From 6e0c7b7ff9c35ee59d30a6785a240186d0f3ac39 Mon Sep 17 00:00:00 2001 From: Jakub Narebski Date: Sun, 5 Dec 2010 21:48:49 +0100 Subject: [PATCH] gitweb/lib - Stat-based cache expiration Add stat-based cache expiration to file-based GitwebCache::SimpleFileCache. Contrary to the way other caching interfaces such as Cache::Cache and CHI do it, the time when cache element expires in is _global_ value associated with cache instance, and is not local property of cache entry. (Currently cache entry does not store any metadata associated with entry... which means that there is no need for serialization / marshalling / freezing and thawing.) Default expire time is -1, which means never expire. To check if cache entry is expired, GitwebCache::SimpleFileCache compares difference between mtime (last modify time) of a cache file and current time with (global) time to expire. It is done using CHI-compatible is_valid() method. Includes some tests checking that expiring works correctly (on the level of API) in t9503. Inspired-by-code-by: John 'Warthog9' Hawley Signed-off-by: Jakub Narebski --- gitweb/lib/GitwebCache/SimpleFileCache.pm | 40 +++++++++++++++++++++++++++++-- t/t9503/test_cache_interface.pl | 19 +++++++++++++++ 2 files changed, 57 insertions(+), 2 deletions(-) diff --git a/gitweb/lib/GitwebCache/SimpleFileCache.pm b/gitweb/lib/GitwebCache/SimpleFileCache.pm index 2f26a6cf56..790383d2cd 100644 --- a/gitweb/lib/GitwebCache/SimpleFileCache.pm +++ b/gitweb/lib/GitwebCache/SimpleFileCache.pm @@ -57,6 +57,10 @@ our $DEFAULT_NAMESPACE = ''; # The number of subdirectories deep to cache object item. This should be # large enough that no cache directory has more than a few hundred objects. # Defaults to $DEFAULT_CACHE_DEPTH unless explicitly set. +# * 'default_expires_in' (Cache::Cache compatibile), +# 'expires_in' (CHI compatibile) [seconds] +# The expiration time for objects place in the cache. +# Defaults to -1 (never expire) if not explicitly set. sub new { my $class = shift; my %opts = ref $_[0] ? %{ $_[0] } : @_; @@ -64,7 +68,7 @@ sub new { my $self = {}; $self = bless($self, $class); - my ($root, $depth, $ns); + my ($root, $depth, $ns, $expires_in); if (%opts) { $root = $opts{'cache_root'} || @@ -73,14 +77,19 @@ sub new { $opts{'cache_depth'} || $opts{'depth'}; $ns = $opts{'namespace'}; + $expires_in = + $opts{'default_expires_in'} || + $opts{'expires_in'}; } $root = $DEFAULT_CACHE_ROOT unless defined($root); $depth = $DEFAULT_CACHE_DEPTH unless defined($depth); $ns = $DEFAULT_NAMESPACE unless defined($ns); + $expires_in = -1 unless defined($expires_in); # <0 means never $self->set_root($root); $self->set_depth($depth); $self->set_namespace($ns); + $self->set_expires_in($expires_in); return $self; } @@ -92,7 +101,7 @@ sub new { # http://perldesignpatterns.com/perldesignpatterns.html#AccessorPattern # creates get_depth() and set_depth($depth) etc. methods -foreach my $i (qw(depth root namespace)) { +foreach my $i (qw(depth root namespace expires_in)) { my $field = $i; no strict 'refs'; *{"get_$field"} = sub { @@ -287,6 +296,31 @@ sub remove { or die "Couldn't remove file '$file': $!"; } +# $cache->is_valid($key) +# +# Returns a boolean indicating whether $key exists in the cache +# and has not expired (global per-cache 'expires_in'). +sub is_valid { + my ($self, $key) = @_; + + my $path = $self->path_to_key($key); + + # does file exists in cache? + return 0 unless -f $path; + # get its modification time + my $mtime = (stat(_))[9] # _ to reuse stat structure used in -f test + or die "Couldn't stat file '$path': $!"; + + # expire time can be set to never + my $expires_in = $self->get_expires_in(); + return 1 unless (defined $expires_in && $expires_in >= 0); + + # is file expired? + my $now = time(); + + return (($now - $mtime) < $expires_in); +} + # Getting and setting # $cache->set($key, $data); @@ -310,6 +344,8 @@ sub set { sub get { my ($self, $key) = @_; + return unless $self->is_valid($key); + return $self->fetch($key);; } diff --git a/t/t9503/test_cache_interface.pl b/t/t9503/test_cache_interface.pl index 1a3f37404b..1517fb6466 100755 --- a/t/t9503/test_cache_interface.pl +++ b/t/t9503/test_cache_interface.pl @@ -82,4 +82,23 @@ subtest 'CHI interface' => sub { done_testing(); }; +# Test cache expiration +# +subtest 'cache expiration' => sub { + $cache->set_expires_in(60*60*24); # set expire time to 1 day + cmp_ok($cache->get_expires_in(), '>', 0, '"expires in" is greater than 0'); + is($cache->get($key), $value, 'get returns cached value (not expired in 1d)'); + + $cache->set_expires_in(-1); # set expire time to never expire + is($cache->get_expires_in(), -1, '"expires in" is set to never (-1)'); + is($cache->get($key), $value, 'get returns cached value (not expired)'); + + $cache->set_expires_in(0); + is($cache->get_expires_in(), 0, '"expires in" is set to now (0)'); + $cache->set($key, $value); + ok(!defined($cache->get($key)), 'cache is expired'); + + done_testing(); +}; + done_testing(); -- 2.11.4.GIT