mi-connector-solace

The Solace connector enables WSO2 Integrator: MI to publish messages and interact with a Solace broker. It supports reliable, asynchronous communication, allowing you to send messages to queues or topics, and manage message acknowledgments.

Operations

All operations are invoked with the solace. prefix and act on a configured connection. Configure the connection once (host, VPN, and credentials) and reference it from each operation.

Messaging

Operation	Description
solace.publishMessage	Publish a message to a topic or queue. Supports DIRECT (topics only), PERSISTENT, and NON_PERSISTENT delivery, with optional wait-for-ack on guaranteed sends.
solace.sendRequest	Send a request message and block until a reply arrives or the timeout expires (synchronous request-reply).
solace.sendReply	Send a reply to an inbound request message, using the reply-to destination from the message context. Pairs with solace.sendRequest.

Consuming

Operation	Description
solace.poll	Synchronously poll a single message from a queue; returns a timed-out result if the queue is empty. Inside a transaction, settlement is deferred to commit/rollback (at-least-once); otherwise the message is acked on receipt (at-most-once).
solace.browse	Browse messages on a queue without consuming them — useful for diagnostics and dead-message-queue inspection.
solace.acknowledgeMessage	Acknowledge an inbound message so the broker removes it from the queue. Requires the inbound endpoint configured with solace.autoAck=false.
solace.nackMessage	Negatively acknowledge an inbound message: FAILED redelivers (then DMQ after max-redelivery), REJECTED routes straight to the DMQ.

Transactions

Operation	Description
solace.beginTransaction	Begin a local transaction; subsequent publishMessage / poll calls on the same flow are transacted.
solace.commit	Commit the active transaction.
solace.rollback	Roll back the active transaction (polled messages are redelivered).

Prerequisites

The Solace JCSMP client (sol-jcsmp) is not bundled with this connector. Solace JCSMP is not Apache-2.0 licensed, so it cannot be redistributed or repackaged. You must install it once into the MI server's shared library directory, <MI_HOME>/lib, before deploying.

Installing it in <MI_HOME>/lib (rather than bundling it inside the connector) is required so that this connector and the Solace inbound endpoint share a single copy of the client. A single shared copy:

• avoids a Netty initialization clash — java.lang.IllegalArgumentException: 'TOTAL_SOCKET_BYTES_SENT' is already in use — that occurs when two copies of the JCSMP Netty transport are loaded in the same server (e.g. the connector and the inbound deployed together, or a hot-redeploy), and
• lets the inbound endpoint hand its received message to this connector's acknowledge / nack operations (both modules must resolve com.solacesystems.jcsmp.BytesXMLMessage from the same classloader).

Install the required JARs

Place the following into <MI_HOME>/lib and restart the server:

Artifact	Version
com.solacesystems:sol-jcsmp	10.30.1
org.apache.servicemix.bundles:org.apache.servicemix.bundles.jzlib	1.1.3_2

Netty does not need to be added — the JCSMP client uses the Netty already shipped with MI (MI 4.6.0 bundles netty-all 4.2.12, which matches sol-jcsmp 10.30.x).

You can fetch both JARs from Maven into lib with:

mvn dependency:copy -Dartifact=com.solacesystems:sol-jcsmp:10.30.1 -DoutputDirectory="$MI_HOME/lib"
mvn dependency:copy -Dartifact=org.apache.servicemix.bundles:org.apache.servicemix.bundles.jzlib:1.1.3_2 -DoutputDirectory="$MI_HOME/lib"

Then restart WSO2 MI.

Example

Once the connection is configured (host, VPN, and credentials) and referenced by a key — e.g. MY_SOLACE — operations reference it via configKey:

<!-- Publish a message to a topic -->
<solace.publishMessage configKey="MY_SOLACE">
    <destinationType>TOPIC</destinationType>
    <destinationName>orders/new</destinationName>
    <messageType>TEXT</messageType>
    <responseVariable>solacePublishResponse</responseVariable>
</solace.publishMessage>

<!-- Synchronously poll one message from a queue -->
<solace.poll configKey="MY_SOLACE">
    <queueName>orders.q</queueName>
    <pollTimeout>5000</pollTimeout>
    <responseVariable>solacePollResponse</responseVariable>
</solace.poll>