[erlang-questions] On Starting A Remote Shell Programmatically

黃耀賢 (Yau-Hsien Huang) <>
Sun Aug 22 18:46:13 CEST 2010


Thank you. Now I can use SSH to execute a remote command as
"erl -rsh ssh -sname gandolf" , and eventually it sometimes show
only the starting message of Erlang Shell and sometimes the starting
message accompanied with the exit message. Then, How to write
an Erlang program to robustly keep an alive remote shell?

Related information is as following:

% Commander
test(Host, NodeName) ->
    erlang:open_port({spawn,"ssh -f " ++ Host ++ " \"erl -rsh ssh -sname "
                          ++ NodeName ++ "\" &",
                 [{env,[{"PATH",os:getenv("PATH")}]}]),
    receive
        AnyThing -> io:format("Receive:" ~w~n.",[AnyThing]), AnyThing
   after
       5000 -> {error,no_response}
   end.
-----------------------------
[ ~]$ erl -rsh ssh -sname me
1> c(test).
{ok,test}
2> test:test("HPC9", "gandolf").
Receive: {#Port<0.126>,{data,[69,115,... ]}}
{#Port<0.126>,{data,"Eshell V5.6.1   (abort with ^G)\n"}}
3> net_adm:ping().
pang

Or,

2> {_,{S,D}} = test:test("HPC11", "mary"), io:format("~w:~s~n",[S,D]).
Receive: {#Port<0.132>,{data,[69,115,... ]}}
data:() 1> *** Terminating erlang ()

ok
3>halt().


2010/8/22 Tim Watson <>

>
> There is an ssh application distributed with OTP which should meet your
> needs. It'll allow you to open an SSH connection and send commands over it,
> so assuming you have installed the emulator on the remote machine, you
> should be able to spin up another node. If you're planning on writing a
> MapReduce framework, may I suggest that you look at riak_core (the
> underpinning framework behind riak), and luke (
> http://github.com/basho/luke) as these things have been done before. There
> is also some excellent stuff in scalaris (
> http://code.google.com/p/scalaris/) for coordinating work (paxos based
> IIRC) and the disco project (http://discoproject.org/) has implemented a
> MapReduce framework too, although jobs are written in python rather than
> Erlang.


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