expire.ctl - Configuration file for article expiration
The file
pathetc/expire.ctl is the default configuration file for
expire and
expireover, which read it at start-up. It serves two
purposes: it defines how long history entries for expired or rejected articles
are remembered, and it determines how long articles stored on the server are
retained.
Normally, if all of the storage methods used by the server are self-expiring
(such as CNFS), all lines except the "/remember/" setting (described
below) are ignored. This can be changed with the
-N option to
expire or
expireover.
Blank lines and lines beginning with a number sign ("#") are ignored.
All other lines should be in one of two formats. The order of the file is
significant, and the last matching entry will be used.
The first format specifies how long to keep history entries for articles that
aren't present in the news spool. These are articles that have either already
expired, or articles which the server rejected (when
remembertrash is
set to true in
inn.conf). There should be one and only one line in this
format, which looks like:
/remember/:<days>
where <days> is a decimal number that specifies the minimum number of days
a history record for a given Message-ID is retained (from its original posting
time), regardless of whether the article is present in the spool. (History
entries for articles still present in the spool are always retained.) Setting
it to "never" means history records will be retained forever, 0
means history records for articles not present in the spool will be purged
when expiry programs run. (This is notably useful in the case you need
re-injecting articles no longer present in your news spool but considered as
duplicate, because still present in history: you'll have to set
"/remember/" to 0, run the
expire process for instance via
news.daily called with the same parameters as in crontab plus
"notdaily", and undo the change in
expire.ctl. All previously
rejected or removed articles will then not be considered as duplicate if their
Message-ID is proposed.)
The primary reason to retain a record of old articles is in case a peer offers
old articles that were previously accepted but have already expired. Without a
history record for such articles, the server would accept the article again
and readers would see duplicate articles. Articles older than a certain number
of days won't be accepted by the server at all (see
artcutoff in
inn.conf(5) and the
-c flag in
innd(8)), and this setting
should probably match that time period to ensure that the server never accepts
duplicates. As the default value for
artcutoff is 10 days, it means
that "/remember/" should be set to 11 days in order to take into
account articles whose posting date is one day into the future.
Most of the lines in this file will be in the second format, which consists of
either four or five colon-separated fields:
<pattern>:<flag>:<min>:<default>:<max>
if
groupbaseexpiry is true in
inn.conf (the default), and
otherwise:
<classnum>:<min>:<default>:<max>
All lines must be in the correct format given the current setting of
groupbaseexpiry, and therefore the two formats cannot co-exist in the
same file.
Normally, a rule matches a newsgroup through the combination of the
<pattern> and <flag> fields. <pattern> is a
uwildmat-style pattern, specifying the newsgroups to which the line is
applied. Note that the last matching entry will be used, so general patterns
(such as defaults for all groups where <pattern> is "*")
should appear at the beginning of the file before more specific settings.
The <flag> field can be used to further limit newsgroups to which the line
applies, and should be chosen from the following set:
M Only moderated groups
U Only unmoderated groups
A All groups
X Remove the article from all groups it appears in
One of "M", "U", or "A" must be specified.
"X" should be used in combination with one of the other letters, not
by itself.
An expiration policy is applied to every article in a newsgroup it matches.
There is no way to set an expiration policy for articles crossposted to groups
you don't carry that's different than other articles in the same group.
Normally, articles are not completely deleted until they expire out of every
group to which they were posted, but if an article is expired following a rule
where <flag> contains "X", it is deleted out of all newsgroups
to which it was posted immediately. (If that behaviour is wanted for all
rules, you may want to give the
-e flag to
expireoverview.)
If
groupbaseexpiry is instead set to false, there is no <pattern>
and <flag> field and the above does not apply. Instead, there is a
single <classnum> field, which is either a number matching the storage
class number specified in
storage.conf or "*" to specify a
default for all storage classes. All articles stored in a storage class will
be expired following the instructions in the line with a matching
<classnum>, and when articles are expired, they're always removed from
all groups to which they were posted.
The remaining three fields are the same in either format, and are used to
determine how long an article should be kept from its original arrival time
(unless the
-p flag is passed to
expire(8) or
expireover(8), in which case its original posting time is used). Each
field should be either a decimal number of days (fractions like 8.5 are
allowed, but remember that articles are only removed when
expire or
expireover is run, normally once a day by
news.daily) or the
word "never".
The middle field, <default>, will be used as the expiration period for
most articles. The other two fields, <min> and <max>, only come
into play if the article requests a particular expiration date with an Expires
header field. Articles with an Expires header field will be expired at the
date given in that header field, subject to the constraints that they will be
retained at least <min> days and no longer than <max> days.
If <min> is set to "never", no article matching that line will
ever be expired. If <default> is set to "never", no article
matching that line without an explicit Expires header field will ever be
expired. If <max> is set to "never", Expires header fields
will be honored no matter how far into the future they are.
One should think of the fields as a lower bound, the default, and an upper
bound. Since most articles do not have an Expires header field, the second
field is the most important and most commonly applied.
Articles that do not match any expiration rule will not be expired, but this is
considered an error and will result in a warning. There should always be a
default line (a line with a <pattern> of "*" and <flag>
of "A", or a line with a <classnum> of "*"), which
can explicitly state that articles should never expire by default if that's
the desired configuration. The default line should generally be the first line
of the file (except for "/remember/") so that other expiration rules
can override it.
It is often useful to honor the Expires header field in articles, especially
those in moderated groups. To do this, set <min> to zero,
<default> to whatever normal expiration you wish, and <max> to
"never" or some large number, like 365 days for a maximum article
life of a year.
To ignore any Expires header field, set all three fields to the same value.
When
groupbaseexpiry is true (the default):
# Keep expired article history for 11 days, matching artcutoff
# plus one.
/remember/:11
# Most articles stay for two weeks, ignoring Expires header fields.
*:A:14:14:14
# Accept Expires header fields in moderated newsgroups for up to
# a year, and retain moderated newsgroups for a bit longer.
*:M:1:30:365
# Keep local newsgroups for a long time and local project
# newsgroups forever.
example.*:A:1:90:90
example.project.*:A:never:never:never
When
groupbaseexpiry is false, for class-based expiration:
# Keep expired article history for 11 days, matching artcutoff
# plus one.
/remember/:11
# Set a default expiration of seven days and honour Expires header
# fields within reasonable limits.
*:1:7:35
# Class 0 is retained for two weeks and honor Expires header fields
# within reasonable limits.
0:1:14:65
Written by Rich $alz <
[email protected]> for InterNetNews. Converted to
POD by Russ Allbery <
[email protected]>.
expire(8),
expireover(8),
inn.conf(5),
innd(8),
libinn_uwildmat(3),
news.daily(8),
storage.conf(5).