CHECKPOINT: Initial part of the big refactor.

rq/exceptions.py

@@ -1,3 +1,6 @@
+class NoSuchJobError(Exception):
+    pass
+
 class NoQueueError(Exception):
     pass
 

rq/job.py

@@ -1,51 +1,131 @@
-from datetime import datetime
+import times
 from uuid import uuid4
 from pickle import loads, dumps
-from .exceptions import UnpickleError
+from .proxy import conn
+from .exceptions import UnpickleError, NoSuchJobError
 
 
 class Job(object):
     """A Job is just a convenient datastructure to pass around job (meta) data.
     """
+
+    # Job construction
     @classmethod
-    def unpickle(cls, pickle_data):
-        """Constructs a Job instance form the given pickle'd job tuple data."""
-        try:
-            unpickled_obj = loads(pickle_data)
-            assert isinstance(unpickled_obj, Job)
-            return unpickled_obj
-        except (AssertionError, AttributeError, IndexError, TypeError, KeyError):
-            raise UnpickleError('Could not unpickle Job.', pickle_data)
+    def for_call(cls, func, *args, **kwargs):
+        """Creates a new Job instance for the given function, arguments, and
+        keyword arguments.
+        """
+        job = Job()
+        job.func = func
+        job.args = args
+        job.kwargs = kwargs
+        return job
 
-    def __init__(self, func, *args, **kwargs):
-        self._id = unicode(uuid4())
-        self.func = func
-        self.args = args
-        self.kwargs = kwargs
+    @classmethod
+    def fetch(cls, id):
+        """Fetches a persisted job from its corresponding Redis key and
+        instantiates it.
+        """
+        job = Job(id)
+        job.refresh()
+        return job
+
+    def __init__(self, id=None):
+        self._id = id
+        self.func = None
+        self.args = None
+        self.kwargs = None
         self.origin = None
-        self.created_at = datetime.utcnow()
+        self.created_at = times.now()
         self.enqueued_at = None
+        self.result = None
         self.exc_info = None
 
-    def pickle(self):
-        """Returns the pickle'd string represenation of a Job.  Suitable for writing to Redis."""
-        return dumps(self)
+
+    # Data access
+    def get_id(self):
+        """The job ID for this job instance. Generates an ID lazily the
+        first time the ID is requested.
+        """
+        if self._id is None:
+            self._id = unicode(uuid4())
+        return self._id
+
+    def set_id(self, value):
+        """Sets a job ID for the given job."""
+        self._id = value
+
+    id = property(get_id, set_id)
 
     @property
-    def rv_key(self):
-        """Returns the Redis key under which the Job's result will be stored, if applicable."""
-        return 'rq:result:%s' % (self._id,)
+    def key(self):
+        """The Redis key that is used to store job data under."""
+        return 'rq:job:%s' % (self.id,)
+
 
     @property
-    def id(self):
-        """Returns the Job's internal ID."""
-        return self._id
+    def job_tuple(self):
+        """Returns the job tuple that encodes the actual function call that this job represents."""
+        return (self.func, self.args, self.kwargs)
+
+    @property
+    def return_value(self):
+        """Returns the return value of the job.
+
+        Initially, right after enqueueing a job, the return value will be None.
+        But when the job has been executed, and had a return value or exception,
+        this will return that value or exception.
+
+        Note that, when the job has no return value (i.e. returns None), the
+        ReadOnlyJob object is useless, as the result won't be written back to
+        Redis.
+
+        Also note that you cannot draw the conclusion that a job has _not_ been
+        executed when its return value is None, since return values written back
+        to Redis will expire after a given amount of time (500 seconds by
+        default).
+        """
+        if self._cached_result is None:
+            rv = conn.hget(self.key, 'result')
+            if rv is not None:
+                # cache the result
+                self._cached_result = loads(rv)
+        return self._cached_result
+
 
