When using async mode with the webhook bridge, queued messages that are
not fully processed when the connection times out could be lost. This
commit fixes this by letting the bridge return a recoverable_error when
this happen. The message send will then be retried in sync mode by the
emqx_resource_buffer_worker.
Fixes: https://emqx.atlassian.net/browse/EMQX-8974
When some resource manager is busy with trying to estabilish a
connection with remote, we hit the "read-from-cache" codepath so the
resource data will not contain any metrics.
With this, we avoid performing work or replying to callers that are no
longer waiting on a result.
Also introduces two new counters:
- `dropped.expired` :: happens when a request expires before being
sent downstream
- `late_reply` :: when a response is receive from downstream, but the
caller is no longer for a reply because the request has expired, and
the caller might even have retried it.
Related: https://emqx.atlassian.net/browse/EMQX-8692
This should also correctly account for `retried.*` metrics for sync
requests.
Also fixes cases where race conditions for retrying async requests
could potentially lead to inconsistent metrics.
Fixes more cases where a stale reference to `replayq` was being held
accidentally after a `pop`.
In order to improve the consistency with other API endpoints, we move
the enable/disable operations to a separate endpoint
/bridges/{id}/enable/[true,false].
In order for the /bridges APIs to be consistent with other APIs, we move
out metrics from GET /bridges/{id} to its own endpoint,
/bridges/{id}/metrics. We also rename /bridges/reset_metrics to
/bridges/metrics/reset.
This fixes https://emqx.atlassian.net/browse/EMQX-8648. The issue
described in `EMQX-8648` is that when deleting a non-existing bridge the
server gives a success response. See below:
```
curl --head -u admin:public2 -X 'DELETE' 'http://localhost:18083/api/v5/bridges/webhook:i_do_not_exist'
HTTP/1.1 204 No Content
date: Tue, 03 Jan 2023 16:59:01 GMT
server: Cowboy
```
After the fix, deleting a non existing bridge will give the following
response:
```
HTTP/1.1 404 Not Found
content-length: 49
content-type: application/json
date: Thu, 05 Jan 2023 12:40:35 GMT
server: Cowboy
```
Closes: EMQX-8648
This makes the buffer/resource workers always use `replayq` for
queuing, along with collecting multiple requests in a single call.
This is done to avoid long message queues for the buffer workers and
rely on `replayq`'s capabilities of offloading to disk and detecting
overflow.
Also, this deprecates the `enable_batch` and `enable_queue` resource
creation options, as: i) queuing is now always enables; ii) batch_size
> 1 <=> batch_enabled. The corresponding metric
`dropped.queue_not_enabled` is dropped, along with `batching`. The
batching is too ephemeral, especially considering a default batch time
of 20 ms, and is not shown in the dashboard, so it was removed.
