cdk_open_pull_requests.sh

function open_pull_requests() {
  if [ "$TRAVIS_PULL_REQUEST" == "false" ]; then
    STAGES=( dev pre pro )
    for STAGE in "${STAGES[@]}"; do
      # Run CDK diff
      cdk diff -c stage=${STAGE}  | tee cdk_diff_${STAGE}.txt

      # Prepare PR message
      read -r -d '' MESSAGE <<-EOM
> :warning: **Please review this changes before merging.**
**This PR will apply these changes(\`cdk diff\`):**
\`\`\`console
$(cat cdk_diff_${STAGE}.txt)
\`\`\`
EOM
      set +e
      CMD_MESSAGE_OUTPUT=$(gh pr create --title "Update $STAGE environment." --body "$MESSAGE" --base "$STAGE" --head "$TRAVIS_BRANCH" 2>&1)
      CMD_RES=$?
      set -e
      if [ $CMD_RES -ne 0 ]; then
          if [[ "$CMD_MESSAGE_OUTPUT" == *"already exists"* ]]; then
              echo "A PR is already opened. Skip opening a new one."
          else
              travis_terminate 1
          fi
      fi
    done
  fi
}