Re: Pasword expiration warning

Sorry, I haven't been following the discussion, but I took a brief look at
the latest patch in the thread.

+ Controls how much time (in seconds) before a role's password expiration
+ a <literal>WARNING</literal> message is sent to the client upon successful
+ connection. It requires that a <command>VALID UNTIL</command> date is set
+ for the role. A value of <literal>0d</literal> disable this behavior. The
+ default value is <literal>7d</literal> and the maximum value <literal>30d</literal>.

I'm not sure we should subject folks to these warnings by default, and I
don't see a reason to restrict the maximum value to 30 days. IMHO we
should have this disabled by default and the maximum value should be
INT_MAX.

+ if (password_expire_warning > 0 && vuntil < PG_INT64_MAX)
+ {
+ TimestampTz result = (vuntil - now) / USECS_PER_SEC; /* in seconds */
+
+ if (result <= (TimestampTz) password_expire_warning)
+ {
+ MyClientConnectionInfo.warning_message =
+ psprintf(_("your password will expire in %d day(s)"),
+ (int) (result / SECS_PER_DAY));
+ }
+ }

nitpick: I suspect we could simplify this code a bit, but I haven't tried.

Also, IMO we should be more precise about the expiration time. There is a
reasonable difference between a password expiring in 1 second as opposed to
23 hours, 59 minutes, 59 seconds, but in both cases this message would say
"0 days". You might be able to borrow from psql/common.c's PrintTiming()
function to add more detail here.

+ /*
+ * Emit a warning message to the client when set, for example
+ * to warn the user that the password will expire.
+ */
+ if (MyClientConnectionInfo.warning_message)
+ ereport(WARNING, (errmsg("%s", MyClientConnectionInfo.warning_message)));

Having a variable for warning messages could come in handy later. For
example, we might add a warning about using MD5 passwords at some point.
In my draft patch for this [0], I put the warning after closing the
transaction, whereas this patch puts it just before. I'm not sure I had a
principled reason for doing so, but it's an interesting difference between
the two patches.

[0] https://postgr.es/m/attachment/177167/v2-0002-WIP-add-warning-upon-authentication-with-MD5-pass.patch

--
nathan