Log Output

2024-10-16

A log is a tool used to record the runtime state of an application in program development, as well as help developers diagnose and troubleshoot problems. Developers can quickly identify the root causes of problems and better understand the behaviors and performance of applications by viewing logs. log feature can output different log levels, including the DEBUG level, WARNING level, and ERROR level.

Log Level

log.DEBUG

Constant of log level. The most detailed information is recorded at the DEBUG level and this level is usually used in development and debugging.

log.INFO

Constant of log level. The information recorded at the INFO level indicates that everything is running normally.

log.WARNING

Constant of log level. The information recorded at the WARNING level indicates that something unexpected has occurred or potentially harmful events, but the application can continue to function normally.

log.ERROR

Constant of log level. The information recorded at the ERROR level indicates that an application is no longer able to execute certain functions due to some serious problems.

log.CRITICAL

Constant of log level. The information recorded at the CRITICAL level indicates a critical error in the application that may stop the application from running.

Set Log

log.basicConfig

Sets the log output level. Default level: log.INFO. The system will only output logs whose levels are greater than or equal to that level.

log.basicConfig(level)

Parameter

  • level - Log level.

Return Value

None

Example

import log
log.basicConfig(level=log.INFO)

log.set_output

Destination where the logs are output. Currently only uart and usys.stdout are supported.

log.set_output(out)

Parameter

  • out - The destination where the logs are output. Set the parameter to a specified serial port or the interaction port. Default value: the interaction port.

Return Value

None

Example

import log
log.basicConfig(level=log.INFO)
Testlog = log.getLogger("TestLog")

# Output the log through the debug UART
from machine import UART
uart = UART(UART.UART0, 115200, 8, 0, 1, 0)

log.set_output(uart)

Testlog.info("this is a Test log") # The logs will be output through the specified UART.

# Output the log through the interaction port
import usys
log.set_output(usys.stdout)

Testlog.info("this is a Test log") # The logs will be output through the interaction port.

Output Log

log.getLogger

Gets the log object which supports logs of different levels.

Testlog = log.getLogger(name)

Parameter

  • name - String type. The topic of the current log object

Return Value

  • A log handle (log object) with the method of outputting logs.

log.debug

Outputs the DEBUG-level logs.

Testlog.debug(msg)

Parameter

  • msg - String type. The content of logs.

log.info

Outputs the INFO-level logs.

Testlog.info(msg)

Parameter

  • msg - String type. The content of logs.

log.warning

Outputs the WARNING-level logs.

Testlog.warning(msg)

Parameter

  • msg - String type. The content of logs.

log.error

Outputs the ERROR-level logs.

Testlog.error(msg)

Parameter

  • msg - String type. The content of logs.

log.critical

Outputs the CRITICAL-level logs.

Testlog.critical(msg)

Parameter

  • msg - String type. The content of logs.

Example

import log

# Set the log output level.
log.basicConfig(level=log.INFO)
# Get the logger object. If "name" is not specified, the default value "root" will be configured. If the "name" is set to the same value multiple times, the same logger object will be returned.
Testlog = log.getLogger("Quec")

Testlog.error("Test error message!!")
Testlog.debug("Test debug message!!")
Testlog.critical("Test critical message!!")
Testlog.info("Test info message!!")
Testlog.warning("Test warning message!!")