Fail to unmarshal event, SimpleReading.Value field is required when a reading contains empty string value

[jinlinGuan]

🐞 Bug Report

Affected Services [REQUIRED]

The issue is located in:

core-data

Is this a regression?

--

Description and Minimal Reproduction [REQUIRED]

When an event from a device service contains a reading with empty value for string type, the SimpleReading.Value validation fails.

🔥 Exception or Error

Remove the required validation in

go-mod-core-contracts/dtos/reading.go

Line 40 in f00d2ae

Value string `json:"value" validate:"required"`

The value can still be checked by

go-mod-core-contracts/dtos/reading.go

Lines 286 to 288 in f00d2ae

	if err := ValidateValue(b.ValueType, simpleReading.Value); err != nil {
	return edgexErrors.NewCommonEdgeX(edgexErrors.KindContractInvalid, fmt.Sprintf("The value does not match the %v valueType", b.ValueType), nil)
	}

🌍 Your Environment

Deployment Environment:

EdgeX Version [REQUIRED]:
main

Anything else relevant?