(#6527) Added pip package provider.

Python's pip package manager is analogous to RubyGems and should be included in Puppet.

Reviewed-by: Matt Robinson <matt@puppetlabs.com>

1 files changed, 115 insertions, 0 deletions

diff --git a/lib/puppet/provider/package/pip.rb b/lib/puppet/provider/package/pip.rb
new file mode 100644
index 000000000..00797563a
--- /dev/null
+++ b/lib/puppet/provider/package/pip.rb
@@ -0,0 +1,115 @@
+# Puppet package provider for Python's `pip` package management frontend.
+# <http://pip.openplans.org/>
+
+require 'puppet/provider/package'
+require 'xmlrpc/client'
+
+Puppet::Type.type(:package).provide :pip,
+  :parent => ::Puppet::Provider::Package do
+
+  desc "Python packages via `pip`."
+
+  has_feature :installable, :uninstallable, :upgradeable, :versionable
+
+  # Parse lines of output from `pip freeze`, which are structured as
+  # _package_==_version_.
+  def self.parse(line)
+    if line.chomp =~ /^([^=]+)==([^=]+)$/
+      {:ensure => $2, :name => $1, :provider => name}
+    else
+      nil
+    end
+  end
+
+  # Return an array of structured information about every installed package
+  # that's managed by `pip` or an empty array if `pip` is not available.
+  def self.instances
+    packages = []
+    execpipe "#{command :pip} freeze" do |process|
+      process.collect do |line|
+        next unless options = parse(line)
+        packages << new(options)
+      end
+    end
+    packages
+  rescue Puppet::DevError
+    []
+  end
+
+  # Return structured information about a particular package or `nil` if
+  # it is not installed or `pip` itself is not available.
+  def query
+    execpipe "#{command :pip} freeze" do |process|
+      process.each do |line|
+        options = self.class.parse(line)
+        return options if options[:name] == @resource[:name]
+      end
+    end
+    nil
+  rescue Puppet::DevError
+    nil
+  end
+
+  # Ask the PyPI API for the latest version number.  There is no local
+  # cache of PyPI's package list so this operation will always have to
+  # ask the web service.
+  def latest
+    client = XMLRPC::Client.new2("http://pypi.python.org/pypi")
+    client.http_header_extra = {"Content-Type" => "text/xml"}
+    result = client.call("package_releases", @resource[:name])
+    result.first
+  end
+
+  # Install a package.  The ensure parameter may specify installed,
+  # latest, a version number, or, in conjunction with the source
+  # parameter, an SCM revision.  In that case, the source parameter
+  # gives the fully-qualified URL to the repository.
+  def install
+    args = %w{install -q}
+    if @resource[:source]
+      args << "-e"
+      if String === @resource[:ensure]
+        args << "#{@resource[:source]}@#{@resource[:ensure]}#egg=#{
+          @resource[:name]}"
+      else
+        args << "#{@resource[:source]}#egg=#{@resource[:name]}"
+      end
+    else
+      case @resource[:ensure]
+      when String
+        args << "#{@resource[:name]}==#{@resource[:ensure]}"
+      when :latest
+        args << "--upgrade" << @resource[:name]
+      else
+        args << @resource[:name]
+      end
+    end
+    lazy_pip *args
+  end
+
+  # Uninstall a package.  Uninstall won't work reliably on Debian/Ubuntu
+  # unless this issue gets fixed.
+  # <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=562544>
+  def uninstall
+    lazy_pip "uninstall", "-y", "-q", @resource[:name]
+  end
+
+  def update
+    install
+  end
+
+  # Execute a `pip` command.  If Puppet doesn't yet know how to do so,
+  # try to teach it and if even that fails, raise the error.
+  private
+  def lazy_pip(*args)
+    pip *args
+  rescue NoMethodError => e
+    if pathname = `which pip`.chomp
+      self.class.commands :pip => pathname
+      pip *args
+    else
+      raise e
+    end
+  end
+
+end