Introduction

The Solace PubSub+ Platform's software event broker efficiently streams event-driven information between applications, IoT devices and user interfaces running in the cloud, on-premises, and hybrid environments using open APIs and protocols like AMQP, JMS, MQTT, REST and WebSocket. It can be installed into a variety of public and private clouds, PaaS, and on-premises environments, and brokers in multiple locations can be linked together in an event mesh to dynamically share events across the distributed enterprise.

Quarkus Extension for Solace

Solace Quarkus Extension provides the ability to integrate with Solace PubSub+ message brokers. The events published by this extension to solace will be available on event mesh and in the same way the extension can subscribe to any event available on event mesh.

Users have the choice to use the extension in two ways

1. com.solace.quarkus:quarkus-solace-client

This extension provides only Solace Java Messaging API and users need to have their own implementation and configuration to interact with Solace PubSub+ broker.

If you want to use this extension, you need to add the com.solace.quarkus:quarkus-solace-client extension first to your build file.

For instance, with Maven, add the following dependency to your POM file:

<dependency>
    <groupId>com.solace.quarkus</groupId>
    <artifactId>quarkus-solace-client</artifactId>
    <version>${release.current-version}</version>
</dependency>

2. com.solace.quarkus:quarkus-solace-messaging-connector

This extension is based on reactive messaging framework and provides pre-defined configurations for incoming and outgoing channels.

If you want to use this extension, you need to add the com.solace.quarkus:quarkus-solace-messaging-connector extension first to your build file.

For instance, with Maven, add the following dependency to your POM file:

<dependency>
    <groupId>com.solace.quarkus</groupId>
    <artifactId>quarkus-solace-messaging-connector</artifactId>
    <version>${release.current-version}</version>
</dependency>

Extension Configuration Reference

Configuration property fixed at build time - All other configuration properties are overridable at runtime

Configuration property

Type

Default

quarkus.solace.metrics.enabled

Whether a metrics is enabled in case the micrometer is present.

Environment variable: QUARKUS_SOLACE_METRICS_ENABLED

boolean

true

quarkus.solace.health.enabled

Whether the liveness health check should be exposed if the smallrye-health extension is present.

Environment variable: QUARKUS_SOLACE_HEALTH_ENABLED

boolean

true

quarkus.solace.devservices.enabled

If DevServices has been explicitly enabled or disabled. DevServices is generally enabled by default, unless there is an existing configuration present.

When DevServices is enabled Quarkus will attempt to automatically configure and start the Solace broker when running in Dev or Test mode and when Docker is running.

Environment variable: QUARKUS_SOLACE_DEVSERVICES_ENABLED

boolean

true

quarkus.solace.devservices.image-name

The container image name to use, for container based DevServices providers.

Environment variable: QUARKUS_SOLACE_DEVSERVICES_IMAGE_NAME

string

quarkus.solace.devservices.shared

Indicates if the Solace broker managed by Quarkus Dev Services is shared. When shared, Quarkus looks for running containers using label-based service discovery. If a matching container is found, it is used, and so a second one is not started. Otherwise, Dev Services for Solace starts a new container.

The discovery uses the quarkus-dev-service-solace label. The value is configured using the service-name property.

Container sharing is only used in dev mode.

Environment variable: QUARKUS_SOLACE_DEVSERVICES_SHARED

boolean

true

quarkus.solace.devservices.service-name

The value of the quarkus-dev-service-solace label attached to the started container. This property is used when shared is set to true. In this case, before starting a container, Dev Services for Solace looks for a container with the quarkus-dev-service-solace label set to the configured value. If found, it will use this container instead of starting a new one. Otherwise, it starts a new container with the quarkus-dev-service-solace label set to the specified value.

This property is used when you need multiple shared Solace broker.

Environment variable: QUARKUS_SOLACE_DEVSERVICES_SERVICE_NAME

string

solace

quarkus.solace.host

The Solace host (hostname:port)

Environment variable: QUARKUS_SOLACE_HOST

string

required

quarkus.solace.vpn

The Solace VPN

Environment variable: QUARKUS_SOLACE_VPN

string

required

quarkus.solace.devservices.container-env

Environment variables that are passed to the container.

