Caddy Module: http.handlers.cache

This is a distributed HTTP cache module for Caddy based on Souin cache.

Warning

Since v1.7.0 Souin (the development repository that cache-handler is based on) implements only one storage. If you need a specific storage you have to take it from the storages repository and add it either in your code, during the build otherwise.
(e.g. with otter using caddy) You have to build your caddy module with the desired storage xcaddy build --with github.com/caddyserver/cache-handler --with github.com/darkweak/storages/otter/caddy and configure otter in your Caddyfile/JSON configuration file.
See the documentation about the storages.

Features

• RFC 7234 compliant HTTP Cache.
• Sets the Cache-Status HTTP Response Header
• REST API to purge the cache and list stored resources.
• ESI tags processing (using the go-esi package).
• Builtin support for distributed cache.

Minimal Configuration

Using the minimal configuration the responses will be cached for 120s

{
cache
}
example.com {
 cache reverse_proxy your-app:8080
}

Global Option Syntax

Here are all the available options for the global options

{
 log {
level debug
}
cache {
allowed_http_verbs GET POST PATCH
api {
basepath /some-basepath
prometheus
souin {
basepath /souin-changed-endpoint-path
}
}
badger {
path the_path_to_a_file.json
}
cache_keys {
.*\.css {
disable_body
disable_host
disable_method
disable_query
headers X-Token Authorization
hide
}
}
cache_name Another
cdn {
api_key XXXX
dynamic
 email darkweak@protonmail.com
hostname domain.com
network your_network
provider fastly
strategy soft
service_id 123456_id
zone_id anywhere_zone
}
etcd {
configuration {
 # Your etcd configuration here
}
}
key {
disable_body
disable_host
disable_method
headers Content-Type Authorization
}
 log_level debug
mode bypass
nuts {
path /path/to/the/storage
}
olric {
url url_to_your_cluster:3320
path the_path_to_a_file.yaml
configuration {
 # Your olric configuration here
}
}
regex {
exclude /test2.*
}
stale 200s
ttl 1000s
default_cache_control no-store
}
}
:4443respond"Hello World!"

Cache directive Syntax

Here are all the available options for the directive options

@match path /path
handle @match {
cache {
cache_name ChangeName
cache_keys {
(host1|host2).*\.css {
disable_body
disable_host
disable_method
disable_query
headers X-Token Authorization
}
}
cdn {
api_key XXXX
dynamic
email darkweak@protonmail.com
hostname domain.com
network your_network
provider fastly
strategy soft
service_id 123456_id
zone_id anywhere_zone
}
key {
disable_body
disable_host
disable_method
disable_query
headers Content-Type Authorization
}
log_level debug
regex {
exclude /test2.*
}
stale 200s
ttl 1000s
default_cache_control no-store
}
}

Provider Syntax

Badger

The badger provider must have either the path or the configuration directive.

badger-path.com {
cache {
badger {
path /tmp/badger/first-match
}
}
}

badger-configuration.com {
cache {
badger {
configuration {
# Required value
ValueDir <string>
# Optional
SyncWrites <bool>
NumVersionsToKeep <int>
ReadOnly <bool>
Compression <int>
InMemory <bool>
MetricsEnabled <bool>
MemTableSize <int>
BaseTableSize <int>
BaseLevelSize <int>
LevelSizeMultiplier <int>
TableSizeMultiplier <int>
MaxLevels <int>
VLogPercentile <float>
ValueThreshold <int>
NumMemtables <int>
BlockSize <int>
BloomFalsePositive <float>
BlockCacheSize <int>
IndexCacheSize <int>
NumLevelZeroTables <int>
NumLevelZeroTablesStall <int>
ValueLogFileSize <int>
ValueLogMaxEntries <int>
NumCompactors <int>
CompactL0OnClose <bool>
LmaxCompaction <bool>
ZSTDCompressionLevel <int>
VerifyValueChecksum <bool>
EncryptionKey <string>
EncryptionKeyRotationDuration <Duration>
BypassLockGuard <bool>
ChecksumVerificationMode <int>
DetectConflicts <bool>
NamespaceOffset <int>
}
}
}
}

Etcd

The etcd provider must have the configuration directive.

etcd-configuration.com {
cache {
etcd {
configuration {
Endpoints etcd1:2379 etcd2:2379 etcd3:2379
AutoSyncInterval 1s
DialTimeout 1s
DialKeepAliveTime 1s
DialKeepAliveTimeout 1s
MaxCallSendMsgSize 10000000
MaxCallRecvMsgSize 10000000
Username john
Password doe
RejectOldCluster false
PermitWithoutStream false
}
}
}
}

NutsDB

The nutsdb provider must have either the path or the configuration directive.

nuts-path.com {
cache {
nuts {
path /tmp/nuts-path
}
}
}

nuts-configuration.com {
cache {
nuts {
configuration {
Dir /tmp/nuts-configuration
EntryIdxMode 1
RWMode 0
SegmentSize 1024
NodeNum 42
SyncEnable true
StartFileLoadingMode 1
}
}
}
}

Olric

The olric provider must have either the url directive to work as client mode.

olric-url.com {
cache {
olric {
url olric:3320
}
}
}

The olric provider must have either the path or the configuration directive to work as embedded mode.

olric-path.com {
cache {
olric {
path /path/to/olricd.yml
}
}
}

olric-configuration.com {
cache {
nuts {
configuration {
Dir /tmp/nuts-configuration
EntryIdxMode 1
RWMode 0
SegmentSize 1024
NodeNum 42
SyncEnable true
StartFileLoadingMode 1
}
}
}
}

Redis

The redis provider must have either the URL or the configuration directive.

redis-url.com {
cache {
redis {
url 127.0.0.1:6379
}
}
}

You can also use the configuration. Refer to the Souin docs or rueidis client options to define your config as key value.

