managementnode/bin/install_perl_libs.pl - vcl - Git at Google

 #!/usr/bin/perl -w
 ###############################################################################
 # $Id$
 ###############################################################################
 # Licensed to the Apache Software Foundation (ASF) under one or more
 # contributor license agreements.  See the NOTICE file distributed with
 # this work for additional information regarding copyright ownership.
 # The ASF licenses this file to You under the Apache License, Version 2.0
 # (the "License"); you may not use this file except in compliance with
 # the License.  You may obtain a copy of the License at
 #
 #     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 ###############################################################################

 =head1 NAME

 install_perl_libs.pl - Script to install VCL Perl module dependencies

 =head1 SYNOPSIS

 Run this script from the command line:

  perl install_perl_libs.pl

 =head1 DESCRIPTION

  This script downloads and installs the Linux packages and Perl modules which
  are required for the backend VCL management node code. The yum utility is used
  to download and install the Linux packages. The CPAN.pm Perl module is used to
  download and install the required Perl modules. A disclaimer is displayed
  before this script downloads any files notifying you of the licenses used by
  the dependencies. You must type YES in order for the script to proceed.

 =cut
 ###############################################################################
 use strict;

 use English;
 use Getopt::Long;

 #//////////////////////////////////////////////////////////////////////////////

 my @LINUX_PACKAGES = (
 	'expat-devel',
 	'gcc',
 	'krb5-devel',
 	'krb5-libs',
 	'libxml2-devel',
 	'make',
 	'nmap',
 	'openssl-devel',
 	'bzip2',
 	'perl-CPAN',
 	'perl-App-cpanminus',
 	'perl-DBD-MySQL',
 	'xmlsec1-openssl',
 );

 my @PERL_MODULES = (
 	'CPAN@2.36',
 	'Archive::Tar@3.02',
 	'Crypt::CBC@3.04',
 	'Crypt::OpenSSL::RSA@0.33',
 	'Crypt::Rijndael@1.16',
 	'DBI@1.643',
 	'Digest::SHA1@2.13',
 	'Expect@1.35',
 	'Frontier::RPC2',
 	'Frontier::Client',
 	'IO::String@1.08',
 	'JSON@4.10',
 	'Net::LDAP@0.68',
 	'LWP::Protocol::https@6.12',
 	'MailTools@2.21',
 	'Mo@0.40',
 	'Mo::builder@0.40',
 	'Net::Jabber@2.0',
 	'Net::Netmask@2.0002',
 	'Net::SSH::Expect@1.09',
 	'Net::Ping::External@0.15',
 	'Object::InsideOut@4.05',
 	'REST::Client@281',
 	'RPC::XML@1.61',
 	'Sub::Util@1.63',
 	'Text::CSV_XS@1.53',
 	'Time::HiRes@1.9764',
 	'XML::Simple@2.25',
 	'YAML@1.31'
 );

 # Store the command line options in hash
 my $AGREE;
 my $INSTALL_LINUX_PACKAGES;
 my $INSTALL_PERL_MODULES;
 my %OPTIONS;
 GetOptions(\%OPTIONS,
 	'y!' => \$AGREE,
 	'linux!' => \$INSTALL_LINUX_PACKAGES,
 	'perl!' => \$INSTALL_PERL_MODULES,
 	'help' => \&help,
 );

 show_disclaimer() if !$AGREE;

 my $ERRORS = {};

 # Check if -l or -y was specified
 if (!defined($INSTALL_PERL_MODULES) && !defined($INSTALL_LINUX_PACKAGES)) {
 	$INSTALL_PERL_MODULES = 1;
 	$INSTALL_LINUX_PACKAGES = 1;
 }
 elsif (defined($INSTALL_PERL_MODULES) && !defined($INSTALL_LINUX_PACKAGES)) {
 	$INSTALL_LINUX_PACKAGES = !$INSTALL_PERL_MODULES;
 }
 elsif (defined($INSTALL_LINUX_PACKAGES) && !defined($INSTALL_PERL_MODULES)) {
 	$INSTALL_PERL_MODULES = !$INSTALL_LINUX_PACKAGES;
 }

 if ($INSTALL_LINUX_PACKAGES) {
 	print_break('=');
 	# Check if yum is available
 	my ($which_exit_status, $which_output) = run_command("which yum");
 	if ($which_exit_status ne '0') {
 		print "WARNING: yum is not available on this OS, skipping Linux package installation\n";
 		return 0;
 	}
 	else {
 		install_epel();
 		print_break('=');
 		install_linux_packages();
 	}
 }

 if ($INSTALL_PERL_MODULES) {
 	print_break('=');
 	install_perl_modules();
 }

 print_break('=');

 my $error_encountered;
 for my $key (keys %$ERRORS) {
 	for my $component (sort keys %{$ERRORS->{$key}}) {
 		print "WARNING: failed to install $key: $component\n";
 		$error_encountered++;
 	}
 }

 if (!$error_encountered) {
 	print "COMPLETE: installed all components\n";
 	exit 0;
 }
 else {
 	exit 1;
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 install_epel

  Parameters  : none
  Returns     : boolean
  Description : Creates a temporary /etc/yum.repos.d/epel-install.repo file and
                installs the epel-release package.

