feat(store): Allow messages to be marked as "don't store" (#1119)

* feat(store): init allow messages to be marked as ephemeral

* feat(store): replace ephemeral with ttl model

* Revert "feat(store): replace ephemeral with ttl model"

This reverts commit 4398c61c919dda8f014b4fcc0679c573c74854e4.

* fix(store): flags and test

* chore(store): remove storeTTL

* chore(store): remove unused utils

* fix: conflict

* fix(store): make test more brief

tests/v2/test_waku_store.nim

@@ -11,6 +11,7 @@ import
 import
   ../../waku/v2/protocol/waku_message,
   ../../waku/v2/protocol/waku_store,
+  ../../waku/v2/node/storage/message/message_store,
   ../../waku/v2/node/storage/message/waku_store_queue,
   ../../waku/v2/node/storage/message/waku_message_store,
   ../../waku/v2/node/peer_manager/peer_manager,
@@ -30,13 +31,15 @@ proc newTestDatabase(): SqliteDatabase =
 proc fakeWakuMessage(
   payload = "TEST-PAYLOAD",
   contentTopic = DefaultContentTopic, 
-  ts = getNanosecondTime(epochTime())
+  ts = getNanosecondTime(epochTime()),
+  ephemeral = false,
 ): WakuMessage = 
   WakuMessage(
     payload: toBytes(payload),
     contentTopic: contentTopic,
     version: 1,
-    timestamp: ts
+    timestamp: ts,
+    ephemeral: ephemeral,
   )
 
 proc newTestSwitch(key=none(PrivateKey), address=none(MultiAddress)): Switch =
@@ -58,6 +61,17 @@ proc newTestWakuStore(switch: Switch): WakuStore =
 
   return proto
 
+proc newTestWakuStore(switch: Switch, store: MessageStore): WakuStore =
+  let
+    peerManager = PeerManager.new(switch)
+    rng = crypto.newRng()
+    proto = WakuStore.init(peerManager, rng, store)
+
+  waitFor proto.start()
+  switch.mount(proto)
+
+  return proto
+
 
 suite "Waku Store":
   
@@ -446,6 +460,28 @@ suite "Waku Store":
     ## Cleanup
     await allFutures(clientSwitch.stop(), serverSwitch.stop())
 
+  asyncTest "handle ephemeral messages":
+    ## Setup
+    let store = StoreQueueRef.new(10)
+    let switch = newTestSwitch()
+    let proto = newTestWakuStore(switch, store)
+    let msgList = @[ 
+      fakeWakuMessage(ephemeral = false, payload = "1"),
+      fakeWakuMessage(ephemeral = true, payload = "2"),
+      fakeWakuMessage(ephemeral = true, payload = "3"),
+      fakeWakuMessage(ephemeral = true, payload = "4"),
+      fakeWakuMessage(ephemeral = false, payload = "5"),
+    ]
+
+    for msg in msgList:
+      await proto.handleMessage(DefaultPubsubTopic, msg)
+
+    check: 
+      store.len == 2
+
+    ## Cleanup
+    await switch.stop()
+
 
 # TODO: Review this test suite test cases
 procSuite "Waku Store - fault tolerant store":

waku/v2/protocol/waku_message.nim

@@ -31,12 +31,16 @@ type
     # this field will be used in the rln-relay protocol
     # XXX Experimental, this is part of https://rfc.vac.dev/spec/17/ spec and not yet part of WakuMessage spec
     proof*: RateLimitProof
+    # The ephemeral field indicates if the message should
+    # be stored. bools and uints are 
+    # equivalent in serialization of the protobuf
+    ephemeral*: bool
     
    
 
 # Encoding and decoding -------------------------------------------------------
 proc init*(T: type WakuMessage, buffer: seq[byte]): ProtoResult[T] =
-  var msg = WakuMessage()
+  var msg = WakuMessage(ephemeral: false)
   let pb = initProtoBuffer(buffer)
 
   discard ? pb.getField(1, msg.payload)
@@ -51,7 +55,15 @@ proc init*(T: type WakuMessage, buffer: seq[byte]): ProtoResult[T] =
   var proofBytes: seq[byte]
   discard ? pb.getField(21, proofBytes)
   msg.proof = ? RateLimitProof.init(proofBytes)
-  
+
+  # Behaviour of ephemeral with storeTTL to be defined,
+  # If a message is marked ephemeral, it should not have a storeTTL.
+  # If a message is not marked ephemeral, it should have a storeTTL.
+  # How would we handle messages that should be stored permanently?
+  var ephemeral: uint
+  if ? pb.getField(31, ephemeral):
+    msg.ephemeral = bool(ephemeral)
+
   ok(msg)
 
 proc encode*(message: WakuMessage): ProtoBuffer =
@@ -62,6 +74,6 @@ proc encode*(message: WakuMessage): ProtoBuffer =
   result.write3(3, message.version)
   result.write3(10, zint64(message.timestamp))
   result.write3(21, message.proof.encode())
-  
+  result.write3(31, uint64(message.ephemeral))
   result.finish3()
 

waku/v2/protocol/waku_store/protocol.nim

@@ -204,6 +204,10 @@ proc handleMessage*(w: WakuStore, topic: string, msg: WakuMessage) {.async.} =
     # Store is mounted but new messages should not be stored
     return
 
+  if msg.ephemeral:
+    # The message is ephemeral, should not be stored
+    return
+
   let index = Index.compute(
     msg,
     receivedTime = getNanosecondTime(getTime().toUnixFloat()),

waku/v2/utils/protobuf.nim

@@ -17,4 +17,4 @@ proc finish3*(proto: var ProtoBuffer) =
     proto.offset = 0
 
 proc `==`*(a: zint64, b: zint64): bool =
-  int64(a) == int64(b)
+  int64(a) == int64(b)