Getting started

Introduction

The teal.logger package utilizes the logger framework to record events within a package. logger is an R package that supports logging namespaces, hierarchical logging, various log destinations, vectorization, and more. For further details about logger, you can refer to:

• GitHub
• CRAN

Default Logging Setup of teal.logger

teal.logger employs the register_logger() function to create a new logger in a user-defined namespace. teal.logger comes with a predefined pair of layout and logging level. Other packages in the teal framework utilize teal.logger to log crucial events, such as setting up teal data, alterations in the filter panel, records of merging data slices inside modules, and so on.

Defaults of teal.logger:

• Logging level: logger.INFO
• Logging layout: [{level}] {format(time, \"%Y-%m-%d %H:%M:%OS4\")} pid:{pid} token:[{token}] {ans} {msg}
• Logs emitted to stdout

For a more comprehensive understanding of various logging levels and layout interpretation, you can explore the logger documentation.

Customizing the Log Level

While utilizing register_logger(), the default logging level for the new logger is logger::INFO. You can modify this behavior in four distinct ways:

1. Using the logger interface.

library(teal.logger)
register_logger("my_namespace")
logger::log_threshold(logger::TRACE, namespace = "my_namespace")

Customizing teal’s logging level:

library(teal.logger)
logger::log_threshold(logger::TRACE, namespace = "teal")

2. Utilizing the function argument of register_logger().

library(teal.logger)
register_logger("my_namespace", level = logger::TRACE)

Customizing teal’s logging level:

library(teal.logger)
register_logger(namespace = "teal", level = logger::TRACE)

3. Setting an environment variable.

library(teal.logger)
Sys.setenv(TEAL.LOG_LEVEL = "TRACE")
register_logger("my_namespace")

Customizing teal’s logging level:

Sys.setenv(TEAL.LOG_LEVEL = "TRACE")
library(teal.logger)

4. Setting an option.

library(teal.logger)
options(teal.log_level = logger::TRACE)
register_logger("my_namespace")

Customizing teal’s logging level:

options(teal.log_level = logger::TRACE)
library(teal.logger)

Do keep in mind that packages in the teal framework register their loggers upon library loading. Therefore, if you intend to alter the default logging level via an option or a system environment variable, ensure you modify the variable before loading the library.

Example below:

# library(teal)
# Sys.setenv(TEAL.LOG_LEVEL = "TRACE") # won't change the default

# Sys.setenv(TEAL.LOG_LEVEL = "TRACE")
# library(teal)
# will change the default because teal is attached after changing the variable

Alternatively, you can change the options after loading a package and then call register_logger() with the appropriate namespace name to change the default of a single package. E.g. this will change the defaults of teal.logger. Replace teal.logger with the name of the package you want to change.

library(teal.logger)
Sys.setenv(TEAL.LOG_LEVEL = "TRACE")
register_logger('teal.logger')

For a more comprehensive understanding, consult the logger documentation and the documentation for register_logger().

Customizing the Log Layout

When using register_logger(), the default log layout for the new logger is [{level}] {format(time, \"%Y-%m-%d %H:%M:%OS4\")} pid:{pid} token:[{token}] {ans} {msg}.You can modify this behavior in four distinct ways:

1. Using the logger interface.

library(teal.logger)
register_logger("my_namespace")
logger::log_layout("{level} {msg}", namespace = "my_namespace")

Customizing teal’s logging layout:

library(teal.logger)
logger::log_layout("{level} {msg}", namespace = "teal")

2. Utilizing the function argument of register_logger().

library(teal.logger)
register_logger("my_namespace", layout = "{level} {msg}")

Customizing teal’s logging layout:

library(teal.logger)
register_logger(namespace = "teal", layout = "{level} {msg}")

3. Setting an environment variable.

library(teal.logger)
Sys.setenv(TEAL.LOG_LAYOUT = "{level} {msg}")
register_logger("my_namespace")

Customizing teal’s logging layout:

Sys.setenv(TEAL.LOG_LAYOUT = "{level} {msg}")
library(teal.logger)

4. Setting an option.

library(teal.logger)
options(teal.log_layout = "{level} {msg}")
register_logger("my_namespace")

Customizing teal’s logging layout:

options(teal.log_layout = "{level} {msg}")
library(teal.logger)

Like changing the log level, remember that teal registers its logger during library loading. Thus, if you aim to modify the default logging layout via an option or a system environment variable, ensure you adjust the variable prior to loading the library.

Example below:

library(teal.logger)
Sys.setenv(TEAL.LOG_LAYOUT = "{level} {msg}") # won't change the default

Sys.setenv(TEAL.LOG_LAYOUT = "{level} {msg}")
library(teal.logger)
# will change the default because teal is attached after changing the variable

Alternatively, you can change the options after loading a package and then call register_logger() with the appropriate namespace name to change the default of a single package. E.g. this will change the defaults of teal.logger. Replace teal.logger with the name of the package you want to change.

library(teal.logger)
Sys.setenv(TEAL.LOG_LAYOUT = "{level} {msg}")
register_logger('teal.logger')

For additional insights, consult the logger documentation and the documentation for register_logger().

Customizing the Log Destination

By default, teal.logger sends logs to stdout. If you wish to alter this behavior, you need to employ logger’s API.

For instance, to redirect teal’s logs to stderr using logger’s API:

library(teal.logger)
logger::log_appender(logger::appender_stderr, namespace = "teal")

Logging in Other teal.X Packages

Additional teal.X packages, such as teal.data, employ register_logger() to enroll loggers in their namespace. Each package establishes a logger in the namespace equivalent to the package name, e.g., teal.data creates a logger in the teal.data namespace. A package initializes its logger during package loading and utilizes default logging settings, subject to modifications explained in the preceding sections.

Example of Usage

Below is a minimal working example that demonstrates logging using teal’s logging setup. The default TEAL.LOG.LEVEL is "INFO", implying that logs with a level above level = 400 won’t appear in stdout.

library(teal.logger)
register_logger(namespace = "my_module")

logger::log_error("This is an ERROR level log from my module", namespace = "my_module") # 200
logger::log_warn("This is a WARN level log from my module", namespace = "my_module") # 300
logger::log_success("This is a SUCCESS level log from my module", namespace = "my_module") # 350
logger::log_info("This is an INFO level log from my module", namespace = "my_module") # 400
logger::log_info("This is a DEBUG level log from my module", namespace = "my_module") # 500
logger::log_trace("This is a TRACE level log from my module", namespace = "my_module") # 600