scripthelper

Helper module for simple command line Python scripts.

Basic usage

example1.py:

#!/usr/bin/env python3
import scripthelper

logger = scripthelper.bootstrap()

logger.critical("critical message")
logger.error("error message")
logger.warning("warning message")
logger.info("info message")
logger.verbose("verbose message")
logger.debug("debug message")
logger.spam("spam message")

It just works. Try --verbose and --quiet command line options, too. It uses colored log messages on a terminal. See --help for more information.

Adding other command line parameters

example2.py:

#!/usr/bin/env python3
import scripthelper

scripthelper.add_argument("-n", "--name", help="Name to greet")
logger, args = scripthelper.bootstrap_args()

if args.name:
    logger.debug("Name was provided")
    logger.info(f"Hello {args.name}")
else:
    logger.warning("Name was not provided")

For bigger scripts it is good idea to have the logger at the very beginning, and encapsulate the argument parsing phase, which is typically in the main function:

example2b.py:

#!/usr/bin/env python3
import scripthelper

logger = scripthelper.getLogger()


def greet(name):
    logger.info(f"Hello {name}")


def main():
    scripthelper.add_argument("--name", default="World")
    args = scripthelper.initialize()
    greet(args.name)


main()

Progressbar works with logging, too

example3.py:

#!/usr/bin/env python3
import scripthelper
import time

logger = scripthelper.bootstrap()

logger.info("Doing the calculations...")
for i in scripthelper.progressbar(range(100)):
    if i % 20 == 0:
        logger.verbose(f"Iteration {i}")
    if i % 5 == 0:
        logger.debug(f"Iteration {i}")
    if logger.isEnabledFor(scripthelper.SPAM):
        logger.spam(f"Iteration {i}")
    time.sleep(0.01)
logger.info("Done")

It is automatically disabled on non-tty stderr by default.

Extended log levels can be used in modules

example4.py:

#!/usr/bin/env python3
import scripthelper
import example4module

scripthelper.bootstrap()
example4module.do_the_things()

example4module.py:

#!/usr/bin/env python3
import scripthelper

logger = scripthelper.getLogger(__name__)


def do_the_things():
    logger.verbose("Calling logger.verbose raises an exception if it does not work.")
    logger.info("Hello from a module.")

You can easily preserve logs in files

example5.py:

#!/usr/bin/env python3
import scripthelper

logger = scripthelper.bootstrap()
scripthelper.setup_file_logging()

logger.critical("critical message")
logger.error("error message")
logger.warning("warning message")
logger.info("info message")
logger.verbose("verbose message")
logger.debug("debug message")
logger.spam("spam message")

It handles exceptions, warnings

example6.py:

#!/usr/bin/env python3
import scripthelper

scripthelper.bootstrap()

scripthelper.warn("This user warning will be captured.")

this_variable = "will be displayed in stack trace"
as_well_as = "the other variables"
raise RuntimeError("This exception should be handled.")

The local variables will be displayed in stack trace, for example:

WARNING example6.py:6: UserWarning: This user warning will be captured.
  scripthelper.warn("This user warning will be captured.")

CRITICAL Uncaught RuntimeError: This exception should be handled.
File "example6.py", line 10, in <module>
    6    scripthelper.warn("This user warning will be captured.")
    7
    8    this_variable = "will be displayed in stack trace"
    9    as_well_as = "the other variables"
--> 10   raise RuntimeError("This exception should be handled.")
    ..................................................
     this_variable = 'will be displayed in stack trace'
     as_well_as = 'the other variables'
    ..................................................

Has built-in colored pretty printer

example7.py:

#!/usr/bin/env python3
import scripthelper
from dataclasses import dataclass

scripthelper.bootstrap()


@dataclass
class Item:
    name: str
    value: int


something = {
    "string": "value1",
    "bool": True,
    "none": None,
    "integer": 1234,
    "item": Item("name", 999),
}

scripthelper.pp(something)

Has built-in persisted state handler

The state is persisted immediately in the background in YAML. Mutable objects (list, dict) also can be used.

example9.py:

#!/usr/bin/env python3
import scripthelper

logger = scripthelper.bootstrap()
state = scripthelper.PersistedState(processed_id=0, to_remember=[])

state.processed_id += 1
state.to_remember.append(f"Element {state.processed_id}")
while len(state.to_remember) > 2:
    state.to_remember.pop(0)

logger.info(f"Processing item #{state.processed_id}")
for item in state.to_remember:
    logger.info(f"- {item}")

$ python3 example9.py
INFO example9 Processing item #1
INFO example9 - Element 1

$ python3 example9.py
INFO example9 Processing item #2
INFO example9 - Element 1
INFO example9 - Element 2

$ python3 example9.py
INFO example9 Processing item #3
INFO example9 - Element 2
INFO example9 - Element 3

Helps issuing a warning only once

example10.py:

#!/usr/bin/env python3
import scripthelper

scripthelper.bootstrap()

for _ in range(10):
    scripthelper.warning_once("Item #12 has some errors")