NETCONF Perl client
===================

       Contents
         * Abstract
         * Supported Platforms
         * Prerequisites
         * Installation
         * Running the Sample Scripts
         * Troubleshooting

Abstract
========

   The NETCONF API provides mechanisms to install, manipulate, and delete the
   configuration of network devices. The NETCONF API uses an Extensible markup 
   Language (XML) based data encoding for the configuration data as well as operations
   and messages defined in the API.

   The Net::Netconf::Manager module provides an object-oriented interface for
   communicating with the NETCONF server so you can start using the NETCONF
   API quickly and easily. There are several modules in this library but
   client applications directly invoke the Manager object only. When the
   client application creates a Net::Netconf::Manager object, it specifies a
   router name and the login name to use when accessing the router (which
   determines the client application's access level).

   The following code segment shows how to use the Net::Netconf::Manager
   object to request information from a routing platform.
   This example invokes the query called get_chassis_inventory.
    
     # Step 1: set up the query
     // RPC tag <get-chassis-inventory> should be querried as below
     my $query = "get_chassis_inventory";
     my %queryargs = ( 'detail' => 'True' );
     # Step 2: Create a Netconf Manager object and connect to Networks routing platform
     my %deviceinfo = (
      access => "ssh",
      login => "johndoe",
      password => "secret",
      hostname => "router11"
      );
      my $jnx = new Net::Netconf::Manager(%deviceinfo);
      unless ( ref $jnx ) {
             croak "ERROR: $deviceinfo{hostname}: failed to connect.\n";
      }
     # Step 3: send the query and receive a reply
     my $res = $jnx->$query( %queryargs );
     # Step 4: check for error
     if ($jnx->has_error) {
          croak "ERROR: in processing request \n $jnx->{request} \n";
      } 
      else {
     # Step 5: do something with the result
      }
     # Step 6: always disconnect from the server when you're done
     $jnx->disconnect();

Supported Platforms
===================

   The current version of this module has been tested on the following
   platforms. Later releases may support additional platforms.

     * Ubuntu 12.04LTS 
     * Fedora 15 i686
     * Centos-6.5-i386
        
Prerequisites
==============

    Following are the Prerequisites for using this API:
       1. Net::SSH2
       2. File::Which
       3. XML::LibXML

Also make sure that your system has libxml2 and libxml2-dev library. If not then either install it from source package in ubuntu website or by using apt-get. 
For more info look at the Troubleshooting 

Installation
=============

    Make sure Perl is installed. If necessary, see Installation of Perl.
    % which perl
    % perl -v
    The NETCONF Perl API requires version 5.6.1 or later of the perl executable. Verify that you are running 
    that version of the perl executable. If not, check your PATH or install the latest release of perl.
            
        There are two ways to install Net::Netconf Module in your system:
        1. Using CPAN
        2. Using source code in github
    Note: If you are using cpan command then you don't have to install prerequisites, they will automatically be
    installed by cpan        
     
        Using CPAN
        -----------------------------------------------------------------------------------------
        Before installing using cpan, make sure your system has cpan, if not then install it either by "apt-get 
        install cpan" or "yum install cpan" (according to the OS you are using)
        1. To install using CPAN make sure your system has C dependencies, i.e. libxml2 and libxml2-dev package.
        2. After installing these two packages in your system install Net::Netconf module by using CPAN command 
        "cpan Net::Netconf". 
       
        Sometimes cpan command gives error then try installing using "cpanm" command. First install cpanm in your 
        system by "apt-get install cpanminus"  and then install this module by "cpanm Net::Netconf"
        
        Using Source code in github
        --------------------------------------------------------------------------------------------
        Instructions for UNIX Systems
        Install the prerequisites of Perl modules. 
        Following are the prerequites
        1. Net::SSH2
        2. File::Which
        3. XML::LibXML
        
        Steps to install Prerequisites in Ubuntu12.04LTS :
        1. cpan Net::SSH2
        2. cpan File::Which
        3. cpan XML::LibXML
            
        After successfully installing Prerequisites install NETCONF PERL CLIENT
          
        1. Download the Perl NETCONF zip archive from Juniper's Repository in github 
        2. Unzip the archive.
            % unzip netconf-Perl-master.zip
        3. Change to the NETCONF directory.
            % cd netconf-perl-master
        4. Create Net::Netconf Makefile.
           If installing Net::Netconf::Manager under the standard directory
            (by default it is /usr/local/lib):
            [/my/netconf-perl-master]% perl Makefile.PL
        5. Install the Net::Netconf module.
            [/my/netconf-perl-master]% make
            [/my/netconf-perl--master]% make install
            (to run make install user should have root permission)
            
Running the Sample Scripts
==========================

The NETCONF Perl distribution includes sample scripts that demonstrate how to use NETCONF to retrieve 
and change the configuration of a Networks routing platform. The samples reside in the netconf-perl-n.n/examples directory.

