How to listen all MeasurementFragment in microservice

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1

I wanted to listen all measurement in my microservices. I am able to get the values in EPL but my EPL implementation is taking too much memory from the available memory.

on all MeasurementFragment(type=“xyz”,valueFragment=“xyz”, valueSeries = “ABC”) as mf {

//

do some calculation
}

2

Two options to achieve that.

  1. Pulling the information periodically using the REST API and (date) filters Cumulocity IoT - OpenAPI Specification
  2. Using Notification API to subscribe on all devices with measurements and filter the relevant one: Cumulocity IoT - OpenAPI Specification

Hint: Don’t use the realTimeAPI but only Notification 2.0

3

Thanks a lot Stefan,

If possible for you , Can you explain me little me more with sample code . It would be great …

4

Hi @prakash.veer06

here is an example subscribing on measurements:

here is an example of polling data (but for the inventory, you can adapt that for the measurements):

5

Hello Stefan,

I am getting below error . I and running this application on my local system and connect with dev tenent.

Could you please help me in this.

023-05-25 17:08:41.087 ERROR 32832 — [subscriptions-0] .s.s.i.MicroserviceSubscriptionScheduler : Error while reacting on microservice subscription

com.cumulocity.sdk.client.SDKException: Error invoking GET http://localhost:8181/application/applicationsByName/hello-microservice-notification
at com.cumulocity.microservice.subscription.repository.impl.LegacyMicroserviceRepository.handleException(LegacyMicroserviceRepository.java:150) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.repository.impl.LegacyMicroserviceRepository.getByName(LegacyMicroserviceRepository.java:101) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.repository.impl.LegacyMicroserviceRepository.register(LegacyMicroserviceRepository.java:62) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.repository.MicroserviceSubscriptionsRepository.register(MicroserviceSubscriptionsRepository.java:110) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.service.impl.MicroserviceSubscriptionsServiceImpl.registerApplication(MicroserviceSubscriptionsServiceImpl.java:169) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.service.impl.MicroserviceSubscriptionsServiceImpl.subscribe(MicroserviceSubscriptionsServiceImpl.java:114) ~[microservice-subscription-1011.0.12.jar!/:na]
at com.cumulocity.microservice.subscription.service.impl.MicroserviceSubscriptionScheduler.lambda$schedulePeriodicSubscription$0(MicroserviceSubscriptionScheduler.java:81) ~[microservice-subscription-1011.0.12.jar!/:na]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) ~[na:na]
at java.base/java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) ~[na:na]
at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:834) ~[na:na]
Caused by: javax.ws.rs.ProcessingException: org.apache.http.conn.HttpHostConnectException: Connect to localhost:8181 [localhost/127.0.0.1, localhost/0:0:0:0:0:0:0:1] failed: Connection refused: connect

6

Hi Prakash,
I think you don’t have done the required configuration set to run a microservice locally:
https://cumulocity.com/guides/microservice-sdk/java/#running-the-microservice-locally

You can also find good examples here:

7

Thanks for your reply Stefan,

I am able to deploy my microservice in Complicity and getting below logs but not getting the measurement data

80 (http) with context path ‘’
2023-05-26 08:10:22.207 INFO 13 — [main] c.e.n.helloworld.NotificationExample : Subscription added for Tenant ID:
2023-05-26 08:10:22.403 INFO 13 — [main] c.e.n.helloworld.NotificationExample : Reusing existing subscription on device <126546272>
2023-05-26 08:10:22.427 INFO 13 — [main] c.e.n.helloworld.NotificationExample : Connecting WebSocket client …
2023-05-26 08:10:22.612 INFO 13 — [WebSocketConnectReadThread-28] c.e.n.helloworld.NotificationExample : Connected to Cumulocity notification service over WebSocket ws://dev.iot.solenis.com/notification/realtime/notification2/consumer/?token=eyJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJ0ZXN0c3Vic2NyaWJlciIsInRvcGljIjoidDU0OTA1L3JlbG5vdGlmL3Rlc3QxMjY1NDYyNzJzdWJzY3JpcHRpb24iLCJqdGkiOiJkM2YwOTVmYi1iOWE0LTRmZGYtODMyOS02OTY5OTQ2OTJkODYiLCJpYXQiOjE2ODUwODg2MjIsImV4cCI6MTY4NTE3NTAyMn0.hlPIqa8NFb2NV5cydb57X3y9JNz5cyu5iEbNMCcj6UVbM6l_22esmjMNIO2SWzqg6JsDkwqMfeq1L5fxHE_zkmB3rGHHakDm9A3VmcI55_mu-DZyWzQu9UiG6pcnQfJ5ECd3DO4rIb4e7hrQx7kdrtnidoK3TV_Blp00XOe5yGaDuQqMWakmhzYgz6m4rhd3AzuY6SHAFr6DeqPBkfiTGrXi-ud_0uOOaZE6xYFYiCpfJSYsyNxNc-8KzBiUz1z0VwuUkdbLDoaCgl08P9y2I1DqgUgi-wSMMSxTMabP4pvL_uNT7JQQ5Ke1I6efetHdWsB6lhBJhSX0GVTJj_MrtQ
2023-05-26 08:10:22.617 INFO 13 — [main] c.e.n.helloworld.HelloWorldApplication : Started HelloWorldApplication in 18.414 seconds (JVM running for 20.565)
2023-05-26 08:10:34.023 INFO 13 — [http-nio-80-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring DispatcherServlet ‘dispatcherServlet’
2023-05-26 08:10:34.023 INFO 13 — [http-nio-80-exec-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet ‘dispatcherServlet’
2023-05-26 08:10:34.101 INFO 13 — [http-nio-80-exec-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 78 ms

8

That’s hard to debug remotely. Most likely there is something wrong with your subscription. Please note that you have to subscribe on “mo” context using “measurements” subscription filter.

https://cumulocity.com/api/core/10.16.0/#operation/postNotificationSubscriptionResource

9

Hello Stefan,

I am able to deploy
SoftwareAG/cumulocity-microservice-templates/tree/main/realtime"*
with my changes and its running fine on local as well as when i deploy on VM and able to get measurements data as in listener.

I am able to deploy this microservices in complicity tenant as well and i got this response when i check the health of microservice.

/service/digitank-calculation/health"*

Response
{
“status”: “UP”,
“components”: {
“diskSpace”: {
“status”: “UP”,
“details”: {
“total”: 158395219968,
“free”: 126023880704,
“threshold”: 10485760,
“exists”: true
}
},
“heapMemory”: {
“status”: “UP”,
“details”: {
“init”: 8388608,
“used”: 34932736,
“committed”: 122683392,
“max”: 392167424,
“threshold”: 19608371
}
},
“livenessState”: {
“status”: “UP”
},
“nonHeapMemory”: {
“status”: “UP”,
“details”: {
“init”: 7667712,
“used”: 87188024,
“committed”: 91262976,
“max”: 377487360,
“threshold”: 18874368
}
},
“ping”: {
“status”: “UP”
},
“readinessState”: {
“status”: “UP”
}
},
“groups”: [
“liveness”,
“readiness”
]
}

But this microservice is not listening the measurement update for specific device or all device.
Am i missing some thing . Please suggest .

10

That one is using the “old” realtime API. You shoud use the notification 2.0 API instead: