URI: 
       tlnworker: implement exponential backoff for retries - electrum - Electrum Bitcoin wallet
  HTML git clone https://git.parazyd.org/electrum
   DIR Log
   DIR Files
   DIR Refs
   DIR Submodules
       ---
   DIR commit 90cb032721ffd8fad883762b3942de7a08b1949a
   DIR parent 86b29603cb87f8b2314bfffb22dd61fbe4d059b0
  HTML Author: SomberNight <somber.night@protonmail.com>
       Date:   Wed, 15 Apr 2020 16:40:16 +0200
       
       lnworker: implement exponential backoff for retries
       
       Diffstat:
         M electrum/lnpeer.py                  |       5 +----
         M electrum/lntransport.py             |       4 ++++
         M electrum/lnworker.py                |      70 +++++++++++++++++++------------
       
       3 files changed, 49 insertions(+), 30 deletions(-)
       ---
   DIR diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py
       t@@ -219,10 +219,7 @@ class Peer(Logger):
                    if constants.net.rev_genesis_bytes() not in their_chains:
                        raise GracefulDisconnect(f"no common chain found with remote. (they sent: {their_chains})")
                # all checks passed
       -        if self.channel_db and isinstance(self.transport, LNTransport):
       -            self.channel_db.add_recent_peer(self.transport.peer_addr)
       -            for chan in self.channels.values():
       -                chan.add_or_update_peer_addr(self.transport.peer_addr)
       +        self.lnworker.on_peer_successfully_established(self)
                self._received_init = True
                self.maybe_set_initialized()
        
   DIR diff --git a/electrum/lntransport.py b/electrum/lntransport.py
       t@@ -155,6 +155,8 @@ class LNTransportBase:
        
        
        class LNResponderTransport(LNTransportBase):
       +    """Transport initiated by remote party."""
       +
            def __init__(self, privkey: bytes, reader: StreamReader, writer: StreamWriter):
                LNTransportBase.__init__(self)
                self.reader = reader
       t@@ -211,7 +213,9 @@ class LNResponderTransport(LNTransportBase):
                self.init_counters(ck)
                return rs
        
       +
        class LNTransport(LNTransportBase):
       +    """Transport initiated by local party."""
        
            def __init__(self, privkey: bytes, peer_addr: LNPeerAddr):
                LNTransportBase.__init__(self)
   DIR diff --git a/electrum/lnworker.py b/electrum/lnworker.py
       t@@ -77,9 +77,11 @@ SAVED_PR_STATUS = [PR_PAID, PR_UNPAID, PR_INFLIGHT] # status that are persisted
        
        
        NUM_PEERS_TARGET = 4
       -PEER_RETRY_INTERVAL = 600  # seconds
       -PEER_RETRY_INTERVAL_FOR_CHANNELS = 30  # seconds
       -GRAPH_DOWNLOAD_SECONDS = 600
       +
       +MAX_RETRY_DELAY_FOR_PEERS = 3600  # sec
       +INIT_RETRY_DELAY_FOR_PEERS = 600  # sec
       +MAX_RETRY_DELAY_FOR_CHANNEL_PEERS = 300  # sec
       +INIT_RETRY_DELAY_FOR_CHANNEL_PEERS = 4  # sec
        
        FALLBACK_NODE_LIST_TESTNET = (
            LNPeerAddr(host='203.132.95.10', port=9735, pubkey=bfh('038863cf8ab91046230f561cd5b386cbff8309fa02e3f0c3ed161a3aeb64a643b9')),
       t@@ -156,6 +158,8 @@ class LNWorker(Logger):
                self.features |= LnFeatures.VAR_ONION_OPT
                self.features |= LnFeatures.PAYMENT_SECRET_OPT
        
       +        self._last_tried_peer = {}  # type: Dict[LNPeerAddr, Tuple[float, int]]  # LNPeerAddr -> (unix ts, num_attempts)
       +
            def channels_for_peer(self, node_id):
                return {}
        
       t@@ -204,8 +208,7 @@ class LNWorker(Logger):
                        continue
                    peers = await self._get_next_peers_to_try()
                    for peer in peers:
       -                last_tried = self._last_tried_peer.get(peer, 0)
       -                if last_tried + PEER_RETRY_INTERVAL < now:
       +                if self._can_retry_peer(peer, now=now):
                            await self._add_peer(peer.host, peer.port, peer.pubkey)
        
