Logger Class — Chromologger Python API Reference

Logger is the primary class in Chromologger. It manages a log file and provides three public methods for writing records — log() for general informational messages, log_e() for structured exception entries, and close() to release the file handle when you are done.

Import

from chromologger import Logger

Constructor

Logger(log_file_name: str = 'log.log') -> None

Creates a new Logger instance, resolves the target log file path, and opens the file in append mode.

str

default:"'log.log'"

Name or path of the log file.

When the default 'log.log' is used, the file is created in the same directory as the calling script, detected automatically via Python’s inspect module.
Any other value is resolved to an absolute path using pathlib.Path.resolve(), so both relative paths (e.g. './logs/app.log') and absolute paths (e.g. '/var/log/app.log') are accepted.

Examples

logger = Logger()                    # log.log beside the calling script
logger = Logger('./logs/app.log')    # resolved to an absolute path
logger = Logger('/var/log/app.log')  # absolute path used as-is

The parent directory of the log file must already exist. Chromologger will not create missing directories — if the directory is absent, __open() will catch a FileNotFoundError, store -1 in self.file, and write the failure to the module’s internal log.

Instance Attributes

After construction, the following attributes are available on every Logger instance.

str

The exact value passed to the constructor (e.g. 'log.log' or './logs/app.log').

str

Absolute path of the directory that contains the script which created this Logger, resolved via inspect.currentframe().f_back.f_code.co_filename.

str

Fully resolved absolute path to the log file. When log_file_name is 'log.log' this is <caller_script>/log.log; otherwise it is the result of FileManager.get_abs_path(log_file_name).

TextIOWrapper | int

The open file object returned by FileManager.open_file(). Set to -1 if the file could not be opened (e.g. the parent directory does not exist).

Methods

`log(msg)`

log(msg: any) -> None

Writes an [INFO] record to the log file. msg can be any Python object — it is converted to str automatically before writing. After writing to the file, log() also prints a colorized informational message to the console via chromolog, showing the path of the log file.

any

required

The value to log. Strings, numbers, dicts, objects — anything that can be meaningfully converted with str() is accepted.

Examples

logger.log('Server started on port 8080')
logger.log({'event': 'login', 'user': 'alice'})
logger.log(42)

Output format

[INFO][2025-01-06 19:52:08.636560] - Server started on port 8080

`log_e(e)`

log_e(e: Exception) -> None

Writes an [ERROR] record with full exception context — exception type, source file, line number, and the exception message — all extracted via traceback.extract_tb(e.__traceback__).

Exception

required

A caught exception instance. The method reads e.__traceback__ to locate the precise file and line where the exception was raised, then reads e.__class__.__name__ for the type name and str(e) for the message.

Example

try:
    result = 10 / 0
except ZeroDivisionError as e:
    logger.log_e(e)

Output format

[ERROR][2025-01-06 19:52:08.636560] - Exception: ZeroDivisionError - File: /app/main.py - ErrorLine: 7 - Message: division by zero

If the exception was never actually raised (i.e. it has no traceback attached), traceback.extract_tb() will return an empty list and indexing into it will itself raise an IndexError. In that case log_e() catches the secondary exception internally via __log() and writes it to the module’s own internal log — it will not propagate to your application code.

`close()`

close() -> bool

Closes the log file and releases the underlying file handle.

bool

True — the file was a valid TextIOWrapper and has been closed successfully.
False — the file was never opened (i.e. self.file is -1); nothing was closed.

Example

success = logger.close()
if not success:
    print('Logger had no valid file to close')

Always call close() when your application exits (or when you are done with the logger) to ensure all buffered writes are flushed to disk and the OS file descriptor is freed.

Module-level Constants

These values are exported from chromologger alongside Logger.

Constant	Value
`chromologger.__version__`	`'0.1.9'`
`chromologger.__author__`	`'Tutos Rive'`

import chromologger

print(chromologger.__version__)  # '0.1.9'
print(chromologger.__author__)   # 'Tutos Rive'

Log Format Reference

Every entry written by Logger follows one of these two formats:

[INFO][2025-01-06 19:52:08.636560] - message
[ERROR][2025-01-06 19:52:08.636560] - Exception: ExceptionType - File: /path/to/file.py - ErrorLine: 35 - Message: error details

The timestamp is produced by Dates.now_date() which returns datetime.now() — local time with microsecond precision. See the Dates reference for details.

​Import

​Constructor

​Instance Attributes

​Methods

​log(msg)

​log_e(e)

​close()

​Module-level Constants

​Log Format Reference

Import

Constructor

Instance Attributes

Methods

`log(msg)`

`log_e(e)`

`close()`

Module-level Constants

Log Format Reference