feat: add user record cleanup script (#677)

Add's a new drop_user command that scans the AccessIndex for
users that haven't connected in the given month and removes the
route records.

Closes #645

autopush/db.py

@@ -47,6 +47,7 @@
 from boto.dynamodb2.layer1 import DynamoDBConnection
 from boto.dynamodb2.table import Table, Item
 from boto.dynamodb2.types import NUMBER
+from typing import Iterable, List  # flake8: noqa
 
 from autopush.exceptions import AutopushException
 from autopush.utils import (
@@ -62,7 +63,13 @@
 
 def get_month(delta=0):
     """Basic helper function to get a datetime.date object iterations months
-    ahead/behind of now."""
+    ahead/behind of now.
+
+    :type delta: int
+
+    :rtype: datetime.datetime
+
+    """
     new = last = datetime.date.today()
     # Move until we hit a new month, this avoids having to manually
     # check year changes as we push forward or backward since the Python
@@ -155,8 +162,9 @@ def create_router_table(tablename="router", read_throughput=5,
                         global_indexes=[
                             GlobalKeysOnlyIndex(
                                 'AccessIndex',
-                                parts=[HashKey('last_connect',
-                                               data_type=NUMBER)],
+                                parts=[
+                                    HashKey('last_connect',
+                                             data_type=NUMBER)],
                                 throughput=dict(read=5, write=5))],
                         )
 
@@ -265,7 +273,13 @@ def wrapper(self, *args, **kwargs):
 
 
 def has_connected_this_month(item):
-    """Whether or not a router item has connected this month"""
+    """Whether or not a router item has connected this month
+
+    :type item: dict
+
+    :rtype: bool
+
+    """
     last_connect = item.get("last_connect")
     if not last_connect:
         return False
@@ -276,17 +290,47 @@ def has_connected_this_month(item):
 
 
 def generate_last_connect():
-    """Generate a last_connect"""
+    """Generate a last_connect
+
+    This intentionally generates a limited set of keys for each month in a
+    known sequence. For each month, there's 24 hours * 10 random numbers for
+    a total of 240 keys per month depending on when the user migrates forward.
+
+    :type date: datetime.datetime
+
+    :rtype: int
+
+    """
     today = datetime.datetime.today()
     val = "".join([
-                  str(today.year),
-                  str(today.month).zfill(2),
-                  str(today.hour).zfill(2),
-                  str(random.randint(0, 10)).zfill(4),
-                  ])
+        str(today.year),
+        str(today.month).zfill(2),
+        str(today.hour).zfill(2),
+        str(random.randint(0, 10)).zfill(4),
+    ])
     return int(val)
 
 
+def generate_last_connect_values(date):
+    """Generator of last_connect values for a given date
+
+    Creates an iterator that yields all the valid values for ``last_connect``
+    for a given year/month.
+
+    :type date: datetime.datetime
+
+    :rtype: Iterable[int]
+
+    """
+    year = str(date.year)
+    month = str(date.month).zfill(2)
+    for hour in range(0, 24):
+        for rand_int in range(0, 11):
+            val = "".join([year, month, str(hour).zfill(2),
+                           str(rand_int).zfill(4)])
+            yield int(val)
+
+
 class Storage(object):
     """Create a Storage table abstraction on top of a DynamoDB Table object"""
     def __init__(self, table, metrics):
@@ -606,6 +650,64 @@ def drop_user(self, uaid):
         return self.table.delete_item(uaid=huaid,
                                       expected={"uaid__eq": huaid})
 
