pygogo 0.8.8

A Python logging library with super powers

pygogo: a Python logger with super powers
=========================================

|travis| |versions| |pypi|

.. image:: https://raw.githubusercontent.com/reubano/pygogo/master/pygogo.png
:alt: sample pygogo usage
:width: 800
:align: center

Introduction
------------

pygogo is a Python logging `library`_ and `command-line interface`_ with super powers.
pygogo leverages the standard Python `logging module`_ under the hood, so there's
no need to learn yet-another logging library. The default implementation sends
all messages to ``stdout``, and any messages at level ``WARNING`` or above to ``stderr``.

With pygogo, you can

- Log via different handlers depending on the event severity
- Format log messages as plain text, csv, json, and more..
- Send logs to stdout, stderr, file, email, sockets, and more..
- Inter-operate with the standard python logging module
- and much more...

Motivation
----------

The standard logging module is great, but requires a ton of boilerplate before
you can do anything really interesting with it. I designed pygogo to provide
many useful logging use-cases out of the box. A reimplementation of
`Using LoggerAdapters to impart contextual information`_ is shown below:

.. _Using LoggerAdapters to impart contextual information: https://docs.python.org/2/howto/logging-cookbook.html#using-loggeradapters-to-impart-contextual-information

.. code-block:: python

import pygogo as gogo

logger = gogo.Gogo(__name__).get_structured_logger(connid='1234')
logger.info('log message')

# Prints the following to stdout

{"message": "log message", "connid": "1234"}


Usage
-----

pygogo is intended to be used either directly as a Python library or from the command line.

.. _library:

