appengine/standard/taskqueue/counter/application.py

# Copyright 2016 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from google.appengine.api import taskqueue
from google.appengine.ext import ndb
import webapp2


COUNTER_KEY = "default counter"


class Counter(ndb.Model):
    count = ndb.IntegerProperty(indexed=False)


class MainPageHandler(webapp2.RequestHandler):
    def get(self):
        counter = Counter.get_by_id(COUNTER_KEY)
        count = counter.count if counter else 0

        self.response.write(
            """
            Count: {count}<br>
            <form method="post" action="/enqueue">
                <label>Increment amount</label>
                <input name="amount" value="1">
                <button>Enqueue task</button>
            </form>
        """.format(
                count=count
            )
        )


class EnqueueTaskHandler(webapp2.RequestHandler):
    def post(self):
        amount = int(self.request.get("amount"))

        task = taskqueue.add(
            url="/update_counter", target="worker", params={"amount": amount}
        )

        self.response.write("Task {} enqueued, ETA {}.".format(task.name, task.eta))


# AsyncEnqueueTaskHandler behaves the same as EnqueueTaskHandler, but shows
# how to queue the task using the asyncronous API. This is not wired up by
# default. To use this, change the MainPageHandler's form action to
# /enqueue_async
class AsyncEnqueueTaskHandler(webapp2.RequestHandler):
    def post(self):
        amount = int(self.request.get("amount"))

        queue = taskqueue.Queue(name="default")
        task = taskqueue.Task(
            url="/update_counter", target="worker", params={"amount": amount}
        )

        rpc = queue.add_async(task)

        # Wait for the rpc to complete and return the queued task.
        task = rpc.get_result()

        self.response.write("Task {} enqueued, ETA {}.".format(task.name, task.eta))


app = webapp2.WSGIApplication(
    [
        ("/", MainPageHandler),
        ("/enqueue", EnqueueTaskHandler),
        ("/enqueue_async", AsyncEnqueueTaskHandler),
    ],
    debug=True,
)