logging

logging

Python-style logging for R.

Basic Usage

library(logging)

# Initialize basic configuration
basicConfig()

# Log messages
logdebug("Debug message")
loginfo("Info message")
logwarn("Warning message")
logerror("Error message")
logfinest("Finest message")

Configuration

# Basic config with level
basicConfig(level = "DEBUG")

# With file handler
basicConfig(level = "INFO")
addHandler(writeToFile, file = "app.log")

# Custom format
basicConfig(level = "INFO")

Log Levels

# Levels (lowest to highest)
# FINEST < FINER < FINE < DEBUG < INFO < WARNING < ERROR

# Set level
setLevel("DEBUG")
setLevel("INFO", container = "logger.name")

# Get level
getLevel()

Named Loggers

# Get/create logger
logger <- getLogger("myapp")

# Set level for specific logger
setLevel("DEBUG", container = "myapp")

# Log with logger name
loginfo("Message", logger = "myapp")

# Hierarchical loggers
setLevel("INFO", container = "myapp")
setLevel("DEBUG", container = "myapp.database")

Handlers

# Console handler (default)
addHandler(writeToConsole)

# File handler
addHandler(writeToFile, file = "app.log")

# Custom handler
myHandler <- function(msg, handler) {
  # Custom logic
  cat(msg, "\n")
}
addHandler(myHandler)

# Remove handler
removeHandler("writeToConsole")

Formatters

# Default format includes:
# - Timestamp
# - Level
# - Logger name
# - Message

# Custom formatter
formatter <- function(record) {
  sprintf("[%s] [%s] %s",
          record$timestamp,
          record$levelname,
          record$msg)
}

Formatted Messages

# Printf-style
loginfo("Processing file: %s", filename)
loginfo("Completed %d of %d items", current, total)

# Multiple arguments
loginfo("User %s action %s", user, action)

Exception Logging

tryCatch({
  risky_operation()
}, error = function(e) {
  logerror("Operation failed: %s", e$message)
})

# With condition
logwarn("Condition: %s", conditionMessage(cond))