Please add a note to set this based on the requirement.

devAddr is not a key.

joinEUI is not a key.

Please add comments to exported functions.

nit: This is only used once. You can consider embedding it.

If the appKey is nil, we should error.

idem

How is this going to work? We can't just make up the AppSKey for the device session and expect the device to communicate with TTS right?

I think if migration with session is required and there are no session keys in the AWS device, we should error or skip the device with a warning.

The EUIs for an end device are mandatory primary identifiers. This is technically correct but I don't feel comfortable passing the IDs out of a function without setting the EUIs.

How about if it's an ABP device? I think it would be better if we refactor abp, otaa := d.sessionKeys() to a setKeys() function that checks if the device is OTAA or ABP and then checks if session is required and sets the appropriate keys and fails when a particular required key is not found.

@KrishnaIyer I will refactor this and fix all the above mentioned things.

But I think it is not possible to export the session context from the AWS IoT. Sorry for realizing this so late but I was a little bit confused by the ABP session keys and the implementation that I took over.

I checked the LoRaWAN specifications and the AWS API doc again and I think what we need for session context is for OTAA devices is the NwkSKey, AppSKey, FCntUp, FCntDown and the DevAddr but AWS doesn't provide these values for OTAA devices. It only provides the root keys

// OTAA device object for v1.0.x
type OtaaV1_0_x struct {

	// The AppEUI value. You specify this value when using LoRaWAN versions v1.0.2 or
	// v1.0.3.
	AppEui *string

	// The AppKey value.
	AppKey *string

	// The GenAppKey value.
	GenAppKey *string

	// The JoinEUI value. You specify this value instead of the AppEUI when using
	// LoRaWAN version v1.0.4.
	JoinEui *string

	noSmithyDocumentSerde
}

For ABP devices we have the session keys (but because by default ABP using the session keys instead of the root keys)

// Session keys for ABP v1.1
type SessionKeysAbpV1_0_x struct {

	// The AppSKey value.
	AppSKey *string

	// The NwkSKey value.
	NwkSKey *string

	noSmithyDocumentSerde
}

But AWS doesn't provide any of the counters FCntUp, FCntDown and for OTAA devices doesn't provide the DevAddr.

So in that sense we can only export the devices without the session context.

AWS SDK doc

Ok I see. Unfortunately, these are not in the API as well.

But AWS doesn't provide any of the counters FCntUp, FCntDown

What about FCntStart? What is it used for?

Ok then let's document the fact that OTAA devices need to rejoin. If FCntSTart isn't something we can use, then let's also document that exporting ABP is not supported. In both cases, please add links to AWS IoT API docs.