Environment variable: QUARKUS_SOLACE_DEVSERVICES_CONTAINER_ENV

Map<String,String>

quarkus.solace

Any extra parameters to pass to the Solace client.


Refer to AuthenticationProperties and TransportLayerProperties for more configuration options


Example: To configure compression quarkus.solace.transport.compression-level

Environment variable: QUARKUS_SOLACE

Map<String,String>

Incoming Configuration Reference

Incoming configuration for Quarkus Solace Messaging Connector

Configuration property

Type

Default

client.type.direct.back-pressure.strategy

The back-pressure strategy to be applied for direct message consumer.

Supported values are oldest, latest & elastic.

Refer to Handling Back-Pressure When Subscribing to Direct Messages

string

elastic

client.type.direct.back-pressure.buffer-capacity

It is possible for the client application to consume messages more quickly than the API can send them to the broker due to network congestion or connectivity issues. This delay can cause the internal buffer to accumulate messages until it reaches its capacity, preventing the API from storing any more messages.

int

1024

consumer.queue.name

The queue name of receiver.

string

required

consumer.queue.type

The queue type of receiver. Supported values durable-exclusive, durable-non-exclusive, non-durable-exclusive

string

durable-exclusive

consumer.queue.missing-resource-creation-strategy

Create resources on broker if not available. When set to create-on-start the extension provision the queue on broker and also sets the queue type and any subscriptions if configured.

string

do-not-create

consumer.queue.add-additional-subscriptions

Whether to add configured subscriptions to queue. Will fail if permissions to configure subscriptions is not allowed on broker.

boolean

false

consumer.subscriptions

The comma separated list of subscriptions, the channel name if empty.

If client.type is persistent this configuration is considered only if consumer.queue.add-additional-subscriptions is set to true.

If client.type is direct this is used by default.

string

required

quarkus.consumer.queue.selector-query

The receiver selector query. If configured, broker will filter messages using this condition.

string

consumer.queue.replay.strategy

The receiver replay strategy. Supported values all-messages, time-based, replication-group-message-id.

string

consumer.queue.replay.timebased-start-time

The receiver replay timebased start time. Set this value if consumer.queue.replay.strategy is time-based.

string

quarkus.consumer.queue.replay.replication-group-message-id

The receiver replay replication group message id.

string

consumer.failure-strategy

Specify the failure strategy to apply when a message consumed from Solace broker is nacked. Accepted values are ignore (default), fail, discard, error_topic.

Following are the failure strategies supported when client.type is persistent.

ignore - Mark the message as IGNORED, will continue processing with next message.

fail - Mark the message as FAILED, broker will redeliver the message. Nacks are supported on event brokers 10.2.1 and later, so enable this strategy based on broker version.

discard - Mark the message as REJECTED, broker will discard the message. The message will be moved to DMQ if DMQ is configured for queue and DMQ Eligible is set on message otherwise message will be lost. Nacks are supported on event brokers 10.2.1 and later, so enable this strategy based on broker version.

error_topic - Will publish the message to configured error topic, on success the message will be acknowledged in the queue.

Following are the failure strategies supported when client.type is direct.

ignore - Mark the message as IGNORED, will continue processing with next message.

error_topic - Will publish the message to configured error topic, on success the message will be acknowledged in the queue.

string

ignore

consumer.error.topic

The error topic where message should be published in case of error.

string

consumer.error.message.dmq-eligible

Whether error message is eligible to move to dead message queue.

boolean

false

consumer.error.message.ttl

TTL for Error message before moving to dead message queue.

long

null

consumer.error.message.max-delivery-attempts

Maximum number of attempts to send a failed message to the error topic in case of failure. Each attempt will have a backoff interval of 1 second. When all delivery attempts have been exhausted, the failed message will be requeued on the queue for redelivery.

int

3

consumer.queue.supports-nacks

Whether to enable negative acknowledgments on failed messages. Nacks are supported on event brokers 10.2.1 and later. If an event broker does not support Nacks, an exception is thrown.

boolean

false

Outgoing Configuration Reference

Outgoing configuration for Quarkus Solace Messaging Connector

Configuration property

Type

Default

client.type.direct.waitForPublishReceipt.timeout

In case of direct messaging broker will not send any acknowledgement for published messages.