Reading configuration: System Information
This example sends a <get-system-information> request to the Networks routing platform and displays the
result to the standard output.It also shows how to parse reply from server

Script: get_system_information.pl
```
        use Net::Netconf::Manager;
        print "Enter hostname\n";
        my $hostname = <>;
        print "Enter username\n";
        my $login= <>;
        print "Enter password\n";
        my $pass = <>;
        chomp($hostname);
        chomp($login);
        chomp($pass);
        $jnx = new Net::Netconf::Manager( 'access' => 'ssh',
                      'login' => $login,
                      'password' => $pass,
                      'hostname' => $hostname);
        if(! $jnx ) {
              print STDERR "Unable to connect to Junos device \n";
              exit 1;
         }
         print "Connection established: " . $jnx->get_session_id . "\n";
         my $reply=$jnx->get_system_information();
         if ($jnx->has_error) {
         print "ERROR: in processing request\n";
         # Get the error
         my $error = $jnx->get_first_error();
         $jnx->print_error_info(%$error);
         exit 1;
         }
 	  print "Server request: \n $jnx->{'request'}\n Server response: \n $jnx->{'server_response'} \n";

         # this parsing is specifically for <get-system-information> tag
         # you can write your own application in similar way
         #parsing reply from server
         my $config= $jnx->get_dom();
         $res= $config->getElementsByTagName("hardware-model")->item(0)->getFirstChild->getData;
         $res2= $config->getElementsByTagName("os-name")->item(0)->getFirstChild->getData;
         $res3= $config->getElementsByTagName("host-name")->item(0)->getFirstChild->getData;
         print "\nhardware information  ". $res ."\n";
         print "os-name  " .$res2 . "\n";
         print "host-name  ". $res3. "\n";
         $jnx->disconnect();
```

Output:  
Run netconf-perl script:
```
perl <script_name>
```
```
priyal@priyal:~/Desktop$ perl get_system_information.pl
Enter hostname: device1
Enter username: foo
Enter password: passwd123

Server request: 
 <rpc message-id='1'>
  <get-system-information/>
</rpc>

 Server response: 
<rpc-reply xmlns="urn:ietf:params:xml:ns:netconf:base:1.0" xmlns:junos="http://xml.juniper.net/junos/15.2I0/junos" message-id='1'>
<system-information>
<hardware-model>olive</hardware-model>
<os-name>junos</os-name>
<os-version>15.2I20151211</os-version>
<host-name>device1</host-name>
</system-information>
</rpc-reply>

hardware information:  olive
os-name:  junos
host-name: device1
```


Troubleshooting  (Ubuntu12.04LTS or higher version) 
=================

    1. Installing libxml2 and libxml2-dev 
       - Install using apt-get
            apt-get install libxml2
            apt-get install libxml2-dev
       - Installing from source code
         Download your system specific package from http://packages.ubuntu.com/
         For Precise(12.04 LTS) download its .dpkg packages
         For libxml2: http://packages.ubuntu.com/precise/libxml2
         For libxml2-dev : http://packages.ubuntu.com/precise/libxml2-dev
         
         Install these packages in your system :
            dpkg -i libxml2_2.7xyz__.dpkg
            dpkg -i libxml2-dev_2xyz__.dpkg
            
      Note : Libxml2 and libxml2-dev should be of same version
      
    If you get libxml related error even after installing its dependency like libxml2 and libxml2-dev then try 
    below  command
            apt-get install libxml-libxml-perl
            
    Sometimes you may get error like "Checking for ability to link against xml2...no " while installing LibXML then 
    use this command
          sudo apt-get install zlib1g-dev
          
    2. For error related to Net::SSH2
       Sometimes you may get error like,
              fatal error: openssl/crypto.h: No such file or directory
              #include <openssl/crypto.h>
                            ^
              compilation terminated.
              make: *** [SSH2.o] Error 1
      then use then command:
      sudo apt-get install libssl-dev
      
    3. For YAML related Errors
       Sometimes you may get that yaml is not installed then run following commands:
             apt-get install libyaml-appconfig-perl
             apt-get install libconfig-yaml-perl

    3. For libz errors like:
             /usr/bin/ld: /usr/local/lib/libz.a(crc32.o): relocation R_X86_64_32 against `.rodata' can not be used when 
               making a shared object; recompile with -fPIC
             /usr/local/lib/libz.a: could not read symbols: Bad value
         try installing from source code:
             download libz source code, https://google-desktop-for-linux-mirror.googlecode.com/files/zlib-1.2.3.tar.gz
             according to platform u are using.
             open Makefile and add -fPIC in cflag, (smth like: CFLAGS=-O3 -DUSE_MMAP -fPIC)
             then compile it:
             ./configure
             make test
             make install
        
    4. For cpan related errors:
       While installing some files using cpan, for example "cpan File::Which" you may get error like checksum mismatch
       for distribution, then try installing that package using "cpanm"
       First install cpanm in your system by:
       apt-get install cpanminus
       and then install desired package by using cpanm, for example:
       cpanm File::Which
       
       While installing perl dependency using cpan, if you get errors like "XML::NamespaceSupport package not found" or
       unmet dependency then first install that package using cpan / cpanm and then install your desired package.
       you can also try installing by force :
       apt-get -f install
             
# CONTRIBUTORS

 - [Ganesh Nalawade](https://github.com/ganeshnalawade)
 - [Priyal Jain](https://github.com/Jainpriyal)
