Integration Graph

Starting with version 4.3, Spring Integration provides access to an application’s runtime object model, which can, optionally, include component metrics. It is exposed as a graph, which may be used to visualize the current state of the integration application. The o.s.i.support.management.graph package contains all the required classes to collect, build, and render the runtime state of Spring Integration components as a single tree-like Graph object. The IntegrationGraphServer should be declared as a bean to build, retrieve, and refresh the Graph object. The resulting Graph object can be serialized to any format, although JSON is flexible and convenient to parse and represent on the client side. A Spring Integration application with only the default components would expose a graph as follows:

{
  "contentDescriptor": {
    "providerVersion": "4.3.0.RELEASE",
    "providerFormatVersion": 1.0,
    "provider": "spring-integration",
    "name": "myApplication"
  },
  "nodes": [
    {
      "nodeId": 1,
      "name": "nullChannel",
      "stats": null,
      "componentType": "channel"
    },
    {
      "nodeId": 2,
      "name": "errorChannel",
      "stats": null,
      "componentType": "publish-subscribe-channel"
    },
    {
      "nodeId": 3,
      "name": "_org.springframework.integration.errorLogger",
      "stats": {
        "duration": {
          "count": 0,
          "min": 0.0,
          "max": 0.0,
          "mean": 0.0,
          "standardDeviation": 0.0,
          "countLong": 0
        },
        "errorCount": 0,
        "standardDeviationDuration": 0.0,
        "countsEnabled": true,
        "statsEnabled": true,
        "loggingEnabled": false,
        "handleCount": 0,
        "meanDuration": 0.0,
        "maxDuration": 0.0,
        "minDuration": 0.0,
        "activeCount": 0
      },
      "componentType": "logging-channel-adapter",
      "output": null,
      "input": "errorChannel"
    }
  ],
  "links": [
    {
      "from": 2,
      "to": 3,
      "type": "input"
    }
  ]
}

In the preceding example, the graph consists of three top-level elements.

The contentDescriptor graph element contains general information about the application providing the data. The name can be customized on the IntegrationGraphServer bean or in the spring.application.name application context environment property. Other properties are provided by the framework and let you distinguish a similar model from other sources.

The links graph element represents connections between nodes from the nodes graph element and, therefore, between integration components in the source Spring Integration application. For example, from a MessageChannel to an EventDrivenConsumer with some MessageHandler or from an AbstractReplyProducingMessageHandler to a MessageChannel. For convenience and to let you determine a link’s purpose, the model includes the type attribute. The possible types are:

input: Identifies the direction from MessageChannel to the endpoint, inputChannel, or requestChannel property
output: The direction from the MessageHandler, MessageProducer, or SourcePollingChannelAdapter to the MessageChannel through an outputChannel or replyChannel property
error: From MessageHandler on PollingConsumer or MessageProducer or SourcePollingChannelAdapter to the MessageChannel through an errorChannel property;
discard: From DiscardingMessageHandler (such as MessageFilter) to the MessageChannel through an errorChannel property.
route: From AbstractMappingMessageRouter (such as HeaderValueRouter) to the MessageChannel. Similar to output but determined at run-time. May be a configured channel mapping or a dynamically resolved channel. Routers typically retain only up to 100 dynamic routes for this purpose, but you can modify this value by setting the dynamicChannelLimit property.

The information from this element can be used by a visualization tool to render connections between nodes from the nodes graph element, where the from and to numbers represent the value from the nodeId property of the linked nodes. For example, the link element can be used to determine the proper port on the target node.

The following “text image” shows the relationships between the types:

              +---(discard)
              |
         +----o----+
         |         |
         |         |
         |         |
(input)--o         o---(output)
         |         |
         |         |
         |         |
         +----o----+
              |
              +---(error)

The nodes graph element is perhaps the most interesting, because its elements contain not only the runtime components with their componentType instances and name values but can also optionally contain metrics exposed by the component. Node elements contain various properties that are generally self-explanatory. For example, expression-based components include the expression property that contains the primary expression string for the component. To enable the metrics, add an @EnableIntegrationManagement to a @Configuration class or add an <int:management/> element to your XML configuration. You can control exactly which components in the framework collect statistics. See Metrics and Management for complete information. See the stats attribute from the o.s.i.errorLogger component in the JSON example shown earlier. In this case, The nullChannel and errorChannel do not provide statistics information, because the configuration for this example was as follows:

@Configuration
@EnableIntegration
@EnableIntegrationManagement(statsEnabled = "_org.springframework.integration.errorLogger.handler",
      countsEnabled = "!*",
      defaultLoggingEnabled = "false")
public class ManagementConfiguration {

    @Bean
    public IntegrationGraphServer integrationGraphServer() {
        return new IntegrationGraphServer();
    }

}

The nodeId represents a unique incremental identifier to let you distinguish one component from another. It is also used in the links element to represent a relationship (connection) of this component to others, if any. The input and output attributes are for the inputChannel and outputChannel properties of the AbstractEndpoint, MessageHandler, SourcePollingChannelAdapter, or MessageProducerSupport. See the next section for more information.

