Introduction

The Super Fast Purger(SFP) API acts as the middle agent between your call and all the Varnish Servers that are part of one group. The Vac enables groups to be created and managed, both through an API and a UI.

The workflow of the SuperFast Purger starts with a client issuing a HTTP request containing both the group name and the purge expression. The SFP receives the request, and validates the group name. Once validated and after all the Varnish endpoints are identified, a purge request is constructed and sent out to the Varnish servers.

The Super Fast Purger API is separate from the VAC API for the purpose of high performance purging. It listens on a separate port (8088 by default,can be changed using the jdi_listening_port parameter).

Features

Flexible and High Performance - Leverages the speed and flexibility of Varnish Cache.
It uses the same syntax as Varnish Cache.
Security - HMAC hashing neither password or secret passed over the connection.
Fast - We’ve measured more than 60000 req/sec on a 6 core CPU machine.

Configurables

There are configurable items that are specific to the Super Fast Purger. These items are specified in /opt/vac/etc/default file. These default values aims to be high performance out of the box and is inspired from Varnish Cache.

Name	Description	Default value
`jdi_listening_host`	The listening host for the Super Fast Purger.	`0.0.0.0`
`jdi_listening_port`	The listening port for the Super Fast Purger.	`8088`
`jdi_client_timeout`	Client socket timeout. Client being the API user.	`5000`
`jdi_cache_timeout`	Cache socket timeout. Cache refers to Varnish Cache. This can also be interpreted as worst-case response time from Varnish Cache.	`3000`
`jdi_corepool_size`	The number of threads to keep in the pool, even if they are idle.	`1000`
`jdi_maxpool_size`	The maximum number of threads to allow in the pool.	`3000`
`jdi_thread_keepalive`	When the number of thread is greater than the core, this is the maximum time that excess idle threads will wait for new tasks before terminating. The value here is in minutes.	`5`
`jdi_retries`	The number of retries the VAC PURGER will attempt.	`3`
`jdi_db_cache_ttl`	The time-to-live for objects in the db cache used only by the Super Fast Purger. Value here is in ms.	`36000000`