ml-logging-js

Logging for MarkLogic Server-Side JavaScript code in the Log4j style.

• Based on Log4J with the standard logging levels: trace, debug, info, warn, error, and fatal.

• Generic addLogEntry method as well as level-specific methods.

• Factory method to retrieve and reuse “named” log within code.

• Ability to attach appenders of different types to store/write out log entries.

  • Each appender has a level defined and only processes log entries of that level or higher.
  • Examples of current appenders include:
    • Category-tagged standard MarkLogic Error Log appender.
    • MarkLogic Directory appender that creates log entry documents within a MarkLogic database asynchronously according to a configured URI directory structure.
    • Filesystem appender that writes individual log entries as files and then consolidates into a rolling log file.
    • Email appender that sends log entry details to a defined address.

• An application_log.sjs module can be created and included in an ML solution to allow a single place to create and configure logging across the project with simple calls to log.info etc. See below.

• Except for the ML specific appenders and SJS file structure, the code can be reused in any JS code (node, browser etc.).

Category Tagging

The category tagging allows you to tail the MarkLogic log and show only those log entries for a “realtime” application log:

tail -f ErrorLog.txt | grep “My Log Name|”

This will only display the MarkLogic Error Log entries that include your custom log name.

Common Application Log

A common application_log.sjs module can be created and included in the ML solution to allow a single place to create and configure logging across the project with simple calls to log.info etc.

An example application_log.sjs file may look like:

//Require the logging module
var logging = require("./logging.sjs");

//Create a log tagged as "application"
var log = logging.getLog("application");

//Add some appenders, with varying levels
var directoryAppender = require("./directory_appender.sjs").createMarkLogicDirectoryAppender(logging.LEVELS.ALL, "logs");
log.addAppender(directoryAppender);

var emailAppender = require("./email_appender.sjs").createEmailAppender(logging.LEVELS.ERROR, {"name": "Application Administrator", "address": "admin@admin.com"});
log.addAppender(emailAppender);

var fileAppender = require("./file_appender.sjs").createFileAppender(logging.LEVELS.TRACE);
log.addAppender(fileAppender);

var errorlogAppender = require("./errorlog_appender.sjs").createMarkLogicErrorLogAppender(logging.LEVELS.WARN);
log.addAppender(errorlogAppender);

//Export the log object for use throughout the solution
module.exports = log;

Then within your code you can include a require statement to add the log and make standard log.info, log.error calls:

var log = require("/application_log.sjs");

log.info("This is an informational message.");

log.error("This is an error!");