            async def _add_peer(self, host, port, node_id) -> Peer:
       t@@ -214,7 +217,8 @@ class LNWorker(Logger):
                port = int(port)
                peer_addr = LNPeerAddr(host, port, node_id)
                transport = LNTransport(self.node_keypair.privkey, peer_addr)
       -        self._last_tried_peer[peer_addr] = time.time()
       +        last_time, num_attempts = self._last_tried_peer.get(peer_addr, (0, 0))
       +        self._last_tried_peer[peer_addr] = time.time(), num_attempts + 1
                self.logger.info(f"adding peer {peer_addr}")
                peer = Peer(self, node_id, transport)
                await self.taskgroup.spawn(peer.main_loop())
       t@@ -233,7 +237,6 @@ class LNWorker(Logger):
                self.network = network
                self.config = network.config
                self.channel_db = self.network.channel_db
       -        self._last_tried_peer = {}  # type: Dict[LNPeerAddr, float]  # LNPeerAddr -> unix timestamp
                self._add_peers_from_config()
                asyncio.run_coroutine_threadsafe(self.main_loop(), self.network.asyncio_loop)
        
       t@@ -259,20 +262,43 @@ class LNWorker(Logger):
                #self.logger.info(f'is_good {peer.host}')
                return True
        
       +    def on_peer_successfully_established(self, peer: Peer) -> None:
       +        if isinstance(peer.transport, LNTransport):
       +            peer_addr = peer.transport.peer_addr
       +            # reset connection attempt count
       +            self._last_tried_peer[peer_addr] = time.time(), 0
       +            # add into channel db
       +            if self.channel_db:
       +                self.channel_db.add_recent_peer(peer_addr)
       +            # save network address into channels we might have with peer
       +            for chan in peer.channels.values():
       +                chan.add_or_update_peer_addr(peer_addr)
       +
       +    def _can_retry_peer(self, peer: LNPeerAddr, *,
       +                        now: float = None, for_channel: bool = False) -> bool:
       +        if now is None:
       +            now = time.time()
       +        last_time, num_attempts = self._last_tried_peer.get(peer, (0, 0))
       +        if for_channel:
       +            delay = min(MAX_RETRY_DELAY_FOR_CHANNEL_PEERS,
       +                        INIT_RETRY_DELAY_FOR_CHANNEL_PEERS * 2 ** num_attempts)
       +        else:
       +            delay = min(MAX_RETRY_DELAY_FOR_PEERS,
       +                        INIT_RETRY_DELAY_FOR_PEERS * 2 ** num_attempts)
       +        next_time = last_time + delay
       +        return next_time < now
       +
            async def _get_next_peers_to_try(self) -> Sequence[LNPeerAddr]:
                now = time.time()
                await self.channel_db.data_loaded.wait()
       -        recent_peers = self.channel_db.get_recent_peers()
       -        # maintenance for last tried times
       -        # due to this, below we can just test membership in _last_tried_peer
       -        for peer in list(self._last_tried_peer):
       -            if now >= self._last_tried_peer[peer] + PEER_RETRY_INTERVAL:
       -                del self._last_tried_peer[peer]
                # first try from recent peers
       +        recent_peers = self.channel_db.get_recent_peers()
                for peer in recent_peers:
       +            if not peer:
       +                continue
                    if peer.pubkey in self.peers:
                        continue
       -            if peer in self._last_tried_peer:
       +            if not self._can_retry_peer(peer, now=now):
                        continue
                    if not self.is_good_peer(peer):
                        continue
       t@@ -289,7 +315,7 @@ class LNWorker(Logger):
                            peer = LNPeerAddr(host, port, node_id)
                        except ValueError:
                            continue
       -                if peer in self._last_tried_peer:
       +                if not self._can_retry_peer(peer, now=now):
                            continue
                        if not self.is_good_peer(peer):
                            continue
       t@@ -304,7 +330,7 @@ class LNWorker(Logger):
                else:
                    return []  # regtest??
        
       -        fallback_list = [peer for peer in fallback_list if peer not in self._last_tried_peer]
       +        fallback_list = [peer for peer in fallback_list if self._can_retry_peer(peer, now=now)]
                if fallback_list:
                    return [random.choice(fallback_list)]
        
       t@@ -1269,18 +1295,10 @@ class LNWallet(LNWorker):
                    peer_addresses.append(LNPeerAddr(host, port, chan.node_id))
                # will try addresses stored in channel storage
                peer_addresses += list(chan.get_peer_addresses())
       +        # Done gathering addresses.
                # Now select first one that has not failed recently.
       -        # Use long retry interval to check. This ensures each address we gathered gets a chance.
       -        for peer in peer_addresses:
       -            last_tried = self._last_tried_peer.get(peer, 0)
       -            if last_tried + PEER_RETRY_INTERVAL < now:
       -                await self._add_peer(peer.host, peer.port, peer.pubkey)
       -                return
       -        # Still here? That means all addresses failed ~recently.
       -        # Use short retry interval now.
                for peer in peer_addresses:
       -            last_tried = self._last_tried_peer.get(peer, 0)
       -            if last_tried + PEER_RETRY_INTERVAL_FOR_CHANNELS < now:
       +            if self._can_retry_peer(peer, for_channel=True, now=now):
                        await self._add_peer(peer.host, peer.port, peer.pubkey)
                        return