ulogger

A micro Python logging library.

Supported handlers:

• stream (stdout)
• syslog
• stackdriver (optional)

Requirements

• Python 3.7. Tests also pass on Python 3.8. PyPy support has been removed due to upstream issues with the grpcio module.
• Support for Linux & OS X

To Use

```sh
(env) $ pip install ulogger
# To use the stackdriver handler, you need to specify an extra dependency:
(env) $ pip install "ulogger[stackdriver]"
```

```python
import logging
from ulogger import setup_logging

# one handler
setup_logging('my_program', 'INFO', ['syslog'])

# multiple handlers
setup_logging('my_program', 'INFO', ['syslog', 'stream'])

# use a different logging facility for syslog (default 16/LOG_LOCAL0)
setup_logging('my_program', 'INFO', ['syslog'], facility=1)
setup_logging('my_program', 'INFO', ['syslog'], facility=logging.handlers.SysLogHandler.LOG_USER)

# then log messages normally
logging.info('ohai')
```

To just setup a specific handler, e.g. Syslog:

```python
import logging
from ulogger import syslog

logger = logging.getLogger('my_logger')
handler = syslog.get_handler('my_program')
logger.addHandler(handler)
```

To setup a Syslog handler with a specific address:

```python
import logging
from ulogger import syslog

logger = logging.getLogger('my_logger')

syslog_addr = ('10.99.0.1', 9514)  # (host, port) tuple
# if just a host is given, the default port 514 is used
syslog_addr = ('localhost', None)  # (host, port)
# filepath is supported
syslog_addr = '/dev/log'

handler = syslog.get_handler('my_program', address=syslog_addr)

# env vars are also supported, but will be overwritten if `address` is explicitly given
os.environ['SYSLOG_HOST'] = 'localhost'
os.environ['SYSLOG_PORT'] = 325
handler = syslog.get_handler('my_program')

# TCP & UDP are supported
proto = 1  # TCP
proto = socket.SOCK_STREAM  # TCP
proto = 2  # UDP - default
proto = socket.SOCK_DGRAM  #  UDP - default

handler = syslog.get_handler('my_program', address=syslog_addr, proto=proto)
logger.addHandler(handler)
```

Formatting

Default

The default date format for all handlers is the following: '%Y-%m-%dT%H:%M:%S' (example 2017-11-02T09:51:33.792).

The default log format is slightly different depending on the handler you select:

Stream Handler Log Format

```python
'%(asctime)s.%(msecs)03dZ <PROGNAME> (%(process)d) %(levelname)s: %(message)s'
```

Example:

```text
2017-11-02T09:51:33.792Z my_awesome_program (63079) INFO: Beginning awesome program v3.
```

Syslog Handler Log Format on Linux

```python
'%(asctime)s.%(msecs)03dZ <PROGNAME> (%(process)d): %(message)s'
```

Example:

```text
2017-11-02T09:51:33.792Z my_awesome_program (63079): Beginning awesome program v3.
```

Syslog Handler Log Format on OS X

```python
'<PROGNAME> (%(process)d): %(message)s'
```

Example:

```text
Aug 25 13:00:51 my-host.example.net my_awesome_program (63079): Beginning awesome program v3.
```

NOTE: Default syslog on OS X appends the date and hostname to the log record.

Stackdriver Handler Log Format

```python
'%(asctime)s.%(msecs)03d <HOST> <PROGNAME> (%(process)d): %(message)s'
```

Example:

```text
2017-11-02T19:00:55.850 my-gcp-host my_awesome_program (63079): Beginning awesome program v3"
```

Custom

To add your custom log and/or date formatter:

```python
import logging
from ulogger import setup_logging

log_fmt = '%(created)f %(levelno)d %(message)s'
log_date_fmt = '%Y-%m-%dT%H:%M:%S'

setup_logging('my_program', 'INFO', ['syslog'], log_fmt, log_date_fmt)
```

Development

For development and running tests, your system must have all supported versions of Python installed. We suggest using pyenv.

Setup

```sh
$ git clone git@github.com:spotify/ulogger.git && cd ulogger
# make a virtualenv
(env) $ pip install -r dev-requirements.txt
```

Running tests

To run the entire test suite:

```sh
# outside of the virtualenv
# if tox is not yet installed
$ pip install tox
$ tox
```

If you want to run the test suite for a specific version of Python:

```sh
# outside of the virtualenv
$ tox -e py37
```

To run an individual test, call pytest directly:

```sh
# inside virtualenv
(env) $ pytest tests/test_syslog.py
```

Code of Conduct

This project adheres to the Open Code of Conduct. By participating, you are expected to honor this code.