@apolitical/health/src/services/health.service.js

Node.js module to expose Apolitical's APIs health checks

'use strict';

module.exports = ({ axios, config }) => {
  const {
    APIS,
    LOCALHOST,
    HEALTH: { STATUS, NEW_STATUS, ENDPOINT },
  } = config;

  function buildURL(name) {
    if (!APIS[name]) {
      throw new Error(`Usupported name`);
    }
    const { HOST, PORT, FALLBACK_PORT } = APIS[name];
    const url =
      HOST && PORT ? `http://${HOST}:${PORT}/${ENDPOINT}` : `http://${LOCALHOST}:${FALLBACK_PORT}/${ENDPOINT}`;
    return url;
  }

  function handleError(error, name) {
    const { message, response, request } = error;
    let errorMessage = `Service ${name} unhealthy: ${message}`;
    if (response) {
      const errorDetails = JSON.stringify({
        status: response.status,
        data: response.data,
      });
      errorMessage += ` - The request was made and the server responded with ${errorDetails}`;
    } else if (request) {
      errorMessage += ' - The request was made but no response was received';
    }
    throw new Error(errorMessage);
  }

  async function checkHealth(name) {
    try {
      const url = buildURL(name);
      const { data } = await axios.get(url);
      if (!data) {
        throw new Error(`Response data undefined`);
      }
      if (data.status !== STATUS && data.status !== NEW_STATUS) {
        throw new Error(`Status is not up`);
      }
    } catch (error) {
      handleError(error, name);
    }
  }

  return { checkHealth };
};