Strongly tie a observation to a server endpoint

[sbernard31]

A registration is now tied to server endpoint. (see https://github.com/eclipse-leshan/leshan/pull/1655) Then observation should also be tied to 1 server endpoint.

This will avoid Observation Token conflict between different server endpoint. (currently a token should be unique by Leshan Server with this modification a Observation Token should be unique by server endpoint)

So concretely that mean that Observation Identifier has changed.
Before it was just a CoAP token, now this is the (CoAP token + server endpoint Uri used). Unfortunately this will break RedisRegistrationStore data compatibility. (see https://github.com/eclipse-leshan/leshan/issues/1418#issuecomment-2419924978)

[sbernard31]

@JaroslawLegierski , @cyril2maq, Oops I did it again. I break the RedisRegistrationStore Data compatibility.

I let you know that as soon as possible, so we can try to anticipate issue about it.

Maybe better to read this comment : https://github.com/eclipse-leshan/leshan/issues/1415#issue-1617480570 too.

Let discuss about that here.

[JaroslawLegierski]

@JaroslawLegierski , @cyril2maq, Oops I did it again. I break the RedisRegistrationStore Data compatibility.

I let you know that as soon as possible, so we can try to anticipate issue about it.

Maybe better to read this comment : #1415 (comment) too.

Let discuss about that here.

I tested this change today and as I understand it, the change in Redis is the addition the field e.g. "epUri": "coaps://0.0.0.0:5684", in JSON presented below for the key "OBS#TKN#...." responsible for observation for partitcular LwM2M client

		{
			"id": "d53329b026af5dd2",
			"epUri": "coaps://0.0.0.0:5684",
			"regid": "mIqhc2qKmg",
			"userContext": {},
			"protocolData": {
				"leshan-cf-obs": {
					"request": "48018072d53329b026af5dd260543333303301300435373030622d17",
					"peer": {
						"address": "127.0.0.1",
						"port": 50926,
						"id": "leshan_1",
						"attributes": {
							"*DTLS_HANDSHAKE_MODE": "auto"
						}
					},
					"context": {
						"leshan-endpoint": "leshan1",
						"leshan-path": "/3303/0/5700n",
						"leshan-regId": "mIqhc2qKmg}}"
					},
					"kind": "single",
					"ct": 11543,
					"path": "/3303/0/5700"
				}
			}
		}

So the change only affects leshan clients with observation. Am I right?

[sbernard31]

This is a bit more than that : see https://github.com/eclipse-leshan/leshan/issues/1418#issuecomment-2419924978

So the change only affects leshan clients with observation. Am I right?

Those keys are only about observations. But I don't know what happens if you are using an old registration using previous key with the new code in case where you don't use observations (I didn't test it)

[JaroslawLegierski]

This is a bit more than that : see #1418 (comment)

So the change only affects leshan clients with observation. Am I right?

Those keys are only about observations. But I don't know what happens if you are using an old registration using previous key with the new code in case where you don't use observations (I didn't test it)

I tested the code change on the server side. After retransmissions (we lost InMemoryReadWriteLockConnectionStore in server after server replace), the LwM2M client (Leshan client demo) initiated a new handshake and finally successfully completed the registration update.

[JaroslawLegierski]

This is a bit more than that : see #1418 (comment)

So the change only affects leshan clients with observation. Am I right?

Those keys are only about observations. But I don't know what happens if you are using an old registration using previous key with the new code in case where you don't use observations (I didn't test it)

I noticed that the secondary index "OBSIDS#REGID#.... in my Redis has always the value null

127.0.0.1:6379> keys *
1) "REG#EP#leshan1"
2) "EP#ADDR#/127.0.0.1:58045"
3) "OBSIDS#REGID#hi8A1xB0n5"
4) "OBS#OBSID#coaps://0.0.0.0:5684##\xcd\xd4z\xc4\xd70\x8c#"
5) "EP#REGID#hi8A1xB0n5"
6) "SEC#EP#leshan1"
7) "EXP#EP"
8) "EP#PSKID"
9) "EP#IDENTITY#{\"type\":\"psk\",\"pskid\":\"leshan_1\"}"
127.0.0.1:6379> mget "OBSIDS#REGID#hi8A1xB0n5"
1) (nil)

Are you also getting this error on your side? (I don't know if the problem is in my Redis or if the lpush method in RedisRegistrationStore is not working properly)

[sbernard31]

OBSIDS#REGID#*has a list value. I don't know if MGET command works on it. In Leshan code we use LRANGE.

[JaroslawLegierski]

OBSIDS#REGID#*has a list value. I don't know if MGET command works on it. In Leshan code we use LRANGE.

Sure I completely forgot that this is list of values. LRAGE reads it. Thx!