We can configure a timeout in milliseconds to check for any publish failures. If no failed event is received during this timeout published message is assumed to be successful.

long

30

producer.topic

The topic to publish messages, by default the channel name.

string

required

producer.max-inflight-messages

The maximum number of messages to be written to Solace broker. It limits the number of messages waiting to be written and acknowledged by the broker. You can set this attribute to 0 remove the limit.

long

1024

producer.waitForPublishReceipt

Whether the client waits to receive publish receipt from Solace broker before sending acknowledgment. This property is considered only when client.type is persistent.

In case of client.type is direct publish receipt is not sent by broker and extension returns success acknowledgment by default. However, the extension will log if there is any failure when publishing the event.

boolean

true

producer.delivery.ack.timeout

Timeout to receive the publish receipt from broker.

integer

producer.delivery.ack.window.size

Publish Window will determine the maximum number of messages the application can send before the Solace API must receive an acknowledgment from the Solace.

integer

producer.back-pressure.strategy

It is possible for the client application to publish messages more quickly than the API can send them to the broker due to network congestion or connectivity issues. This delay can cause the internal buffer to accumulate messages until it reaches its capacity, preventing the API from storing any more messages.

Supported strategies reject, elastic, wait. Refer to link.

string

elastic

producer.back-pressure.buffer-capacity

Outgoing messages backpressure buffer capacity.

integer

1024

Common Configuration Reference

Common configuration for Quarkus Solace Messaging Connector Incoming and Outgoing channels

Configuration property

Type

Default

client.type

The type of client when establishing connection to Solace. Solace supports two types of client Direct and Persistent.

Use Direct client where message loss can be tolerated. The publisher publishes the event and the broker doesn’t send any acknowledgement back to publisher for guaranteed delivery.

Use Persistent client where message loss cannot be tolerated. The publisher publishes the event and the broker sends an acknowledgement that message is guaranteed for delivery.

string

persistent

client.lazy.start

Whether the receiver or publisher is started at initialization or lazily at subscription time.

boolean

false

client.graceful-shutdown

Whether to shutdown client gracefully.

boolean

true

client.graceful-shutdown.wait-timeout

Timeout in milliseconds to wait for messages to finish processing before shutdown.

long

10000

client.tracing-enabled

Whether to enable or disable tracing for consumer or producer.

boolean

false

Configuring Quarkus Solace Client

Solace Broker supports different ways to connect and authenticate users. This section shows how to pass extra properties to quarkus solace client in different scenarios. Please refer to Solace Properties for supported properties and definitions.

1. Connecting to a standalone broker with basic authentication

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=test
quarkus.solace.authentication.basic.password=test

2. Connecting to a standalone broker with TLS and basic authentication. This assumes you have a publicly signed CA.

quarkus.solace.host=tcps://localhost:55443
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=test
quarkus.solace.authentication.basic.password=test

3. Connecting to a standalone broker with TLS, basic authentication and custom trust store which hold your CA.

quarkus.solace.host=tcps://localhost:55443
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=test
quarkus.solace.authentication.basic.password=test
quarkus.solace.tls.trust-store-path=
quarkus.solace.tls.trust-store-type=
quarkus.solace.tls.trust-store-password=

4. Connecting to a standalone broker with TLS, trust store and client certificate authentication. In case of client certificate authentication broker will read from configured username source(ex: Common Name, Subject Alt Name etc…​). Refer to Solace Client Certificate Authentication.

