There are a few context.WithDeadline calls that can be simplified by
using context.WithTimeout.
At the time they were added, WithTimeout was too new so we didn't want
to depend on it. But now that the minimum Go version has been raised to
1.9, we can simplify the calls.
This patch does that simplification, which is purely mechanical, and
does not change the logic itself.
This patch adds a missing docstrings for exported identifiers, and
adjust some of the existing ones to match the standard style.
In some cases, the identifiers were un-exported after noticing they had
no external users.
Besides improving documentation, it also reduces the linter noise
significantly.
The current default is "procmail" for historical reasons, but the
program has been unmaintained for years and its use is not generally
advisable.
This patch changes the default MDA binary to "maildrop", which is a more
modern and reasonable MDA to use.
We keep the courier.Procmail name for now, as that's internal, but it
may be changed later. Its documentation is updated to note that the
name is just for reference but it actually works with almost any binary.
This patch reviews various debug and informational messages, making more
uniform use of tracing, and extends the monitoring http server with
useful information like an index and a queue dump.
This patch performs some minor cleanups for things detected by "go vet":
- Remove one line of unreachable code.
- Don't leak contexts until their deadline expires, cancel them.
This patch makes the queue and couriers distinguish between permanent and
transient errors when delivering mail to individual recipients.
Pipe delivery errors are always permanent.
Procmail delivery errors are almost always permanent, except if the command
exited with code 75, which is an indication of transient.
SMTP delivery errors are almost always transient, except if the DNS resolution
for the domain failed.
This patch tidies up the Procmail courier:
- Move the configuration options to the courier instance, instead of using
global variables.
- Implement more useful string replacement options.
- Use exec.CommandContext for running the command with a timeout.
As a consequence of the first item, the queue now takes the couriers via its
constructor.
This patch does various minor style and simplification cleanups, fixing things
detected by tools such as go vet, gofmt -s, and golint.
There are no functional changes, this change is purely cosmetic, but will
enable us to run those tools more regularly now that their output is clean.
This patch introduces an "envelope" package which, for now, provides simple
utilities for getting the user and domain of an address.
It also changes the couriers to use it (but other implementations remain, will
be moved over in subsequent patches).
This patch adds configuration options for the MDA binary and command line
arguments, and changes the (soon to be renamed) procmail courier to make use
of them.
Sanitize only lets some ascii characters go through, which is very unfriendly
to non-ascii usernames.
This patch changes it to be more inclusive, and filter out only selected
characters that may be problematic for the subprocesses, specially considering
UNIX shell environments. It's not meant to catch all possible problems, just
help prevent some common ones.
This patch introduces the couriers, which the queue uses to deliver mail.
We have a local courier (using procmail), a remote courier (uses SMTP), and a
router courier that decides which of the two to use based on a list of local
domains.
There are still a few things pending, but they all have their basic
functionality working and tested.
