public class HttpFeed
extends AbstractFeed

Provides a feed of attribute values, by polling over http. Example usage (e.g. in an entity that extends SoftwareProcessImpl):

 private HttpFeed feed;
 
 //@Override
 protected void connectSensors() {
   super.connectSensors();
   
   feed = HttpFeed.builder()
       .entity(this)
       .period(200)
       .baseUri(String.format("http://%s:%s/management/subsystem/web/connector/http/read-resource", host, port))
       .baseUriVars(ImmutableMap.of("include-runtime","true"))
       .poll(new HttpPollConfig<Boolean>(SERVICE_UP)
           .onSuccess(HttpValueFunctions.responseCodeEquals(200))
           .onError(Functions.constant(false)))
       .poll(new HttpPollConfig<Integer>(REQUEST_COUNT)
           .onSuccess(HttpValueFunctions.jsonContents("requestCount", Integer.class)))
       .build();
 }
 
 {@literal @}Override
 protected void disconnectSensors() {
   super.disconnectSensors();
   if (feed != null) feed.stop();
 }
 
 

This also supports giving a Supplier for the URL (e.g. Entities.attributeSupplier(brooklyn.entity.Entity, brooklyn.event.AttributeSensor)) from a sensor. Note however that if a Supplier-based sensor is *https*, https-specific initialization may not occur if the URL is not available at start time, and it may report errors if that sensor is not available. Some guidance for controlling enablement of a feed based on availability of a sensor can be seen in HttpLatencyDetector (in brooklyn-policy).