purge_cloudflare_cache.sh

#!/usr/bin/env bash

readonly DELAY_STEP_SECONDS=15
readonly INTERVAL_SECONDS=5
readonly TIMEOUT_SECONDS=120

readonly GITHUB_USER=schnerring
readonly GITHUB_REPO=schnerring.github.io

##################################################
# Poll status of latest GitHub Pages build every INTERVAL_SECONDS seconds for up
# to TIMEOUT_SECONDS seconds.
# Globals:
#   GITHUB_REPO
#   GITHUB_TOKEN
#   GITHUB_USER
#   INTERVAL_SECONDS
#   TIMEOUT_SECONDS
# Arguments:
#   None
# Outputs:
#   Success message to stdout or error message to stderr.
# Returns:
#   0 on success, 1 otherwise.
##################################################
function poll_build_status() {
  echo "Awaiting completion of latest GitHub Pages build ..."
  local waited_seconds=0
  while [[ "${waited_seconds}" -lt "${TIMEOUT_SECONDS}" ]]; do
    if curl \
      --silent \
      --user "${GITHUB_USER}:${GITHUB_TOKEN}" \
      --header "Accept: application/vnd.github.v3+json" \
      "https://api.github.com/repos/${GITHUB_USER}/${GITHUB_REPO}/pages/builds/latest" \
      | grep -q '"status": "built"'; then
      echo "Success."
      return 0
    fi
    echo "  Sleeping ${INTERVAL_SECONDS} seconds until next status poll ..."
    sleep "${INTERVAL_SECONDS}"
    (( waited_seconds += INTERVAL_SECONDS ))
  done
  echo "Failure." >&2
  return 1
}

##################################################
# Purge entire Cloudflare cache.
# Globals:
#   CLOUDFLARE_API_TOKEN
#   CLOUDFLARE_ZONE_ID
# Arguments:
#   None
# Outputs:
#   Success message to stdout or error message to stderr.
# Returns:
#   0 on success, 1 otherwise.
##################################################
function purge_cache() {
  echo "Purging Cloudflare cache ..."
  if curl \
    --silent \
    --request POST \
    --header "Authorization: Bearer ${CLOUDFLARE_API_TOKEN}" \
    --header "Content-Type: application/json" \
    --data '{"purge_everything":true}' \
    "https://api.cloudflare.com/client/v4/zones/${CLOUDFLARE_ZONE_ID}/purge_cache" \
    | grep -q '"success": true'; then
    echo "Success."
    return 0
  else
  echo "Failure." >&2
    return 1
  fi
}

##################################################
# Main function of script.
# Globals:
#   DELAY_STEP_SECONDS
# Arguments:
#   None
##################################################
function main() {
  echo "Sleeping ${DELAY_STEP_SECONDS} seconds ..."
  sleep "${DELAY_STEP_SECONDS}"
  poll_build_status || exit 1

  echo "Sleeping ${DELAY_STEP_SECONDS} seconds ..."
  sleep "${DELAY_STEP_SECONDS}"
  purge_cache || exit 1
}

# Entrypoint
main "$@"