How can I set the message processor interval parameter using a non fixed value? (using a value stored in a property\registry\etc)

Question

I am very new to WSO2 ESB and I have the following problem with a message processor.

I have this message processor definiation that every second extract an element (an XML document previously stored) from a queue and process it calling a sequence named transferProcessorSequence. This is the configuration:

<?xml version="1.0" encoding="UTF-8"?>
<messageProcessor class="org.apache.synapse.message.processor.impl.sampler.SamplingProcessor" messageStore="transferFromMessageStore" name="transferFromMessageProcessor" xmlns="http://ws.apache.org/ns/synapse">
    <parameter name="sequence">transferProcessorSequence</parameter>
    <parameter name="interval">1000</parameter>
    <parameter name="is.active">true</parameter>
    <parameter name="concurrency">1</parameter>
</messageProcessor>

It works fine. My problem is that I have not to do it every second (it should not be a fixed value) but have to use a value that I have stored into a registry (eventually I can store this value elsewhere).

Instead of having this setting:

<parameter name="interval">1000</parameter>

I have to retrieve a stored value from a registry or something like this (also a property).

How can I do something like this?

**EDIT 1: I am trying to follow the solution provided by Jean-Michel but I am finding some difficulties trying to build my project with Maven.

I created a simple Maven project, this is my pom.xml file content (at this time I have yet no implemented the Java class, I am only trying to compile an empty project):

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany.toolkit</groupId>
    <artifactId>SamplingProcessorHeaderRateLimitation</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>bundle</packaging>
    <name>Sampling Processor Header Rate Limitation</name>
    <description>Custom Sampling Mesageprocessor using response header to implement the rate limitation</description>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.0</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-bundle-plugin</artifactId>
                <version>2.3.4</version>
                <extensions>true</extensions>
                <configuration>
                    <instructions>
                        <Bundle-SymbolicName>com.sample.messageprocessor</Bundle-SymbolicName>
                        <Bundle-Name>com.sample.messageprocessor</Bundle-Name>
                        <Export-Package>com.sample.*</Export-Package>
                        <DynamicImport-Package>*</DynamicImport-Package>
                        <Implementation-Build>${buildNumber}</Implementation-Build>
                        <Scm-Root>${project.scm.connection}</Scm-Root>
                    </instructions>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <releases>
                <updatePolicy>daily</updatePolicy>
                <checksumPolicy>ignore</checksumPolicy>
            </releases>
            <id>wso2-nexus</id>
            <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <releases>
                <updatePolicy>daily</updatePolicy>
                <checksumPolicy>ignore</checksumPolicy>
            </releases>
            <id>wso2-nexus</id>
            <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
        </pluginRepository>
    </pluginRepositories>
    <dependencies>
        <dependency>
            <groupId>org.apache.synapse</groupId>
            <artifactId>synapse-core</artifactId>
            <version>2.1.7-wso2v3</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>
    </dependencies>
    <properties>
        <CApp.type>lib/synapse/mediator</CApp.type>
    </properties>
</project>

The problem is that when I perfrom the mvn package statment for this Maven project I obtain the following error message:

