Group.__init() should be parallelised

• Bitbucket: https://bitbucket.org/hpk42/execnet/issue/28
• Originally reported by: @crusaderky
• Originally created at: 2014-01-22T16:51:21.959

Consider the following snippet:

hosts = [...list of hosts...]
group = execnet.Group(("ssh %s" % host for host in hosts))
group.remote_exec(something)

Imagine having a grid of 200 hosts.
While Group.remote_exec() will run on all the hosts in parallel, Group.__init__() will connect via ssh to each one of them, serially. On a typical LAN, this easily accounts to minutes.

I attach a patch for multi.py (on top of the latest hg commit) that is intended to fix the problem. However, with that patch the program deadlocks in gateway_base.py, line 360, and I can't figure out the reason.

multi.py の Group.init から始め、報告されたパッチがデッドロックを引き起こす gateway_base.py の 360 行目付近を調査してください。多数の SSH ゲートウェイを使って初期化を再現し、添付されたパッチとの挙動を比較してください。完了条件は、Group の初期化がデッドロックせずにホストへ並列接続し、Group.remote_exec() も引き続き動作することです。