Merge branch 'OHAI-434'

lib/ohai/mixin/ec2_metadata.rb

@@ -22,11 +22,28 @@
 
 module Ohai
   module Mixin
+    ##
+    # This code parses the EC2 Instance Metadata API to provide details
+    # of the running instance.
+    #
+    # Earlier version of this code assumed a specific version of the
+    # metadata API was available. Unfortunately the API versions
+    # supported by a particular instance are determined at instance
+    # launch and are not extended over the life of the instance. As such
+    # the earlier code would fail depending on the age of the instance.
+    #
+    # The updated code probes the instance metadata endpoint for
+    # available versions, determines the most advanced version known to
+    # work and executes the metadata retrieval using that version.
+    #
+    # If no compatible version is found, an empty hash is returned.
+    #
     module Ec2Metadata
 
       EC2_METADATA_ADDR = "169.254.169.254" unless defined?(EC2_METADATA_ADDR)
-      EC2_METADATA_URL = "/2012-01-12/meta-data" unless defined?(EC2_METADATA_URL)
-      EC2_USERDATA_URL = "/2012-01-12/user-data" unless defined?(EC2_USERDATA_URL)
+      EC2_SUPPORTED_VERSIONS = %w[ 1.0 2007-01-19 2007-03-01 2007-08-29 2007-10-10 2007-12-15
+                                   2008-02-01 2008-09-01 2009-04-04 2011-01-01 2011-05-01 2012-01-12 ]
+
       EC2_ARRAY_VALUES = %w(security-groups)
       EC2_ARRAY_DIR    = %w(network/interfaces/macs)
       EC2_JSON_DIR     = %w(iam)
@@ -57,67 +74,99 @@ def can_metadata_connect?(addr, port, timeout=2)
         connected
       end
 
+      def best_api_version
+        response = http_client.get("/")
+        unless response.code == '200'
+          raise "Unable to determine EC2 metadata version (returned #{response.code} response)"
+        end
+        # Note: Sorting the list of versions may have unintended consequences in
+        # non-EC2 environments. It appears to be safe in EC2 as of 2013-04-12.
+        versions = response.body.split("\n")
+        versions = response.body.split("\n").sort
+        until (versions.empty? || EC2_SUPPORTED_VERSIONS.include?(versions.last)) do
+          pv = versions.pop
+          Ohai::Log.debug("EC2 shows unsupported metadata version: #{pv}") unless pv == 'latest'
+        end
+        Ohai::Log.debug("EC2 metadata version: #{versions.last}")
+        if versions.empty?
+          raise "Unable to determine EC2 metadata version (no supported entries found)"
+        end
+        versions.last
+      end
+
       def http_client
         Net::HTTP.start(EC2_METADATA_ADDR).tap {|h| h.read_timeout = 600}
       end
 
-      def fetch_metadata(id='')
+      def metadata_get(id, api_version)
+        response = http_client.get("/#{api_version}/meta-data/#{id}")
+        unless response.code == '200'
+          raise "Encountered error retrieving EC2 metadata (returned #{response.code} response)"
+        end
+        response
+      end
+
+      def fetch_metadata(id='', api_version=nil)
+        api_version ||= best_api_version
+        return Hash.new if api_version.nil?
         metadata = Hash.new
-        http_client.get("#{EC2_METADATA_URL}/#{id}").body.split("\n").each do |o|
+        metadata_get(id, api_version).body.split("\n").each do |o|
           key = expand_path("#{id}#{o}")
           if key[-1..-1] != '/'
             metadata[metadata_key(key)] =
               if EC2_ARRAY_VALUES.include? key
-                http_client.get("#{EC2_METADATA_URL}/#{key}").body.split("\n")
+                metadata_get(key, api_version).body.split("\n")
               else
-                http_client.get("#{EC2_METADATA_URL}/#{key}").body
+                metadata_get(key, api_version).body
               end
           elsif not key.eql?(id) and not key.eql?('/')
             name = key[0..-2]
-	    sym = metadata_key(name)
+            sym = metadata_key(name)
             if EC2_ARRAY_DIR.include?(name)
-              metadata[sym] = fetch_dir_metadata(key)
+              metadata[sym] = fetch_dir_metadata(key, api_version)
             elsif EC2_JSON_DIR.include?(name)
-              metadata[sym] = fetch_json_dir_metadata(key)
+              metadata[sym] = fetch_json_dir_metadata(key, api_version)
             else
-              fetch_metadata(key).each{|k,v| metadata[k] = v}
+              fetch_metadata(key, api_version).each{|k,v| metadata[k] = v}
             end
           end
         end
         metadata
       end
 