quarkus.solace.host=tcps://localhost:55443
quarkus.solace.vpn=default
quarkus.solace.authentication.scheme=AUTHENTICATION_SCHEME_CLIENT_CERTIFICATE
quarkus.solace.tls.trust-store-path=
quarkus.solace.tls.trust-store-type=
quarkus.solace.tls.trust-store-password=
quarkus.solace.authentication.client-cert.keystore=
quarkus.solace.authentication.client-cert.keystore-password=
quarkus.solace.authentication.client-cert.keystore-format=

5. Connecting to a standalone broker with OAUTH authentication scheme.

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.scheme=AUTHENTICATION_SCHEME_OAUTH2
quarkus.solace.oidc.client-name=solace // client name provided in oidc client config below
quarkus.solace.oidc.refresh.interval=50s // Refresh interval should be less than access token expiry time. Otherwise extension will fail to update access token in solace session.
quarkus.solace.oidc.refresh.timeout=10s // Token Refresh API timeout. Default is set to 10 seconds.

quarkus.oidc-client.solace.auth-server-url=http://localhost:7777/auth/realms/master
quarkus.oidc-client.solace.client-id=<client-id>
quarkus.oidc-client.solace.credentials.secret=<client-secret>
# 'client' is a shortcut for `client_credentials`
quarkus.oidc-client.solace.grant.type=client

6. Connecting to a standalone broker with TLS and OAUTH authentication scheme.

quarkus.solace.host=tcps://localhost:55443
quarkus.solace.vpn=default
quarkus.solace.authentication.scheme=AUTHENTICATION_SCHEME_OAUTH2
quarkus.solace.tls.trust-store-path=
quarkus.solace.tls.trust-store-type=
quarkus.solace.tls.trust-store-password=
quarkus.solace.oidc.client-name=solace // client name provided in oidc client config below
quarkus.solace.oidc.refresh.interval=50s // Refresh interval should be less than access token expiry time. Otherwise extension will fail to update access token in solace session.
quarkus.solace.oidc.refresh.timeout=10s // Token Refresh API timeout. Default is set to 10 seconds.

quarkus.oidc-client.solace.auth-server-url=http://localhost:7777/auth/realms/master
quarkus.oidc-client.solace.client-id=<client-id>
quarkus.oidc-client.solace.credentials.secret=<client-secret>
# 'client' is a shortcut for `client_credentials`
quarkus.oidc-client.solace.grant.type=client
quarkus.oidc-client.solace.tls.trust-store-file=<path-to-truststore-file>
quarkus.oidc-client.solace.tls.key-store-password=
quarkus.oidc-client.solace.tls.verification=<enable-or-disable-tls-verification>

For more details on Quarkus OIDC client supported configuration please refer to OPENID CONNECT (OIDC) AND OAUTH2 CLIENT AND FILTERS and OIDC configuration reference

The current version is tested with client_credentials grant type where Solace broker is configured as Resource Server.

7. Connecting to a HA broker. Here you can configure both active and standby URL and the client will switch connectivity based on availability. Remaining configurations and authentication mechanisms can be used as-is.

quarkus.solace.host=tcp://active-host-name:55555,tcp://standby-host-name:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=test
quarkus.solace.authentication.basic.password=test

In similar way other authentication mechanisms can be enabled

Configuring Quarkus Solace Messaging Connector

Reactive Messaging framework supports different messaging backends it employs a generic vocabulary:

  • Applications send and receive messages. A message wraps a payload and can be extended with some metadata. With the Solace connector, a message corresponds to Inbound or Outbound Message.

  • Messages transit on channels. Application components connect to channels to publish and consume messages. The Solace connector maps channels to Solace queues and topics.

  • Channels are connected to message backends using connectors. Connectors are configured to map incoming messages to a specific channel (consumed by the application) and collect outgoing messages sent to a specific channel. Each connector is dedicated to a specific messaging technology. For example, the connector dealing with Solace is named quarkus-solace.

The extension supports two types of messaging client direct and persistent. By default persistent client is enabled.