Library
~~~~~~~

Examples
^^^^^^^^

*Hello World*

.. code-block:: bash

import pygogo as gogo

gogo.Gogo().logger.debug('hello world')
gogo.Gogo().logger.error('hello error')

# Prints the following to `stdout`

hello world
hello error

# Prints the following to `stderr`

hello error

*Log based debugging*

.. code-block:: bash

import pygogo as gogo

def main(verbose=False):
logger = gogo.Gogo(__name__, verbose=verbose).logger
logger.debug('I will log to `stdout` only if `verbose` is True')
logger.info('I will log to `stdout` always')
logger.warning('I will log to both `stdout` and `stderr` always')

*Disabled dual logging*

.. code-block:: bash

import pygogo as gogo

logger = gogo.Gogo(monolog=True).logger
logger.debug('debug message')
logger.info('info message')
logger.warning('warning message')
logger.error('error message')
logger.critical('critical message')

# Prints the following to `stdout.log` (all messages at level `INFO` or below):

debug message
info message

# Prints the following to `stderr` (messages at level `WARNING` or above):

warning message
error message
critical message

*Custom formatter* [1]_

.. code-block:: python

import logging
import pygogo as gogo

log_format = '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
formatter = logging.Formatter(log_format)

logger = gogo.Gogo(
'examples.fmt',
low_hdlr=gogo.handlers.file_hdlr('custom_fmt.log'),
low_formatter=formatter,
high_level='error',
high_formatter=formatter).logger

# Now let's log something!

logger.debug('debug message')
logger.info('info message')
logger.warn('warn message')
logger.error('error message')
logger.critical('critical message')

# Prints the following to `custom_fmt.log` (all messages):

2015-12-18 18:51:30,416 - examples.fmt.base - DEBUG - debug message
2015-12-18 18:51:30,416 - examples.fmt.base - INFO - info message
2015-12-18 18:51:30,416 - examples.fmt.base - WARNING - warn message
2015-12-18 18:51:30,416 - examples.fmt.base - ERROR - error message
2015-12-18 18:51:30,416 - examples.fmt.base - CRITICAL - critical message

# Prints the following to `stderr` (messages at level `ERROR` or above):

2015-12-18 18:51:30,416 - examples.fmt.base - ERROR - error message
2015-12-18 18:51:30,416 - examples.fmt.base - CRITICAL - critical message

*Structured logging* [2]_

.. code-block:: python

import pygogo as gogo

formatter = gogo.formatters.structured_formatter
kwargs = {'low_level': 'info', 'low_formatter': formatter}
logger = gogo.Gogo('examples.structured', **kwargs).logger
extra = {'set_value': set([1, 2, 3]), 'snowman': '☃'}
logger.info('log message', extra=extra) # doctest: +ELLIPSIS

# Prints the following to `stdout`:

{"snowman": "\u2603", "name": "examples.structured.base", "level": "INFO", "message": "log message", "time": "2015-12-18 18:52:39", "msecs": 58.973073959350586, "set_value": [1, 2, 3]}

*Using Filters to impart contextual information* [3]_

.. code-block:: python

import logging
import pygogo as gogo

levels = ('DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL')
log_frmt = (
'%(asctime)-4s %(name)-5s %(levelname)-8s IP: %(ip)-15s User: '
'%(user)-8s %(message)s')

formatter = logging.Formatter(log_frmt)
going = gogo.Gogo('a', low_formatter=formatter)
a1 = going.get_logger('b.c', ip='123.231.231.123', user='fred')
a2 = going.get_logger('e.f', ip='192.168.0.1', user='sheila')

# Now let's log something!

a1.debug('A debug message')
a1.info('An info %s', 'message')

for level in [getattr(logging, l) for l in levels]:
name = logging.getLevelName(level)
a2.log(level, 'A %s msg', name)

# Prints the following to `stdout` (all messages):

2015-12-19 10:12:24,479 a.b.c DEBUG IP: 123.231.231.123 User: fred A debug message
2015-12-19 10:12:24,479 a.b.c INFO IP: 123.231.231.123 User: fred An info message
2015-12-19 10:12:24,479 a.e.f DEBUG IP: 192.168.0.1 User: sheila A DEBUG msg
2015-12-19 10:12:24,479 a.e.f INFO IP: 192.168.0.1 User: sheila A INFO msg
2015-12-19 10:12:24,479 a.e.f WARNING IP: 192.168.0.1 User: sheila A WARNING msg
2015-12-19 10:12:24,479 a.e.f ERROR IP: 192.168.0.1 User: sheila A ERROR msg
2015-12-19 10:12:24,479 a.e.f CRITICAL IP: 192.168.0.1 User: sheila A CRITICAL msg

# Prints the following to `stderr` (messages at level `WARNING` or above):

2015-12-19 10:12:24,479 a.e.f WARNING IP: 192.168.0.1 User: sheila A WARNING msg
2015-12-19 10:12:24,479 a.e.f ERROR IP: 192.168.0.1 User: sheila A ERROR msg
2015-12-19 10:12:24,479 a.e.f CRITICAL IP: 192.168.0.1 User: sheila A CRITICAL msg

*Multiple loggers* [4]_

.. code-block:: python

import pygogo as gogo

going = gogo.Gogo(
'examples.lggrs',
low_hdlr=gogo.handlers.file_hdlr('multi_lggrs.log'),
low_formatter=gogo.formatters.fixed_formatter,
high_level='info',
high_formatter=gogo.formatters.console_formatter)

root = going.logger
logger1 = going.get_logger('area1')
logger2 = going.get_logger('area2')

# Now let's log something!

root.info('Jackdaws love my big sphinx.')
logger1.debug('Quick zephyrs blow, daft Jim.')
logger1.info('How daft jumping zebras vex.')
logger2.warning('Jail zesty vixen who grabbed pay.')
logger2.error('The five boxing wizards jump.')

# Prints the following to `multi_lggrs.log` (all messages):

2015-12-18 17:21:37.417 examples.lggrs.base INFO Jackdaws love my big sphinx.
2015-12-18 17:21:37.417 examples.lggrs.area1 DEBUG Quick zephyrs blow, daft Jim.
2015-12-18 17:21:37.417 examples.lggrs.area1 INFO How daft jumping zebras vex.
2015-12-18 17:21:37.417 examples.lggrs.area2 WARNING Jail zesty vixen who grabbed pay.
2015-12-18 17:21:37.417 examples.lggrs.area2 ERROR The five boxing wizards jump.

# Prints the following to `stderr` (messages at level `INFO` or above):

examples.lggrs.base: INFO Jackdaws love my big sphinx.
examples.lggrs.area1: INFO How daft jumping zebras vex.
examples.lggrs.area2: WARNING Jail zesty vixen who grabbed pay.
examples.lggrs.area2: ERROR The five boxing wizards jump.

Notes
^^^^^

.. [1] https://docs.python.org/2/howto/logging-cookbook.html#multiple-handlers-and-formatters
.. [2] https://docs.python.org/2/howto/logging-cookbook.html#implementing-structured-logging
.. [3] https://docs.python.org/2/howto/logging-cookbook.html#using-filters-to-impart-contextual-information
.. [4] https://docs.python.org/2/howto/logging-cookbook.html#logging-to-multiple-destinations

Command-line Interface
~~~~~~~~~~~~~~~~~~~~~~

