X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=chiark-utils.git;a=blobdiff_plain;f=scripts%2Fexpire-iso8601;h=76006783bbfe17f818e810cfdc9bc8a553a32c70;hp=55cdd7f457ba3f35ce74f196340f0798efced718;hb=041833cff43c78a9c588590473977632649de31b;hpb=e86eb780462cd2f1e6b60f7ab9c75d0bf8336703 diff --git a/scripts/expire-iso8601 b/scripts/expire-iso8601 index 55cdd7f..7600678 100755 --- a/scripts/expire-iso8601 +++ b/scripts/expire-iso8601 @@ -1,58 +1,108 @@ #!/bin/bash -# usage: -# expire-iso8601 -# -# [ ...] -# -# eg -# /home/ian/junk/expire-iso8601 86400 10000 1 14 7 4 -# uses units of 86400s (1 day) with a slop of 10ks; -# it keeps daily copies (that is, dated no more than 86400+10000s apart) -# for at least 1*14 days, ie the oldest will be at least 86400s*1*14-10000s -# older than the very newest -# and weekly copies (that is, dated no more than 7*86400+10000s apart) -# for at least 7*4 days, ie the oldest will be at least 86400s*7*4-10000s -# older than the very newest - set -e + usage () { + cat <] x [x ...] +options: + -u is measured in units of seconds + (default is 86400, so is in days) + -s allow kept items to be seconds shorter apart than + specified; default is 10% of + -n do not really delete + -r recursive removal (rm -r) +example: + /home/ian/junk/expire-iso8601 14x1 4x7 + uses units of 86400s (1 day) with a slop of 8640 + it keeps 14 daily items + (that is 14 items, dated no less than 86400-8640 apart) + and 4 weekly items + (that is 4 items, dated no less than 7*86400-8640 apart) + the 14 daily and 7 weekly items may be the same, or not + There is no need to sort the list of x pairs. +exit status: + 0 ok + 4 rm failed + 8 bad usage + 16 catastrophic failure +END + } -fail () { echo >&2 "$*"; exit 2; } -badusage () { fail "bad usage: $*"; } +# Copyright 2006 Ian Jackson +# +# This script and its documentation (if any) are free software; you +# can redistribute it and/or modify them under the terms of the GNU +# General Public License as published by the Free Software Foundation; +# either version 3, or (at your option) any later version. +# +# chiark-named-conf and its manpage are distributed in the hope that +# it will be useful, but WITHOUT ANY WARRANTY; without even the +# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR +# PURPOSE. See the GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License along +# with this program; if not, consult the Free Software Foundation's +# website at www.fsf.org, or the GNU Project website at www.gnu.org. + + +trap 'exit 16' 0 +badusage () { echo >&2 "bad usage: $*"; usage >&2; trap '' 0; exit 8; } #-------------------- argument parsing -------------------- -[ $# -ge 4 ] || badusage 'too few arguments' - -unit=$1 -slop=$2 -shift;shift - -[ $(($# % 2)) = 0 ] || badusage 'odd keep arguments (need min/extent pairs)' -argl="$*" - alldigits () { - [ "x${1##*[^0-9]}" = "x$1" ] || badusage "$2 must be all digits" - [ x$1 ] || badusage "$2 must be nonempty" + [ "x${2##*[^0-9]}" = "x$2" ] || \ + badusage "bad $1 \`$2'; must be all digits" + [ "$2" ] || badusage "bad $2; must be nonempty" + eval $1='$2' } -while [ $# -gt 0 ]; do - min=$1; shift; extent=$1; shift - alldigits $min min - alldigits $extent extent +rm=rm +recurse='' +unit=86400 +slop='' + +while [ $# -ge 1 ]; do + arg=$1; shift + case "$arg" in + --|-) break ;; + --help) usage; exit 0 ;; + --*) badusage "unknown option $arg" ;; + -*) + val=${arg#-?} + case "$arg" in + -n*) rm=: ;; + -r*) recurse=-r ;; + -u*) alldigits unit "$val"; arg='' ;; + -s*) alldigits slop "$val"; arg='' ;; + *) badusage "unknown option ${1:0:2}" ;; + esac + arg=-${arg#-?} + if test "x$arg" != x-; then set -- "$arg" "$@"; fi + ;; + *) set "$arg" "$@"; break ;; + esac +done + +[ $# -ge 1 ] || badusage 'too few arguments' +[ "$slop" ] || slop=$(( $unit / 10 )) + +for ni in "$@"; do + case "$ni" in *x*);; *) badusage "bad x $ni";; esac + alldigits number "${ni%%x*}" + alldigits interval "${ni#*x}" done #-------------------- scanning the directory ---------- # We build in $l a list of the relevant filenames and the time_t's -# they represent. And, while we're at it, we find the most recent -# such time_t ($ls) and its name ($ln). +# they represent. # # Each entry in $l is $time_t/$filename, and the list is # newline-separated for the benefit of sort(1). ls=0 for cn in [0-9]*; do - echo $cn case "$cn" in ????-??-??) conv="$cn";; @@ -65,104 +115,113 @@ for cn in [0-9]*; do continue;; esac cs=$(date -d "$conv" +%s) - if [ $cs -gt $ls ]; then - ls=$cs; ln=$cn - fi l="$cs/$cn $l" done -echo "newest $ln" - #-------------------- main computation -------------------- -# We go through the items from most to least recent +# We process each minimum/extent pair, to have it select a bunch of +# versions to keep. We annotate entries in $l: if we are keeping +# an entry we prepend a colon; temporarily, if we are keeping an entry +# because of this particular minimum/extent, we prepend a comma. + +# For each minimum/extent pair we look at the list from most recent +# to least recent, # ie in order of increasing age # ie in order of decreasing time_t -# We constantly maintain records of this item (c) and the last two -# (b and a). -# -# We then check to see if any of the specified minimum/extent pairs -# mean we should keep c and b. -# -# We can delete c if b is older than every specified extent. b will -# then be the latest version we keep and is old enough. (Note that if -# the density isn't satisfied, the expected number of old items may -# not be satisfied either; in the worst case, if b is very old, we -# might end up with just two items left.) -# -# If we delete c then we just go on to the next c, which will -# definitely be older, so will be deleted too (because b remains -# unchanged): ie we then delete all the rest. -# -# If we don't delete c, we look at the gap between a and c. If this -# gap is not too long (according to any of the minimum/extent pairs) -# then it is OK to delete b. (A gap is too long if it's longer than a -# relevant pair's minimum, but a pair isn't relevant if c is older -# than the extent.) If we delete b then current c becomes the new b. +# and each time we're more than min older than the last item we kept, +# we mark the item to keep, until we have as many as we want. # -# If we don't delete either then b and c become the new a and b. - -- because b is clearly sufficient to -# satisfy the -# if we delete - -# {l,a,b,c}{s,n,a} = seconds, name of a,b,c where -# c is one we're looking at now and -# b is previous one -# a is one before that -# l is last (most recent) -# where a, b, c have not been removed - -as='' -an='' -bs='' -bn='' - -remove () { - echo "expire $1 (have $2)" -} +# We build the new list (space-separated) in lnew. l=$(sort -nr <