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https://issues.apache.org/jira/browse/BROOKLYN-356?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15625023#comment-15625023
]
ASF GitHub Bot commented on BROOKLYN-356:
-----------------------------------------
Github user aledsage commented on a diff in the pull request:
https://github.com/apache/brooklyn-server/pull/390#discussion_r85903486
--- Diff:
camp/camp-brooklyn/src/main/java/org/apache/brooklyn/camp/brooklyn/spi/dsl/methods/DslComponent.java
---
@@ -353,6 +386,33 @@ public DslSensorSupplier(DslComponent component,
Object sensorIndicator) {
}
@Override
+ public Maybe<Sensor<?>> getImmediately() {
+ return getImmediately(sensorName, false);
+ }
+
+ protected Maybe<Sensor<?>> getImmediately(Object si, boolean
resolved) {
+ if (si instanceof Sensor) {
+ return Maybe.<Sensor<?>>of((Sensor<?>)si);
+ } else if (si instanceof String) {
+ Entity targetEntity = component.get();
+ Sensor<?> result = null;
+ if (targetEntity!=null) {
+ result =
targetEntity.getEntityType().getSensor((String)si);
+ }
+ if (result!=null) return Maybe.<Sensor<?>>of(result);
+ return Maybe.<Sensor<?>>of(Sensors.newSensor(Object.class,
(String)si));
--- End diff --
Not sure I follow. In `attributeWhenReady`, if we're given a sensor name
then we will instantiate a new sensor object if it's not defined on the entity
type; and then we look up the sensor's value (returning Maybe.absent if it's
null). Here, we just want it to return the sensor object (rather than a sensor
value) so we do the first half: instantiate a new sensor object if it's not
defined on the entity type.
This is consistent with the blocking `get()` method. We return
`Maybe.absent()` if the `get()` method would have blocked, and otherwise we
return the same value as `get()` would have returned.
> The sensor Transformer enricher fails to resolve its targetValue
> indeterministically.
> -------------------------------------------------------------------------------------
>
> Key: BROOKLYN-356
> URL: https://issues.apache.org/jira/browse/BROOKLYN-356
> Project: Brooklyn
> Issue Type: Bug
> Reporter: Svetoslav Neykov
>
> The sensor {{Transformer}} enricher fails to resolve its {{targetValue}}
> indeterministically, especially so on loaded systems. This is especially
> problematic if sourceSensor/triggerSensors change infrequently or do not
> change ever (when using default values).
> Bueprints using the {{Transformer}} behave perfectly fine during development
> and on test setups, but will fail on production machines (i.e. under load).
> The code [doing the value
> resolving|https://github.com/apache/brooklyn-server/blob/b59e7463a9b337c2d0e7931cd420d5bac68d8549/core/src/main/java/org/apache/brooklyn/enricher/stock/Transformer.java#L90-L94]
> tries to do so in a non-blocking fashion by spinning a thread to try to
> resolve and cancelling it after a short while without guarantees it ever got
> scheduled to run. It's more likely to fail when nesting DSLs, for example
> nesting several levels of {{$brooklyn:formatString}} and ending with a
> {{$brooklyn:attributeWhenRready}}. It's a common pattern in moderately
> complex blueprints. It needs to schedule a thread for each nesting level thus
> maximizing the chance that the value will not be resolved in the allotted
> time even if resolvabe. This is especially bad for sensors which don't get
> updated, for example {{PortAttributeSensorAndConfigKey} set only when
> initializing the entity or any config values which are always resolvable.
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