Examples
^^^^^^^^

*Basic Usage*

.. code-block:: bash

gogo [options] <message>

*show help*

.. code-block:: bash

gogo -h

.. code-block:: bash

usage: gogo [options] <message>

description: Logs a given message

positional arguments:
message The message to log (defaults to reading from stdin).

optional arguments:
-h, --help show this help message and exit
-l LEVEL, --msg-level LEVEL
The level to log the message (default: info).
Must be one of: critical, error, warning, info, debug.

-n NAME, --name NAME The logger name (default: pygogo)
-D HANDLER, --high-hdlr HANDLER
The high pass log handler (default: stderr).
Must be one of: buffered, email, file, fileobj,
socket, stderr, stdout, syslog, webhook.

-d HANDLER, --low-hdlr HANDLER
The low pass log handler (default: stdout).
Must be one of: buffered, email, file, fileobj,
socket, stderr, stdout, syslog, webhook.

-L LEVEL, --high-level LEVEL
Min level to log to the high pass handler
(default: warning).
Must be one of: buffered, email, file, fileobj,
socket, stderr, stdout, syslog, webhook.

-e LEVEL, --low-level LEVEL
Min level to log to the low pass handler
(default: debug).
Must be one of: buffered, email, file, fileobj,
socket, stderr, stdout, syslog, webhook.

-F FORMAT, --high-format FORMAT
High pass handler log format (default: basic).
Must be one of: basic, bom, console, csv,
fixed, json, structured.

-o FORMAT, --low-format FORMAT
Low pass handler log format (default: basic).
Must be one of: basic, bom, console, csv,
fixed, json, structured.

-m, --monolog Log high level events only to high pass handler.
-f FILENAME, --filename FILENAME
The filename to log to.
Required for the follow handlers: file.

-s SUBJECT, --subject SUBJECT
The log subject (default: You've got mail).
Used in the follow handlers: email.

-u URL, --url URL The log url. Required for the follow handlers: webhook.
-H HOST, --host HOST The host.
Used in the follow handlers: socket and syslog.

-p NUM, --port NUM The port number.
Used in the follow handlers: socket and syslog.

-t, --tcp Use TCP instead of UDP.
Used in the follow handlers: socket and syslog.

-g, --get Use a GET request instead of POST.
Used in the follow handlers: webhook.

-v, --version Show version and exit.
-V, --verbose Increase output verbosity.

