Question

I’m building a web service using Flask and I’m trying to deploy a simple “Hello, World” app using Paster. I’m having trouble get everything configured to work together though. I’ve seen the Google hit about running Flask with paste using virtualenv and zcbuildout, but that seems like it’s overkill for a pretty basic application. Right now, when I try to load a URL with my app, I get this error:

Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/paste/httpserver.py", line 1068, in process_request_in_thread
  self.finish_request(request, client_address)
File "/usr/lib/python2.7/SocketServer.py", line 323, in finish_request
  self.RequestHandlerClass(request, client_address, self)
File "/usr/lib/python2.7/SocketServer.py", line 639, in __init__
  self.handle()
File "/usr/lib/python2.7/dist-packages/paste/httpserver.py", line 442, in handle
  BaseHTTPRequestHandler.handle(self)
File "/usr/lib/python2.7/BaseHTTPServer.py", line 343, in handle
  self.handle_one_request()
File "/usr/lib/python2.7/dist-packages/paste/httpserver.py", line 437, in handle_one_request
  self.wsgi_execute()
File "/usr/lib/python2.7/dist-packages/paste/httpserver.py", line 287, in wsgi_execute
  self.wsgi_start_response)
AttributeError: GraffitiApp instance has no __call__ method

My application configuration looks like:

[DEFAULT]
loglevel = WARN
browser_cache_ttl = 30

[app:main]
use = egg:GraffitiService

[server:main]
use = egg:Paste#http
host = 0.0.0.0
port = %(graffiti_port)s

My application code looks like:

from flask import Flask

app = Flask(__name__)
app.debug = True

class GraffitiApp:

    @app.route('/')
    def hello_world():
        return "Hello World!"

    @app.route('/other')
    def other_page():
        return "Other page!"

    def main():
        app.run(debug = True)

if __name__ == "__main__":
    app.run(debug = True)

Do I need to create a __call__() method and map whatever URL was passed to the appropriate function, or is there a change I need to make to my configuration?

EDIT

I’m using a factory named main.py as a result of errors I was getting about not finding an entry point named “main”:

import logging

from graffiti import GraffitiApp

def make_app(globalArgs, **localArgs):
    loglevelname = globalArgs.get("loglevel", "INFO").lower()

    if loglevelname == 'critical':
        loglevel = logging.CRITICAL
    elif loglevelname == 'debug':
        loglevel = logging.DEBUG
    elif loglevelname == 'error':
        loglevel = logging.ERROR
    elif loglevelname == 'fatal':
        loglevel = logging.FATAL
    elif loglevelname == 'info':
        loglevel = logging.INFO
    elif loglevelname == 'warn' or loglevelname == 'warning':
        loglevel = logging.WARN
    else:
        loglevel = logging.NOTSET
        loglevelname = 'notset'

    FORMAT = "%(asctime)s %(name)s %(levelname)s %(message)s"
    logging.basicConfig(format = FORMAT, level = loglevel)
    logging.info("Log level set to %s" % (loglevelname.upper()))

    return GraffitiApp()

Answer 1

It looks like the server is trying to run your GraffitiApp() class when it should run the Flask() instance app.