+    def delete_uaids(self, uaids):
+        """Issue a batch delete call for the given uaids
+
+        :type uaids: List[str]
+
+        """
+        with self.table.batch_write() as batch:
+            for uaid in uaids:
+                batch.delete_item(uaid=uaid)
+
+    def drop_old_users(self, months_ago=2):
+        """Drops user records that have no recent connection
+
+        Utilizes the last_connect index to locate users that haven't
+        connected in the given time-frame.
+
+        The caller must iterate through this generator to trigger batch
+        delete calls. Caller should wait as appropriate to avoid exceeding
+        table limits.
+
+        Each iteration will result in a batch delete for the currently
+        iterated batch. This implies a set of writes equal in size to the
+        ``25 * record-size`` minimum.
+
+        .. warning::
+
+            Calling list() on this generator will likely exceed provisioned
+            write through-put as the batch-delete calls will be made as
+            quickly as possible.
+
+        :param months_ago: how many months ago since the last connect
+        :type months_ago: int
+
+        :returns: Iterable of how many deletes were run
+        :rtype: Iterable[int]
+
+        """
+        prior_date = get_month(-months_ago)
+
+        batched = []
+        for hash_key in generate_last_connect_values(prior_date):
+            result_set = self.table.query_2(
+                last_connect__eq=hash_key,
+                index="AccessIndex",
+            )
+            for result in result_set:
+                batched.append(result["uaid"])
+
+                if len(batched) == 25:
+                    self.delete_uaids(batched)
+                    batched = []
+                    yield 25
+
+        # Delete any leftovers
+        if batched:
+            self.delete_uaids(batched)
+            yield len(batched)
+
     @track_provisioned
     def update_message_month(self, uaid, month):
         """Update the route tables current_message_month

autopush/scripts/__init__.py

@@ -0,0 +1 @@
+#

autopush/scripts/drop_user.py

@@ -0,0 +1,39 @@
+import time
+
+import click
+
+from autopush.db import (
+    get_router_table,
+    Router,
+)
+from autopush.metrics import SinkMetrics
+
+
+@click.command()
+@click.option('--router_table_name', help="Name of the router table.")
+@click.option('--months-ago', default=2, help="Months ago to remove.")
+@click.option('--batch_size', default=25,
+              help="Deletes to run before pausing.")
+@click.option('--pause_time', default=1,
+              help="Seconds to pause between batches.")
+def drop_users(router_table_name, months_ago, batch_size, pause_time):
+    router_table = get_router_table(router_table_name)
+    router = Router(router_table, SinkMetrics())
+
+    click.echo("Deleting users with a last_connect %s months ago."
+               % months_ago)
+
+    count = 0
+    for deletes in router.drop_old_users(months_ago):
+        click.echo("")
+        count += deletes
+        if count >= batch_size:
+            click.echo("Deleted %s user records, pausing for %s seconds."
+                       % pause_time)
+            time.sleep(pause_time)
+            count = 0
+    click.echo("Finished old user purge.")
+
+
+if __name__ == '__main__':  # pragma: nocover
+    drop_users()

autopush/tests/test_db.py

@@ -1,7 +1,7 @@
 import unittest
 import uuid
 
-from autopush.exceptions import AutopushException
+from autopush.websocket import ms_time
 from boto.dynamodb2.exceptions import (
     ConditionalCheckFailedException,
     ProvisionedThroughputExceededException,
@@ -23,7 +23,9 @@
     Storage,
     Message,
     Router,
+    generate_last_connect,
 )
+from autopush.exceptions import AutopushException
 from autopush.metrics import SinkMetrics
 from autopush.utils import WebPushNotification
 
@@ -361,6 +363,25 @@ def setUp(self):
     def tearDown(self):
         self.real_table.connection = self.real_connection
 
+    def _create_minimal_record(self):
+        data = {
+            "uaid": str(uuid.uuid4()),
+            "router_type": "webupsh",
+            "last_connect": generate_last_connect(),
+            "connected_at": ms_time(),
+        }
+        return data
+
+    def test_drop_old_users(self):
+        # First create a bunch of users
+        r = get_router_table()
+        router = Router(r, SinkMetrics())
+        for _ in range(0, 53):
+            router.register_user(self._create_minimal_record())
+
+        results = router.drop_old_users(months_ago=0)
+        eq_(list(results), [25, 25, 3])
+
     def test_custom_tablename(self):
         db = DynamoDBConnection()
         db_name = "router_%s" % uuid.uuid4()

base-requirements.txt

@@ -13,6 +13,7 @@ boto3==1.4.0
 botocore==1.4.50
 cffi==1.7.0
 characteristic==14.3.0
+click==6.6
 contextlib2==0.5.4
 cryptography==1.5
 cyclone==1.1

setup.py

@@ -40,6 +40,7 @@
       autoendpoint = autopush.main:endpoint_main
       autokey = autokey:main
       endpoint_diagnostic = autopush.diagnostic_cli:run_endpoint_diagnostic_cli
+      drop_users = autopush.scripts.drop_user:drop_users
       [nose.plugins]
       object-tracker = autopush.noseplugin:ObjectTracker
       """,