nobil@DESKTOP-VCON7T6 MINGW64 ~/OneDrive/Documenti/MyCompany/JAVA/workspace-sts-3.8.4.RELEASE/SamplingProcessorHeaderRateLimitation
$ mvn -e package
[INFO] Error stacktraces are turned on.
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building Sampling Processor Header Rate Limitation 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.0.2:resources (default-resources) @ SamplingProcessorHeaderRateLimitation ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.0:compile (default-compile) @ SamplingProcessorHeaderRateLimitation ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-resources-plugin:3.0.2:testResources (default-testResources) @ SamplingProcessorHeaderRateLimitation ---
[WARNING] Using platform encoding (Cp1252 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:2.0:testCompile (default-testCompile) @ SamplingProcessorHeaderRateLimitation ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- maven-surefire-plugin:2.20:test (default-test) @ SamplingProcessorHeaderRateLimitation ---
[INFO]
[INFO] --- maven-bundle-plugin:2.3.4:bundle (default-bundle) @ SamplingProcessorHeaderRateLimitation ---
[WARNING] Warning building bundle com.mycompany.toolkit:SamplingProcessorHeaderRateLimitation:bundle:0.0.1-SNAPSHOT : Instructions in Export-Package that are never used: com\.sample\..*|com\.sample
Classpath: Jar:.,Jar:synapse-core,Jar:org.wso2.securevault,Jar:axiom-api,Jar:geronimo-activation_1.1_spec,Jar:geronimo-javamail_1.4_spec,Jar:jaxen,Jar:geronimo-stax-api_1.0_spec,Jar:axiom-impl,Jar:wstx-asl,Jar:log4j,Jar:jline,Jar:commons-cli,Jar:commons-io,Jar:commons-codec,Jar:synapse-commons,Jar:commons-dbcp,Jar:commons-pool,Jar:activation,Jar:axis2-transport-base,Jar:snmp4j-agent,Jar:snmp4j,Jar:axis2-transport-http,Jar:spring-core,Jar:commons-vfs2,Jar:cache-api,Jar:commons-net,Jar:oro,Jar:javax.servlet-api,Jar:bcpkix-jdk15on,Jar:bcprov-jdk15on,Jar:synapse-tasks,Jar:quartz,Jar:c3p0,Jar:slf4j-api,Jar:geronimo-jta_1.1_spec,Jar:commons-collections,Jar:synapse-nhttp-transport,Jar:httpcore,Jar:httpcore-nio,Jar:httpclient,Jar:wso2caching-core,Jar:axis2-clustering,Jar:tomcat-tribes,Jar:tomcat-juli,Jar:tomcat-embed-logging-juli,Jar:xmlunit,Jar:aspectjweaver,Jar:jms,Jar:amqp-client,Jar:antlr-runtime,Jar:stringtemplate,Jar:antlr,Jar:axis2-saaj,Jar:geronimo-saaj_1.3_spec,Jar:axiom-dom,Jar:axis2-kernel,Jar:geronimo-ws-metadata_2.0_spec,Jar:servlet-api,Jar:commons-httpclient,Jar:commons-fileupload,Jar:wsdl4j,Jar:XmlSchema,Jar:woden-api,Jar:XmlSchema,Jar:woden-impl-dom,Jar:woden-impl-commons,Jar:jsr311-api,Jar:junit,Jar:hamcrest-core,Jar:handy-uri-templates,Jar:commons-lang,Jar:jettison,Jar:jettison,Jar:stax-api,Jar:json-path,Jar:json-smart,Jar:wso2eventing-api,Jar:axis2-adb,Jar:sandesha2-core,Jar:axis2-codegen,Jar:neethi,Jar:axis2-mtompolicy,Jar:saxon-dom,Jar:saxon,Jar:xalan,Jar:serializer,Jar:xml-apis,Jar:axis2-transport-local,Jar:json-schema-validator-all,Jar:json-schema-validator,Jar:jsr305,Jar:joda-time,Jar:libphonenumber,Jar:mailapi,Jar:jopt-simple,Jar:json-schema-core,Jar:rhino,Jar:uri-template,Jar:guava,Jar:msg-simple,Jar:btf,Jar:jackson-coreutils,Jar:jackson-databind,Jar:jackson-annotations,Jar:jackson-core,Jar:commons-logging