*Hello World*

.. code-block:: bash

gogo 'hello world'

*Log based debugging*

.. code-block:: bash

gogo 'default info level will log to `stdout`'
gogo --level=debug "debug won't log"
gogo --level=debug -V 'verbose will log to `stdout`'
gogo --level=info 'info will log to `stdout`'
gogo --level=warning 'warning will log to both `stdout` and `stderr`'

# Prints the following to `stdout`:

default info level will log to `stdout`
verbose will log to `stdout`
info will log to `stdout`
warning will log to both `stdout` and `stderr`

# Prints the following to `stderr`:

warning will log to both `stdout` and `stderr`

*Disable dual logging*

.. code-block:: bash

gogo --level=debug -V 'debug message'
gogo --level=info 'info message'
gogo --level=warning -m 'warning message'
gogo --level=error -m 'error message'
gogo --level=critical -m 'critical message'

# Prints the following to `stdout.log` (all messages at level `INFO` or below):

debug message
info message

# Prints the following to `stderr` (messages at level `WARNING` or above):

warning message
error message
critical message

*Structured logging*

.. code-block:: bash

gogo --low-format=json 'log message'

# Prints the following to `stdout`:

{"time": "2015-12-19 11:26:53.776", "name": "pygogo.runner", "level": "INFO", "message": "log message"}

*Alternate handler*

.. code-block:: bash

gogo --low-hdlr=file 'log message'

# Prints the following to `pygogo.log` in the current dir (assuming the current dir is named `pygogo`):

{"time": "2015-12-19 11:26:53.776", "name": "pygogo.runner", "level": "INFO", "message": "log message"}

Installation
------------

(You are using a `virtualenv`_, right?)

At the command line, install pygogo using either ``pip`` (*recommended*)

.. code-block:: bash

pip install pygogo

or ``easy_install``

.. code-block:: bash

easy_install pygogo

Please see the `installation doc`_ for more details.

Project structure
-----------------

.. code-block:: bash

┌── AUTHORS.rst
├── CHANGES.rst
├── CONTRIBUTING.rst
├── INSTALLATION.rst
├── LICENSE
├── MANIFEST.in
├── Makefile
├── pygogo.png
├── README.rst
├── TODO.rst
├── bin
│   └── gogo
├── dev-requirements.txt
├── examples.py
├── helpers
│   ├── check-stage
│   ├── clean
│   ├── docs
│   ├── sdist
│   ├── srcdist
│   ├── test
│   └── wheel
├── manage.py
├── pygogo
│   ├── __init__.py
│   ├── formatters.py
│   ├── handlers.py
│   ├── main.py
│   └── utils.py
├── requirements.txt
├── setup.cfg
├── setup.py
├── tests
│   ├── __init__.py
│   ├── standard.rc
│   ├── test.py
│   └── test_main.py
└── tox.ini

Design Principles
-----------------

- the built-in ``logging`` module isn't broken so don't reinvent the wheel
- prefer functions over objects
- keep the API as simple as possible

Structured Logging
------------------

There are severals ways to get structured (machine readable) log messages using pygogo.
Each method makes a different customization/complexity trade-off which is
outlined below:

Setup
~~~~~

The following methods make use of these variables.

.. code-block:: python

import pygogo as gogo

kwargs = {'contextual': True}
extra = {'additional': True}

Methods
~~~~~~~

basic structured logger
^^^^^^^^^^^^^^^^^^^^^^^

The simplest to use. Useful if you don’t need message metadata, i.e., log level,
log name, and log time.

.. code-block:: python

logger = gogo.Gogo('basic').get_structured_logger('base', **kwargs)
logger.debug('message', extra=extra)

# Prints the following to `stdout`:

{"additional": true, "contextual": true, "message": "message"}

structured formatter
^^^^^^^^^^^^^^^^^^^^

Requires an additional step of specifying a formatter. Useful if you need
message metadata, i.e., log level, log name, and log time.

.. code-block:: python

formatter = gogo.formatters.structured_formatter
logger = gogo.Gogo('struct', low_formatter=formatter).get_logger(**kwargs)
logger.debug('message', extra=extra)

# Prints the following to `stdout`:

{"additional": true, "contextual": true, "level": "DEBUG", "message": "message", "msecs": 760.5140209197998, "name": "struct.base", "time": "2015-12-19 14:25:58"}

JSON formatter
^^^^^^^^^^^^^^

Requires an additional step of specifying a formatter. Useful if you require
millisecond precision in the date. If you are ok with having the milliseconds
in a separate field, consider the ``structured formatter`` since it supports
the ``extra`` keyword and contextual information.

