145 lines
4.2 KiB
Nim
145 lines
4.2 KiB
Nim
## Nim-Libp2p
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## Copyright (c) 2018 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))
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## * MIT license ([LICENSE-MIT](LICENSE-MIT))
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## at your option.
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## This file may not be copied, modified, or distributed except according to
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## those terms.
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{.push raises: [Defect].}
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## This module implements Pool of StreamTransport.
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import chronos
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const
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DefaultPoolSize* = 8
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## Default pool size
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type
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ConnectionFlags = enum
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None, Busy
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PoolItem = object
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transp*: StreamTransport
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flags*: set[ConnectionFlags]
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PoolState = enum
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Connecting, Connected, Closing, Closed
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TransportPool* = ref object
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## Transports pool object
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transports: seq[PoolItem]
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busyCount: int
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state: PoolState
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bufferSize: int
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event: AsyncEvent
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TransportPoolError* = object of AsyncError
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proc waitAll[T](futs: seq[Future[T]]): Future[void] =
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## Performs waiting for all Future[T].
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var counter = len(futs)
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var retFuture = newFuture[void]("connpool.waitAllConnections")
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proc cb(udata: pointer) =
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dec(counter)
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if counter == 0:
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retFuture.complete()
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for fut in futs:
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fut.addCallback(cb)
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return retFuture
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proc newPool*(address: TransportAddress, poolsize: int = DefaultPoolSize,
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bufferSize = DefaultStreamBufferSize,
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): Future[TransportPool] {.async.} =
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## Establish pool of connections to address ``address`` with size
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## ``poolsize``.
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var pool = new TransportPool
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pool.bufferSize = bufferSize
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pool.transports = newSeq[PoolItem](poolsize)
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var conns = newSeq[Future[StreamTransport]](poolsize)
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pool.state = Connecting
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for i in 0..<poolsize:
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conns[i] = connect(address, bufferSize)
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# Waiting for all connections to be established.
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await waitAll(conns)
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# Checking connections and preparing pool.
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for i in 0..<poolsize:
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if conns[i].failed:
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raise conns[i].error
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else:
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let transp = conns[i].read()
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let item = PoolItem(transp: transp)
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pool.transports[i] = item
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# Setup available connections event
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pool.event = newAsyncEvent()
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pool.state = Connected
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result = pool
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proc acquire*(pool: TransportPool): Future[StreamTransport] {.async.} =
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## Acquire non-busy connection from pool ``pool``.
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var transp: StreamTransport
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if pool.state in {Connected}:
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while true:
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if pool.busyCount < len(pool.transports):
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for conn in pool.transports.mitems():
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if Busy notin conn.flags:
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conn.flags.incl(Busy)
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inc(pool.busyCount)
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transp = conn.transp
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break
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else:
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await pool.event.wait()
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pool.event.clear()
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if not isNil(transp):
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break
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else:
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raise newException(TransportPoolError, "Pool is not ready!")
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result = transp
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proc release*(pool: TransportPool, transp: StreamTransport) =
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## Release connection ``transp`` back to pool ``pool``.
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if pool.state in {Connected, Closing}:
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var found = false
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for conn in pool.transports.mitems():
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if conn.transp == transp:
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conn.flags.excl(Busy)
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dec(pool.busyCount)
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pool.event.fire()
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found = true
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break
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if not found:
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raise newException(TransportPoolError, "Transport not bound to pool!")
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else:
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raise newException(TransportPoolError, "Pool is not ready!")
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proc join*(pool: TransportPool) {.async.} =
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## Waiting for all connection to become available.
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if pool.state in {Connected, Closing}:
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while true:
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if pool.busyCount == 0:
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break
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else:
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await pool.event.wait()
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pool.event.clear()
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elif pool.state == Connecting:
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raise newException(TransportPoolError, "Pool is not ready!")
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proc close*(pool: TransportPool) {.async.} =
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## Closes transports pool ``pool`` and release all resources.
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if pool.state == Connected:
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pool.state = Closing
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# Waiting for all transports to become available.
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await pool.join()
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# Closing all transports
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var pending = newSeq[Future[void]](len(pool.transports))
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for i in 0..<len(pool.transports):
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let transp = pool.transports[i].transp
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transp.close()
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pending[i] = transp.join()
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# Waiting for all transports to be closed
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await waitAll(pending)
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# Mark pool as `Closed`.
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pool.state = Closed
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