287 lines
9.6 KiB
Nim
287 lines
9.6 KiB
Nim
# Nimbus
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# Copyright (c) 2021 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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# http://www.apache.org/licenses/LICENSE-2.0)
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# * MIT license ([LICENSE-MIT](LICENSE-MIT) or
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# http://opensource.org/licenses/MIT)
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# at your option. This file may not be copied, modified, or distributed
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# except according to those terms.
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## Sync worker peers scheduler template
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## ====================================
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##
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## Virtual method/interface functions to be provided as `mixin`:
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##
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## *runSetup(ctx: CtxRef[S]; tickerOK: bool): bool*
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## Global set up. This function will be called before any worker peer is
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## started. If that function returns `false`, no worker peers will be run.
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##
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## *runRelease(ctx: CtxRef[S])*
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## Global clean up, done with all the worker peers.
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##
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##
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## *runStart(buddy: BuddyRef[S,W]): bool*
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## Initialise a new worker peer.
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##
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## *runStop(buddy: BuddyRef[S,W])*
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## Clean up this worker peer.
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##
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##
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## *runPool(buddy: BuddyRef[S,W], last: bool)*
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## Once started, the function `runPool()` is called for all worker peers in
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## sequence as the body of an iteration. There will be no other worker peer
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## functions activated simultaneously.
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##
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## This procedure is started if the global flag `buddy.ctx.poolMode` is set
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## `true` (default is `false`.) It is the responsibility of the `runPool()`
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## instance to reset the flag `buddy.ctx.poolMode`, typically at the first
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## peer instance.
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##
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## The argument `last` is set `true` if the last entry is reached.
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##
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## Note that this function does not run in `async` mode.
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##
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##
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## *runSingle(buddy: BuddyRef[S,W]) {.async.}*
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## This worker peer method is invoked if the peer-local flag
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## `buddy.ctrl.multiOk` is set `false` which is the default mode. This flag
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## is updated by the worker peer when deemed appropriate.
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## * For all workers, there can be only one `runSingle()` function active
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## simultaneously for all worker peers.
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## * There will be no `runMulti()` function active for the same worker peer
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## simultaneously
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## * There will be no `runPool()` iterator active simultaneously.
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##
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## Note that this function runs in `async` mode.
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##
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## *runMulti(buddy: BuddyRef[S,W]) {.async.}*
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## This worker peer method is invoked if the `buddy.ctrl.multiOk` flag is
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## set `true` which is typically done after finishing `runSingle()`. This
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## instance can be simultaneously active for all worker peers.
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##
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##
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## Additional import files needed when using this template:
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## * eth/[common/eth_types, p2p]
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## * chronicles
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## * chronos
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## * stew/[interval_set, sorted_set],
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## * "."/[sync_desc, sync_sched, protocol]
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##
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import
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std/hashes,
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chronos,
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eth/[common/eth_types, p2p, p2p/peer_pool, p2p/private/p2p_types],
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stew/keyed_queue,
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./sync_desc
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{.push raises: [Defect].}
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type
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ActiveBuddies[S,W] = ##\
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## List of active workers, using `Hash(Peer)` rather than `Peer`
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KeyedQueue[Hash,RunnerBuddyRef[S,W]]
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RunnerSyncRef*[S,W] = ref object
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## Module descriptor
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ctx*: CtxRef[S] ## Shared data
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pool: PeerPool ## For starting the system
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buddies: ActiveBuddies[S,W] ## LRU cache with worker descriptors
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tickerOk: bool ## Ticker logger
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singleRunLock: bool ## For worker initialisation
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monitorLock: bool ## For worker monitor
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activeMulti: int ## Activated runners
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RunnerBuddyRef[S,W] = ref object
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## Per worker peer descriptor
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dsc: RunnerSyncRef[S,W] ## Scheduler descriptor
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worker: BuddyRef[S,W] ## Worker peer data
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# ------------------------------------------------------------------------------
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# Private helpers
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# ------------------------------------------------------------------------------
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proc hash(peer: Peer): Hash =
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## Needed for `buddies` table key comparison
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peer.remote.id.hash
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# ------------------------------------------------------------------------------
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# Private functions
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# ------------------------------------------------------------------------------
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proc workerLoop[S,W](buddy: RunnerBuddyRef[S,W]) {.async.} =
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mixin runMulti, runSingle, runPool, runStop
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let
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dsc = buddy.dsc
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ctx = dsc.ctx
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worker = buddy.worker
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peer = worker.peer
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# Continue until stopped
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while not worker.ctrl.stopped:
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if dsc.monitorLock:
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await sleepAsync(50.milliseconds)
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continue
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# Invoke `runPool()` over all buddies if requested
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if ctx.poolMode:
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# Grab `monitorLock` (was `false` as checked above) and wait until clear
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# to run as the only activated instance.
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dsc.monitorLock = true
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while 0 < dsc.activeMulti:
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await sleepAsync(50.milliseconds)
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while dsc.singleRunLock:
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await sleepAsync(50.milliseconds)
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var count = dsc.buddies.len
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for w in dsc.buddies.nextValues:
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count.dec
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worker.runPool(count == 0)
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dsc.monitorLock = false
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continue
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# Rotate connection table so the most used entry is at the top/right
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# end. So zombies will end up leftish.
