This commit implements a kumomta-specific message transfer
protocol that is intended to be used to migrate messages
from one kumomta node to another.
The transfer is carried out using an HTTP POST request
to the destination node's http listener.
The request includes the full message metadata and body,
in a compressed form.
An xfer request can be made via `kcli xfer` (and thus also via an HTTP API
endpoint). It works similarly to a rebind operation; you specify the
criteria to be used to match scheduled queues, along with the target
node for the xfer, and kumomta will find matching queues, drain out the
messages, make an adjustment to the metadata to capture current
scheduling information, and then place the messages into an xfer queue.
The xfer queue has hard-coded scheduling queue configuration of its own,
with the base retry interval set to 10 seconds, which should be suitably
aggressive for the intended use case.
You may apply shaping to affect the number of concurrent requests in a
similar way to how TSA shaping is configured.
On the receiving side, the incoming xfer sanity check to prohibit
trying to xfer to itself.
The spool id of the Message is not suitable to be reused verbatim on
another node (spool ids include the local mac address and creation
timestamp information, as well as a random component), so the receiving
side will derive an id that should be suitable for use on that node.
The originating node id and spool id will be preserved in metadata to
aid in tracing.
It is possible for an xfer request to target an existing xfer queue, so
that you can correct/update the target in various circumstances. In that
situation the messages will be "simply" moved from the source queue to
the destination queue.
It is possible to cancel an xfer request via `kcli xfer-cancel` (and
thus also via an HTTP API endpoint). You specify the target queue,
which must be an xfer queue, and it will have its messages drained and
the metadata changes that were applied when the xfer was initiated will
be reversed, allowing the messages to then be reinserted into their
originating queue.
refs: https://github.com/KumoCorp/kumomta/issues/311
We've been hoping that mkdocs-material will ship the much anticipated
search enhancements for some time, but it's time to recognize that
we need to do something to improve the search results with how
things work right now.
This is a big commit that changes the titles of the various pages
from the code-annotated synopsis to just the name of the function.
This makes it much easier now to match things like `kumo.reject`
directly, but `reject` remains awkward to find.
I think this is the best that we can do at this time.
A few functions have been annotated with the `status: deprecated` to
show as deprecated in the toc/nav (shows with a little trash can next
to the name).
It is now possible to trace outbound SMTP sessions, filtering
by a variety of properties.
Details are in `kcli trace-smtp-client --help` and also in
the docs at /reference/kcli/trace-smtp-client.md
refs: #87
Wez Furlong