What does these directives mean?

Key	Description	Value example
allowed_http_verbs	The HTTP verbs allowed to be cached	GET POST PATCH (default: GET HEAD)
api	The cache-handler API cache management
api.basepath	BasePath for all APIs to avoid conflicts	/your-non-conflict-route (default: /souin-api)
api.prometheus	Enable the Prometheus metrics
api.souin.basepath	Souin API basepath	/another-souin-api-route (default: /souin)
badger	Configure the Badger cache storage
badger.path	Configure Badger with a file	/anywhere/badger_configuration.json
badger.configuration	Configure Badger directly in the Caddyfile or your JSON caddy configuration	See the Badger configuration for the options
cache_name	Override the cache name to use in the Cache-Status response header	AnotherCaddyCache-HandlerSouin
cache_keys	Define the key generation rules for each URI matching the key regexp
cache_keys.{your regexp}	Regexp that the URI should match to override the key generation	.+\.css
cache_keys.{your regexp}	Regexp that the URI should match to override the key generation	.+\.css
cache_keys.{your regexp}.disable_body	Disable the body part in the key matching the regexp (GraphQL context)	true (default: false)
cache_keys.{your regexp}.disable_host	Disable the host part in the key matching the regexp	true (default: false)
cache_keys.{your regexp}.disable_method	Disable the method part in the key matching the regexp	true (default: false)
cache_keys.{your regexp}.disable_query	Disable the query string part in the key matching the regexp	true (default: false)
cache_keys.{your regexp}.headers	Add headers to the key matching the regexp	Authorization Content-Type X-Additional-Header
cache_keys.{your regexp}.hide	Prevent the key from being exposed in the Cache-Status HTTP response header	true (default: false)
cdn	The CDN management, if you use any cdn to proxy your requests Souin will handle that
cdn.provider	The provider placed before Souin	akamai fastly souin
cdn.api_key	The api key used to access to the provider	XXXX
cdn.dynamic	Enable the dynamic keys returned by your backend application	(default: true)
cdn.email	The api key used to access to the provider if required, depending the provider	XXXX
cdn.hostname	The hostname if required, depending the provider	domain.com
cdn.network	The network if required, depending the provider	your_network
cdn.strategy	The strategy to use to purge the cdn cache, soft will keep the content as a stale resource	hard (default: soft)
cdn.service_id	The service id if required, depending the provider	123456_id
cdn.zone_id	The zone id if required, depending the provider	anywhere_zone
default_cache_control	Set the default value of Cache-Control response header if not set by upstream (Souin treats empty Cache-Control as public if omitted)	no-store
key	Override the key generation with the ability to disable unecessary parts
key.disable_body	Disable the body part in the key (GraphQL context)	true (default: false)
key.disable_host	Disable the host part in the key	true (default: false)
key.disable_method	Disable the method part in the key	true (default: false)
key.disable_query	Disable the query string part in the key	true (default: false)
key.disable_scheme	Disable the scheme string part in the key	true (default: false)
key.hash	Hash the key before store it in the storage to get smaller keys	true (default: false)
key.headers	Add headers to the key matching the regexp	Authorization Content-Type X-Additional-Header
key.hide	Prevent the key from being exposed in the Cache-Status HTTP response header	true (default: false)
key.template	Use caddy templates to create the key (when this option is enabled, disable_* directives are skipped)	KEY-{http.request.uri.path}-{http.request.uri.query}
max_cacheable_body_bytes	Set the maximum size (in bytes) for a response body to be cached (unlimited if omited)	1048576 (1MB)
mode	Bypass the RFC respect	One of bypassbypass_requestbypass_responsestrict (default strict)
nuts	Configure the Nuts cache storage
nuts.path	Set the Nuts file path storage	/anywhere/nuts/storage
nuts.configuration	Configure Nuts directly in the Caddyfile or your JSON caddy configuration	See the Nuts configuration for the options
etcd	Configure the Etcd cache storage
etcd.configuration	Configure Etcd directly in the Caddyfile or your JSON caddy configuration	See the Etcd configuration for the options
olric	Configure the Olric cache storage
olric.path	Configure Olric with a file	/anywhere/olric_configuration.json
olric.configuration	Configure Olric directly in the Caddyfile or your JSON caddy configuration	See the Olric configuration for the options
otter	Configure the Otter cache storage
otter.configuration	Configure Otter directly in the Caddyfile or your JSON caddy configuration
otter.configuration.size	Set the size of the pool in Otter	999999 (default 10000)
redis	Configure the Redis cache storage
redis.url	Set the Redis url storage	localhost:6379
redis.configuration	Configure Redis directly in the Caddyfile or your JSON caddy configuration	See the Nuts configuration for the options
regex.exclude	The regex used to prevent paths being cached	^[A-z]+.*$
stale	The stale duration	25m
storers	Storers chain to fallback if a previous one is unreachable or don't have the resource	otter nuts badger redis
timeout	The timeout configuration
timeout.backend	The timeout duration to consider the backend as unreachable	10s
timeout.cache	The timeout duration to consider the cache provider as unreachable	10ms
ttl	The TTL duration	120s
log_level	The log level	One of DEBUG, INFO, WARN, ERROR, DPANIC, PANIC, FATAL it's case insensitive

Other resources

You can find an example for the Caddyfile or the JSON file.
See the Souin configuration for the full configuration, and its associated Caddyfile

Development and Stable Versions

The Souin repository serves as the development version, where new features are introduced and tested. Once these features have been thoroughly stabilized, they are integrated into the cache-handler repository through a dependency update. This ensures that cache-handler remains the stable and reliable version for production use.