CenterForOpenScience/scrapi

from __future__ import unicode_literals

import logging
import inspect
from functools import wraps

import six
from fluent import event
from raven import Client

from scrapi import settings


logger = logging.getLogger(__name__)
sentry = Client(dsn=settings.SENTRY_DSN)

if not settings.USE_FLUENTD:
    logger.warning('USE_FLUENTD is set to False; logs will not be stored')

# Events
PROCESSING = 'processing'
HARVESTER_RUN = 'runHarvester'
CHECK_ARCHIVE = 'checkArchive'
NORMALIZATION = 'normalization'

# statuses
FAILED = 'failed'
SKIPPED = 'skipped'
CREATED = 'created'
STARTED = 'started'
COMPLETED = 'completed'


def log_to_sentry(message, **kwargs):
    if not settings.SENTRY_DSN:
        return logger.warn('send_to_raven called with no SENTRY_DSN')
    return sentry.captureMessage(message, extra=kwargs)


class Skip(Exception):
    pass


def serialize_fluent_data(data):
    if isinstance(data, dict):
        return {
            key: serialize_fluent_data(val)
            for key, val in data.items()
        }
    elif isinstance(data, list):
        return [
            serialize_fluent_data(item)
            for item in data
        ]
    elif isinstance(data, six.string_types):
        return data
    else:
        return repr(data)


# Ues _index here as to not clutter the namespace for kwargs
def dispatch(_event, status, _index=None, **kwargs):
    if not settings.USE_FLUENTD:
        return

    evnt = {
        'event': _event,
        'status': status
    }

    evnt.update(serialize_fluent_data(kwargs))

    if _index:
        _event = '{}.{}'.format(_event, _index)

    logger.debug('[{}][{}]{!r}'.format(_event, status, kwargs))
    event.Event(_event, evnt)


def logged(event, index=None):
    def _logged(func):
        @wraps(func)
        def wrapped(*args, **kwargs):
            context = extract_context(func, *args, **kwargs)
            dispatch(event, STARTED, _index=index, **context)
            try:
                res = func(*args, **kwargs)
            except Skip as e:
                # args[0] instead of message for Py3
                dispatch(event, SKIPPED, _index=index, reason=e.args[0], **context)
                return None
            except Exception as e:
                if settings.SENTRY_DSN:
                    sentry.captureException()
                dispatch(event, FAILED, _index=index, exception=e, **context)
                raise
            else:
                dispatch(event, COMPLETED, _index=index, **context)
            return res
        return wrapped
    return _logged


def extract_context(func, *args, **kwargs):
    arginfo = inspect.getargspec(func)
    arg_names = arginfo.args
    defaults = {
        arg_names.pop(-1): kwarg
        for kwarg in (arginfo.defaults or [])
    }

    computed_args = list(zip(arg_names, args))
    if arginfo.varargs:
        computed_args.append(('args', list(args[len(arg_names):])))

    if kwargs:
        defaults['kwargs'] = kwargs

    return dict(computed_args, **defaults)


def creates_task(event):
    def _creates_task(func):
        @wraps(func)
        def wrapped(*args, **kwargs):
            res = func(*args, **kwargs)
            dispatch(event, CREATED, **extract_context(func, *args, **kwargs))
            return res
        return wrapped
    return _creates_task