+    # Persistence
+    def refresh(self):
+        """Overwrite the current instance's properties with the values in the
+        corresponding Redis key.
+
+        Will raise a NoSuchJobError if no corresponding Redis key exists.
+        """
+        key = self.key
+        pickled_data = conn.hget(key, 'data')
+        if pickled_data is None:
+            raise NoSuchJobError('No such job: %s' % (key,))
+
+        self.func, self.args, self.kwargs = loads(pickled_data)
+
+        self.created_at = times.to_universal(conn.hget(key, 'created_at'))
+
+    def save(self):
+        """Persists the current job instance to its corresponding Redis key."""
+        pickled_data = dumps(self.job_tuple)
+
+        key = self.key
+        conn.hset(key, 'data', pickled_data)
+        conn.hset(key, 'created_at', times.format(self.created_at, 'UTC'))
+
+
+    # Job execution
     def perform(self):
         """Invokes the job function with the job arguments.
         """
         return self.func(*self.args, **self.kwargs)
 
+
+    # Representation
     @property
     def call_string(self):
         """Returns a string representation of the call, formatted as a regular
@@ -59,5 +139,31 @@ class Job(object):
     def __str__(self):
         return '<Job %s: %s>' % (self.id, self.call_string)
 
+
+    # Job equality
     def __eq__(self, other):
-        return cmp(self.id, other.id)
+        return self.id == other.id
+
+    def __hash__(self):
+        return hash(self.id)
+
+
+    # TODO: TO REFACTOR / REMOVE
+    def pickle(self):
+        """Returns the pickle'd string represenation of a Job.  Suitable for
+        writing to Redis.
+        """
+        return dumps(self)
+
+    @classmethod
+    def unpickle(cls, pickle_data):
+        """Constructs a Job instance form the given pickle'd job tuple data."""
+        try:
+            unpickled_obj = loads(pickle_data)
+            assert isinstance(unpickled_obj, Job)
+            return unpickled_obj
+        except (AssertionError, AttributeError, IndexError, TypeError, KeyError):
+
+            raise UnpickleError('Could not unpickle Job.', pickle_data)
+
+

rq/queue.py

@@ -1,44 +1,10 @@
 from datetime import datetime
 from functools import total_ordering
-from pickle import loads
 from .proxy import conn
 from .job import Job
 from .exceptions import UnpickleError
 
 
-class DelayedResult(object):
-    """Proxy object that is returned as a result of `Queue.enqueue()` calls.
-    Instances of DelayedResult can be polled for their return values.
-    """
-    def __init__(self, key):
-        self.key = key
-        self._rv = None
-
-    @property
-    def return_value(self):
-        """Returns the return value of the job.
-
-        Initially, right after enqueueing a job, the return value will be None.
-        But when the job has been executed, and had a return value or exception,
-        this will return that value or exception.
-
-        Note that, when the job has no return value (i.e. returns None), the
-        DelayedResult object is useless, as the result won't be written back to
-        Redis.
-
-        Also note that you cannot draw the conclusion that a job has _not_ been
-        executed when its return value is None, since return values written back
-        to Redis will expire after a given amount of time (500 seconds by
-        default).
-        """
-        if self._rv is None:
-            rv = conn.get(self.key)
-            if rv is not None:
-                # cache the result
-                self._rv = loads(rv)
-        return self._rv
-
-
 @total_ordering
 class Queue(object):
     redis_queue_namespace_prefix = 'rq:queue:'
@@ -99,13 +65,14 @@ class Queue(object):
         if f.__module__ == '__main__':
             raise ValueError('Functions from the __main__ module cannot be processed by workers.')
 