[WARNING] Warning building bundle com.mycompany.toolkit:SamplingProcessorHeaderRateLimitation:bundle:0.0.1-SNAPSHOT : Superfluous export-package instructions: [com.sample.*]
[ERROR] Error building bundle com.mycompany.toolkit:SamplingProcessorHeaderRateLimitation:bundle:0.0.1-SNAPSHOT : The JAR is empty: dot
[ERROR] Error(s) found in bundle configuration
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 3.568 s
[INFO] Finished at: 2017-07-17T14:25:45+02:00
[INFO] Final Memory: 16M/284M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.felix:maven-bundle-plugin:2.3.4:bundle (default-bundle) on project SamplingProcessorHeaderRateLimitation: Error(s) found in bundle configuration -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.felix:maven-bundle-plugin:2.3.4:bundle (default-bundle) on project SamplingProcessorHeaderRateLimitation: Error(s) found in bundle configuration
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
        at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
        at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
        at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
        at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
        at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
        at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
        at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
        at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
        at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
        at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
        at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Error(s) found in bundle configuration
        at org.apache.felix.bundleplugin.BundlePlugin.execute(BundlePlugin.java:341)
        at org.apache.felix.bundleplugin.BundlePlugin.execute(BundlePlugin.java:224)
        at org.apache.felix.bundleplugin.BundlePlugin.execute(BundlePlugin.java:215)
        at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
        at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
        ... 20 more
Caused by: org.apache.maven.plugin.MojoFailureException: Error(s) found in bundle configuration
        at org.apache.felix.bundleplugin.BundlePlugin.execute(BundlePlugin.java:293)
        ... 24 more
[ERROR]
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

So, why? What is the problem? I think that maybe I have to configure the manven-bundle-plugin plugin. But what exactly have I to do to correctly configure it? And what this plugin does?

@chsdk this is a WSO2 ESB project. Why are you asking me if am I using Spring? — AndreaNobili, Jul 17 '17 at 08:44
Because spring has a utility to load external properties in XML, take a look at [this](http://docs.spring.io/spring/docs/2.5.x/reference/beans.html#beans-factory-placeholderconfigurer). — cнŝdk, Jul 17 '17 at 08:46

score 3 · Answer 1 · edited Jul 17 '17 at 13:29

Option 1 : Develop a custom MessageProcessor that extends the SamplingProcessor class from WSO2. (Have a look to https://github.com/wso2/wso2-synapse modules\core\src\main\java\org\apache\synapse\message\processor\impl)

Extends org.apache.synapse.message.processor.impl.sampler.SamplingProcessor (or directly org.apache.synapse.message.processor.impl.ScheduledMessageProcessor) and override method setParameters

Call super.setParameters and then update interval attribute with a value that you can read where you want.

In your MessageProcessor definition, use your own class behind class XML attribute

Option 2 : Use admin services

edit carbon.xml and set HideAdminServiceWSDLs to false
admin services listen on https://host:9443/carbon
you will find an admin service named MessageProcessorAdminService

Sample pom.xml to compile / package your custom message processor :

<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.sample</groupId>
    <artifactId>MyMessageProcessors</artifactId>
    <version>1.0.0</version>
    <packaging>bundle</packaging>
    <name>custom MessageProcessors</name>
    <description>sample</description>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>2.0</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.felix</groupId>
                <artifactId>maven-bundle-plugin</artifactId>
                <version>2.3.4</version>
                <extensions>true</extensions>
                <configuration>
                    <instructions>
                        <Bundle-SymbolicName>com.sample.messageprocessor</Bundle-SymbolicName>
                        <Bundle-Name>com.sample.messageprocessor</Bundle-Name>
                        <Export-Package>com.sample.*</Export-Package>
                        <DynamicImport-Package>*</DynamicImport-Package>
                        <Implementation-Build>${buildNumber}</Implementation-Build>
                        <Scm-Root>${project.scm.connection}</Scm-Root>
                    </instructions>
                </configuration>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <releases>
                <updatePolicy>daily</updatePolicy>
                <checksumPolicy>ignore</checksumPolicy>
            </releases>
            <id>wso2-nexus</id>
            <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <releases>
                <updatePolicy>daily</updatePolicy>
                <checksumPolicy>ignore</checksumPolicy>
            </releases>
            <id>wso2-nexus</id>
            <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
        </pluginRepository>
    </pluginRepositories>
    <dependencies>
        <dependency>
            <groupId>org.apache.synapse</groupId>
            <artifactId>synapse-core</artifactId>
            <version>2.1.7-wso2v3</version>
        </dependency>
        <dependency>
            <groupId>commons-logging</groupId>
            <artifactId>commons-logging</artifactId>
            <version>1.1.1</version>
        </dependency>
    </dependencies>
    <properties>
        <CApp.type>lib/synapse/mediator</CApp.type>
    </properties>
</project>

adapt groupId, artifactId, and version
adapt packages in maven-bundle-plugin config
execute mvn package from the command line

