This patch implements "via" aliases, which let us explicitly select a
server to use for delivery.
This feature is useful in different scenarios, such as a secondary MX
server that forwards all incoming email to a primary.
For now, it is experimental and the syntax and semantics are subject to
change.
ioutil package was deprecated in Go 1.16, replace all uses with their
respective replacements.
This patch was generated with a combination of `gofmt -r`, `eg`, and
manually (for `ioutil.ReadDir`).
We've accumulated a few linter issues around comments and a couple of
variable names.
While none of them is major, this patch cleans them up so it's easier to
go through the linter output, and we can start being more strict about
it.
This patch contains some readability improvements to testlib: it
adds/reformats some comments for exported functions for consistency, and
unexports some structs that are not used outside the library.
The testing couriers are currently only used in the queue tests, but we
also want to use them in smtpsrv tests so we can make them more robusts
by checking the emails got delivered.
This patch moves the testing couriers to testlib, and makes both queue
and smtpsrv use them.
Some tests require picking ports, and today resort to hard-coding,
which is brittle.
This patch adds a testlib.GetFreePort function to help pick free ports.
It is not totally race-free, but is much better than hard-coding.
This patch makes chasquid reload domaininfo periodically, so it notices
any external changes made to it.
It is in line with what we do for aliases and authentication already,
and makes it possible for external removals an additions to the
domaininfo database to be picked up without a restart.
We have many places in our tests where we create temporary directories,
which we later remove (most of the time). We have at least 3 helpers to
do this, and various places where it's done ad-hoc (and the cleanup is
not always present).
To try to reduce the clutter, and make the tests more uniform and
readable, this patch introduces two helpers in a new "testutil" package:
one for creating and one for removing temporary directories.
These new functions are safer, better tested, and make the tests more
consistent. All the tests are updated to use them.