-        job = Job(f, *args, **kwargs)
+        job = Job.for_call(f, *args, **kwargs)
         job.origin = self.name
         return job
 
-    def _push(self, pickled_job):
+    def enqueue_job(self, job):
         """Enqueues a pickled_job on the corresponding Redis queue."""
-        conn.rpush(self.key, pickled_job)
+        job.save()
+        conn.rpush(self.key, job.id)
 
     def enqueue(self, f, *args, **kwargs):
         """Enqueues a function call for delayed execution.
@@ -115,8 +82,8 @@ class Queue(object):
         """
         job = self._create_job(f, *args, **kwargs)
         job.enqueued_at = datetime.utcnow()
-        self._push(job.pickle())
-        return DelayedResult(job.rv_key)
+        self.enqueue_job(job)
+        return Job(job.id)
 
     def requeue(self, job):
         """Requeues an existing (typically a failed job) onto the queue."""

setup.py

@@ -15,7 +15,7 @@ def get_version():
     raise RuntimeError('No version info found.')
 
 def get_dependencies():
-    deps = ['redis', 'procname']
+    deps = ['redis', 'procname', 'times']
     deps += ['logbook']  # should be soft dependency?
     if sys.version_info < (2, 7) or \
        sys.version_info >= (3, 0) and sys.version_info < (3, 2):

tests/test_job.py

@@ -1,8 +1,8 @@
+from datetime import datetime
 from tests import RQTestCase
 from pickle import dumps, loads
 from rq.job import Job
-#from rq import Queue, Worker
-from rq.exceptions import UnpickleError
+from rq.exceptions import NoSuchJobError, UnpickleError
 
 
 def arbitrary_function(x, y, z=1):
@@ -10,25 +10,91 @@ def arbitrary_function(x, y, z=1):
 
 
 class TestJob(RQTestCase):
-    def test_create_job(self):
-        """Creation of jobs."""
-        job = Job(arbitrary_function, 3, 4, z=2)
+    def test_create_empty_job(self):
+        """Creation of new empty jobs."""
+        job = Job()
+
+        # Jobs have a random UUID
+        self.assertIsNotNone(job.id)
+
+        # Jobs have no data yet...
+        self.assertEquals(job.func, None)
+        self.assertEquals(job.args, None)
+        self.assertEquals(job.kwargs, None)
+        self.assertEquals(job.origin, None)
+        self.assertEquals(job.enqueued_at, None)
+        self.assertEquals(job.result, None)
+        self.assertEquals(job.exc_info, None)
+
+        # ...except for a created_at property
+        self.assertIsNotNone(job.created_at)
+
+    def test_create_normal_job(self):
+        """Creation of jobs for function calls."""
+        job = Job.for_call(arbitrary_function, 3, 4, z=2)
+
+        # Jobs have a random UUID
+        self.assertIsNotNone(job.id)
+        self.assertIsNotNone(job.created_at)
+
+        # Job data is set...
         self.assertEquals(job.func, arbitrary_function)
         self.assertEquals(job.args, (3, 4))
         self.assertEquals(job.kwargs, {'z': 2})
+
+        # ...but metadata is not
         self.assertIsNone(job.origin)
-        self.assertIsNotNone(job.created_at)
         self.assertIsNone(job.enqueued_at)
-        self.assertIsNotNone(job.rv_key)
+        self.assertIsNone(job.result)
+
+
+    def test_save(self):
+        """Storing jobs."""
+        job = Job.for_call(arbitrary_function, 3, 4, z=2)
 
