Need help with Apama EPL

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1

Hi Community,
please see my question below.

What product/components do you use and which version/fix level?

Cumulocity
Backend: 1011.0.12
UI: 1010.0.24

Are you using a free trial or a product with a customer license?

License

What are trying to achieve? Please describe in detail.

I try to write an EPL flow to create an operation for a device.

It only works when I remove line (1),

image
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then I can Set the Parameters as direct input in the Field like this

image
image351×750 17.4 KB

Resulting in

image

Now, what I need to have instead of “my Command” - I need to have a fragment & value of an Event Object (the last occurrence of an Event)

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But I just cant manage to extract this fragment from the Event Object and also I can not manage to send the fixed values necessary to the input channel of the Operations creator.

Which block I need to use to extract?

Any help is much appreciate.
Also, if there is a place where I can find sample flows of EPL I would like to check out working solutions…

Thank you very much
BR Manfred

2

Hi,

You can use the Extract Properties block (Eigen­schaft extrahieren) to extract properties from the incoming event. You can combine the extracted properties with additional values using the Set Properties block (Eigenschaften festlegen). See the example below:

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extract properties.zip (951 Bytes)

Thanks,
Gyan

3

Hi BR Manfred,

Is the issue resolved for you or do you need further help on it?

Thanks,
Gyan

4

Hello Gyan,
sorry for not replying and thank you for reaching out again.

I was on holidays and afterwards - not surprisingly - there was waiting some urgent matters I had to handle.

But no, I still could not finish this task.

Maybe you could take a look on my trial, attached.
Instead of an event I would like to use for the basic test a contant value.

None of the parameters are used on the operation. Only an operation is created, nothing more.

image
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In the Shell there is nothing, means also “c8y_Command” is not recogniced.

Thank you in advance.
BR
Manfred
Timer1 (3).zip (1.2 KB)

5

The model you attached currently generate following operation json:

{
  "Description": {
    "value": "myTestOperation"
  },
  "creationTime": "2022-09-02T08:17:17.347Z",
  "ParameterValue": {
    "value": "Para-Value"
  },
  "apama_analytics_modelName": "Timer1",
  "OperationName": {
    "value": "c8y_Command"
  },
  "self": "http://t322920.latest.stage.c8y.io/devicecontrol/operations/1205204",
  "ParameterName": {
    "value": "Para-Name"
  },
  "id": "1205204",
  "deviceId": "1194307",
  "deviceName": "dev_1",
  "modelTime": "2022-09-02T08:17:16.300+00:00",
  "status": "PENDING"
}

So Extract Properties and Set Properties block are working properly. But I suppose this is not the JSON format you want?
For comparison, if you directly specify values in the output block instead of using the properties, following Operation json is generated:

{
	"creationTime": "2022-09-02T08:59:48.673Z",
	"deviceId": "1194307",
	"deviceName": "dev_1",
	"self": "https://t322920.latest.stage.c8y.io/devicecontrol/operations/1205213",
	"id": "1205213",
	"status": "PENDING",
	"apama_analytics_modelName": "Timer1",
	"c8y_Command": {
		"Para-Name": "Para-Value"
	},
	"description": "myTestOperation",
	"modelTime": "2022-09-02T08:59:47.600+00:00"
}

To help you properly with this, can you provide following details:

  • The exact JSON format of the Operation you want to create.
  • Part of the operation data which would be fixed
  • Part of the operation data which comes from incoming Event
  • The JSON format of the incoming Event or exact JSON format of the Event data which you want to extract

Thanks,
Gyan

6

Hi Gyan
I just tried for some time, but I just cant figure out how it really works. So I will provide you the necessary information. In advance a big Thank You for your time and support.

First - the Event I need to extract some information.
On the other hand, at the moment, I don’t see any disadvantage in sending the complete information with the Operation (all text that I receive from the Event)

But absolutly necessary is c8y_ua_DataValue.value.value: 5.0

       {
            "creationTime": "2022-09-01T20:59:29.672Z",
            "source": {
                "name": "V2-EVENT (CCC-0)",
                "id": "40345879"
            },
            "type": "f5sMachineStateOPC",
            "lastUpdated": "2022-09-01T20:59:29.672Z",
            "time": "2022-09-01T22:59:25.096+02:00",
            "id": "45938246",
            "text": "Maschinen Status",
            "c8y_ua_SourceNodeId_ns=6;s=::OPCUaMappi:OPCInterf.WriteMES.c8yMaschinenStatus.Status": {},
            "c8y_ua_DataValue": {
                "sourceTimestamp": 133065395650965765,
                "serverTimestamp": 133065395650965765,
                "value": {
                    "value": 5.0
                },
                "statusCode": 0
            }
        },

The Operation I want to create is this

            "description": "connectionStatus update",
            "ConnectionStatus": {
                "text": "*TEXT FROM EVENT GOES HERE*"
            },

What I find - and dont know how to solve: When I use the “Operations Output” block with direct filling in of the parameters (without “live” data from the event), the operation created looks like this
image

But when I connect the “SetParameter” Block to merge live data from Event, it looks different. I refer to your remarks on the answer from you…

I hope I could provide you with all necessary information.

Thank you a lot
BR Manfred

7

Hi Gyan,
in the mean-time this issue is solved.
Thank you for spending your time on the issue and helping me.
Finally solution is cascading the “set-property” blocks to get the structure I need.

Thanks again
BR Manfred

8

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