9.2. HTTP compression
9.3. Stream Processing Offload Engine (SPOE)
+10. Cache
1. Quick reminder about HTTP
----------------------------
sc-inc-gpc0(<sc-id>) |
sc-set-gpt0(<sc-id>) <int> |
silent-drop |
- send-spoe-group
+ send-spoe-group |
+ cache-use
}
[ { if | unless } <condition> ]
Access control for Layer 7 requests
If the slot <id> doesn't exist, then HAProxy fails parsing the
configuration to prevent unexpected behavior at run time.
+ - cache-use <name> :
+ See section 10.2 about cache setup.
+
- { track-sc0 | track-sc1 | track-sc2 } <key> [table <table>] :
enables tracking of sticky counters from current request. These rules
do not stop evaluation and do not change default action. Three sets of
sc-inc-gpc0(<sc-id>) |
sc-set-gpt0(<sc-id>) <int> |
silent-drop |
- send-spoe-group
+ send-spoe-group |
+ cache-store
}
[ { if | unless } <condition> ]
Access control for Layer 7 responses
If the slot <id> doesn't exist, then HAProxy fails parsing the
configuration to prevent unexpected behavior at run time.
+ - cache-store <name> :
+ See section 10.2 about cache setup.
+
- "redirect" : this performs an HTTP redirection based on a redirect rule.
This supports a format string similarly to "http-request redirect" rules,
with the exception that only the "location" type of redirect is possible
The SPOE filter is highly experimental for now and was not heavily
tested. It is really not production ready. So use it carefully.
+10. Cache
+---------
+
+HAProxy provides a cache, which was designed to perform cache on small objects
+(favicon, css...). This is a minimalist low-maintenance cache which runs in
+RAM.
+
+The cache is based on a memory which is shared between processes and threads,
+this memory is splitted in blocks of 1k.
+
+If an object is not used anymore, it can be deleted to store a new object
+independently of its expiration date. The oldest objects are deleted first
+when we try to allocate a new one.
+
+The cache use a hash of the host header and the URI as the key.
+
+It's possible to view the status of a cache using the Unix socket command
+"show cache" consult section 9.3 "Unix Socket commands" of Management Guide
+for more details.
+
+When an object is delivered from the cache, the server name in the log is
+replaced by "<CACHE>".
+
+10.1 Limitation
+---------------
+
+The cache won't store and won't deliver objects in these cases:
+
+- If the response is not a 200
+- If the response contains a Vary header
+- If the response does not contain a Content-Length header or if the
+ Content-Length + the headers size is greater than a buffer size - the
+ reserve.
+- If the response is not cacheable
+
+- If the request is not a GET
+- If the HTTP version of the request is smaller than 1.1
+
+Caution!: Due to the current limitation of the filters, it is not recommended
+to use the cache with other filters. Using them can cause undefined behavior
+if they modify the response (compression for exemple).
+
+10.2 Setup
+----------
+
+To setup a cache, you must define a cache section and use it in a proxy with
+the corresponding http-request and response actions.
+
+10.2.1 Cache section
+--------------------
+
+cache <name>
+ Declare a cache section, allocate a shared cache memory named <name>, the
+ size of cache is mandatory.
+
+total-max-size <megabytes>
+ Define the size in RAM of the cache in megabytes. this size is splitted in
+ blocks of 1kb which are used by the cache entries.
+
+max-age <seconds>
+ Define the maximum expiration duration. The expiration is set has the lowest
+ value between the s-maxage or max-age (in this order) directive in the
+ Cache-Control response header and this value. The default value is 60
+ seconds, which means that you can't cache an object more than 60 seconds by
+ default.
+
+10.2.2 Proxy section
+--------------------
+
+http-request cache-use <name>
+ Try to deliver a cached object from the cache <name>. This directive is also
+ mandatory to store the cache as it calculates the cache hash. If you want to
+ use a condition for both storage and delivering that's a good idea to put it
+ after this one.
+
+http-response cache-store <name>
+ Store an http-response within the cache. The storage of the response headers
+ is done at this step, which means you can use others http-response actions
+ to modify headers before or after the storage of the response. This action
+ is responsible for the setup of the cache storage filter.
+
+
+Example:
+
+ backend bck1
+ mode http
+
+ http-request cache-use foobar
+ http-response cache-store foobar
+ server srv1 127.0.0.1:80
+
+ cache foobar
+ total-max-size 4
+ max-age 240
+
/*
* Local variables:
* fill-column: 79
127.0.0.2:9969 user 2
[::1]:9999 operator 2
+show cache
+ List the configurated caches and the objects stored in each cache tree.
+
+ $ echo 'show cache' | socat stdio /tmp/sock1
+ 0x7f6ac6c5b03a: foobar (shctx:0x7f6ac6c5b000, available blocks:3918)
+ 1 2 3 4
+
+ 1. pointer to the cache structure
+ 2. cache name
+ 3. pointer to the mmap area (shctx)
+ 4. number of blocks available for reuse in the shctx
+
+ 0x7f6ac6c5b4cc hash:286881868 size:39114 (39 blocks), refcount:9, expire:237
+ 1 2 3 4 5 6
+
+ 1. pointer to the cache entry
+ 2. first 32 bits of the hash
+ 3. size of the object in bytes
+ 4. number of blocks used for the object
+ 5. number of transactions using the entry
+ 6. expiration time, can be negative if already expired
+
show env [<name>]
Dump one or all environment variables known by the process. Without any
argument, all variables are dumped. With an argument, only the specified
projects / thirdparty / haproxy.git / commitdiff
