harvestmon_check_height

#!/bin/sh

# return comma separated value of 'ok' and 'msg'.
mon_file=/tmp/catapult-harvestmon.txt

# create file to store latest height
create_mon_file() {
  resp=$(curl -sS ${API_ENDPOINT})

  # exit if endpoint is not reachable
  if [ -z "$resp" ]; then
    echo "curl command failed. is the endpoint (${API_ENDPOINT}) reachable?"
    return
  fi
  echo $resp > $mon_file
}

harvestmon_check_height() {
  if [ -z "$API_ENDPOINT" ]; then
    echo "error: API_ENDPOINT env var is not set."
    return
  fi

  # initiate mon file
  if [ ! -f "$mon_file" ]; then
    create_mon_file
    current_height=$(curl -sS ${API_ENDPOINT} | jq .numBlocks)
    printf '{"ok":true,"msg":"catapult-harvestmon initiated. current block height: %s"}' $current_height
    return
  fi

  last_height=$(cat $mon_file | jq .numBlocks)

  resp=$(curl -sS ${API_ENDPOINT})
  current_height=$(echo $resp | jq .numBlocks)

  # handle node not running
  if [ -z "$current_height" ]; then
    echo '{"ok":false,"msg":"empty response from endpoint. is the node reachable?"}'
    return
  fi

  if [ "$current_height" = "$last_height" ]; then
    printf '{"ok":false,"msg":"block height did not increment from %s. is the node still harvesting?"}' $last_height
  elif [ "$current_height" -lt "$last_height" ]; then
    printf '{"ok":false,"msg":"block height decremented from %s to %s. was the node re-initiated?"}' $last_height $current_height
  else
    printf '{"ok":true,"msg":"block height incremented from %s to %s"}' $last_height $current_height

    # update mon file
    echo $resp > $mon_file
    last_height=$current_height
  fi
}

echo HTTP/1.1 200 OK;
echo Content-Type\: text/plain;
echo Cache-Control: no-cache, no-store, must-revalidate;
echo Pragma: no-cache;
echo Expires: 0;
echo;
echo $(harvestmon_check_height);