A minimal configuration for the Solace connector with an incoming channel and persistent client looks like the following:

The following lines of configuration assumes that a exclusive queue is already provisioned on the broker

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=basic
quarkus.solace.authentication.basic.password=basic

mp.messaging.incoming.temperatures.connector=quarkus-solace
mp.messaging.incoming.temperatures.consumer.queue.name=temperatures

The extension also supports provisioning queues and subscriptions on broker given that the user has role access to create queues with subscriptions. Configuration is as follows

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=basic
quarkus.solace.authentication.basic.password=basic

mp.messaging.incoming.temperatures.connector=quarkus-solace
mp.messaging.incoming.temperatures.consumer.queue.missing-resource-creation-strategy=create-on-start
mp.messaging.incoming.temperatures.consumer.queue.add-additional-subscriptions=true
mp.messaging.incoming.temperatures.consumer.subscriptions=hello/foobar

A minimal configuration for the Solace connector with an incoming channel and direct client looks like the following:

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=basic
quarkus.solace.authentication.basic.password=basic

mp.messaging.incoming.temperatures.client.type=direct
mp.messaging.incoming.temperatures.connector=quarkus-solace
mp.messaging.incoming.temperatures.consumer.subscriptions=sensor/temperatures

  1. When running in dev mode or tests dev services will automatically start a Solace PubSub+ broker and if broker configuration details are not provided the extension automatically picks up the details of broker started by dev services.

  2. If consumer.queue.name property is not specified, channel name will be used as queue name.

Receiving messages from Solace

Using the previous configuration, Quarkus application can receive message in several possible ways.

Direct Payload

import org.eclipse.microprofile.reactive.messaging.Incoming;
import jakarta.enterprise.context.ApplicationScoped;
@ApplicationScoped
public class TemperaturesConsumer {
    @Incoming("temperatures")
    public void consume(byte[] temperature) {
        // process.
    }
}

Message

@ApplicationScoped
public class TemperaturesConsumer {
    @Incoming("temperatures")
    public CompletionStage<Void> consume(Message<byte[]> msg) {
        // access record metadata
        SolaceInboundMetadata metadata = msg.getMetadata(SolaceInboundMetadata.class).orElseThrow();
        // process the message payload.
        double temperature = Double.parseDouble(new String(p.getPayload()));
        // Acknowledge the incoming message
        return msg.ack();
    }
}

SolaceInboundMessage This is a wrapper to incoming Inbound Message from Solace Messaging API

import com.solace.messaging.receiver.InboundMessage;
@ApplicationScoped
public class TemperaturesConsumer {
    @Incoming("temperatures")
    public void consume(InboundMessage inboundMessage) {
        // process the message payload.
        String temperature = inboundMessage.getPayloadAsString();
    }
}

Acknowledgment Handling

By default, for persistent client acknowledgement strategy is set to client acknowledgement. This gives greater control over acknowledgement and ensures that messages are acknowledged only after successful processing.

In case of direct client no acknowledgement is sent to the broker.

@ApplicationScoped
public class TemperaturesConsumer {
    @Incoming("temperatures")
    public CompletionStage<Void> consume(Message<byte[]> msg) {
        // access record metadata
        SolaceInboundMetadata metadata = msg.getMetadata(SolaceInboundMetadata.class).orElseThrow();
        // process the message payload.
        double temperature = Double.parseDouble(new String(p.getPayload()));
        // Acknowledge the incoming message
        return msg.ack();
    }
}

Failure Strategies

If a message is nacked, a failure strategy is applied. Refer to Incoming Configuration Reference[quarkus-solace_quarkus.consumer.failure-strategy]. The default strategy is set to ignore and move on to next message. Following are the strategies supported by Quarkus Solace Messaging Connector extension.

ignore - Mark the message as IGNORED, will continue processing with next message. It TTL and DMQ are configured on the queue message will be moved to DMQ once TTL is reached. If no DMQ is configured but TTL is set message will be lost.

fail - Mark the message as FAILED, broker will redeliver the message. Nacks are supported on event brokers 10.2.1 and later, so enable this strategy based on broker version.

discard - Mark the message as REJECTED, broker will discard the message. The message will be moved to DMQ if DMQ is configured for queue and DMQ Eligible is set on message otherwise message will be lost. Nacks are supported on event brokers 10.2.1 and later, so enable this strategy based on broker version.

error_topic - Will publish the message to configured error topic, on success the message will be acknowledged in the queue.