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discard dsc.buddies.lruFetch(peer.hash)
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# Allow task switch
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await sleepAsync(50.milliseconds)
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# Multi mode
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if worker.ctrl.multiOk:
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if not dsc.singleRunLock:
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dsc.activeMulti.inc
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# Continue doing something, work a bit
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await worker.runMulti()
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dsc.activeMulti.dec
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continue
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# Single mode as requested. The `multiOk` flag for this worker was just
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# found `false` in the pervious clause.
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if not dsc.singleRunLock:
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# Lock single instance mode and wait for other workers to finish
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dsc.singleRunLock = true
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while 0 < dsc.activeMulti:
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await sleepAsync(50.milliseconds)
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# Run single instance and release afterwards
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await worker.runSingle()
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dsc.singleRunLock = false
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# End while
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# Note that `runStart()` was dispatched in `onPeerConnected()`
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worker.runStop()
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proc onPeerConnected[S,W](dsc: RunnerSyncRef[S,W]; peer: Peer) =
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mixin runStart, runStop
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# Check for known entry (which should not exist.)
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let
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maxWorkers = dsc.ctx.buddiesMax
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peers = dsc.pool.len
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workers = dsc.buddies.len
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if dsc.buddies.hasKey(peer.hash):
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trace "Reconnecting zombie peer rejected", peer, peers, workers, maxWorkers
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return
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# Initialise worker for this peer
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let buddy = RunnerBuddyRef[S,W](
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dsc: dsc,
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worker: BuddyRef[S,W](
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ctx: dsc.ctx,
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peer: peer))
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if not buddy.worker.runStart():
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trace "Ignoring useless peer", peer, peers, workers, maxWorkers
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buddy.worker.ctrl.zombie = true
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return
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# Check for table overflow. An overflow might happen if there are zombies
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# in the table (though preventing them from re-connecting for a while.)
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if dsc.ctx.buddiesMax <= workers:
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let leastPeer = dsc.buddies.shift.value.data
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if leastPeer.worker.ctrl.zombie:
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trace "Dequeuing zombie peer",
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oldest=leastPeer.worker, peers, workers=dsc.buddies.len, maxWorkers
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discard
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else:
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# This could happen if there are idle entries in the table, i.e.
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# somehow hanging runners.
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trace "Peer table full! Dequeuing least used entry",
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oldest=leastPeer.worker, peers, workers=dsc.buddies.len, maxWorkers
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leastPeer.worker.runStop()
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leastPeer.worker.ctrl.zombie = true
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# Add peer entry
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discard dsc.buddies.lruAppend(peer.hash, buddy, dsc.ctx.buddiesMax)
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trace "Running peer worker", peer, peers,
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workers=dsc.buddies.len, maxWorkers
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asyncSpawn buddy.workerLoop()
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proc onPeerDisconnected[S,W](dsc: RunnerSyncRef[S,W], peer: Peer) =
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let
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peers = dsc.pool.len
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maxWorkers = dsc.ctx.buddiesMax
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workers = dsc.buddies.len
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rc = dsc.buddies.eq(peer.hash)
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if rc.isErr:
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debug "Disconnected, unregistered peer", peer, peers, workers, maxWorkers
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return
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if rc.value.worker.ctrl.zombie:
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# Don't disconnect, leave them fall out of the LRU cache. The effect is,
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# that reconnecting might be blocked, for a while.
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trace "Disconnected, zombie", peer, peers, workers, maxWorkers
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else:
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rc.value.worker.ctrl.stopped = true # in case it is hanging somewhere
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dsc.buddies.del(peer.hash)
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trace "Disconnected buddy", peer, peers, workers=dsc.buddies.len, maxWorkers
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# ------------------------------------------------------------------------------
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# Public functions
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# ------------------------------------------------------------------------------
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proc initSync*[S,W](
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dsc: RunnerSyncRef[S,W];
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node: EthereumNode;
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slots: int;
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noisy = false) =
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## Constructor
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# Leave one extra slot so that it can holds a *zombie* even if all slots
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# are full. The effect is that a re-connect on the latest zombie will be
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# rejected as long as its worker descriptor is registered.
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dsc.ctx = CtxRef[S](
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buddiesMax: max(1, slots + 1),
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chain: node.chain)
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dsc.pool = node.peerPool
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dsc.tickerOk = noisy
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dsc.buddies.init(dsc.ctx.buddiesMax)
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proc startSync*[S,W](dsc: RunnerSyncRef[S,W]): bool =
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## Set up syncing. This call should come early.
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mixin runSetup
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# Initialise sub-systems
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if dsc.ctx.runSetup(dsc.tickerOk):
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var po = PeerObserver(
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onPeerConnected:
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proc(p: Peer) {.gcsafe.} =
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dsc.onPeerConnected(p),
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onPeerDisconnected:
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proc(p: Peer) {.gcsafe.} =
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dsc.onPeerDisconnected(p))
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po.setProtocol eth
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dsc.pool.addObserver(dsc, po)
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return true
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proc stopSync*[S,W](dsc: RunnerSyncRef[S,W]) =
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## Stop syncing
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mixin runRelease
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dsc.pool.delObserver(dsc)
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dsc.ctx.runRelease()
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# ------------------------------------------------------------------------------
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# End
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# ------------------------------------------------------------------------------
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