Initialize and Manage Event Logging Features
Source:vignettes/Logging_Features.Rmd
Logging_Features.RmdBeginning with release of v1.1.0 of hawkinR, users will be able to
take advantage of event logging with the addition of
logger v0.3.0. This will now make it easier for users to
understand background processes of hawkinR, as well as debug in a more
efficient manner.
1. Event Logging With Logger
If you are not only using R in the interactive console for ad-hoc data analysis, but running eg batch jobs (for ETL, reporting, modeling, forecasting etc) as well, then logging the status(changes) of your script is a must so that later on you can review / debug what have happened. Logger is a lightweight, modern and flexibly logging utility for R – heavily inspired by the futile.logger R package and logging Python module.
2. Logs With hawkinR
To simplify logging within hawkinR, the logger package features have
been mostly preset with exception to 3 primary attributes that can be
initialized and controlled by the initialize_logger
function: Appender, Threshold, and Log File.
initialize_logger(log_output = "stdout", log_threshold_stdout = "INFO", log_file = "hawkinRlog.log", log_threshold_file = "INFO")Appender
The appender gives direction as to where the output of the event log
messages should go. This can be controlled with the
log_output argument. Default to “stdout”, the log messages
with print to the standard output of the console. Users can select have
the option to change it to “file”, directing the messages to a log file
of their choice, or “both”.
Threshold
Depending on the log_output argument, you will want to
select the message threshold for the selected output (or both). The
threshold is the minimum message level of importance that you care to
have printed (levels include: “TRACE”, “DEBUG”, “INFO”, “SUCCESS”,
“WARN”, “ERROR”, “FATAL”, “OFF”). The hawkinR package contains logs from
as simple as process execution logs as “TRACE” logs, to process ending
“ERROR” logs describing the execution failure. Log thresholds within
hawkinR are default to “INFO”.
Along with passing log_outout = "both", users can set
separate and different thresholds for stdout and log files. This can be
helpful when working with the package during app development and stdout
messages may be of little to no importance, while an event log can be
very helpful for debugging.
Log File
If log_output is set to “file” or “both”, log messages
will be sent to a .log file. By default the file is named
“hawkinRlog.log” and will be saved to the project directory. But this
behavior can be changed by passing a new name and/or location argument
to log_file. If you want to change the location of the
file, simply provide the desired path before the name of the file.
Examples
# Log only error messages to the console
initialize_logger(log_output = "stdout", log_threshold_stdout = "ERROR")
# Log all messages to the default `hawkinRlog.log` file
initialize_logger(log_output = "file", log_threshold_file = "TRACE")
# Log all messages to the log file in the log folder subdirectory, and only success and above to the console
initialize_logger(log_output = "both",log_file = "/logFiles/MyLog.log", log_threshold_file = "TRACE", log_threshold_stdout = "SUCCESS")