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Flume >> mail # user >> Why does a Flume source need to recognize the format of the message?

Praveen Sripati 2013-10-22, 17:59
Jarek Jarcec Cecho 2013-10-22, 18:07
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Re: Why does a Flume source need to recognize the format of the message?
At a minimum it needs to know how to split incoming data into individual
events. Typically a newline is used as the separator.

 Avro & thrift are special purpose sources/sinks which handle headers and
body. Avro, Thrift & HTTP sources will parse the incoming data into header
+ body. AFAIKT most other sources treat the whole thing as a body. They
should not need any more info other than line/event delimiter.

You can write custom deserializer which is supported by some sources to
parse custom incoming data format.


On Tue, Oct 22, 2013 at 11:07 AM, Jarek Jarcec Cecho <[EMAIL PROTECTED]>wrote:

> Hi Praveen,
> I think that there is a confusion between message and payload. Whereas
> Flume do not need to understand the payload structure, it do need to
> understand the message to understand what events (what payloads) are there
> with what headers. To put it differently, Flume do not need to understand
> structure of the data that you are sending (payload is just a byte array
> for Flume), but that unknown structure needs to be transferred via known
> protocol (such as AVRO RPC).
> Jarcec
> On Tue, Oct 22, 2013 at 06:59:17PM +0100, Praveen Sripati wrote:
> > According to the Flume documentation
> >
> > >>    A Flume source consumes events delivered to it by an external
> source
> > like a web server. The external source sends events to Flume in a format
> > that is recognized by the target Flume source. For example, an Avro Flume
> > source can be used to receive Avro events from Avro clients or other
> Flume
> > agents in the flow that send events from an Avro sink.
> >
> > Why does a Flume source need to recognize or understand the format of the
> > message? While all it does it does is to forward the message to one of
> the
> > channel.
> >
> > Thanks,
> > Praveen

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