@code-nl/cloud-logging/index.js

Interface over @google-cloud/logging

'use strict';

const { Logging } = require('@google-cloud/logging');

/**
 * The Logging instance cache
 * @var {Logging}
 */
let _logging = null;

/**
 * The logs name (grouper) cache
 * @var {String}
 */
let _logName = null;

/**
 * Merge the message with payload to one data object 
 *
 * @param {String} message The log message
 * @param {Object} payload The log message's payload
 * @return {Object}
 */
const mergeMessageWithPayload = (message, payload) => {
  const data = Object.assign(
    payload || {},
    {
      message: message
    }
  );

  return data;
};

/**
 * Write a log
 *
 * @param {Object} data  Log message setup, like message, labels, severity
 */
const _writeLog = (severity, data) => {
  // guard: logging client must be initialized
  if (_logging === null || _logName === null) {
    throw new Error("Logging client is not yet initialized. Use the init() method.");
  }

  // guard: must have a message
  if (typeof data.message !== "string" || data.message.length < 1) {
    throw new Error("A message is required when logging.");
  }

  // init a new log
  const log = _logging.log(_logName);

  // set metadata
  const metadata = {
    resource: {
      type: "global",
    },
    severity: severity
  };

  // prepare log entry
  const entry = log.entry(
    metadata,
    data
  );

  // write log entry failsafe
  return log
    .write(entry)
    .catch(error => {
      console.error("Something went wrong with Google Cloud logging.");
      console.error(error);
      return Promise.resolve();
    });
};

/**
 * Log to GCP Stackdriver
 */
module.exports = {
  /**
   * Initialize the logger interface
   *
   * @param {String} projectId The GCP project id
   * @param {String} logName   The log name used to group all log messages into
   */
  init: (projectId, logName) => {
    // only initialize once
    if (_logging === null) {
      // initialize logging with projectId
      _logging = new Logging({
        projectId: projectId
      });

      // set the log name (a log grouper)
      _logName = logName || "unknown";
    }
  },

  /**
   * Log a message with severity "debug"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  debug: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("DEBUG", data);
  },

  /**
   * Log a message with severity "info"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  info: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("INFO", data);
  },

  /**
   * Log a message with severity "notice"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  notice: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("NOTICE", data);
  },

  /**
   * Log a message with severity "warning"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  warning: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("WARNING", data);
  },

  /**
   * Log a message with severity "error"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  error: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("ERROR", data);
  },

  /**
   * Log a message with severity "critical"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  critical: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("CRITICAL", data);
  },

  /**
   * Log a message with severity "alert"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  alert: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("ALERT", data);
  },

  /**
   * Log a message with severity "emergency"
   *
   * @param {String} message The log message
   * @param {Object} payload Optional: Extra log message payload
   */
  emergency: (message, payload) => {
    const data = mergeMessageWithPayload(message, payload);
    return _writeLog("EMERGENCY", data);
  }
};