Logging in R Programming Language
Here’s the translation of the Go logging example to R, formatted in Markdown suitable for Hugo:
Our example demonstrates various logging techniques in R. We’ll use the logger
package for basic logging and the jsonlite
package for JSON-formatted structured logging.
First, let’s install and load the necessary packages:
install.packages(c("logger", "jsonlite"))
library(logger)
library(jsonlite)
Now, let’s go through different logging scenarios:
# Basic logging with the logger package
log_info("standard logger")
# Set log level to include microseconds
log_threshold(TRACE)
log_formatter(formatter_sprintf)
log_layout(layout_glue_generator(
format = '{level} [{time}] {msg}'
))
Sys.setenv(LOG_TIMESTAMP_FORMAT = "%Y-%m-%d %H:%M:%OS6")
log_info("with micro")
# Include file and line information
log_layout(layout_glue_generator(
format = '{level} [{time}] {caller}: {msg}'
))
log_info("with file/line")
# Create a custom logger with a prefix
mylog <- function(msg) {
log_info(paste("my:", msg))
}
mylog("from mylog")
# Change the prefix
mylog <- function(msg) {
log_info(paste("ohmy:", msg))
}
mylog("from mylog")
# Log to a file
log_appender(appender_file("log.txt"))
log_info("hello")
# Read and print the contents of the log file
cat("from logfile:", readLines("log.txt"), "\n")
# JSON-formatted structured logging
log_json <- function(msg, ...) {
json_data <- toJSON(list(time = Sys.time(), level = "INFO", msg = msg, ...))
cat(json_data, "\n")
}
log_json("hi there")
log_json("hello again", key = "val", age = 25)
Sample output; the date and time emitted will depend on when the example ran:
INFO [2023-05-22 10:45:16] standard logger
INFO [2023-05-22 10:45:16.904141] with micro
INFO [2023-05-22 10:45:16.904141] #5: with file/line
INFO [2023-05-22 10:45:16.904141] #7: my: from mylog
INFO [2023-05-22 10:45:16.904141] #11: ohmy: from mylog
from logfile: INFO [2023-05-22 10:45:16.904141] #14: hello
{"time":["2023-05-22 10:45:16"],"level":["INFO"],"msg":["hi there"]}
{"time":["2023-05-22 10:45:16"],"level":["INFO"],"msg":["hello again"],"key":["val"],"age":[25]}
This example demonstrates various logging techniques in R:
- Basic logging using the
logger
package. - Configuring log format to include microseconds.
- Including file and line information in logs.
- Creating custom loggers with prefixes.
- Logging to a file.
- JSON-formatted structured logging using the
jsonlite
package.
Note that R doesn’t have built-in logging capabilities as extensive as Go’s, so we use third-party packages to achieve similar functionality. The logger
package provides a flexible logging system, while jsonlite
allows us to create JSON-formatted logs for structured logging.