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Dispatchers and receivers

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cihub edited this page Dec 13, 2011 · 29 revisions

The concept

Receivers

We use 'receivers' term for back-end byte receivers, like log files, network channels, etc.

Dispatchers

We use 'dispatchers' term for intermediate elements which send messages to multiple underlying receivers/dispatchers.

Example

This is a simple example that visualizes these two concepts. Here dispatchers are green and receivers are white. Note the 'filter' dispatcher: it sends only 'critical' messages to its underlying elements.

Dispatchers and receivers example

The main goal of creating such configurations is to create different groups with common format options or allowed log levels. For example, let's create an example config for the diagram above:

<sealog>
    <outputs>
        <splitter formatid="common">
            <console/>
            <file path="file.log"/>
            <network address="192.168.0.2" port="8123"/>
        </splitter>
        <filter levels="critical">
            <file path="critical.log" formatid="critical"/>
            <smtp credentialsfile="smtp.cred" address="��admin@cin.io" formatid="criticalemail"/>
        </filter>
    </outputs>
    <formats>
        <format id="common" format="[%LVL] %Msg"/>
        <format id="critical" format="%Time %Date %RelFile %Func %Msg"/>
        <format id="criticalemail" format="Critical error on our server!\n    %Time %Date %RelFile %Func %Msg \nSent by Sealog"/>
    </formats>
</sealog>

So, here we use a 'splitter' element to group three receivers by format ('common') and other two receivers are grouped by allowed log level using a 'filter'. Note that top element 'outputs' is a splitter itself, so we could simplify the config:

<sealog>
    <outputs formatid="common">
        <console/>
        <file path="file.log"/>
        <network address="192.168.0.2" port="8123"/>
        <filter levels="critical">
            <file path="critical.log" formatid="critical"/>
            <smtp credentialsfile="smtp.cred" address="��admin@cin.io" formatid="criticalemail"/>
        </filter>
    </outputs>
    <formats>
        <format id="common" format="[%LVL] %Msg"/>
        <format id="critical" format="%Time %Date %RelFile %Func %Msg"/>
        <format id="criticalemail" format="Critical error on our server!\n    %Time %Date %RelFile %Func %Msg \nSent by Sealog"/>
    </formats>
</sealog>

This config would practically do the same as the config above, but it is more efficient. Dispatcher diagram for this config looks like:

Dispatcher example 2

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