Backport/facter 2/fact 185 ec2 metadata

lib/facter/core/suitable.rb

@@ -108,10 +108,6 @@ def weight
   #
   # @api private
   def suitable?
-    unless defined? @suitable
-      @suitable = ! @confines.detect { |confine| ! confine.true? }
-    end
-
-    return @suitable
+    @confines.all? { |confine| confine.true? }
   end
 end

lib/facter/ec2.rb

@@ -1,37 +1,45 @@
 require 'facter/util/ec2'
-require 'open-uri'
 
-def metadata(id = "")
-  open("http://169.254.169.254/2008-02-01/meta-data/#{id||=''}").read.
-    split("\n").each do |o|
-    key = "#{id}#{o.gsub(/\=.*$/, '/')}"
-    if key[-1..-1] != '/'
-      value = open("http://169.254.169.254/2008-02-01/meta-data/#{key}").read.
-        split("\n")
-      symbol = "ec2_#{key.gsub(/\-|\//, '_')}".to_sym
-      Facter.add(symbol) { setcode { value.join(',') } }
-    else
-      metadata(key)
+Facter.define_fact(:ec2_metadata) do
+  define_resolution(:rest) do
+    confine do
+      Facter.value(:virtual).match /^xen/
+    end
+
+    confine do
+      Facter::Util::EC2.uri_reachable?("http://169.254.169.254/latest/meta-data/")
+    end
+
+    setcode do
+      metadata_uri = "http://169.254.169.254/latest/meta-data/"
+      Facter::Util::EC2.recursive_fetch(metadata_uri)
     end
   end
-rescue => details
-  Facter.warn "Could not retrieve ec2 metadata: #{details.message}"
 end
 
-def userdata()
-  Facter.add(:ec2_userdata) do
+Facter.define_fact(:ec2_userdata) do
+  define_resolution(:rest) do
+    confine do
+      Facter.value(:virtual).match /^xen/
+    end
+
+    confine do
+      Facter::Util::EC2.uri_reachable?("http://169.254.169.254/latest/user-data/")
+    end
+
     setcode do
-      if userdata = Facter::Util::EC2.userdata
-        userdata.split
-      end
+      userdata_uri = "http://169.254.169.254/latest/user-data/"
+      output = Facter::Util::EC2.fetch(userdata_uri)
+      output.join("\n")
     end
   end
 end
 
-if (Facter::Util::EC2.has_euca_mac? || Facter::Util::EC2.has_openstack_mac? ||
-    Facter::Util::EC2.has_ec2_arp?) && Facter::Util::EC2.can_connect?
-  metadata
-  userdata
-else
-  Facter.debug "Not an EC2 host"
+# The flattened version of the EC2 facts are deprecated and will be removed in
+# a future release of Facter.
+if (ec2_metadata = Facter.value(:ec2_metadata))
+  ec2_facts = Facter::Util::Values.flatten_structure("ec2", ec2_metadata)
+  ec2_facts.each_pair do |factname, factvalue|
+    Facter.add(factname, :value => factvalue)
+  end
 end

lib/facter/util/ec2.rb

@@ -3,99 +3,99 @@
 
 # Provide a set of utility static methods that help with resolving the EC2
 # fact.
+#
+# @see http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AESDG-chapter-instancedata.html
 module Facter::Util::EC2
-  class << self
-    # Test if we can connect to the EC2 api. Return true if able to connect.
-    # On failure this function fails silently and returns false.
-    #
-    # The +wait_sec+ parameter provides you with an adjustable timeout.
-    #
-    def can_connect?(wait_sec=2)
-      url = "http://169.254.169.254:80/"
-      Timeout::timeout(wait_sec) {open(url)}
-      return true
-    rescue Timeout::Error
-      return false
-    rescue
-      return false
-    end
+  CONNECTION_ERRORS = [
+    Errno::EHOSTDOWN,
+    Errno::EHOSTUNREACH,
+    Errno::ENETUNREACH,
+    Errno::ECONNABORTED,
+    Errno::ECONNREFUSED,
+    Errno::ECONNRESET,
+    Errno::ETIMEDOUT,
+  ]
 
-    # Test if this host has a mac address used by Eucalyptus clouds, which
-    # normally is +d0:0d+.
-    def has_euca_mac?
-      !!(Facter.value(:macaddress) =~ %r{^[dD]0:0[dD]:})
-    end
+  # Query a specific AWS metadata URI.
+  #
+  # @api private
+  def self.fetch(uri)
+    body = open(uri).read
 
-    # Test if this host has a mac address used by OpenStack, which
-    # normally starts with FA:16:3E (older versions of OpenStack
-    # may generate mac addresses starting with 02:16:3E)
-    def has_openstack_mac?
-      !!(Facter.value(:macaddress) =~ %r{^(02|[fF][aA]):16:3[eE]})
+    lines = body.split("\n").map do |line|
+      if (match = line.match(/^(\d+)=.*$/))
+        # Metadata arrays are formatted like '<index>=<associated key>/', so
+        # we need to extract the index from that output.
+        "#{match[1]}/"
+      else
+        line
+      end
     end
 
-    # Test if the host has an arp entry in its cache that matches the EC2 arp,
-    # which is normally +fe:ff:ff:ff:ff:ff+.
-    def has_ec2_arp?
-      kernel = Facter.value(:kernel)
+    lines
+  rescue OpenURI::HTTPError => e
+    if e.message.match /404 Not Found/i
+      return nil
+    else
+      Facter.log_exception(e, "Failed to fetch ec2 uri #{uri}: #{e.message}")
+      return nil
+    end
+  rescue *CONNECTION_ERRORS => e
+    Facter.log_exception(e, "Failed to fetch ec2 uri #{uri}: #{e.message}")
+  end
 
