gerouter: Gerrit Event Router

Author: rinrinne
Repository: https://github.com/rinrinne/gerrit-event-router

Synopsis

gerouter is a server application for routing Gerrit events to message broker. Now only AMQP broker is supported (recommend RabbitMQ as message queue server)

Motivation

Gerrit provides events via ssh stream. Client can receive them using ssh connection. But both of them has no dedicated queue. It means that client may miss many events if ssh is disconnected.

Gerrit events are not required to be processed in real-time. So we can improve this by using asynchronous communication protocol.

This application can achieve this purpose by a combination with message queue service.

Usage

Install gem:

$ gem install gerouter

Install from repository:

$ rake build
$ bundle install

Command help:

$ bundle exec gerouter --help
Usage: gerouter [options]
    -d, --debug                      Debug mode
    -c, --config CONFIGFILE          Path to config file
    -n, --name NAME                  Name of gerrit
    -i, --appid APPID                Application ID (default: gerouter)

You should specify -c and -n options.

$ bundle exec gerouter -c gerouter.conf -n foobar

If -n is not specified, gerouter displays name list.

$ bundle exec gerouter -c gerouer.conf
---
:gerrit:
- foobar
:broker:
- foo

This application has user process and runs in foreground. If you want to run as daemon, recommend to use God. Samples are stored in here.

Note that sample is configured to use shared rbenv

Config

--- !ruby/object:GER::Gerrit::Config
name: gerrit
uri: ssh://user@localhost:29418
weburl: http://localhost/       # Frontend URL for Gerrit WebUI
ssh_keys: 
  - /home/user/.ssh/id_dsa
  - /home/user/.ssh/id_rsa
broker: amqp-broker
routing_key: gerrit.event.localhost

--- !ruby/object:GER::Broker::AMQP::Config
name: amqp-broker
uri: amqp://localhost   # amqp / amqps
mode:                   # raw / normal (same as empty)
exchange:
  type: topic           # direct / fanout /topic
  name: gerrit.event

The above is also stored in here.

YAML format with object information
gerrit and broker items
You can add any number of them
broker in gerrit has the broker name
gerrits can share one broker

Additional properties

gerouter adds some properties into each messages.

content_type: application/json
app_id: gerouter

You can change app_id to your own id using -i option.

And, headersproperty is added as below.

{
  "headers": {
    "gerrit-name":"<gerrit name in config>",
    "gerrit-host":"<gerrit host>",
    "gerrit-port":"<gerrit port>",
    "gerrit-scheme":"ssh",
    "gerrit-front-url":"<gerrit frontend url>",
    "gerrit-version":"<gerrit version>",
    "event_id":"<SHA256 message digest (generated from origin event)>"
  }
}

Additional attribute in Gerrit event

As below, gerouter adds provider attribute into Gerrit event then send to broker.

{
  "provider": {
    "name":"<gerrit name in config>",
    "host":"<gerrit host>",
    "port":"<gerrit port>",
    "scheme":"ssh",
    "url":"<gerrit frontend url>",
    "version":"<gerrit version>",
    "event_id":"<SHA256 message digest (generated from origin event)>"
  }
}

If you want to treat raw Gerrit event, you should set "raw" to mode in broker config.

Notice

This application generates only exchange on message queue service. No any queues/bindings are generated. It should be consumer's responsible.

Material

License

MIT License