 =cut

 sub install_epel {
 	my $epel_install_repo_path = '/etc/yum.repos.d/epel-install.repo';

 	my $epel_install_repo_contents = <<EOF;
 [epel-install]
 name=EPEL Repository
 mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=epel-\$releasever&arch=\$basearch
 failovermethod=priority
 enabled=1
 gpgcheck=0
 EOF

 	unlink $epel_install_repo_path;

 	print "Creating file: $epel_install_repo_path\n";
 	if (!open FILE, ">", $epel_install_repo_path) {
 		print "ERROR: failed to create file: $epel_install_repo_path\n";
 		exit 1;
 	}
 	if (!print FILE $epel_install_repo_contents) {
 		print "ERROR: failed to write to file: $epel_install_repo_path\n";
 		exit 1;
 	}
 	close FILE;

 	my $result = yum_install_linux_package('epel-release');

 	if (unlink $epel_install_repo_path) {
 		print "Removed file: $epel_install_repo_path\n";
 	}
 	else {
 		print "WARNING: failed to remove file: $epel_install_repo_path\n";
 	}

 	return $result;
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 install_linux_packages

  Parameters  : none
  Returns     : boolean
  Description : Installs the Linux operating system packages required by the VCL
                managment node components.

 =cut

 sub install_linux_packages {
 	for my $linux_package (@LINUX_PACKAGES) {
 		print_break('*');
 		if (!yum_install_linux_package($linux_package)) {
 			$ERRORS->{'Linux package'}{$linux_package} = 1;
 		}
 	}
 	return 1;
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 yum_install_linux_package

  Parameters  : $linux_package
  Returns     : boolean
  Description : Attempts to install a single Linux package using yum.

 =cut

 sub yum_install_linux_package {
 	my ($linux_package) = @_;
 	if (!$linux_package) {
 		print "ERROR: package name argument was not provided\n";
 		return;
 	}

 	print "Attempting to install Linux package using yum: $linux_package\n";

 	my $yum_command = "yum install $linux_package -y --nogpgcheck";
 	#print "Yum command: $yum_command\n";

 	my $yum_output = `$yum_command 2>&1 | grep -v '^\\(Load\\|Setting\\|Nothing\\| \\*\\)'`;
 	my $yum_exit_status = $? >> 8;

 	chomp $yum_output;
 	print "$yum_output\n\n";

 	if ($yum_exit_status ne '0') {
 		print "WARNING: failed to install Linux package: '$linux_package', exit status: $yum_exit_status\n";
 		return 0;
 	}
 	elsif ($yum_output =~ /$linux_package[^\n]*already installed/i) {
 		print "SUCCESS: Linux package is already installed: $linux_package\n";
 	}
 	elsif ($yum_output =~ /Complete\!/i) {
 		print "SUCCESS: installed Linux package: $linux_package\n";
 	}
 	elsif ($yum_output =~ /No package.*available/i) {
 		print "WARNING: Linux package is not available via yum: $linux_package\n";
 		return 0;
 	}
 	else {
 		print "WARNING: unexpected output returned while installing Linux package: $linux_package\n";
 		return 0;
 	}

 	return 1;
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 configure_cpan

  Parameters  : none
  Returns     : boolean
  Description : Attempts to configure CPAN so that modules can be installed
                without user interaction.

 =cut

 sub configure_cpan {
 	eval {
 		require CPAN;
 	};
 	if ($EVAL_ERROR) {
 		print "Unable to install Perl modules, CPAN module could not be loaded.\n";
 		exit 1;
 	}

 	$ENV{PERL_MM_USE_DEFAULT} = 1;
 	$ENV{PERL_MM_NONINTERACTIVE} = 1;
 	$ENV{AUTOMATED_TESTING} = 1;
 	$ENV{FTP_PASSIVE} = 1;

 	my $cpan_directory = $ENV{HOME} . '/.cpan';
 	my $config_file_path = "$cpan_directory/CPAN/MyConfig.pm";
 	`mkdir -p $cpan_directory/CPAN`;

