Provides a standardized facility for handling log messages in a VBA application. This library was heavily influenced by the Python logging library and there is a lot of similar functionality.

Logging functions are named after the level or severity of the events they are used to track. The standard levels and their applicability are described below (in increasing order of severity):

Default level is WARNING, which means events of this level and above will be tracked unless package is configured to do otherwise.

Tracked events (e.g. logs) can be handled many different ways, however the simplest (and default way) is to print to the console (VBA immediate window).

Import the logging modules into the VBA project. Note most of the class objects have VB_PredeclaredId set to True so you get a default instance available. To log to the immediate window, add the following lines to your procedure

Logging.LogWarning ("Look out!") 'Prints to immediate window
Logging.LogInfo ("Told you so.") 'Will not print to immediate window

If you type these lines into a script and run, you’ll see:

WARNING - RootLogger - 2023-12-31 17:40:09 - Look out!

The logging library takes a modular approach to implemenation and consists of: loggers, handlers, filters, and formatters.

• Loggers expose the interface that application code directly uses.
• Handlers send the log records (created by loggers) to the appropriate destination.
• Filters provide a finer grained facility for determining which log records to output.
• Formatters specify the layout of log records in the final output.

graph TD;
id1[Logging Call in User Code]
id2{"Logging Enabled
for Level"}
id3([Stop])
id4[Create Log Record]
id5[Pass to Log Handlers]
id6{"Handler Enabled
for Level"}
id7["Emit record
(includes formatting"]
id1-->id2;
id2-->|No|id3
id2-->|Yes|id4
id4-->id5
id5-->id6
id6-->|No|id3
id6-->|Yes|id7

Loggers have the following attributes and methods.

Sets the threshold for logging to this logger instance. Log messages below this threshold will be ignored. Log messages at this trheshold or higher will be processed by LogHandlers.

Logs a message with level LogCritical on this logger. The LogMessage is the message formated as a string. When creating a log message, the Logger determines if the LogMessage severity level is greater than the server level set in the Logger. Log messages below the current LogLevel will be ignored. Log messages at this threshold or higher will be passed to the LogHandlers.

Logs a message with level LogError on this logger. Log is processed in the same manner as LogCritical()

Logs a message with level LogWarning on this logger. Log is processed in the same manner as LogCritical()

Logs a message with level LogInfo on this logger. Log is processed in the same manner as LogCritical()

Logs a message with level LogDebug on this logger. Log is processed in the same manner as LogCritical()

Sets the threshold for logging to this handler instance. Log messages below this threshold will be ignored. Log messages at this threshold or higher will be processed.

Sets the formatter for this handler. If no Formatter is specified, the default LogFormatter is used when creating log messages.

Conditionally emits the specified logging record, depending on filters which may have been added to the handler.

Resonible for emission of the log record. This method is not called idrectly but invoked by the HandleRecord method

Handled formatting of the log record by applying the assigned formatter. If no formatter is assigned, the default formatter is used. Returns a string value representation of the log record

Check to see if a formatter is assigned; returns true is one is assigned and false if no formatter is assigned.

Not implemented yet

Formatters are assigned to Handlers and are responsible for formatting the log records. Only one formatter can be assigned to a handler at a time.

Returns a string formatted represenation of the log record.