OPTION 1 QUESTION: Ok, I obtained the SamplingProcessor class from the GitHub repository. I will try to modify it. My first doubt (maybe trivial) is: after that I modify it what have I to do? Have I to compile it or what? — AndreaNobili, Jul 17 '17 at 09:48
OPTION 2 QUESTION: What is this admin services and what is its pourpose? — AndreaNobili, Jul 17 '17 at 09:49
Of course, you will have to compile and package your class and put the jar in repository/components/lib (ESB <= 5.0.0) — Jean-Michel, Jul 17 '17 at 10:08
admin services offers you a way to manage wso2 without the web console (calling web services). If you start wso2 with -DosgiConsole, you can type listAdminServices to get all of them. — Jean-Michel, Jul 17 '17 at 10:10
Ok, coming back to the option 1: I saw that the SamplingProcessor class have some dependency (its import). So what exactly have I to do, I think something like this (correct me if I a doing wrong assertion): 1) I create a new Java Maven project. 2) I import these classes using Maven (exist a list of the artifact that have to be used in Maven?). 3) Compile my project. Is it? What is the standard workflow to compile my custom message processor class? — AndreaNobili, Jul 17 '17 at 10:22
I am trying to use your solution building a yet empty Maven project but I have some errors when I perform the "mvn package" statment. I added an edit at the end of my oringinal post describing what I have done and the obtained error. — AndreaNobili, Jul 17 '17 at 13:24
Your error is "The JAR is empty" : update Export-Package in bundle-plugin config — Jean-Michel, Jul 17 '17 at 13:37
Ok...so I created a com.sample.messageprocessor package in my project and here I put an HelloWorld class (to do a very minimalistic build test), running again Maven it seems to compile. Is it ok? — AndreaNobili, Jul 17 '17 at 13:38
open the .jar file in target directory and verify if you can find your class — Jean-Michel, Jul 17 '17 at 14:58
Ok...the class is into the generated jar file. Where have I to put this jar in my WSO2 installation? (I am using WSO2 EI) — AndreaNobili, Jul 17 '17 at 15:06
But it seems to me that the setParameters() method is executed only once at the message processor startup. I need to do it not at the startup but every time that an element is retrieved from the message store and before the the related sequence is performed. So I think that I override another method. Is it correct? If yes: what method have I to override? — AndreaNobili, Jul 21 '17 at 11:33

score 2 · Answer 2 · answered Jul 19 '17 at 16:20

As others have mentioned you will need to create your own message processor by extending the SampleProcessor and overriding the setParameter methods.

org.apache.synapse.message.processor.impl.sampler.SamplingProcessor

Where in setParameters method read the parameters from registry and over write the parameter map.

Custom message processor which reads parameters from a property file which is defined in governance space of registry

package org.apache.synapse.message.custom.processor.impl;

import java.io.IOException;
import java.io.StringReader;
import java.util.Map;
import java.util.Properties;

import org.wso2.carbon.context.CarbonContext;
import org.wso2.carbon.context.RegistryType;
import org.wso2.carbon.registry.api.Registry;
import org.wso2.carbon.registry.api.RegistryException;
import org.wso2.carbon.registry.api.Resource;

import org.apache.synapse.message.processor.impl.sampler.SamplingProcessor;;

public class CustomSamplingProcessor extends SamplingProcessor {
    private final static String REGISTRY_PATH = "reg";