 	$CPAN::Config = {
 		"applypatch" => "",
 		"auto_commit" => "1",
 		"build_cache" => "1",
 		"build_dir" => "$cpan_directory/build",
 		"build_requires_install_policy" => "yes",
 		"bzip2" => `echo -n \`which bzip2\`` || "",
 		"cache_metadata" => "1",
 		"check_sigs" => "0",
 		"connect_to_internet_ok" => "1",
 		"cpan_home" => "$cpan_directory",
 		"curl" => `echo -n \`which curl\`` || "",
 		"ftp" => `echo -n \`which ftp\`` || "",
 		"ftp_passive" => "1",
 		"ftp_proxy" => "",
 		"getcwd" => "cwd",
 		"gpg" => `echo -n \`which gpg\`` || "",
 		"gzip" => `echo -n \`which gzip\`` || "",
 		"halt_on_failure" => "0",
 		"histfile" => "$cpan_directory/histfile",
 		"histsize" => "1000",
 		"http_proxy" => "",
 		"inactivity_timeout" => "60",
 		"index_expire" => "10",
 		"inhibit_startup_message" => "1",
 		"keep_source_where" => "$cpan_directory/sources",
 		"load_module_verbosity" => "1",
 		"make" => `echo -n \`which make\`` || "",
 		"make_arg" => "",
 		"make_install_arg" => "",
 		"make_install_make_command" => `echo -n \`which make\`` || "",
 		"makepl_arg" => "",
 		"mbuild_arg" => "",
 		"mbuild_install_arg" => "",
 		"mbuild_install_build_command" => "./Build",
 		"mbuildpl_arg" => "",
 		"ncftp" => "",
 		"ncftpget" => "",
 		"no_proxy" => "",
 		"pager" => `echo -n \`which less\`` || "",
 		"perl5lib_verbosity" => "",
 		"prefer_installer" => "MB",
 		"prefs_dir" => "$cpan_directory/prefs",
 		"prerequisites_policy" => "follow",
 		"proxy_user" => "",
 		"randomize_urllist" => "1",
 		"scan_cache" => "never",
 		"shell" => `echo -n \`which bash\`` || "",
 		"show_upload_date" => "0",
 		"tar" => `echo -n \`which tar\`` || "",
 		"tar_verbosity" => "",
 		"term_ornaments" => "1",
 		"trust_test_report_history" => "1",
 		"unzip" => `echo -n \`which unzip\`` || "",
 		"urllist" => [q[https://cpan.metacpan.org/], q[https://mirrors.namecheap.com/CPAN/], q[https://mirrors.syringanetworks.net/CPAN/], q[https://ftp.wayne.edu/CPAN/]],
 		"use_sqlite" => "0",
 		"wget" => `echo -n \`which wget\`` || "",
 		"yaml_load_code" => "0",
 	};

 	# Use $CPAN::Config once to avoid warning
 	if ($CPAN::Config) {};

 	eval { CPAN::Config->commit($config_file_path) };
 	if ($EVAL_ERROR) {
 		print "\nERROR: failed to create CPAN configuration file: $config_file_path\n$EVAL_ERROR\n";
 		exit 1;
 	}
 	else {
 		print "Created CPAN configuration file: $config_file_path\n";
 	}

 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 install_perl_modules

  Parameters  :
  Returns     :
  Description :

 =cut

 sub install_perl_modules {
 	eval { require CPAN };
 	if ($EVAL_ERROR) {
 		print "ERROR: failed to install perl modules, CPAN module is not available\n";
 		$ERRORS->{'Perl module'}{'ALL'} = 1;
 		return;
 	}
 	print "Running CPAN version: $CPAN::VERSION\n";

 	configure_cpan();

 	PERL_MODULE: for my $perl_module (@PERL_MODULES) {
 		print_break('*');

 		#my $cpan_version = get_perl_module_cpan_version($perl_module);
 		my ($pModule, $cpan_version ) = split(/@/, $perl_module);
 		if (!defined $cpan_version) {
 			$cpan_version = 'undef';
 		}
 		my $cpan_version_available = `cpanm --info -q $perl_module | grep -i failed | wc -l`;
 		#if (!$cpan_version) {
 		if ($cpan_version_available == 1) {
 			print "ERROR: unable to install $perl_module Perl module, information could not be obtained from CPAN\n";
 			$ERRORS->{'Perl module'}{$perl_module} = 1;
 			next PERL_MODULE;
 		}

 		# Check if installed version matches what is available from CPAN
 		my $installed_version = get_perl_module_installed_version($pModule);
 		if ($installed_version && $installed_version eq $cpan_version) {
 			print "$perl_module Perl module is up to date\n";
 		}
 		else {

 			print "Attempting to install Perl module using CPANMinus:  $perl_module\n";
 			my $returnval = system("cpanm", "--notest", "--force", $perl_module);