Starting with version 5.1, the IntegrationGraphServer accepts a Function<NamedComponent, Map<String, Object>> additionalPropertiesCallback for population of additional properties on the IntegrationNode for a particular NamedComponent. For example you can expose the SmartLifecycle autoStartup and running properties into the target graph:

server.setAdditionalPropertiesCallback(namedComponent -> {
            Map<String, Object> properties = null;
            if (namedComponent instanceof SmartLifecycle) {
                SmartLifecycle smartLifecycle = (SmartLifecycle) namedComponent;
                properties = new HashMap<>();
                properties.put("auto-startup", smartLifecycle.isAutoStartup());
                properties.put("running", smartLifecycle.isRunning());
            }
            return properties;
        });

Graph Runtime Model

Spring Integration components have various levels of complexity. For example, any polled MessageSource also has a SourcePollingChannelAdapter and a MessageChannel to which to periodically send messages from the source data. Other components might be middleware request-reply components (such as JmsOutboundGateway) with a consuming AbstractEndpoint to subscribe to (or poll) the requestChannel (input) for messages, and a replyChannel (output) to produce a reply message to send downstream. Meanwhile, any MessageProducerSupport implementation (such as ApplicationEventListeningMessageProducer) wraps some source protocol listening logic and sends messages to the outputChannel.

Within the graph, Spring Integration components are represented by using the IntegrationNode class hierarchy, which you can find in the o.s.i.support.management.graph package. For example, you can use the ErrorCapableDiscardingMessageHandlerNode for the AggregatingMessageHandler (because it has a discardChannel option) and can produce errors when consuming from a PollableChannel by using a PollingConsumer. Another example is CompositeMessageHandlerNode — for a MessageHandlerChain when subscribed to a SubscribableChannel by using an EventDrivenConsumer.

The @MessagingGateway (see Messaging Gateways) provides nodes for each of its method, where the name attribute is based on the gateway’s bean name and the short method signature. Consider the following example of a gateway:

@MessagingGateway(defaultRequestChannel = "four")
public interface Gate {

	void foo(String foo);

	void foo(Integer foo);

	void bar(String bar);

}

The preceding gateway produces nodes similar to the following:

{
  "nodeId" : 10,
  "name" : "gate.bar(class java.lang.String)",
  "stats" : null,
  "componentType" : "gateway",
  "output" : "four",
  "errors" : null
},
{
  "nodeId" : 11,
  "name" : "gate.foo(class java.lang.String)",
  "stats" : null,
  "componentType" : "gateway",
  "output" : "four",
  "errors" : null
},
{
  "nodeId" : 12,
  "name" : "gate.foo(class java.lang.Integer)",
  "stats" : null,
  "componentType" : "gateway",
  "output" : "four",
  "errors" : null
}

You can use this IntegrationNode hierarchy for parsing the graph model on the client side as well as to understand the general Spring Integration runtime behavior. See also Programming Tips and Tricks for more information.

Integration Graph Controller

If your application is web-based (or built on top of Spring Boot with an embedded web container) and the Spring Integration HTTP or WebFlux module (see HTTP Support and WebFlux Support, respectively) is present on the classpath, you can use a IntegrationGraphController to expose the IntegrationGraphServer functionality as a REST service. For this purpose, the @EnableIntegrationGraphController and @Configuration class annotations and the <int-http:graph-controller/> XML element are available in the HTTP module. Together with the @EnableWebMvc annotation (or <mvc:annotation-driven/> for XML definitions), this configuration registers an IntegrationGraphController @RestController where its @RequestMapping.path can be configured on the @EnableIntegrationGraphController annotation or <int-http:graph-controller/> element. The default path is /integration.

The IntegrationGraphController @RestController provides the following services:

@GetMapping(name = "getGraph"): To retrieve the state of the Spring Integration components since the last IntegrationGraphServer refresh. The o.s.i.support.management.graph.Graph is returned as a @ResponseBody of the REST service.
@GetMapping(path = "/refresh", name = "refreshGraph"): To refresh the current Graph for the actual runtime state and return it as a REST response. It is not necessary to refresh the graph for metrics. They are provided in real-time when the graph is retrieved. Refresh can be called if the application context has been modified since the graph was last retrieved. In that case, the graph is completely rebuilt.

You can set security and cross-origin restrictions for the IntegrationGraphController with the standard configuration options and components provided by the Spring Security and Spring MVC projects. The following example achieves those goals:

<mvc:annotation-driven />

<mvc:cors>
	<mvc:mapping path="/myIntegration/**"
				 allowed-origins="http://localhost:9090"
				 allowed-methods="GET" />
</mvc:cors>

<security:http>
    <security:intercept-url pattern="/myIntegration/**" access="ROLE_ADMIN" />
</security:http>


<int-http:graph-controller path="/myIntegration" />

The following example shows how to do the same thing with Java configuration:

@Configuration
@EnableWebMvc // or @EnableWebFlux
@EnableWebSecurity // or @EnableWebFluxSecurity
@EnableIntegration
@EnableIntegrationGraphController(path = "/testIntegration", allowedOrigins="http://localhost:9090")
public class IntegrationConfiguration extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
	    http
            .authorizeRequests()
               .antMatchers("/testIntegration/**").hasRole("ADMIN")
            // ...
            .formLogin();
    }

    //...

}

Note that, for convenience, the @EnableIntegrationGraphController annotation provides an allowedOrigins attribute. This provides GET access to the path. For more sophistication, you can configure the CORS mappings by using standard Spring MVC mechanisms.