    @Override
    public void setParameters(Map<String, Object> parameters) {
        if (parameters.get(REGISTRY_PATH) != null) {
            String resourcePath = (String) parameters.get(REGISTRY_PATH);
            parameters = populateParamsFromReg(resourcePath, parameters);
        }
        System.out.println("############################## set params################");
        super.setParameters(parameters);
    }

    private Map<String, Object> populateParamsFromReg(String resourcePath, Map<String, Object> parameters) {
        Properties prop = readPropertyFile(resourcePath);
        if (prop != null) {
            for (String key : prop.stringPropertyNames()) {
                String value = prop.getProperty(key);
                parameters.put(key, value);
            }
        }
        return parameters;
    }

    private Properties readPropertyFile(String resourcePath) {
        Properties prop = null;
        try {
            CarbonContext cCtx = CarbonContext.getThreadLocalCarbonContext();
            Registry registry = cCtx.getRegistry(RegistryType.USER_GOVERNANCE);
            Resource resource = registry.get(resourcePath);
            Object content = resource.getContent();
            String output = new String((byte[]) content);
            System.out.println(output);
            prop = parseProperties(output);
        } catch (RegistryException e) {
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return prop;
    }

    public Properties parseProperties(String fileContent) throws IOException {
        final Properties properties = new Properties();
        properties.load(new StringReader(fileContent));
        return properties;
    }
}

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.apache.synapse.message.custom.processor.impl</groupId>
    <artifactId>custom-message-processor</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>message.custom.processor</name>
    <url>http://maven.apache.org</url>
    <repositories>
        <repository>
            <id>wso2-nexus</id>
            <name>WSO2 internal Repository</name>
            <url>http://maven.wso2.org/nexus/content/groups/wso2-public/</url>
            <releases>
                <enabled>true</enabled>
                <updatePolicy>daily</updatePolicy>
                <checksumPolicy>fail</checksumPolicy>
            </releases>
        </repository>
    </repositories>


    <dependencies>
        <dependency>
            <groupId>org.apache.synapse</groupId>
            <artifactId>synapse-core</artifactId>
            <version>2.1.2-wso2v4</version>
        </dependency>
        <dependency>
            <groupId>org.wso2.carbon</groupId>
            <artifactId>org.wso2.carbon.registry.api</artifactId>
            <version>4.3.0</version>
        </dependency>

        <dependency>
            <groupId>org.wso2.carbon</groupId>
            <artifactId>org.wso2.carbon.registry.core</artifactId>
            <version>4.3.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Create a property file and add the parameters which should be read from registry e.g

File location in registry

/_system/governance/custom-message-processor/customprocessor.properties

content

interval:1000
concurrency:1
sequence:replySeq
is.active:true

How to use the custom processor in EI

Built the custom message processor, and add the jar to <EI_HOME>\lib (since this jar is an none osgi jar)
Restart/Start the EI
Add the property file to registry
Create custom message processor and add the registry file path of the property file as parameter to custom message processor configuration with parameter name "reg" (Give the relative registry path since in code level we read from governance space. i.e /custom-message-processor/customprocessor.properties).

  <messageProcessor xmlns="http://ws.apache.org/ns/synapse" class="org.apache.synapse.message.custom.processor.impl.CustomSamplingProcessor" name="CustomSamplingProcessor" messageStore="JMSMS">   
       <parameter name="reg">/custom-message-processor/customprocessor.properties</parameter>   
  </messageProcessor>

Full source code can be found here[1] https://github.com/jenananthan/wso2-esb-customization/tree/master/sampling_custom_message_processor

The problem is that I need to set this interval value each time that the sequence related to this message processor is call (before the sequence is call). So, I extended the SamplingProcessor class overiding the setParameters() method but it seems to me that it is executed once at the message processor initizialization. It is not good for me because I have to do this operation each time that the sequence related the message processor is executed (before its execution). From what I can understand to do this I have to override also the SamplingService classthat contains the "scheduler" — AndreaNobili, Jul 24 '17 at 08:02
ScheduledMessageProcessor(parent of SamplingProcessor) has the taskmanager which schedule the task (SamplingService) according to the given interval parameter via setParameters method. where setParameter method will be invoked by MessageProcessorFactory when create or update the message processor configuration. Task manger defined in ScheduledMessageProcessor is a private member, so it is not possible to update the interval within the execute method of task(SamplingService) — Jenananthan, Jul 24 '17 at 11:40

score 0 · Answer 3 · answered Jul 17 '17 at 08:40

It doesn't look like that this is not possible out of the box with WSO2ESB. But you can try to override

org.apache.synapse.message.processor.impl.sampler.SamplingProcessor

and write custom logic to pull parameter value for interval from a registry or any other source instead of using the XML Configuration and use that overridden implementation in your XML configuration