 			# Check if the module was successfully installed
 			$installed_version = get_perl_module_installed_version($pModule);
 			if (!$installed_version) {
 				print "ERROR: failed to install $perl_module Perl module\n";
 				$ERRORS->{'Perl module'}{$perl_module} = 1;
 				next PERL_MODULE;
 			}
 		}

 		# Check if corresponding Linux package failed - remove from %ERRORS
 		my $linux_package_name = "perl-$pModule";
 		$linux_package_name =~ s/::/-/g;
 		if (defined $ERRORS->{'Linux package'}{$linux_package_name}) {
 			print "Removed $linux_package_name from list of failed Linux packages\n";
 			delete $ERRORS->{'Linux package'}{$linux_package_name};
 		}
 	}

 	print_break("*");
 	return 1;
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 get_perl_module_installed_version

  Parameters  : $perl_module
  Returns     :
  Description :

 =cut

 sub get_perl_module_installed_version {
 	my $perl_module = shift;

 	my $cpan_module = CPAN::Shell->expand("Module", $perl_module);
 	if ($cpan_module) {
 		my $cpan_installed_version = $cpan_module->inst_version;

 		if ($cpan_installed_version) {
 			print "$perl_module $cpan_installed_version Perl module is installed\n";
 			return $cpan_installed_version;
 		}
 		else {
 			print "$perl_module Perl module is NOT installed\n";
 			return;
 		}
 	}
 	else {
 		print "$perl_module Perl module information could not be obtained from CPAN, checking if it is installed on local computer\n";

 		my $command = "perl -e \"eval \\\"use $perl_module\\\"; print \\\$" . $perl_module . "::VERSION\" 2>&1";
 		my $output = `$command`;
 		my $exit_status = $? >> 8;

 		if ($output =~ /Can't locate/i) {
 			print "$perl_module Perl module is NOT installed\n";
 			return;
 		}

 		my ($version) = $output =~ /^(\d[\d\.]+\d)$/;
 		if (defined($version)) {
 			print "$perl_module Perl module is installed, version: $version\n";
 			return $version;
 		}
 		else {
 			print "$perl_module Perl module appears to be installed but the version could not be determined\ncommand: $command\noutput:\n$output\n";
 			return;
 		}
 	}
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 get_perl_module_cpan_version

  Parameters  : $perl_module
  Returns     :
  Description :

 =cut

 sub get_perl_module_cpan_version {
 	my $perl_module = shift;

 	my $cpan_module = CPAN::Shell->expand("Module", $perl_module);
 	if ($cpan_module) {
 		my $cpan_source_version = $cpan_module->cpan_version;

 		if ($cpan_source_version) {
 			print "$perl_module $cpan_source_version Perl module is available from CPAN\n";
 			return $cpan_source_version;
 		}
 		else {
 			print "WARNING: $perl_module Perl module appears to be available from CPAN but version could not be obtained\n";
 			return;
 		}
 	}
 	else {
 		print "WARNING: $perl_module Perl module is NOT available from CPAN\n";
 		return;
 	}
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 run_command

  Parameters  : $command
  Returns     : array ($exit_status, $output)
  Description :

 =cut

 sub run_command {
 	my $command = shift;

 	print "Attempting to execute command: '$command'\n";
 	my $output = `$command 2>&1`;
 	my $exit_status = $? >> 8;
 	print "Executed command: '$command', exit status: $exit_status\n";
 	return ($exit_status, $output);
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 show_disclaimer

  Parameters  : none
  Returns     :
  Description :

 =cut

 sub show_disclaimer {
 	my $disclaimer .= <<"EOF";
 *** NOTICE ***

 This script will download and install Linux packages and Perl modules
 distributed under the following licenses:
 - The "Artistic License"
 - BSD License
 - GNU General Public License (GPL)
 - GNU Library or "Lesser" General Public License (LGPL)
 - MIT License

 See the README file for more information.
 EOF

 	print '=' x 76 . "\n";
 	print $disclaimer;
 	print '=' x 76 . "\n";

 	while (1) {
 		print 'Type YES to proceed, type NO to abort: ';
 		my $input = <>;
 		if ($input =~ /^\s*YES\s*$/i) {
 			last;
 		}
 		elsif ($input =~ /^\s*NO\s*$/i) {
 			exit 2;
 		}
 		else {
 			next;
 		}
 	}
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 print_break

  Parameters  : $character (optional)
  Returns     :
  Description :

 =cut

 sub print_break {
 	my $character = shift;
 	$character = '-' if !defined($character);
 	print $character x 100 . "\n";
 }

 #//////////////////////////////////////////////////////////////////////////////

 =head2 help

  Parameters  : none
  Returns     : exits
  Description :

 =cut

 sub help {
 	print <<EOF;
 Usage: perl $0 [OPTION]...
 Install all of the Linux packages and Perl modules required by the VCL
 management node daemon (vcld).