-      def fetch_dir_metadata(id)
+      def fetch_dir_metadata(id, api_version)
         metadata = Hash.new
-        http_client.get("#{EC2_METADATA_URL}/#{id}").body.split("\n").each do |o|
+          metadata_get(id, api_version).body.split("\n").each do |o|
           key = expand_path(o)
           if key[-1..-1] != '/'
-            metadata[metadata_key(key)] = http_client.get("#{EC2_METADATA_URL}/#{id}#{key}").body
+            metadata[metadata_key(key)] = metadata_get("#{id}#{key}", api_version).body
           elsif not key.eql?('/')
-            metadata[key[0..-2]] = fetch_dir_metadata("#{id}#{key}")
+            metadata[key[0..-2]] = fetch_dir_metadata("#{id}#{key}", api_version)
           end
         end
         metadata
       end
 
-      def fetch_json_dir_metadata(id)
+      def fetch_json_dir_metadata(id, api_version)
         metadata = Hash.new
-        http_client.get("#{EC2_METADATA_URL}/#{id}").body.split("\n").each do |o|
+        metadata_get(id, api_version).body.split("\n").each do |o|
           key = expand_path(o)
           if key[-1..-1] != '/'
-            data = http_client.get("#{EC2_METADATA_URL}/#{id}#{key}").body
+            data = metadata_get("#{id}#{key}", api_version).body
             json = StringIO.new(data)
             parser = Yajl::Parser.new
             metadata[metadata_key(key)] = parser.parse(json)
           elsif not key.eql?('/')
-            metadata[key[0..-2]] = fetch_json_dir_metadata("#{id}#{key}")
+            metadata[key[0..-2]] = fetch_json_dir_metadata("#{id}#{key}", api_version)
           end
         end
         metadata
       end
 
       def fetch_userdata()
-        response = http_client.get("#{EC2_USERDATA_URL}/")
+        api_version = best_api_version
+        return nil if api_version.nil?
+        response = http_client.get("/#{api_version}/user-data/")
         response.code == "200" ? response.body : nil
       end
 
@@ -138,4 +187,3 @@ def metadata_key(key)
     end
   end
 end
-

spec/unit/mixin/ec2_metadata_spec.rb

@@ -0,0 +1,82 @@
+#
+# Author:: Bryan McLellan <btm@loftninjas.org>
+# Copyright:: Copyright (c) 2013 Opscode, Inc.
+# License:: Apache License, Version 2.0
+#
+# Licensed 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 CONDIT"Net::HTTP Response"NS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+require File.expand_path(File.dirname(__FILE__) + '/../../spec_helper.rb')
+require 'ohai/mixin/ec2_metadata'
+
+describe Ohai::Mixin::Ec2Metadata do
+  let(:mixin) {
+    metadata_object = Object.new.extend(Ohai::Mixin::Ec2Metadata)
+    http_client = mock("Net::HTTP client")
+    http_client.stub!(:get).and_return(response)
+    metadata_object.stub!(:http_client).and_return(http_client)
+    metadata_object
+  }
+
+  context "#best_api_version" do
+    context "with a sorted list of metadata versions" do
+      let(:response) { mock("Net::HTTP Response", :body => "1.0\n2011-05-01\n2012-01-12\nUnsupported", :code => "200") }
+
+      it "returns the most recent version" do
+        mixin.best_api_version.should == "2012-01-12"
+      end
+    end
+
+    context "with an unsorted list of metadata versions" do
+      let(:response) { mock("Net::HTTP Response", :body => "1.0\n2009-04-04\n2007-03-01\n2011-05-01\n2008-09-01\nUnsupported", :code => "200") }
+
+      it "returns the most recent version (using string sort)" do
+        mixin.best_api_version.should == "2011-05-01"
+      end
+    end
+
+    context "when no supported versions are found" do
+      let(:response) { mock("Net::HTTP Response", :body => "2020-01-01\nUnsupported", :code => "200") }
+
+      it "raises an error" do
+        lambda { mixin.best_api_version}.should raise_error
+      end
+    end
+
+    context "when the response code is 404" do
+      let(:response) { mock("Net::HTTP Response", :body => "1.0\n2011-05-01\n2012-01-12\nUnsupported", :code => "404") }
+
+      it "raises an error" do
+        lambda { mixin.best_api_version}.should raise_error
+      end
+    end
+
+    context "when the response code is unexpected" do
+      let(:response) { mock("Net::HTTP Response", :body => "1.0\n2011-05-01\n2012-01-12\nUnsupported", :code => "418") }
+
+      it "raises an error" do
+        lambda { mixin.best_api_version}.should raise_error
+      end
+    end
+  end
+
+  context "#metadata_get" do
+    context "when the response code is unexpected" do
+      let(:response) { mock("Net::HTTP Response", :body => "", :code => "418") }
+
+      it "raises an error" do
+        lambda { mixin.metadata_get('', '2012-01-12') }.should raise_error(RuntimeError)
+      end
+    end
+  end
+end