<?xml version="1.0" encoding="UTF-8"?>
<messageProcessor class="my.custom.CustomSamplingProcessor" messageStore="transferFromMessageStore" name="transferFromMessageProcessor" xmlns="http://ws.apache.org/ns/synapse">
    <parameter name="sequence">transferProcessorSequence</parameter>
    <parameter name="is.active">true</parameter>
    <parameter name="concurrency">1</parameter>
</messageProcessor>

score 0 · Answer 4 · answered Jul 17 '17 at 08:47

0

Well if you are using Spring you can use an application.properties file in your application classpath and use the PropertyPlaceholderConfigurer to load resources from this external shared properties file. This is how you should declare the PropertyPlaceholderConfigurer in your XML file:

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <value>classpath:wso2esb.properties</value>
    </property>
</bean>

<bean id="messageProcessor" 
   class="org.apache.synapse.message.processor.impl.sampler.SamplingProcessor" messageStore="transferFromMessageStore" name="transferFromMessageProcessor" xmlns="http://ws.apache.org/ns/synapse">
    <property name="sequence" value="${wso2esb.sequence}"/>
    <property name="interval" value="${wso2esb.interval}"/>
    <property name="isactive" value="${wso2esb.isactive}"/>
    <property name="concurrency" value="${wso2esb.concurrency}"/>
</bean>

And you will just need to update the properties and parametrs of your WSO2 ESB in this properties file.

For further details you can check:

answered Jul 17 '17 at 08:47

cнŝdk

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mmm, I know Spring. But have you experience in WSO2 ESB? Because it seems to me that you are defining a Spring project composed by a single "messageProcessor" bean in which you inhect the configuration. But, unless I miss something, in WSO2 ESB I can't do something like this because: 1) The messageProcessor configuration is defined into an ESB XML configuration file. – AndreaNobili Jul 17 '17 at 08:57
2) Ok, using your way: I create a Spring project, I compile this and so I should obtain a .jar file but I think that I can't use a jar file containing a message processor is a simple class inside the project – AndreaNobili Jul 17 '17 at 08:57
@AndreaNobili Why can't you use a jar? And you aren't obliged to use a jar, anyway, and you said you are using Spring so this will be a good alternative for you. – cнŝdk Jul 17 '17 at 09:01
So are you proposing me something like this: 1) Wrap the WSO2 SamplingProcessor into a Spring Bean and inject the interval value. The problem is that I have to obtain this interval value in some way because it is put into a WSO2 registry and I can't retrieve it from the Spring XML configuration where I do the injection – AndreaNobili Jul 17 '17 at 09:51
@AndreaNobili Yes indeed, but as I said the `interval` and ither parameters will be taken from the `application.properties` in your projetc, where you will define/change them dynamically. – cнŝdk Jul 17 '17 at 10:07

curledUpSheep · Answer 5 · 2017-07-17T09:07:04.447

I believe the message processor itself does not provide such a feature. However, it is possible to do this another way. I am proposing a way without any custom Java code (which may or not be an advantage to you).

Let's assume you want to do this every X seconds (with X stored in the registry). You would then leave the message processor interval at 1 second. Then, in the sequence that your processor injects its message to, start by looking at a counter that you store as a global property. The counter keeps track of how many times you skipped the action. If the skipped counter is smaller than X - 1, you increase the counter and do nothing. If the skipped counter equals X - 1 (or is higher, which can happen if you change X in the registry), you reset the counter to zero and perform the action.

How can I set the message processor interval parameter using a non fixed value? (using a value stored in a property\registry\etc)

5 Answers5