   -y             skip license agreement
   -l, --linux    install Linux packages
   -p, --perl     install Perl modules
   --help         display this help and exit

 If no -l or -p option is specified, Linux packages and Perl modules are both
 installed.
 EOF
 	exit 0;
 }

 #//////////////////////////////////////////////////////////////////////////////

 1;
 __END__

 =head1 SEE ALSO

 L<http://cwiki.apache.org/VCL/>

 =cut
	#!/usr/bin/perl -w
	###############################################################################
	# $Id$
	###############################################################################
	# Licensed to the Apache Software Foundation (ASF) under one or more
	# contributor license agreements. See the NOTICE file distributed with
	# this work for additional information regarding copyright ownership.
	# The ASF licenses this file to You under the Apache License, Version 2.0
	# (the "License"); you may not use this file except in compliance with
	# the License. You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	###############################################################################

	=head1 NAME

	install_perl_libs.pl - Script to install VCL Perl module dependencies

	=head1 SYNOPSIS

	Run this script from the command line:

	perl install_perl_libs.pl

	=head1 DESCRIPTION

	This script downloads and installs the Linux packages and Perl modules which
	are required for the backend VCL management node code. The yum utility is used
	to download and install the Linux packages. The CPAN.pm Perl module is used to
	download and install the required Perl modules. A disclaimer is displayed
	before this script downloads any files notifying you of the licenses used by
	the dependencies. You must type YES in order for the script to proceed.

	=cut
	###############################################################################
	use strict;

	use English;
	use Getopt::Long;

	#//////////////////////////////////////////////////////////////////////////////

	my @LINUX_PACKAGES = (
	'expat-devel',
	'gcc',
	'krb5-devel',
	'krb5-libs',
	'libxml2-devel',
	'make',
	'nmap',
	'openssl-devel',
	'bzip2',
	'perl-CPAN',
	'perl-App-cpanminus',
	'perl-DBD-MySQL',
	'xmlsec1-openssl',
	);

	my @PERL_MODULES = (
	'CPAN@2.36',
	'Archive::Tar@3.02',
	'Crypt::CBC@3.04',
	'Crypt::OpenSSL::RSA@0.33',
	'Crypt::Rijndael@1.16',
	'DBI@1.643',
	'Digest::SHA1@2.13',
	'Expect@1.35',
	'Frontier::RPC2',
	'Frontier::Client',
	'IO::String@1.08',
	'JSON@4.10',
	'Net::LDAP@0.68',
	'LWP::Protocol::https@6.12',
	'MailTools@2.21',
	'Mo@0.40',
	'Mo::builder@0.40',
	'Net::Jabber@2.0',
	'Net::Netmask@2.0002',
	'Net::SSH::Expect@1.09',
	'Net::Ping::External@0.15',
	'Object::InsideOut@4.05',
	'REST::Client@281',
	'RPC::XML@1.61',
	'Sub::Util@1.63',
	'Text::CSV_XS@1.53',
	'Time::HiRes@1.9764',
	'XML::Simple@2.25',
	'YAML@1.31'
	);

	# Store the command line options in hash
	my $AGREE;
	my $INSTALL_LINUX_PACKAGES;
	my $INSTALL_PERL_MODULES;
	my %OPTIONS;
	GetOptions(\%OPTIONS,
	'y!' => \$AGREE,
	'linux!' => \$INSTALL_LINUX_PACKAGES,
	'perl!' => \$INSTALL_PERL_MODULES,
	'help' => \&help,
	);

	show_disclaimer() if !$AGREE;

	my $ERRORS = {};

	# Check if -l or -y was specified
	if (!defined($INSTALL_PERL_MODULES) && !defined($INSTALL_LINUX_PACKAGES)) {
	$INSTALL_PERL_MODULES = 1;
	$INSTALL_LINUX_PACKAGES = 1;
	}
	elsif (defined($INSTALL_PERL_MODULES) && !defined($INSTALL_LINUX_PACKAGES)) {
	$INSTALL_LINUX_PACKAGES = !$INSTALL_PERL_MODULES;
	}
	elsif (defined($INSTALL_LINUX_PACKAGES) && !defined($INSTALL_PERL_MODULES)) {
	$INSTALL_PERL_MODULES = !$INSTALL_LINUX_PACKAGES;
	}

	if ($INSTALL_LINUX_PACKAGES) {
	print_break('=');
	# Check if yum is available
	my ($which_exit_status, $which_output) = run_command("which yum");
	if ($which_exit_status ne '0') {
	print "WARNING: yum is not available on this OS, skipping Linux package installation\n";
	return 0;
	}
	else {
	install_epel();
	print_break('=');
	install_linux_packages();
	}
	}

	if ($INSTALL_PERL_MODULES) {
	print_break('=');
	install_perl_modules();
	}

	print_break('=');

	my $error_encountered;
	for my $key (keys %$ERRORS) {
	for my $component (sort keys %{$ERRORS->{$key}}) {
	print "WARNING: failed to install $key: $component\n";
	$error_encountered++;
	}
	}

	if (!$error_encountered) {
	print "COMPLETE: installed all components\n";
	exit 0;
	}
	else {
	exit 1;
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 install_epel

	Parameters : none
	Returns : boolean
	Description : Creates a temporary /etc/yum.repos.d/epel-install.repo file and
	installs the epel-release package.

