pulsar Study Notes 1: helloworld

pulsar known is the next generation messaging system, which two years of fame , a great kill kafka of momentum, if you want to quickly experience, the stand-alone version can build a local following steps: (mac environment + jdk8)

First, download

wget https://www.apache.org/dyn/mirrors/mirrors.cgi?action=download&filename=pulsar/pulsar-2.3.2/apache-pulsar-2.3.2-bin.tar.gz

The latest version is 2.3.2　

Second, unzip

tar -zxvf apache-pulsar-2.3.2-bin.tar.gz

Third, the stand-alone mode is activated

cd apache-press-2.3.2
bin/pulsar standalone

Fourth, the test messaging

pulsar own client tools, send and receive test messages directly.

Message received command is as follows:

bin/pulsar-client consume my-topic -s "first-subscription"

Consumer represent a message from the "my-topic" of this topic, and specify the subscription name as "first-subscription"

Message command is as follows:

bin/pulsar-client produce my-topic --messages "hello pulsar"

It indicates a message transmitted to the my-topic this topic.

NOTE: When tested alone can start Terminal 2, in which a first running Consumer, and then produce the other one in the running

Attachment: If you want to write code to achieve java messaging, reference https://github.com/yjmyzz/pulsar-sample

Five, Function Test

function is a very promising features, it can be ejected in a message topic, and receive real-time post-processing, and then sent to another topic processing result, corresponding to lightweight flow calculations.

Api-examples.jar a package, which comes with some examples of the Function ./examples directory.

5.1 deployment Function

The deployment process, in fact, the jar package with processing logic, put on a cluster, the command is as follows:

bin/pulsar-admin functions create \
--jar examples/api-examples.jar \
--className org.apache.pulsar.functions.api.examples.ExclamationFunction \
--inputs persistent://public/default/exclamation-input \
--output persistent://public/default/exclamation-output \
--name exclamation

Generally it is to create a function, source of examples / api-examples.jar this file and specify a specific class name (as a jar package, you can write multiple function, you must specify the specific className), then this function into this parameter is Topic exclamation-input, processed results, and outputs to the exclamation-output, this last function in the name pulsar exclamation

Attached: ExclamationFunction following java source code, the logic is very simple, just after a plus input parameter!

package org.apache.pulsar.functions.api.examples;

import java.util.function.Function;

public class ExclamationFunction implements Function<String, String> {
    @Override
    public String apply(String input) {
        return String.format("%s!", input);
    }
}

5.2 View a list of function deployed

bin/pulsar-admin functions list \
--tenant public \
--namespace default

5.3 Start consumer, view real-time processing results 　　

bin/pulsar-client consume persistent://public/default/exclamation-output \
--subscription-name my-subscription \
--num-messages 0

5.4 start producers, the processing required to produce real-time material

bin/pulsar-client produce persistent://public/default/exclamation-input \
--num-produce 1 \
--messages "Hello world"

Reference article:

http://pulsar.apache.org/docs/en/functions-quickstart/

pulsar Study Notes 1: helloworld

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