Sending messages to Solace

Outgoing channel configuration to publish persistent messages to Solace.

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=basic
quarkus.solace.authentication.basic.password=basic

mp.messaging.outgoing.temperatures-out.connector=quarkus-solace
mp.messaging.outgoing.temperatures-out.producer.topic=temperatures

Outgoing channel configuration to publish direct messages to Solace.

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=basic
quarkus.solace.authentication.basic.password=basic

mp.messaging.outgoing.temperatures-out.client.type=direct
mp.messaging.outgoing.temperatures-out.connector=quarkus-solace
mp.messaging.outgoing.temperatures-out.producer.topic=temperatures

  1. When running in dev mode or tests dev services will automatically start a Solace PubSub+ broker and if broker configuration details are not provided the extension automatically picks up the details of broker started by dev services.

  2. If producer.topic property is not specified, channel name will be used as topic name.

Using the previous configuration Quarkus application can publish messages as follows

import io.smallrye.mutiny.Multi;
import org.eclipse.microprofile.reactive.messaging.Outgoing;

import jakarta.enterprise.context.ApplicationScoped;
import java.time.Duration;
import java.util.Random;

@ApplicationScoped
public class TemperaturesProducer {

    private final Random random = new Random();

    @Outgoing("temperatures-out")
    public Multi<Double> generate() {
        // Emit 1000 records
        return Multi.createFrom().range(0, 1000)
            .map(x -> random.nextDouble());
    }

}

You can also generate a org.eclipse.microprofile.reactive.messaging.Message with required metadata and publish to Solace.

@ApplicationScoped
public class TemperaturesProducer {
    private final Random random = new Random();

    @Outgoing("temperatures-out")
    Multi<Message<Double>> publishTemperatures() {
        return Multi.createFrom().range(0, 1000)
            .map(i -> {
                 SolaceOutboundMetadata outboundMetadata = SolaceOutboundMetadata.builder()
                .setApplicationMessageId(Integer.toString(i)).createPubSubOutboundMetadata();
                 return Message.of(random.nextDouble(), Metadata.of(outboundMetadata));
            });
    }
}

SolaceOutboundMetadata allows to configure metadata for the message. It supports all the headers supported by Solace and custom user properties. In addition to this it also supports configuring dynamic topic which overrides the default topic in application configuration file.

Generating org.eclipse.microprofile.reactive.messaging.Message with dynamic topic and publish to Solace.

@ApplicationScoped
public class TemperaturesProducer {
    private final Random random = new Random();

    @Outgoing("temperatures-out")
    Multi<Message<Double>> publishTemperatures() {
        return Multi.createFrom().range(0, 1000)
            .map(i -> {
                 SolaceOutboundMetadata outboundMetadata = SolaceOutboundMetadata.builder()
                .setApplicationMessageId(Integer.toString(i))
                .setDynamicDestination("device/" + Integer.toString(i) + "/temperature").createPubSubOutboundMetadata();
                 return Message.of(random.nextDouble(), Metadata.of(outboundMetadata));
            });
    }
}

Generating org.eclipse.microprofile.reactive.messaging.Message with partition key and publish to Solace.