	=cut

	sub install_epel {
	my $epel_install_repo_path = '/etc/yum.repos.d/epel-install.repo';

	my $epel_install_repo_contents = <<EOF;
	[epel-install]
	name=EPEL Repository
	mirrorlist=https://mirrors.fedoraproject.org/mirrorlist?repo=epel-\$releasever&arch=\$basearch
	failovermethod=priority
	enabled=1
	gpgcheck=0
	EOF

	unlink $epel_install_repo_path;

	print "Creating file: $epel_install_repo_path\n";
	if (!open FILE, ">", $epel_install_repo_path) {
	print "ERROR: failed to create file: $epel_install_repo_path\n";
	exit 1;
	}
	if (!print FILE $epel_install_repo_contents) {
	print "ERROR: failed to write to file: $epel_install_repo_path\n";
	exit 1;
	}
	close FILE;

	my $result = yum_install_linux_package('epel-release');

	if (unlink $epel_install_repo_path) {
	print "Removed file: $epel_install_repo_path\n";
	}
	else {
	print "WARNING: failed to remove file: $epel_install_repo_path\n";
	}

	return $result;
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 install_linux_packages

	Parameters : none
	Returns : boolean
	Description : Installs the Linux operating system packages required by the VCL
	managment node components.

	=cut

	sub install_linux_packages {
	for my $linux_package (@LINUX_PACKAGES) {
	print_break('*');
	if (!yum_install_linux_package($linux_package)) {
	$ERRORS->{'Linux package'}{$linux_package} = 1;
	}
	}
	return 1;
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 yum_install_linux_package

	Parameters : $linux_package
	Returns : boolean
	Description : Attempts to install a single Linux package using yum.

	=cut

	sub yum_install_linux_package {
	my ($linux_package) = @_;
	if (!$linux_package) {
	print "ERROR: package name argument was not provided\n";
	return;
	}

	print "Attempting to install Linux package using yum: $linux_package\n";

	my $yum_command = "yum install $linux_package -y --nogpgcheck";
	#print "Yum command: $yum_command\n";

	my $yum_output = `$yum_command 2>&1 \| grep -v '^\\(Load\\\|Setting\\\|Nothing\\\| \\*\\)'`;
	my $yum_exit_status = $? >> 8;

	chomp $yum_output;
	print "$yum_output\n\n";

	if ($yum_exit_status ne '0') {
	print "WARNING: failed to install Linux package: '$linux_package', exit status: $yum_exit_status\n";
	return 0;
	}
	elsif ($yum_output =~ /$linux_package[^\n]*already installed/i) {
	print "SUCCESS: Linux package is already installed: $linux_package\n";
	}
	elsif ($yum_output =~ /Complete\!/i) {
	print "SUCCESS: installed Linux package: $linux_package\n";
	}
	elsif ($yum_output =~ /No package.*available/i) {
	print "WARNING: Linux package is not available via yum: $linux_package\n";
	return 0;
	}
	else {
	print "WARNING: unexpected output returned while installing Linux package: $linux_package\n";
	return 0;
	}

	return 1;
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 configure_cpan

	Parameters : none
	Returns : boolean
	Description : Attempts to configure CPAN so that modules can be installed
	without user interaction.

	=cut

	sub configure_cpan {
	eval {
	require CPAN;
	};
	if ($EVAL_ERROR) {
	print "Unable to install Perl modules, CPAN module could not be loaded.\n";
	exit 1;
	}

	$ENV{PERL_MM_USE_DEFAULT} = 1;
	$ENV{PERL_MM_NONINTERACTIVE} = 1;
	$ENV{AUTOMATED_TESTING} = 1;
	$ENV{FTP_PASSIVE} = 1;

	my $cpan_directory = $ENV{HOME} . '/.cpan';
	my $config_file_path = "$cpan_directory/CPAN/MyConfig.pm";
	`mkdir -p $cpan_directory/CPAN`;

