Request distributor

Broadcasts requests to multiple Varnish caches from a single entry point. The initial thought is to ease-up purging/banning across multiple Varnish cache instances. The broadcaster consists out of a web-server which will handle the distribution of requests against all configured caches.

Installation

go get -u github.com/mariusmagureanu/broadcaster

Usage

See this file as an example on how to configure your caches.

Start the app with any of the following command line args:

port: The port under which the broadcaster is exposed. Defaults to 8088.
goroutines: Sets the number of available goroutines which will handle the broadcast against the caches. Defaults to a number of 8, a higher number does not necesarilly imply a better performance. Can be tweaked though depending on the number of caches.
cfg: Path to an .ini file containing configured caches. This is a required parameter.
retries: Number of items to retry if a request fails to execute. Defaults to 1.
enforce: If true, the response code will be set according to the first non-200 received from the Varnish nodes.
log-file: Path to a log file. If none specified it defaults to stdout.
enable-log: Switches logging on/off. Disabled by default.

HTTPS support.

By default, the broadcaster starts listening on the http port, however - if both crt and key options are set, it will automatically switch onto https.

https-port: Broadcaster https listening port. If none specified it defaults to 8443.
crt: CRT file used for HTTPS support.
key: KEY file used for HTTPS support.

Optional headers.

X-Group: Name of the group to broadcast against, if not used - the broadcast will be done against all caches.

Configuration reload.

If the broadcaster receives a SIGHUP notification, it will trigger a configuration reload from disk.

Examples:

Purge /something/to/purge in all caches within the [default] group:

curl -is http://localhost:8088/something/to/purge -H "X-Group: default"  -X PURGE

Ban /foo in all caches within the [prod] group:

curl -is http://localhost:8088/foo -H "X-Group: prod"  -X BAN

Purge everything in all your caches:

curl -is http://localhost:8088/ -X PURGE

Purge everything in all your caches over https:

curl -is https://localhost:8443/ -X PURGE --cacert server.crt

Output sample:

HTTP/1.1 200 OK
Content-Type: application/json
Date: Tue, 06 Dec 2016 11:03:07 GMT
Content-Length: 164

{
  "Cache11": 200,
  "Cache12": 200,
  "Cache13": 501
}

Note that your VCL needs to be aware of your purging/banning intentions. See here for more cache invalidation details.