kratos

Kratos middleware: Souin

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

Features

• RFC 7234 compliant HTTP Cache.
• Sets the Cache-Status HTTP Response Header
• REST API to purge the cache and list stored resources.
• Builtin support for distributed cache.
• Tag-based invalidation.

Example

There is the example about the Souin initialization.

import (
	httpcache "github.com/darkweak/souin/plugins/kratos"
	kratos_http "github.com/go-kratos/kratos/v2/transport/http"
)

func main() {
	kratos_http.NewServer(
		kratos_http.Filter(
			httpcache.NewHTTPCacheFilter(httpcache.DevDefaultConfiguration),
		),
	)
}

With that your application will be able to cache the responses if possible and returns at least the Cache-Status HTTP header with the different directives mentionned in the RFC specification.
You have to pass a Kratos Configuration structure into the New method (you can use the DefaultConfiguration variable to have a built-in production ready configuration).
See the full detailled configuration names here.

You can also use the configuration file to configuration the HTTP cache. Refer to the code block below:

server: #...
data: #...
# HTTP cache part
httpcache:
  api:
    souin: {}
  default_cache:
    regex:
      exclude: /excluded
    ttl: 5s
  log_level: debug

After that you have to edit your server instanciation to use the HTTP cache configuration parser

import (
	httpcache "github.com/darkweak/souin/plugins/kratos"
	kratos_http "github.com/go-kratos/kratos/v2/transport/http"
)

func main() {
  c := config.New(
		config.WithSource(file.NewSource("examples/configuration.yml")),
		config.WithDecoder(func(kv *config.KeyValue, v map[string]interface{}) error {
			return yaml.Unmarshal(kv.Value, v)
		}),
	)
	if err := c.Load(); err != nil {
		panic(err)
	}

	server := kratos_http.NewServer(
		kratos_http.Filter(
			httpcache.NewHTTPCacheFilter(httpcache.ParseConfiguration(c)),
		),
	)
  // ...
}

Other resources

You can find an example for a docker-compose stack inside the examples folder.
See the Souin configuration for the full configuration, and its associated development kratos middleware