Class: SSHKit::Backend::ConnectionPool::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/sshkit/backends/connection_pool/cache.rb

Overview

A Cache holds connections for a given key. Each connection is stored along with an expiration time so that its idle duration can be measured.

Instance Method Summary collapse

Constructor Details

#initialize(idle_timeout, closer) ⇒ Cache

Returns a new instance of Cache.



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# File 'lib/sshkit/backends/connection_pool/cache.rb', line 4

def initialize(idle_timeout, closer)
  @connections = []
  @connections.extend(MonitorMixin)
  @idle_timeout = idle_timeout
  @closer = closer
end

Instance Method Details

#clear ⇒ Object

Close all connections and completely clear the cache.



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# File 'lib/sshkit/backends/connection_pool/cache.rb', line 49

def clear
  connections.synchronize do
    connections.map(&:last).each(&closer)
    connections.clear
  end
end

#evict ⇒ Object

Close and remove any connections in this Cache that have been idle for too long.



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# File 'lib/sshkit/backends/connection_pool/cache.rb', line 33

def evict
  # Peek at the first connection to see if it is still fresh. If so, we can
  # return right away without needing to use `synchronize`.
  first_expires_at, _connection = connections.first
  return if first_expires_at.nil? || fresh?(first_expires_at)

  connections.synchronize do
    fresh, stale = connections.partition do |expires_at, _|
      fresh?(expires_at)
    end
    connections.replace(fresh)
    stale.each { |_, conn| closer.call(conn) }
  end
end

#pop ⇒ Object

Remove and return a fresh connection from this Cache. Returns ‘nil` if the Cache is empty or if all existing connections have gone stale.



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# File 'lib/sshkit/backends/connection_pool/cache.rb', line 13

def pop
  connections.synchronize do
    evict
    _, connection = connections.pop
    connection
  end
end

#push(conn) ⇒ Object

Return a connection to this Cache.



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# File 'lib/sshkit/backends/connection_pool/cache.rb', line 22

def push(conn)
  # No need to cache if the connection has already been closed.
  return if closed?(conn)

  connections.synchronize do
    connections.push([Time.now + idle_timeout, conn])
  end
end