= Java RELP Library (rlp_01)

rlp_01 implements RELP protocol in Java using NIO interface and enables users to send syslog formatted messages to a RELP server such as link:https://github.com/rsyslog/rsyslog[rsyslog].

== License Apache License Version 2.0

== Features Current

• RELP Client
• RELP TLS
• RELP Server (See https://github.com/teragrep/rlp_03)

== Example [source,xml]

<?xml version="1.0" encoding="UTF-8"?> <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">

[source,java]

import com.teragrep.rlp_01.RelpBatch; import com.teragrep.rlp_01.RelpConnection;

import java.io.IOException; import java.nio.charset.StandardCharsets; import java.security.AlgorithmConstraints; import java.security.GeneralSecurityException; import java.util.Date; import java.util.concurrent.TimeoutException; import java.util.function.Supplier;

import com.cloudbees.syslog.Facility; import com.cloudbees.syslog.Severity; import com.cloudbees.syslog.SyslogMessage;

import javax.net.ssl.SSLContext; import javax.net.ssl.SSLEngine; import javax.net.ssl.SSLParameters;

class Main {

public static void main(String[] args) {

    final String serverHostname = "127.0.0.1";
    final int serverPort = 601;

    boolean useTls = false;

    RelpConnection relpConnection;
    if (useTls) {
        try {
            SSLContext sslContext = SSLContextFactory.authenticatedContext(
                    "keystore.jks",
                    "changeit",
                    "TLSv1.3"
            );

            Supplier<SSLEngine> sslEngineSupplier = sslContext::createSSLEngine;
            /*
            // in case there is a need to configure these:
            SSLEngine sslEngine = sslContext.createSSLEngine();
            SSLParameters sslParameters = new SSLParameters();
            sslParameters.setAlgorithmConstraints();
            sslParameters.setCipherSuites();
            sslEngine.setSSLParameters(sslParameters);
             */

            relpConnection = new RelpConnection(sslEngineSupplier);
        } catch (GeneralSecurityException | IOException exception) {
            exception.printStackTrace();
        }
    } else {
        relpConnection = new RelpConnection();
    }

    Main.openConnection(relpConnection, serverHostname, serverPort); // connection helper method

    RelpBatch relpBatch = new RelpBatch(); // create new relpBatch

    // Craft syslog message
    SyslogMessage syslog = new SyslogMessage()
            .withTimestamp(new Date().getTime())
            .withSeverity(Severity.WARNING)
            .withAppName("appName")
            .withHostname("hostName")
            .withFacility(Facility.USER)
            .withMsg("Hello RELP World!");

    relpBatch.insert(syslog.toRfc5424SyslogMessage().getBytes(StandardCharsets.UTF_8)); // insert one message

    boolean notSent = true;
    while (notSent) { // retry until sent

        try {
            relpConnection.commit(relpBatch); // send batch
        } catch (IOException | TimeoutException e) {
            e.printStackTrace();
        }

        if (!relpBatch.verifyTransactionAll()) { // failed batch
            relpBatch.retryAllFailed(); // re-queue failed events
            relpConnection.tearDown(); // teardown connection
            Main.openConnection(relpConnection, serverHostname, serverPort); // reconnect
        } else { // successful batch
            notSent = false;
        }
    }
}

private static void openConnection(RelpConnection relpConnection,
                                   String serverHostname,
                                   int serverPort) {
    // connect helper method
    boolean connected = false;
    while (!connected) {
        try {
            connected = relpConnection.connect(serverHostname, serverPort);  // connect
        } catch (IOException | TimeoutException e) { // error happened during the connect
            e.printStackTrace();
            relpConnection.tearDown(); // retry with clean connection
        }

        if (!connected) {
            // reconnect after an interval
            try {
                Thread.sleep(500); // reconnect interval
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

}

== Debugging Configure slf4j provider to enable debug messages. RelpParser logs only on trace level.

== Contributing

// Change the repository name in the issues link to match with your project's name

You can involve yourself with our project by https://github.com/teragrep/rlp_01/issues/new/choose[opening an issue] or submitting a pull request.

Contribution requirements:

. All changes must be accompanied by a new or changed test. If you think testing is not required in your pull request, include a sufficient explanation as why you think so. . Security checks must pass . Pull requests must align with the principles and http://www.extremeprogramming.org/values.html[values] of extreme programming. . Pull requests must follow the principles of Object Thinking and Elegant Objects (EO).

Read more in our https://github.com/teragrep/teragrep/blob/main/contributing.adoc[Contributing Guideline].

=== Contributor License Agreement

Contributors must sign https://github.com/teragrep/teragrep/blob/main/cla.adoc[Teragrep Contributor License Agreement] before a pull request is accepted to organization's repositories.

You need to submit the CLA only once. After submitting the CLA you can contribute to all Teragrep's repositories.