[jira] [Updated] (CAMEL-15748) Paho consumer never connects if the broker is not reachable at startup

["Claus Ibsen (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CAMEL-15748?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Claus Ibsen updated CAMEL-15748:
--------------------------------
    Fix Version/s: 3.7.0
                   3.4.5

> Paho consumer never connects if the broker is not reachable at startup
> ----------------------------------------------------------------------
>
>                 Key: CAMEL-15748
>                 URL: https://issues.apache.org/jira/browse/CAMEL-15748
>             Project: Camel
>          Issue Type: Bug
>          Components: camel-paho
>    Affects Versions: 3.5.0, 3.4.4, 3.6.0
>            Reporter: Marco Collovati
>            Priority: Major
>             Fix For: 3.4.5, 3.7.0
>
>
> Having a route with a paho consumer in a route, if the broker is not reachable at startup, camel context fail fast and shuts down.
>  This can be avoided by setting the *SupervisingRouteController*, but this way, even if camel context does not fail, the consumer is never able to establish a connection.
> The reason is that when *PahoConsumer* starts for the first time, it creates a *MqttClient* and stores it into *client* field; the call to *client.connect* throws an exception due to broker down;
>  
> {code:java}
>  
>     @Override
>     protected void doStart() throws Exception {
>         super.doStart();        connectOptions = PahoEndpoint.createMqttConnectOptions(getEndpoint().getConfiguration());        if (client == null) {
>             clientId = getEndpoint().getConfiguration().getClientId();
>             if (clientId == null) {
>                 clientId = "camel-" + MqttClient.generateClientId();
>             }
>             stopClient = true;
>             client = new MqttClient(
>                     getEndpoint().getConfiguration().getBrokerUrl(),
>                     clientId,
>                     PahoEndpoint.createMqttClientPersistence(getEndpoint().getConfiguration()));
>             LOG.debug("Connecting client: {} to broker: {}", clientId, getEndpoint().getConfiguration().getBrokerUrl());
>             client.connect(connectOptions);
>         }
>         
>         // other code omitted for brevity
>         
>         client.subscribe(getEndpoint().getTopic(), getEndpoint().getConfiguration().getQos());{code}
>  
> after that *doStop* is invoked but the *client* instance is not nullified, because it is not connected
>  
> {code:java}
>     @Override
>     protected void doStop() throws Exception {
>         super.doStop();        if (stopClient && client != null && client.isConnected()) {
>             String topic = getEndpoint().getTopic();
>             // only unsubscribe if we are not durable
>             if (getEndpoint().getConfiguration().isCleanSession()) {
>                 LOG.debug("Unsubscribing client: {} from topic: {}", clientId, topic);
>                 client.unsubscribe(topic);
>             } else {
>                 LOG.debug("Client: {} is durable so will not unsubscribe from topic: {}", clientId, topic);
>             }
>             LOG.debug("Disconnecting client: {} from broker: {}", clientId, getEndpoint().getConfiguration().getBrokerUrl());
>             client.disconnect();
>             client = null;
>         }
>     }
> {code}
>  
> when the supervisor tries to restart the route, *client* instance already exists, but the call to *client.subscribe* fails because the client is not connected.
> Perhaps always nullify *client* in *doStop* should resolve the issue; however I have no idea it this solution will impact in other ways.
>  A better solution may be to handle automatic reconnect in the consumer, like *RabbitConsumer* does, for example.



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