-    def test_pickle_job(self):
-        """Pickling of jobs."""
-        job = Job(arbitrary_function, 3, 4, z=2)
-        job2 = loads(dumps(job))
+        # Saving creates a Redis hash
+        self.assertEquals(self.testconn.exists(job.key), False)
+        job.save()
+        self.assertEquals(self.testconn.type(job.key), 'hash')
+
+        # Saving writes pickled job data
+        unpickled_data = loads(self.testconn.hget(job.key, 'data'))
+        self.assertEquals(unpickled_data[0], arbitrary_function)
+
+    def test_fetch(self):
+        """Fetching jobs."""
+        # Prepare test
+        self.testconn.hset('rq:job:some_id', 'data', "(ctest_job\narbitrary_function\np0\n(I3\nI4\ntp1\n(dp2\nS'z'\np3\nI2\nstp4\n.")
+        self.testconn.hset('rq:job:some_id', 'created_at', "2012-02-07 22:13:24+0000")
+
+        # Fetch returns a job
+        job = Job.fetch('some_id')
+        self.assertEquals(job.id, 'some_id')
+        self.assertEquals(job.func, arbitrary_function)
+        self.assertEquals(job.args, (3, 4))
+        self.assertEquals(job.kwargs, dict(z=2))
+        self.assertEquals(job.created_at, datetime(2012, 2, 7, 22, 13, 24))
+
+
+    def test_persistence_of_jobs(self):
+        """Storing and fetching of jobs."""
+        job = Job.for_call(arbitrary_function, 3, 4, z=2)
+        job.save()
+
+        job2 = Job.fetch(job.id)
         self.assertEquals(job.func, job2.func)
         self.assertEquals(job.args, job2.args)
         self.assertEquals(job.kwargs, job2.kwargs)
 
+        # Mathematical equation
+        self.assertEquals(job, job2)
+
+    def test_fetching_can_fail(self):
+        """Fetching fails for non-existing jobs."""
+        with self.assertRaises(NoSuchJobError):
+            Job.fetch('b4a44d44-da16-4620-90a6-798e8cd72ca0')
+
+
     def test_unpickle_errors(self):
         """Handling of unpickl'ing errors."""
         with self.assertRaises(UnpickleError):
@@ -37,7 +103,7 @@ class TestJob(RQTestCase):
         with self.assertRaises(UnpickleError):
             Job.unpickle(13)
 
-        pickle_data = dumps(Job(arbitrary_function, 2, 3))
+        pickle_data = dumps(Job.for_call(arbitrary_function, 2, 3))
         corrupt_data = pickle_data.replace('arbitrary', 'b0rken')
         with self.assertRaises(UnpickleError):
             Job.unpickle(corrupt_data)

tests/test_queue.py

@@ -31,26 +31,26 @@ class TestQueue(RQTestCase):
 
     def test_queue_empty(self):
         """Detecting empty queues."""
-        q = Queue('my-queue')
+        q = Queue('example')
         self.assertEquals(q.is_empty(), True)
 
-        self.testconn.rpush('rq:queue:my-queue', 'some val')
+        self.testconn.rpush('rq:queue:example', 'sentinel message')
         self.assertEquals(q.is_empty(), False)
 
 
     def test_enqueue(self):
-        """Putting work on queues."""
-        q = Queue('my-queue')
+        """Enqueueing writes job IDs to queues."""
+        q = Queue()
         self.assertEquals(q.is_empty(), True)
 
         # testjob spec holds which queue this is sent to
-        q.enqueue(testjob, 'Nick', foo='bar')
-        self.assertEquals(q.is_empty(), False)
-        for job in q.jobs:
-            if job.func == testjob:
-                break
-        else:
-            self.fail('Job not found on queue.')
+        job = q.enqueue(testjob, 'Nick', foo='bar')
+        job_id = job.id
+
+        # Inspect data inside Redis
+        q_key = 'rq:queue:default'
+        self.assertEquals(self.testconn.llen(q_key), 1)
+        self.assertEquals(self.testconn.lrange(q_key, 0, -1)[0], job_id)
 
 
     def test_dequeue(self):

tests/test_worker.py

@@ -31,7 +31,7 @@ class TestWorker(RQTestCase):
         # NOTE: We have to fake this enqueueing for this test case.
         # What we're simulating here is a call to a function that is not
         # importable from the worker process.
-        job = Job(failing_job, 3)
+        job = Job.for_call(failing_job, 3)
         pickled_job = job.pickle()
         invalid_data = pickled_job.replace(
                 'failing_job', 'nonexisting_job')