.. code-block:: python

formatter = gogo.formatters.json_formatter
logger = gogo.Gogo('json', low_formatter=formatter).get_logger(**kwargs)
logger.debug('message', extra=extra)

# Prints the following to `stdout`:

{"level": "DEBUG", "message": "message", "name": "json.base", "time": "2015-12-19 14:25:58.760"}

# Note that both `extra` and `kwargs` were ignored

custom logger
^^^^^^^^^^^^^

The most complex and customizable. Useful if you need a custom
log or date format not provided by the above methods. However, even though this
method supports the ``extra`` keyword when logging, it is static (unlike the
``structured logger`` or ``structured formatter``). This is because the log
format must be specified at the time of the log's creation and therefore can't
adapt to log messages with differing ``extra`` parameters.

.. code-block:: python

logfmt = (
'{"time": "%(asctime)s.%(msecs)d", "name": "%(name)s", "level":'
' "%(levelname)s", "message": "%(message)s", '
'"contextual": "%(contextual)s", "additional": "%(additional)s"}')

fmtr = logging.Formatter(logfmt, datefmt=gogo.formatters.DATEFMT)
logger = gogo.Gogo('custom', low_formatter=fmtr).get_logger(**kwargs)
logger.debug('message', extra=extra)

# Prints the following to `stdout`:

{"additional": "True", "contextual": "True", "level": "DEBUG", "message": "message", "name": "custom.logger", "time": "2015-12-19 14:25:58.760"}

Summary
~~~~~~~

The following table can help make sense of the different methods:

+-------------------------------+-------------------+----------------------+----------------+---------------+
| | structured logger | structured formatter | json formatter | custom logger |
+===============================+===================+======================+================+===============+
| contextual information | ✔ | ✔ | | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| ``extra`` param support | ✔ | ✔ | | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| dynamic ``extra`` support | ✔ | ✔ | | |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| message metadata | | ✔ | ✔ | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| available via the command line| | ✔ | ✔ | |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| ``msecs`` field | | ✔ | | |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| milliseconds in time field | | | ✔ | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| custom date format | | | | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+
| custom log format | | | | ✔ |
+-------------------------------+-------------------+----------------------+----------------+---------------+

Formatters
----------

pygogo has several builtin formatters and also supports any ``logging.Formatter``
instance.

Examples
~~~~~~~~

builtin CSV format in python
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: python

import pygogo as gogo

formatter = gogo.formatters.csv_formatter
gogo.Gogo('csv', low_formatter=formatter).logger.debug('message')

# Prints the following to `stdout`:

2015-12-19 17:03:48.99,csv.base,DEBUG,"message"


``logging.Formatter`` instance in python
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: python

import logging
import pygogo as gogo

datefmt = gogo.formatters.DATEFMT
formatter = logging.Formatter(gogo.formatters.CSV_FORMAT, datefmt=datefmt)
gogo.Gogo('csv', low_format=formatter).get_logger('custom').debug('message')

# Prints the following to `stdout`:

2015-12-19 17:03:48.99,csv.custom,DEBUG,"message"

builtin CSV format via CLI
^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: bash

gogo --low-format=csv 'message'

# Prints the following to `stdout`:

2015-12-19 15:51:32.16,pygogo.runner,INFO,"message"

