nproxy

Networked Proxy (nproxy)

nsdci/dcicommon/nproxy.c

Introduction

The Networked Proxy API (nproxy) is used to send scripts or commands to remote servers for execution. The result is sent back to the client.

Additional Reading: rpc

TCL API

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nproxy.send

Used to send scripts or commands to a named nproxy. See the "Configuration" section for more information.

nproxy.send server script ?timeout?

Argument
Description

server
String. A named nproxy server. See the "Configuration" section for more information.

script
String. The script or command to send.

?timeout?
Integer. Optional. How long to wait for the result.

Result
Description

String
Success. The result of script or command.

TCL_ERROR
Failure. An error occurred. See the server log for more information.

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nproxy.debug

Used to retrieve the current debug value, or to set a new debug value.

nt.proxy ?boolean?

Argument
Description

?boolean?
Boolean. Optional. Specifies whether or not debugging is enabled.

Result
Description

1
Success. Returned if a boolean was specified.

BOOLEAN
Success. If a boolean was not specified, then the current debug value is returned.

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Configuration

Server:

    ns_section "ns/server/$server/modules"
        ns_param nssock nssock.so
        ns_param dci dci.so

    ns_section "ns/server/$server/module/nssock"
        ns_param hostname $hostName
        ns_param address $address
        ns_param port $httpPort

    ns_section "ns/server/$server/module/dci/rpc/server/nproxy"
        ns_param http 1

    ns_section "ns/server/$server/module/dci/rpc/server/nproxy/acl"
        ns_param allow 127.0.0.1

    ns_section "ns/server/$server/module/dci/nproxy"
        ns_param debug 1

    ns_section "ns/server/$server/module/dci/nproxy/servers"
        ns_param $nproxyServerName $nproxyServerName

    ns_section "ns/server/$server/module/dci/nproxy/server/$nproxyServerName"
        ns_param handshakeName $nproxyServerName

    ns_section "ns/server/$server/module/dci/nproxy/server/$nproxyServerName/clients"
        # This section has no params but is required.
        # Legacy client list before HTTP RPC.
        # See the rpc/server acl section above.

Client:

    ns_section "ns/server/$server/module/dci/rpc/client/nproxy:${$nproxyServerName}"
        ns_param address $nproxyServerAddress
        ns_param port $nproxyServerPort
        ns_param httpkeepalive true
        ns_param httpnumconnections 1

    ns_section "ns/server/$server/module/dci/nproxy"
        ns_param debug 1

    ns_section "ns/server/$server/module/dci/nproxy/clients"
        ns_param $nproxyServerName $nproxyServerName

    ns_section "ns/server/$server/module/dci/nproxy/client/$nproxyServerName"
        ns_param timeout 1

Usage

Use the frontend Control Port to send a command to the tool server (See Topology for more information):

    % telnet 127.0.0.1 9900
    Trying 127.0.0.1...
    Connected to localhost.
    Escape character is '^]'.
    login: 
    Password:

    Welcome to frontend running at /usr/local/aolserver/bin/nsd (pid 7893)
    AOLserver/4.5.0 (aolserver4_5) for osx built on Jan  4 2007 at 17:11:28
    CVS Tag: $Name:  $
    frontend:nscp 1> nproxy.send tool "expr 2 + 2"
    4
    frontend:nscp 2>

If you tail the tool server log you will see the following notice:

    [08/Jan/2007:15:28:54][7884.25210880][-conn:0-] Notice: eval: 0 expr 2 + 2 ...

The tool server accepted the request and evaluated the script. The result was sent back to the frontend server and was seen in the frontend AOLserver Control Port. Send a log notice to the tool server (See Topology for more information):

    frontend:nscp 2> nproxy.send tool {ns_log notice "Sent this from the frontend server."}

    frontend:nscp 3> exit

    Goodbye!
    Connection closed by foreign host.

There is no returned result for a log notice. But if you look in the tool server log you will see the evaluation notice as well as the result of the script:

    [08/Jan/2007:15:30:08][7884.25210880][-conn:0-] Notice: eval: 0 ns_log notice "Sent this from the fronte ...
    [08/Jan/2007:15:30:08][7884.25210880][-conn:0-] Notice: Sent this from the frontend server.