This low-level interface allows consuming from a queue with timeouts.
This can be used to either consume in batches (with an upper timeout),
or one-at-a-time. This is notably more performant than calling
`.get()` repeatedly (what json_drain_queue does under the hood), which
is "*highly discouraged* as it is *very inefficient*"[1].
Before this change:
```
$ ./manage.py queue_rate --count 10000 --batch
Purging queue...
Enqueue rate: 11158 / sec
Dequeue rate: 3075 / sec
```
After:
```
$ ./manage.py queue_rate --count 10000 --batch
Purging queue...
Enqueue rate: 11511 / sec
Dequeue rate: 19938 / sec
```
[1] https://www.rabbitmq.com/consumers.html#fetching
`loopworker_sleep_mock` is a file-level variable used to mock out the
sleep() call in LoopQueueProcessingWorker; don't reuse the variable
name for something else.
Despite its name, the `queue_size` method does not return the number
of items in the queue; it returns the number of items that the local
consumer has delivered but unprocessed. These are often, but not
always, the same.
RabbitMQ's queues maintain the queue of unacknowledged messages; when
a consumer connects, it sends to the consumer some number of messages
to handle, known as the "prefetch." This is a performance
optimization, to ensure the consumer code does not need to wait for a
network round-trip before having new data to consume.
The default prefetch is 0, which means that RabbitMQ immediately dumps
all outstanding messages to the consumer, which slowly processes and
acknowledges them. If a second consumer were to connect to the same
queue, they would receive no messages to process, as the first
consumer has already been allocated them. If the first consumer
disconnects or crashes, all prior events sent to it are then made
available for other consumers on the queue.
The consumer does not know the total size of the queue -- merely how
many messages it has been handed.
No change is made to the prefetch here; however, future changes may
wish to limit the prefetch, either for memory-saving, or to allow
multiple consumers to work the same queue.
Rename the method to make clear that it only contains information
about the local queue in the consumer, not the full RabbitMQ queue.
Also include the waiting message count, which is used by the
`consume()` iterator for similar purpose to the pending events list.
This styles the vertical scrollbar similar to the horizontal
one for <pre/> (which can be seen in narrow windows). Strictly
speaking, this change shouldn't go in rendered_markdown.scss, but
placing it there helps unify the two scrollbar stylings rather than
duplicating them.
Since both the original button svg's have their own individual height
and width, this commit tweaks it to values height=20 and width=16 which
works well for both buttons.
Z-index is added to the base class. This doesn't affect copy_code_button
in any way.
Attributes dropped/changed:
- background-color
- Base class on-hover property is now used.
- height, width, padding is now the base classes.
We can also remove the TODO now.
The base class will contain common styling which is used by both
copy_codeblock and copy_message buttons. This sets us up nicely
for following commit(s) which aims to unify the two button styling.
We modify access_stream_for_delete_or_update function to return
Subscription object also along with stream. This change will be
helpful in avoiding an extra query to get subscription object in
code for updating subscription role.
For streams in which only full members are allowed to post,
we block guest users from posting there.
Guests users were blocked from posting to admin only streams
already. So now, guest users can only post to
STREAM_POST_POLICY_EVERYONE streams.
This is not a new feature but a bugfix which should have
happened when implementing full member stream policy / guest users.
In addition to being generally more correct, this works around a bug
in Node.js that causes webpack-dev-server to corrupt the terminal
state when exiting as a background process.
https://github.com/nodejs/node/issues/35536
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Alex Vandiver
Anders Kaseorg
Sumanth V Rao
sahil839
Aman Agrawal