-      mac_address_re = case kernel
-                       when /Windows/i
-                         /fe-ff-ff-ff-ff-ff/i
-                       else
-                         /fe:ff:ff:ff:ff:ff/i
-                       end
+  def self.recursive_fetch(uri)
+    results = {}
 
-      arp_command = case kernel
-                    when /Windows/i, /SunOS/i
-                      "arp -a"
-                    else
-                      "arp -an"
-                    end
+    keys = fetch(uri)
 
-      if arp_table = Facter::Core::Execution.exec(arp_command)
-        return true if arp_table.match(mac_address_re)
+    keys.each do |key|
+      if key.match(%r[/$])
+        # If a metadata key is suffixed with '/' then it's a general metadata
+        # resource, so we have to recursively look up all the keys in the given
+        # collection.
+        name = key[0..-2]
+        results[name] = recursive_fetch("#{uri}#{key}")
+      else
+        # This is a simple key/value pair, we can just query the given endpoint
+        # and store the results.
+        ret = fetch("#{uri}#{key}")
+        results[key] = ret.size > 1 ? ret : ret.first
       end
-      return false
     end
+
+    results
   end
 
-  ##
-  # userdata returns a single string containing the body of the response of the
-  # GET request for the URI http://169.254.169.254/latest/user-data/  If the
-  # metadata server responds with a 404 Not Found error code then this method
-  # retuns `nil`.
-  #
-  # @param version [String] containing the API version for the request.
-  # Defaults to "latest" and other examples are documented at
-  # http://aws.amazon.com/archives/Amazon%20EC2
+  # Is the given URI reachable?
   #
-  # @api public
+  # @param uri [String] The HTTP URI to attempt to reach
   #
-  # @return [String] containing the response body or `nil`
-  def self.userdata(version="latest")
-    uri = "http://169.254.169.254/#{version}/user-data/"
+  # @return [true, false] If the given URI could be fetched after retry_limit attempts
+  def self.uri_reachable?(uri, retry_limit = 3)
+    timeout = 0.2
+    able_to_connect = false
+    attempts = 0
+
     begin
-      read_uri(uri)
-    rescue OpenURI::HTTPError => detail
-      case detail.message
-      when /404 Not Found/i
-        Facter.debug "No user-data present at #{uri}: server responded with #{detail.message}"
-        return nil
+      Timeout.timeout(timeout) do
+        open(uri).read
+      end
+      able_to_connect = true
+    rescue OpenURI::HTTPError => e
+      if e.message.match /404 Not Found/i
+        able_to_connect = false
       else
-        raise detail
+        retry if attempts < retry_limit
       end
+    rescue Timeout::Error
+      retry if attempts < retry_limit
+    rescue *CONNECTION_ERRORS
+      retry if attempts < retry_limit
+    ensure
+      attempts = attempts + 1
     end
-  end
 
-  ##
-  # read_uri provides a seam method to easily test the HTTP client
-  # functionality of a HTTP based metadata server.
-  #
-  # @api private
-  #
-  # @return [String] containing the body of the response
-  def self.read_uri(uri)
-    open(uri).read
+    able_to_connect
   end
-  private_class_method :read_uri
 end

lib/facter/util/resolution.rb

@@ -62,6 +62,10 @@ def initialize(name, fact)
     @weight = nil
   end
 
+  def resolution_type
+    :simple
+  end
+
   # Evaluate the given block in the context of this resolution. If a block has
   # already been evaluated emit a warning to that effect.
   #

lib/facter/util/values.rb

@@ -1,3 +1,4 @@
+
 module Facter
   module Util
     # A util module for facter containing helper methods
@@ -75,6 +76,34 @@ def convert(value)
         value = value.downcase if value.is_a?(String)
         value
       end
+
+      # Flatten the given data structure to something that's suitable to return
+      # as flat facts.
+      #
+      # @param path [String] The fact path to be prefixed to the given value.
+      # @param structure [Object] The data structure to flatten. Nested hashes
+      #   will be recursively flattened, everything else will be returned as-is.
+      #
+      # @return [Hash] The given data structure prefixed with the given path
+      def flatten_structure(path, structure)
+        results = {}
+
+        if structure.is_a? Hash
+          structure.each_pair do |name, value|
+            new_path = "#{path}_#{name}".gsub(/\-|\//, '_')
+            results.merge! flatten_structure(new_path, value)
+          end
+        elsif structure.is_a? Array
+          structure.each_with_index do |value, index|
+            new_path = "#{path}_#{index}"
+            results.merge! flatten_structure(new_path, value)
+          end
+        else
+          results[path] = structure
+        end
+
+        results
+      end
     end
   end
 end

spec/fixtures/unit/util/ec2/meta-data/root

@@ -0,0 +1,20 @@
+ami-id
+ami-launch-index
+ami-manifest-path
+block-device-mapping/
+hostname
+instance-action
+instance-id
+instance-type
+kernel-id
+local-hostname
+local-ipv4
+mac
+metrics/
+network/
+placement/
+profile
+public-hostname
+public-ipv4
+public-keys/
+reservation-id

spec/unit/core/suitable_spec.rb

@@ -92,5 +92,15 @@ def initialize
 
       expect(subject).to_not be_suitable
     end
+
+    it "recalculates suitability on every invocation" do
+      subject.confine :kernel => 'Linux'
+
+      subject.confines.first.stubs(:true?).returns false
+      expect(subject).to_not be_suitable
+      subject.confines.first.unstub(:true?)
+      subject.confines.first.stubs(:true?).returns true
+      expect(subject).to be_suitable
+    end
   end
 end