Summary
~~~~~~~

The following table can help make sense of the different builtin formatters:

+------------+------------------------------------------------------------------------------------------------------------------+
| name | message |
+============+==================================================================================================================+
| basic | message |
+------------+------------------------------------------------------------------------------------------------------------------+
| bom | message |
+------------+------------------------------------------------------------------------------------------------------------------+
| console | name: INFO message |
+------------+------------------------------------------------------------------------------------------------------------------+
| csv | 2015-12-19 15:51:32.16,name,INFO,"message" |
+------------+------------------------------------------------------------------------------------------------------------------+
| fixed | 2015-12-19 15:51:32.16 name INFO message |
+------------+------------------------------------------------------------------------------------------------------------------+
| json | {"level": "INFO", "message": "message", "name": "name", "time": "2015-12-19 15:51:32.16"} |
+------------+------------------------------------------------------------------------------------------------------------------+
| structured | {"level": "INFO", "message": "message", "msecs": 16.5140209197998, "name": "name", "time": "2015-12-19 15:51:32"}|
+------------+------------------------------------------------------------------------------------------------------------------+

Handlers
--------

pygogo has several builtin handlers and also supports any instance from the
``logging.handlers`` module.

Examples
~~~~~~~~

builtin stdout handler in python
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: python

import pygogo as gogo

hdlr = gogo.handlers.stdout_hdlr()
gogo.Gogo('stdout', low_hdlr=hdlr).logger.debug('message')

# Prints 'message' to `stdout`

``logging.StreamHandler`` instance in python
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: python

import logging
import sys
import pygogo as gogo

hdlr = logging.StreamHandler(sys.stdout)
gogo.Gogo('stdout', low_hdlr=hdlr).get_logger('custom').debug('message')

# Prints 'message' to `stdout`

builtin CSV format via CLI
^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: bash

gogo --low-hdlr=stdout 'message'

# Prints 'message' to `stdout`

Summary
~~~~~~~

The following table can help make sense of the different builtin handlers:

+------------+------------------------------------------+
| name | description |
+============+==========================================+
| buffered | Holds log in memory until it reaches its |
| | capacity, or it logs a message with a |
| | level at or above the flush level |
+------------+------------------------------------------+
| email | Emails log to a given email address |
+------------+------------------------------------------+
| file | Writes log to a given filename |
+------------+------------------------------------------+
| fileobj | Writes log to a given file-like object |
+------------+------------------------------------------+
| socket | Writes log to a given network socket |
+------------+------------------------------------------+
| stderr | Writes log to standard error |
+------------+------------------------------------------+
| stdout | Writes log to standard output |
+------------+------------------------------------------+
| syslog | Writes log to syslog |
+------------+------------------------------------------+
| webhook | POSTs log to a url |
+------------+------------------------------------------+

Scripts
-------

pygogo comes with a built in task manager ``manage.py``

Setup
~~~~~

.. code-block:: bash

pip install -r dev-requirements.txt

Examples
~~~~~~~~

*Run python linter and nose tests*

.. code-block:: bash

manage lint
manage test

License
-------

pygogo is distributed under the `MIT License`_.

.. _MIT License: http://opensource.org/licenses/MIT

Contributing
------------

Please mimic the coding style/conventions used in this repo.
If you add new classes or functions, please add the appropriate doc blocks with
examples. Also, make sure the python linter and nose tests pass.

Please see the `contributing doc`_ for more details.

.. |travis| image:: https://img.shields.io/travis/reubano/pygogo.svg
:target: https://travis-ci.org/reubano/pygogo

.. |versions| image:: https://img.shields.io/pypi/pyversions/pygogo.svg
:target: https://pypi.python.org/pypi/pygogo

.. |pypi| image:: https://img.shields.io/pypi/v/pygogo.svg
:target: https://pypi.python.org/pypi/pygogo

.. _logging module: https://docs.python.org/2/library/logging.html
.. _virtualenv: http://www.virtualenv.org/en/latest/index.html
.. _contributing doc: https://github.com/reubano/pygogo/blob/master/CONTRIBUTING.rst
.. _installation doc: https://github.com/reubano/pygogo/blob/master/INSTALLATION.rst


=========
Changelog
=========

Here you can find the recent changes to pygogo..

.. changelog::
:version: dev
:released: Ongoing

.. change::
:tags: docs

Updated CHANGES.

.. changelog::
:version: 0.1.0
:released: 2015-12-05

.. change::
:tags: docs

First release on PyPi.

.. todo:: vim: set filetype=rst: