如何登录python和bottle web服务器的文件？

Question

Following is my code for server. I need to add logging to it . This is a very basic rest api server. I have deployed it on Amazon EC2 . Sometimes due to errors or some other reason the http server shuts down. If I am logged on to EC2 i can see the erros while they happen . But if I am not monitoring it realtime i don't know what error occurred. Therefore I want to add logging which would log the erros in a log file which I can look at later. Please suggest how do i do that.

import json
import uuid # this is for generating unique id
import datetime
import bottle
from bottle import route, run, request, abort
from pymongo import Connection

connection = Connection('localhost', 27017)
db = connection.mydatabase

@route('/documents', method='PUT')
def put_document():
    data = request.body.readline()
    if not data:
        abort(400, 'No data received')
    entity = json.loads(data)
    if not entity.has_key('_id'):
        abort(400, 'No _id specified')
    try:
        db['documents'].save(entity)
    except ValidationError as ve:
        abort(400, str(ve))

@route('/documents/:id', method='GET')
def get_document(id):
    entity = db['documents'].find_one({'_id':id})
    if not entity:
        abort(404, 'No document with id %s' % id)
    return entity

@route('/startSession', method = 'GET')
def startSession():
    #here we need to create a unique id and store it in the database.
    date = str(datetime.datetime.utcnow());
    id = str(uuid.uuid4())
    reply = {'date' : date,
                'user_id': id
                }

    response = {'date' : date,
        'user_id': id
        }
    return_id = db['users'].save(reply)
#print 'the id returned is', return_id
#print 'the changed reply is',reply
#print 'the NON changed respponse is ',response
    return json.dumps(response)

@route('/set_bus_location', method = 'PUT')
def set_bus_location():
    data = request.body.readline()
    print 'data is ',data
    if not data:
        abort(400, 'No data received')
    entity = json.loads(data)
    db['bus_locations'].save(entity)

run(host='0.0.0.0', port=8080)

Answer 1

Use the python Logging library. To log exceptions, you'll need to use try and except blocks.

import logging
logging.basicConfig(filename='log.txt', format=logging.BASIC_FORMAT)
logging.error('OH NO!')
try:
    raise Exception('Foo')
except:
    logging.exception("Oops:")

Contents of log.txt :

ERROR:root:OH NO!

You can add many different loggers that go to different places, have different names, or use different formats. However, the Python logging library is what you want.