	$CPAN::Config = {
	"applypatch" => "",
	"auto_commit" => "1",
	"build_cache" => "1",
	"build_dir" => "$cpan_directory/build",
	"build_requires_install_policy" => "yes",
	"bzip2" => `echo -n \`which bzip2\`` \|\| "",
	"cache_metadata" => "1",
	"check_sigs" => "0",
	"connect_to_internet_ok" => "1",
	"cpan_home" => "$cpan_directory",
	"curl" => `echo -n \`which curl\`` \|\| "",
	"ftp" => `echo -n \`which ftp\`` \|\| "",
	"ftp_passive" => "1",
	"ftp_proxy" => "",
	"getcwd" => "cwd",
	"gpg" => `echo -n \`which gpg\`` \|\| "",
	"gzip" => `echo -n \`which gzip\`` \|\| "",
	"halt_on_failure" => "0",
	"histfile" => "$cpan_directory/histfile",
	"histsize" => "1000",
	"http_proxy" => "",
	"inactivity_timeout" => "60",
	"index_expire" => "10",
	"inhibit_startup_message" => "1",
	"keep_source_where" => "$cpan_directory/sources",
	"load_module_verbosity" => "1",
	"make" => `echo -n \`which make\`` \|\| "",
	"make_arg" => "",
	"make_install_arg" => "",
	"make_install_make_command" => `echo -n \`which make\`` \|\| "",
	"makepl_arg" => "",
	"mbuild_arg" => "",
	"mbuild_install_arg" => "",
	"mbuild_install_build_command" => "./Build",
	"mbuildpl_arg" => "",
	"ncftp" => "",
	"ncftpget" => "",
	"no_proxy" => "",
	"pager" => `echo -n \`which less\`` \|\| "",
	"perl5lib_verbosity" => "",
	"prefer_installer" => "MB",
	"prefs_dir" => "$cpan_directory/prefs",
	"prerequisites_policy" => "follow",
	"proxy_user" => "",
	"randomize_urllist" => "1",
	"scan_cache" => "never",
	"shell" => `echo -n \`which bash\`` \|\| "",
	"show_upload_date" => "0",
	"tar" => `echo -n \`which tar\`` \|\| "",
	"tar_verbosity" => "",
	"term_ornaments" => "1",
	"trust_test_report_history" => "1",
	"unzip" => `echo -n \`which unzip\`` \|\| "",
	"urllist" => [q[https://cpan.metacpan.org/], q[https://mirrors.namecheap.com/CPAN/], q[https://mirrors.syringanetworks.net/CPAN/], q[https://ftp.wayne.edu/CPAN/]],
	"use_sqlite" => "0",
	"wget" => `echo -n \`which wget\`` \|\| "",
	"yaml_load_code" => "0",
	};

	# Use $CPAN::Config once to avoid warning
	if ($CPAN::Config) {};

	eval { CPAN::Config->commit($config_file_path) };
	if ($EVAL_ERROR) {
	print "\nERROR: failed to create CPAN configuration file: $config_file_path\n$EVAL_ERROR\n";
	exit 1;
	}
	else {
	print "Created CPAN configuration file: $config_file_path\n";
	}

	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 install_perl_modules

	Parameters :
	Returns :
	Description :

	=cut

	sub install_perl_modules {
	eval { require CPAN };
	if ($EVAL_ERROR) {
	print "ERROR: failed to install perl modules, CPAN module is not available\n";
	$ERRORS->{'Perl module'}{'ALL'} = 1;
	return;
	}
	print "Running CPAN version: $CPAN::VERSION\n";

	configure_cpan();

	PERL_MODULE: for my $perl_module (@PERL_MODULES) {
	print_break('*');

	#my $cpan_version = get_perl_module_cpan_version($perl_module);
	my ($pModule, $cpan_version ) = split(/@/, $perl_module);
	if (!defined $cpan_version) {
	$cpan_version = 'undef';
	}
	my $cpan_version_available = `cpanm --info -q $perl_module \| grep -i failed \| wc -l`;
	#if (!$cpan_version) {
	if ($cpan_version_available == 1) {
	print "ERROR: unable to install $perl_module Perl module, information could not be obtained from CPAN\n";
	$ERRORS->{'Perl module'}{$perl_module} = 1;
	next PERL_MODULE;
	}

	# Check if installed version matches what is available from CPAN
	my $installed_version = get_perl_module_installed_version($pModule);
	if ($installed_version && $installed_version eq $cpan_version) {
	print "$perl_module Perl module is up to date\n";
	}
	else {

	print "Attempting to install Perl module using CPANMinus: $perl_module\n";
	my $returnval = system("cpanm", "--notest", "--force", $perl_module);

	# Check if the module was successfully installed
	$installed_version = get_perl_module_installed_version($pModule);
	if (!$installed_version) {
	print "ERROR: failed to install $perl_module Perl module\n";
	$ERRORS->{'Perl module'}{$perl_module} = 1;
	next PERL_MODULE;
	}
	}

