mirror of
https://git.zx2c4.com/cgit
synced 2024-11-22 00:18:41 +00:00
55 lines
1.6 KiB
Plaintext
55 lines
1.6 KiB
Plaintext
|
Cache algorithm
|
||
|
|
===============
|
||
|
|
|
||
|
|
Cgit normally returns cached pages when invoked. If there is no cache file, or
|
||
|
|
the cache file has expired, it is regenerated. Finally, the cache file is
|
||
|
|
printed on stdout.
|
||
|
|
|
||
|
|
When it is decided that a cache file needs to be regenerated, an attempt is
|
||
|
|
made to create a corresponding lockfile. If this fails, the process gives up
|
||
|
|
and uses the expired cache file instead.
|
||
|
|
|
||
|
|
When there is no cache file for a request, an attempt is made to create a
|
||
|
|
corresponding lockfile. If this fails, the process calls sched_yield(2) before
|
||
|
|
restarting the request handling.
|
||
|
|
|
||
|
|
In pseudocode:
|
||
|
|
|
||
|
|
name = generate_cache_name(request);
|
||
|
|
top:
|
||
|
|
if (!exists(name)) {
|
||
|
|
if (lock_cache(name)) {
|
||
|
|
generate_cache(request, name);
|
||
|
|
unlock_cache(name);
|
||
|
|
} else {
|
||
|
|
sched_yield();
|
||
|
|
goto top;
|
||
|
|
}
|
||
|
|
} else if (expired(name)) {
|
||
|
|
if (lock_cache(name)) {
|
||
|
|
generate_cache(request, name);
|
||
|
|
unlock_cache(name);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
print_file(name);
|
||
|
|
|
||
|
|
|
||
|
|
The following options can be set in /etc/cgitrc to control cache behaviour:
|
||
|
|
cache-root: root directory for cache files
|
||
|
|
cache-root-ttl: TTL for the repo listing page
|
||
|
|
cache-repo-ttl: TTL for any repos summary page
|
||
|
|
cache-dynamic-ttl: TTL for pages with symbolic references (not SHA1)
|
||
|
|
cache-static-ttl: TTL for pages with sha1 references
|
||
|
|
|
||
|
|
TTL is specified in minutes, -1 meaning "infinite caching".
|
||
|
|
|
||
|
|
|
||
|
|
Naming of cache files
|
||
|
|
---------------------
|
||
|
|
Repository listing: <cachedir>/index.html
|
||
|
|
Repository summary: <cachedir>/<repo>/index.html
|
||
|
|
Repository subpage: <cachedir>/<repo>/<page>/<querystring>.html
|
||
|
|
|
||
|
|
The corresponding lock files have a ".lock" suffix.
|
||
|
|
|