Re: [geomesa-users] kafka streaming

[Matteo Cusmai <cusmaimatteo@xxxxxxxxx>]

Hi Emilio,

thanks for the suggestions.

I have another question about kafka, when I use the following instructions on producer side

final String sftName = "KafkaQuickStart7";
final String sftSchema = "name:String,age:Int,*geom:Point:srid=4326";
SimpleFeatureType sft = SimpleFeatureTypes.createType(sftName, sftSchema);
SimpleFeatureType streamingSFT = KafkaDataStoreHelper.createStreamingSFT(sft, zkPath);

It seems it creates a durable topic on kafka, and I cannot reuse the same sftName. There is a way to create temporary topic or reuse the same one?

Thanks a lot,

Matteo.

Matteo Cusmai

On Mon, Dec 4, 2017 at 5:15 PM, Emilio Lahr-Vivaz <elahrvivaz@xxxxxxxx> wrote:

You can register a feature event listener on a feature source, but there is no way to register a filter through the geotools API, so you'll have to check for events that interest you in your listener. The events that you will receive are outlined here:

https://github.com/locationtech/geomesa/blob/1.3.x/geomesa-kafka/geomesa-kafka-datastore/geomesa-kafka-datastore-common/src/main/scala/org/locationtech/geomesa/kafka/KafkaFeatureEvent.scala#L55-L71

You can see an example of using a listener here:

https://github.com/locationtech/geomesa/blob/1.3.x/geomesa-kafka/geomesa-kafka-datastore/geomesa-kafka-09-datastore/src/test/scala/org/locationtech/geomesa/kafka09/LiveKafkaConsumerFeatureSourceTest.scala#L146-L158

The 'TestLambdaFeatureListener' is just a helper class that accepts a lambda (closure) and executes it on events:

https://github.com/locationtech/geomesa/blob/1.3.x/geomesa-kafka/geomesa-kafka-datastore/geomesa-kafka-datastore-common/src/test/scala/org/locationtech/geomesa/kafka/TestLambdaFeatureListener.scala#L14

hope that helps,

Emilio

On 12/04/2017 10:53 AM, Matteo Cusmai wrote:

Hi Emilio,

thanks a lot for the answer.

I was wronging because I was using 1.4.0-SNAPSHOT. Now I am using 1.3.4 and I see the helper class.

By the way, I have another question: is it possible to use FeatureListener with a such of CQL Filter? I would like to subcribe to a topic by specifing a BBOX.

Thanks,

Matteo.

Matteo Cusmai

On Mon, Dec 4, 2017 at 2:48 PM, Emilio Lahr-Vivaz <elahrvivaz@xxxxxxxx> wrote:

Hello,

The KafkaDataStoreHelper is here:

https://github.com/locationtech/geomesa/blob/geomesa_2.11-1.3.5/geomesa-kafka/geomesa-kafka-datastore/geomesa-kafka-datastore-common/src/main/scala/org/locationtech/geomesa/kafka/KafkaDataStoreHelper.scala

However, this class has been removed in the current master branch (1.4.0-SNAPSHOT), so make sure you are using a 1.3.x version of GeoMesa. If you'd prefer to use the 1.4.x version, the docs for that are not yet hosted anywhere, but can be seen here:

https://github.com/locationtech/geomesa/pull/1777

To manually build the 1.4 docs, you can pull that branch and run:

mvn clean install -P docs -pl docs

that will generate the HTML files under docs/target/html/.

Thanks,

Emilio

On 12/02/2017 12:02 PM, Matteo Cusmai wrote:

Hi all,

I am trying to use kafka geomesa datastore capability, but I am not able to use code at http://www.geomesa.org/documentation/user/kafka/producers.html

I cannot resolve KafkaDataStoreHelper class. Which is the right dependency?

Thanks a lot.

Matteo Cusmai

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