	# Check if corresponding Linux package failed - remove from %ERRORS
	my $linux_package_name = "perl-$pModule";
	$linux_package_name =~ s/::/-/g;
	if (defined $ERRORS->{'Linux package'}{$linux_package_name}) {
	print "Removed $linux_package_name from list of failed Linux packages\n";
	delete $ERRORS->{'Linux package'}{$linux_package_name};
	}
	}

	print_break("*");
	return 1;
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 get_perl_module_installed_version

	Parameters : $perl_module
	Returns :
	Description :

	=cut

	sub get_perl_module_installed_version {
	my $perl_module = shift;

	my $cpan_module = CPAN::Shell->expand("Module", $perl_module);
	if ($cpan_module) {
	my $cpan_installed_version = $cpan_module->inst_version;

	if ($cpan_installed_version) {
	print "$perl_module $cpan_installed_version Perl module is installed\n";
	return $cpan_installed_version;
	}
	else {
	print "$perl_module Perl module is NOT installed\n";
	return;
	}
	}
	else {
	print "$perl_module Perl module information could not be obtained from CPAN, checking if it is installed on local computer\n";

	my $command = "perl -e \"eval \\\"use $perl_module\\\"; print \\\$" . $perl_module . "::VERSION\" 2>&1";
	my $output = `$command`;
	my $exit_status = $? >> 8;

	if ($output =~ /Can't locate/i) {
	print "$perl_module Perl module is NOT installed\n";
	return;
	}

	my ($version) = $output =~ /^(\d[\d\.]+\d)$/;
	if (defined($version)) {
	print "$perl_module Perl module is installed, version: $version\n";
	return $version;
	}
	else {
	print "$perl_module Perl module appears to be installed but the version could not be determined\ncommand: $command\noutput:\n$output\n";
	return;
	}
	}
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 get_perl_module_cpan_version

	Parameters : $perl_module
	Returns :
	Description :

	=cut

	sub get_perl_module_cpan_version {
	my $perl_module = shift;

	my $cpan_module = CPAN::Shell->expand("Module", $perl_module);
	if ($cpan_module) {
	my $cpan_source_version = $cpan_module->cpan_version;

	if ($cpan_source_version) {
	print "$perl_module $cpan_source_version Perl module is available from CPAN\n";
	return $cpan_source_version;
	}
	else {
	print "WARNING: $perl_module Perl module appears to be available from CPAN but version could not be obtained\n";
	return;
	}
	}
	else {
	print "WARNING: $perl_module Perl module is NOT available from CPAN\n";
	return;
	}
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 run_command

	Parameters : $command
	Returns : array ($exit_status, $output)
	Description :

	=cut

	sub run_command {
	my $command = shift;

	print "Attempting to execute command: '$command'\n";
	my $output = `$command 2>&1`;
	my $exit_status = $? >> 8;
	print "Executed command: '$command', exit status: $exit_status\n";
	return ($exit_status, $output);
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 show_disclaimer

	Parameters : none
	Returns :
	Description :

	=cut

	sub show_disclaimer {
	my $disclaimer .= <<"EOF";
	* NOTICE *

	This script will download and install Linux packages and Perl modules
	distributed under the following licenses:
	- The "Artistic License"
	- BSD License
	- GNU General Public License (GPL)
	- GNU Library or "Lesser" General Public License (LGPL)
	- MIT License

	See the README file for more information.
	EOF

	print '=' x 76 . "\n";
	print $disclaimer;
	print '=' x 76 . "\n";

	while (1) {
	print 'Type YES to proceed, type NO to abort: ';
	my $input = <>;
	if ($input =~ /^\sYES\s$/i) {
	last;
	}
	elsif ($input =~ /^\sNO\s$/i) {
	exit 2;
	}
	else {
	next;
	}
	}
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 print_break

	Parameters : $character (optional)
	Returns :
	Description :

	=cut

	sub print_break {
	my $character = shift;
	$character = '-' if !defined($character);
	print $character x 100 . "\n";
	}

	#//////////////////////////////////////////////////////////////////////////////

	=head2 help

	Parameters : none
	Returns : exits
	Description :

	=cut

	sub help {
	print <<EOF;
	Usage: perl $0 [OPTION]...
	Install all of the Linux packages and Perl modules required by the VCL
	management node daemon (vcld).

	-y skip license agreement
	-l, --linux install Linux packages
	-p, --perl install Perl modules
	--help display this help and exit

	If no -l or -p option is specified, Linux packages and Perl modules are both
	installed.
	EOF
	exit 0;
	}

	#//////////////////////////////////////////////////////////////////////////////

	1;
	__END__

	=head1 SEE ALSO

	L<http://cwiki.apache.org/VCL/>

	=cut