URL" >/dev/null; then
+              echo "Found ${DEP_NAME}==${VERSION_NUMBER} on PyPI."
+              exit 0
+            fi
+            echo "Maybe transient error (attempt $i/30). Sleeping..."
+            sleep 60
+          done
+
+          echo "Timed out waiting for ${DEP_NAME}==${PIP_VERSION} on PyPI."
+          echo "Is the revision available on PyPI ?"
+          exit 1
+
+      - name: Trigger Airflow DAG
+        env:
+          PIP_VERSION: ${{ inputs.single-kernel-version }}
+        run: |
+          #shellcheck disable=SC2016
+          response=$(curl -s -w "\n%{http_code}" -X POST \
+            'https://airflow.data-platform.ps7.canonical.com/api/v2/dags/mongodb_8/dagRuns' \
+            -H 'Content-Type: application/json' \
+            -H 'Authorization: Bearer ${{ secrets.AIRFLOW_API_TOKEN }}' \
+            -d "{
+              \"dag_run_id\": \"promote-${{ github.run_id }}\",
+              \"logical_date\": \"$(date -u +%Y-%m-%dT%H:%M:%SZ)\",
+              \"conf\": {
+                \"pip_version\": \"${PIP_VERSION}\"
+              }
+            }")
+          http_code=$(echo "$response" | tail -n1)
+          body=$(echo "$response" | sed '$d')
+          echo "$body"
+          if echo "$body" | grep -q '"detail":"Token Expired"'; then
+            echo "::error::Airflow API token has expired"
+            exit 1
+          fi
+          if [ "$http_code" -lt 200 ] || [ "$http_code" -ge 300 ]; then
+            echo "::error::Airflow API request failed with status $http_code"
+            exit 1
+          fi