spec/unit/plugins/ec2_spec.rb

@@ -42,21 +42,24 @@
       t = mock("connection")
       t.stub!(:connect_nonblock).and_raise(Errno::EINPROGRESS)
       Socket.stub!(:new).and_return(t)
+      @http_client.should_receive(:get).
+        with("/").twice.
+        and_return(mock("Net::HTTP Response", :body => "2012-01-12", :code => "200"))
     end
 
     it "should recursively fetch all the ec2 metadata" do
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/").
-        and_return(mock("Net::HTTP Response", :body => "instance_type\nami_id\nsecurity-groups"))
+        and_return(mock("Net::HTTP Response", :body => "instance_type\nami_id\nsecurity-groups", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/instance_type").
-        and_return(mock("Net::HTTP Response", :body => "c1.medium"))
+        and_return(mock("Net::HTTP Response", :body => "c1.medium", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/ami_id").
-        and_return(mock("Net::HTTP Response", :body => "ami-5d2dc934"))
+        and_return(mock("Net::HTTP Response", :body => "ami-5d2dc934", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/security-groups").
-        and_return(mock("Net::HTTP Response", :body => "group1\ngroup2"))
+        and_return(mock("Net::HTTP Response", :body => "group1\ngroup2", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/user-data/").
         and_return(mock("Net::HTTP Response", :body => "By the pricking of my thumb...", :code => "200"))
@@ -71,22 +74,22 @@
     it "should parse ec2 network/ directory as a multi-level hash" do
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/").
-        and_return(mock("Net::HTTP Response", :body => "network/"))
+        and_return(mock("Net::HTTP Response", :body => "network/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/network/").
-        and_return(mock("Net::HTTP Response", :body => "interfaces/"))
+        and_return(mock("Net::HTTP Response", :body => "interfaces/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/network/interfaces/").
-        and_return(mock("Net::HTTP Response", :body => "macs/"))
+        and_return(mock("Net::HTTP Response", :body => "macs/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/network/interfaces/macs/").
-        and_return(mock("Net::HTTP Response", :body => "12:34:56:78:9a:bc/"))
+        and_return(mock("Net::HTTP Response", :body => "12:34:56:78:9a:bc/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/network/interfaces/macs/12:34:56:78:9a:bc/").
-        and_return(mock("Net::HTTP Response", :body => "public_hostname"))
+        and_return(mock("Net::HTTP Response", :body => "public_hostname", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/network/interfaces/macs/12:34:56:78:9a:bc/public_hostname").
-        and_return(mock("Net::HTTP Response", :body => "server17.opscode.com"))
+        and_return(mock("Net::HTTP Response", :body => "server17.opscode.com", :code => "200"))
       @ohai._require_plugin("ec2")
 
