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This page covers the most common runtime errors developers encounter when using Chromologger, along with their root causes and step-by-step fixes.
Cause: The parent directory of the log file path you passed to Logger() does not exist. Chromologger opens the file with FileManager.open_file() and does not auto-create missing parent directories — it only creates the file itself.
# ❌ Fails if ./nonexistent_dir/ does not already exist
logger = Logger('./nonexistent_dir/app.log')
Fix: Create the directory with os.makedirs before instantiating the logger.
import os
from chromologger import Logger

os.makedirs('./logs', exist_ok=True)
logger = Logger('./logs/app.log')  # ✅ directory exists, file is created safely
When you use the default Logger() (i.e. log_file_name='log.log'), the file is placed in the same directory as your calling script — a directory that always exists. You do not need os.makedirs for the default case.
Cause: Logger.__open() returned -1 (an int) because the log file could not be opened — typically due to a missing directory or a permission error. The close() method checks type(self.file) == TextIOWrapper before attempting to close; when self.file is -1, it skips the close and returns False.How to detect it before calling close():
from io import TextIOWrapper
from chromologger import Logger

logger = Logger('./logs/app.log')

if not isinstance(logger.file, TextIOWrapper):
    print('Logger did not open the file correctly — check the path.')
Fix: Resolve the underlying cause (missing directory or insufficient permissions) so that __open() succeeds and self.file is a valid TextIOWrapper.
If close() returns False, no log entries were written to disk either. Any calls to log() or log_e() will have silently failed. See the “Log entries not appearing in the file” section below.
Cause: Chromologger depends on chromolog==0.2.5 for colorized console output (via chromolog.Print). If chromolog is missing, Python raises ModuleNotFoundError the moment chromologger is imported.Fix: Install the missing dependency manually.
pip install chromolog==0.2.5
chromolog==0.2.5 is listed as a dependency in Chromologger’s pyproject.toml, so running pip install chromologger should install it automatically. If it did not (e.g. you installed from source or a custom wheel), the command above resolves it.
This symptom has two common causes.Cause 1 — File never opened: If Logger.__open() returned -1, every call to log() or log_e() reaches the internal __write() method, which tries to call self.file.writelines(...) on an integer. The resulting AttributeError is caught silently by __write’s internal error handler and written to the module’s own log.log — not your file.Cause 2 — Logger not closed: Without calling logger.close(), buffered content may not be fully flushed to disk. Although Chromologger uses writelines (which generally flushes line-by-line), explicitly closing the file is still strongly recommended.Fix:
from io import TextIOWrapper
from chromologger import Logger

logger = Logger('./logs/app.log')

# 1. Confirm the file opened correctly
if not isinstance(logger.file, TextIOWrapper):
    print('Logger failed to open — no entries will be written.')
else:
    logger.log('Application started')
    # ... your work ...
    logger.close()  # 2. Always close when done
When Chromologger’s internal error handler fires, it writes a log.log file inside the package directory and prints the path to the console via chromolog. Check that output for a quick pointer to the root cause.
Cause: When you call Logger() with the default log_file_name='log.log', Chromologger places the file beside the calling script — not the current working directory. It determines the script’s location at runtime using:
inspect.currentframe().f_back.f_code.co_filename
If your script lives in /home/user/myproject/src/app.py but you run Python from /home/user/myproject/, the log file appears in src/, which can be surprising.Fix: Pass an explicit path to Logger() so the location is always predictable.
from chromologger import Logger

# Relative to cwd — consistent regardless of where the script lives
logger = Logger('./logs/app.log')  # ✅ predictable location
For absolute control over the output path, pass an absolute path string: Logger('/var/log/myapp/app.log'). Chromologger resolves it via pathlib.Path(...).resolve().absolute().

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