omrabbitmq: RabbitMQ output module

Module Name:

omrabbitmq

Authors:

Jean-Philippe Hilaire <jean-philippe.hilaire@pmu.fr> / Philippe Duveau <philippe.duveau@free.fr> / Hamid Maadani <hamid@dexo.tech>

Purpose

This module sends syslog messages into RabbitMQ server. Only v6 configuration syntax is supported.

omrabbitmq is tested and is running in production with 8.x version of rsyslog.

Compile

To successfully compile omrabbitmq module you need rabbitmq-c library version >= 0.4.

./configure –enable-omrabbitmq …

Configuration Parameters

Action Parameters

host

type

mandatory

format

default

string

yes

hostname[:port][ hostname2[:port2]]

rabbitmq server(s). See HA configuration

port

type

mandatory

format

default

string

no

port

5672

virtual_host

type

mandatory

format

default

string

yes

path

virtual message broker

user

type

mandatory

format

default

string

yes

user

user name

password

type

mandatory

format

default

string

yes

password

user password

ssl

type

mandatory

format

default

binary

no

off

enable TLS for AMQP connection

init_openssl

type

mandatory

format

default

binary

no

off

should rabbitmq-c initialize OpenSSL? This is included to prevent crashes caused by OpenSSL double initialization. Should stay off in most cases. ONLY turn on if SSL does not work due to OpenSSL not being initialized.

verify_peer

type

mandatory

format

default

binary

no

off

SSL peer verification

verify_hostname

type

mandatory

format

default

binary

no

off

SSL certificate hostname verification

ca_cert

type

mandatory

format

default

string

no

file path

CA certificate to be used for the SSL connection

heartbeat_interval

type

mandatory

format

default

integer

no

0

AMQP heartbeat interval in seconds. 0 means disabled, which is default.

exchange

type

mandatory

format

default

string

no

name

exchange name

routing_key

type

mandatory

format

default

string

no

name

value of routing key

routing_key_template

type

mandatory

format

default

string

no

template_name

template used to compute the routing key

body_template

type

mandatory

format

default

string

no

template

StdJSONFmt

template used to compute the message body. If the template is an empty string the sent message will be %rawmsg%

delivery_mode

type

mandatory

format

default

string

no

TRANSIENT|PERSISTANT

TRANSIENT

persistence of the message in the broker

expiration

type

mandatory

format

default

string

no

milliseconds

no expiration

ttl of the amqp message

populate_properties

type

mandatory

format

default

binary

no

off

fill timestamp, appid, msgid, hostname (custom header) with message informations

content_type

type

mandatory

format

default

string

no

value

content type as a MIME value

declare_exchange

type

mandatory

format

default

binary

no

off

Rsyslog tries to declare the exchange on startup. Declaration failure (already exists with different parameters or insufficient rights) is warned but does not cancel the module instance.

recover_policy

type

mandatory

format

default

string

no

check_interval;short_failure_interval; short_failure_nb_max;graceful_interval

60;6;3;600

See HA configuration

HA configuration

The module can use two rabbitmq server in a fail-over mode. To configure this mode, the host parameter has to reference the two rabbitmq servers separated by space. Each server can be optionally completed with the port (useful when they are different). One of the servers is chosen on startup as a preferred one. The module connects to this server with a fail-over policy which can be defined through the action parameter “recover_policy”.

The module launch a back-ground thread to monitor the connection. As soon as the connection fails, the thread retries to restablish the connection and switch to the back-up server if needed to recover the service. While connected to backup server, the thread tries to reconnect to the preferred server using a “recover_policy”. This behaviour allow to load balance the client across the two rabbitmq servers on normal conditions, switch to the running server in case of failure and rebalanced on the two server as soon as the failed server is recovered without restarting clients.

The recover policy is based on 4 parameters :

  • check_interval is the base duration between connection retries (default is 60 seconds)

  • short_failure_interval is a duration under which two successive failures are considered as abnormal for the rabbitmq server (default is check_interval/10)

  • short_failure_nb_max is the number of successive short failure are detected before to apply the graceful interval (default is 3)

  • graceful_interval is a longer duration used if the rabbitmq server is unstable (default is check_interval*10).

The short failures detection is applied in case of unstable network or server and force to switch to back-up server for at least ‘graceful-interval’ avoiding heavy load on the unstable server. This can avoid dramatic scenarios in a multisites deployment.

Examples

Example 1

This is the simplest action :

  • No High Availability

  • The routing-key is constant

  • The sent message use JSON format

module(load='omrabbitmq')
action(type="omrabbitmq"
       host="localhost"
       virtual_host="/"
       user="guest"
       password="guest"
       exchange="syslog"
       routing_key="syslog.all")

Example 2

Action characteristics :

  • No High Availability

  • The routing-key is computed

  • The sent message is a raw message

module(load='omrabbitmq')
template(name="rkTpl" type="string" string="%syslogtag%.%syslogfacility-text%.%syslogpriority-text%")

action(type="omrabbitmq"
       host="localhost"
       virtual_host="/"
       user="guest"
       password="guest"
       exchange="syslog"
       routing_key_template="rkTpl"
       template_body="")

Example 3

HA action :

  • High Availability between server1:5672 and server2:1234

  • The routing-key is computed

  • The sent message is formatted using RSYSLOG_ForwardFormat standard template

module(load='omrabbitmq')
template(name="rkTpl" type="string" string="%syslogtag%.%syslogfacility-text%.%syslogpriority-text%")

action(type="omrabbitmq"
       host="server1 server2:1234"
       virtual_host="production"
       user="guest"
       password="guest"
       exchange="syslog"
       routing_key_template="rkTpl"
       template_body="RSYSLOG_ForwardFormat")

Example 4

SSL enabled connection, with Heartbeat :

  • No High Availability

  • The routing-key is constant

  • The sent message use JSON format

  • Heartbeat is set to 20 seconds

module(load='omrabbitmq')
action(type="omrabbitmq"
       host="localhost"
       virtual_host="/"
       user="guest"
       password="guest"
       ssl="on"
       verify_peer="off"
       verify_hostname="off"
       heartbeat_interval="20"
       exchange="syslog"
       routing_key="syslog.all")

See also

Help with configuring/using Rsyslog:

See also

Contributing to Rsyslog:

Copyright 2008-2023 Rainer Gerhards (Großrinderfeld), and Others.