@ApplicationScoped
public class TemperaturesProducer {
    private final Random random = new Random();

    @Outgoing("temperatures-out")
    Multi<Message<Double>> publishTemperatures() {
        return Multi.createFrom().range(0, 1000)
            .map(i -> {
                String partitionKey = "Group-1";
                if(i % 2 == 0) {
                    partitionKey = "Group-2";
                }
                 SolaceOutboundMetadata outboundMetadata = SolaceOutboundMetadata.builder()
                .setApplicationMessageId(Integer.toString(i))
                .setPartitionKey(partitionKey).createPubSubOutboundMetadata();
                 return Message.of(random.nextDouble(), Metadata.of(outboundMetadata));
            });
    }
}

Sending messages with @Emitter

@Path("/temperatures")
public class PublisherResource {

    @Channel("temperatures-out")
    MutinyEmitter<Temperature> temperatureEmitter;

    @POST
    @Path("/publish")
    public Uni<Void> publish(Temperature temperature) {
        return temperatureEmitter.send(temperature);
    }
}

Producer Acknowledgement

Producer can return successful acknowledgement when [quarkus-solace_quarkus.producer.waitForPublishReceipt] is enabled.

This property is considered only when [quarkus-solace_quarkus.client.type] is set to persistent. The connector will wait for response from broker and will return success or failed acknowledgement.

In case of [quarkus-solace_quarkus.client.type] is set to direct this property is ignored as broker will not send any response. By default, success acknowledgement is returned and any failures during publish are logged as exceptions.

Producer Back-Pressure strategies

Quarkus Solace Messaging connector provides three different strategies to handle back-pressure when publishing messages

1.Reject - Publisher will start rejecting messages once specified limit is reached

2.Wait - Publisher is throttled when a specified limit is reached

3.Elastic - Use an unlimited internal buffer (default)

In the current version we don’t recommend to use back-pressure strategy Reject as it is in evolving phase.

Refer to Outgoing Configuration Reference[quarkus-solace_quarkus.producer.back-pressure.strategy] and Outgoing Configuration Reference[quarkus-solace_quarkus.producer.back-pressure.buffer-capacity] on how to configure back-pressure for producer.

Processing Messages

Applications streaming data often need to consume some events from a topic, process them and publish the result to a different topic. A processor method can be simply implemented using both the @Incoming and @Outgoing annotations:

import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Outgoing;

import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped
public class TemperaturesProcessor {

    @Incoming("temperatures-in")
    @Outgoing("temperatures-out")
    public double process(byte[] temperature) {
        return (Double.parseDouble(new String(p.getPayload())) - 32) * 5 / 9;
    }

}

Open Telemetry Tracing

Extension supports generating trace messages for th messages consumed and published by the extension. To enabling tracing for consumers and producers use the below configuration.

quarkus.solace.host=tcp://localhost:55555
quarkus.solace.vpn=default
quarkus.solace.authentication.basic.username=test
quarkus.solace.authentication.basic.password=test

mp.messaging.incoming.temperatures.connector=quarkus-solace
mp.messaging.incoming.temperatures.consumer.queue.name=temperatures
mp.messaging.incoming.temperatures.client.tracing-enabled=true

mp.messaging.outgoing.temperatures-out.connector=quarkus-solace
mp.messaging.outgoing.temperatures-out.producer.topic=temperatures
mp.messaging.outgoing.temperatures-out.client.tracing-enabled=true
Context Propagation is not fully supported in current version.

Health Checks

Quarkus provides several health checks for Solace. These checks are used in combination with the quarkus-smallrye-health extension.

Reactive Messaging Health Checks

When using Reactive Messaging and the Quarkus Solace Messaging Connector, each configured channel (incoming or outgoing) provides startup, liveness and readiness checks.

The startup check verifies that the communication with Solace Broker is established.

The liveness check captures any unrecoverable failure happening during the communication with Solace.

The readiness check verifies that the Quarkus Solace Messaging Connector is ready to consume/produce messages to the configured Solace queues/topics.

Dev Services

Solace Dev Services for Quarkus will spin up latest version of Solace PubSub standard with label solace when running tests or in dev mode. Solace Dev Services are enabled by default and will check for any existing containers with same label to reuse. If none is present a new container is started.

Metrics

Quarkus Solace Messaging Connector exposes different metrics provided by Solace Java Messaging API. The metrics are enabled by default and can be accessed at http://localhost:8080/q/dev-ui/io.quarkus.quarkus-micrometer/prometheus