[flask]出错时发送异常信息邮件（包含异常堆栈，request 信息，发生异常时的局部变量）

最终效果（邮件内容）:

Message type:       ERROR
Location:           /home/xxx/site-packages/flask_restful/__init__.py:292
Module:             __init__
Function:           handle_error
Time:               2014-12-24 17:59:47,876

Message:

Internal Error


Traceback (most recent call last):
  File "/home/xxx/site-packages/flask/app.py", line 1475, in full_dispatch_request
    rv = self.dispatch_request()
  ....
  File "/home/xx/foo.py", line 81, in get
    raise Exception(u'a')
Exception: a


Locals:

{
    'self': <Bar object at 0x2ab4ed05d710>,
    'data': <Foo 10, bar>,
    'id': 10,
}

Request:

{
    'view_args': {
        'id': 10,
    },
    'url_rule': <Rule '/api/foos/<id>' (HEAD, GET, PATCH, POST, OPTIONS, DELETE) -> foo.xapi>,
    'cookies': {
    },
    'shallow': False,
    'environ': {
        'wsgi.multiprocess': True,
        'SERVER_SOFTWARE': 'Werkzeug/0.9.6',
        'SCRIPT_NAME': '',
        'REQUEST_METHOD': 'GET',
        'PATH_INFO': '/api/foos/10',
        'SERVER_PROTOCOL': 'HTTP/1.1',
        'QUERY_STRING': '',
        'werkzeug.server.shutdown': <function shutdown_server at 0x2ab4ed05ea28>,
        'CONTENT_LENGTH': '',
        'HTTP_USER_AGENT': 'foo/0.8.0',
        'HTTP_CONNECTION': 'keep-alive',
        'SERVER_NAME': '0.0.0.0',
        'REMOTE_PORT': 56413,
        'wsgi.url_scheme': 'http',
        'SERVER_PORT': '8900',
        'werkzeug.request': <Request 'http://localhost:8000/api/foos/10' [GET]>,
        'wsgi.input': <socket._fileobject object at 0x2ab4ed066050>,
        'HTTP_HOST': 'localhost:8900',
        'wsgi.multithread': False,
        'HTTP_ACCEPT': '*/*',
        'wsgi.version': (1, 0),
        'wsgi.run_once': False,
        'wsgi.errors': <open file '<stderr>', mode 'w' at 0x2ab4e6b811e0>,
        'REMOTE_ADDR': '127.0.0.1',
        'CONTENT_TYPE': '',
        'HTTP_ACCEPT_ENCODING': 'gzip, deflate',
    },
}

主要通过配置 logging SMTPHandler 来实现:

import inspect
from logging.handlers import SMTPHandler
from flask import request

mail_handler = SMTPHandler('127.0.0.1', 'foo@example.com',
                           'dev@bar.com', 'App exception')
mail_handler.setFormatter(NewFormatter('''
Message type:       %(levelname)s
Location:           %(pathname)s:%(lineno)d
Module:             %(module)s
Function:           %(funcName)s
Time:               %(asctime)s

Message:

%(message)s

'''))
mail_handler.setLevel(logging.ERROR)
app.logger.addHandler(mail_handler)


class NewFormatter(logging.Formatter):
    def format(self, record):
        s = super(NewFormatter, self).format(record)
        msg = '''

Locals:

%(locals)s

Request:

%(request)s
        '''
        s += msg % {
            'locals': pretty_dict_to_string(inspect.trace()[-1][0].f_locals),
            'request': pretty_dict_to_string(request.__dict__),
        }

        return s

pertty_dict_to_string 函数:

def pretty_dict_to_string(d, tab=1):
    s = ['{\n']
    for k, v in d.items():
        if isinstance(v, dict):
            v = pretty_dict_to_string(v, tab + 1)
        else:
            v = repr(v)
        s.append('%s%r: %s,\n' % ('    ' * tab, k, v))
    s.append('%s}' % ('    ' * (tab - 1)))
    return ''.join(s)