       @ohai[:ec2].should_not be_nil
@@ -96,16 +99,16 @@
     it "should parse ec2 iam/ directory and its JSON files properly" do
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/").
-        and_return(mock("Net::HTTP Response", :body => "iam/"))
+        and_return(mock("Net::HTTP Response", :body => "iam/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/iam/").
-        and_return(mock("Net::HTTP Response", :body => "security-credentials/"))
+        and_return(mock("Net::HTTP Response", :body => "security-credentials/", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/iam/security-credentials/").
-        and_return(mock("Net::HTTP Response", :body => "MyRole"))
+        and_return(mock("Net::HTTP Response", :body => "MyRole", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/iam/security-credentials/MyRole").
-        and_return(mock("Net::HTTP Response", :body => "{\n  \"Code\" : \"Success\",\n  \"LastUpdated\" : \"2012-08-22T07:47:22Z\",\n  \"Type\" : \"AWS-HMAC\",\n  \"AccessKeyId\" : \"AAAAAAAA\",\n  \"SecretAccessKey\" : \"SSSSSSSS\",\n  \"Token\" : \"12345678\",\n  \"Expiration\" : \"2012-08-22T11:25:52Z\"\n}"))
+        and_return(mock("Net::HTTP Response", :body => "{\n  \"Code\" : \"Success\",\n  \"LastUpdated\" : \"2012-08-22T07:47:22Z\",\n  \"Type\" : \"AWS-HMAC\",\n  \"AccessKeyId\" : \"AAAAAAAA\",\n  \"SecretAccessKey\" : \"SSSSSSSS\",\n  \"Token\" : \"12345678\",\n  \"Expiration\" : \"2012-08-22T11:25:52Z\"\n}", :code => "200"))
       @ohai._require_plugin("ec2")
 
       @ohai[:ec2].should_not be_nil
@@ -116,7 +119,7 @@
     it "should ignore \"./\" and \"../\" on ec2 metadata paths to avoid infinity loops" do
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/").
-        and_return(mock("Net::HTTP Response", :body => ".\n./\n..\n../\npath1/.\npath2/./\npath3/..\npath4/../"))
+        and_return(mock("Net::HTTP Response", :body => ".\n./\n..\n../\npath1/.\npath2/./\npath3/..\npath4/../", :code => "200"))
 
       @http_client.should_not_receive(:get).
         with("/2012-01-12/meta-data/.")
@@ -131,16 +134,16 @@
 
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/path1/").
-        and_return(mock("Net::HTTP Response", :body => ""))
+        and_return(mock("Net::HTTP Response", :body => "", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/path2/").
-        and_return(mock("Net::HTTP Response", :body => ""))
+        and_return(mock("Net::HTTP Response", :body => "", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/path3/").
-        and_return(mock("Net::HTTP Response", :body => ""))
+        and_return(mock("Net::HTTP Response", :body => "", :code => "200"))
       @http_client.should_receive(:get).
         with("/2012-01-12/meta-data/path4/").
-        and_return(mock("Net::HTTP Response", :body => ""))
+        and_return(mock("Net::HTTP Response", :body => "", :code => "200"))
 
       @ohai._require_plugin("ec2")
 
@@ -164,7 +167,7 @@
       @ohai[:network][:interfaces][:eth0][:arp] = {"169.254.1.0"=>"00:50:56:c0:00:08"}
     end
   end
-  
+
   describe "with ec2 cloud file" do
     it_should_behave_like "ec2"
 
@@ -178,22 +181,22 @@
 
   describe "without cloud file" do
     it_should_behave_like "!ec2"
-  
+
     before(:each) do
       File.stub!(:exist?).with('/etc/chef/ohai/hints/ec2.json').and_return(false)
       File.stub!(:exist?).with('C:\chef\ohai\hints/ec2.json').and_return(false)
     end
   end
-  
+
   describe "with rackspace cloud file" do
     it_should_behave_like "!ec2"
-  
+
     before(:each) do
       File.stub!(:exist?).with('/etc/chef/ohai/hints/rackspace.json').and_return(true)
       File.stub!(:read).with('/etc/chef/ohai/hints/rackspace.json').and_return('')
       File.stub!(:exist?).with('C:\chef\ohai\hints/rackspace.json').and_return(true)
       File.stub!(:read).with('C:\chef\ohai\hints/rackspace.json').and_return('')
     end
   end
-  
+
 end