Use /etc/os-release to detect linux platforms

This is the modern way of identifying Linux platforms and versions. It's
far more reliable than the brittle regex mess that we have built up over
the last decade. It also allows us to easily detect unknown / obscure
distros.

Signed-off-by: Tim Smith <tsmith@chef.io>

2 files changed, 75 insertions, 42 deletions

diff --git a/lib/ohai/plugins/linux/platform.rb b/lib/ohai/plugins/linux/platform.rb
index 31cda3fb..625cb91b 100644
--- a/lib/ohai/plugins/linux/platform.rb
+++ b/lib/ohai/plugins/linux/platform.rb
@@ -20,16 +20,20 @@ Ohai.plugin(:Platform) do
   provides "platform", "platform_version", "platform_family"
   depends "lsb"
 
+  # @deprecated
   def get_redhatish_platform(contents)
     contents[/^Red Hat/i] ? "redhat" : contents[/(\w+)/i, 1].downcase
   end
 
   # Amazon Linux AMI release 2013.09
   # Amazon Linux 2
+  # Amazon Linux 2 (Karoo)
   # Fedora release 28 (Twenty Eight)
   # CentOS release 5.8 (Final)
   # CentOS release 6.7 (Final)
   # Red Hat Enterprise Linux Server release 7.5 (Maipo)
+  #
+  # @deprecated
   def get_redhatish_version(contents)
     contents[/Rawhide/i] ? contents[/((\d+) \(Rawhide\))/i, 1].downcase : contents[/(release)? ([\d\.]+)/, 2]
   end
@@ -81,6 +85,8 @@ Ohai.plugin(:Platform) do
   #
   # Determines the platform version for Cumulus Linux systems
   #
+  # @deprecated
+  #
   # @returns [String] cumulus Linux version from /etc/cumulus/etc.replace/os-release
   #
   def cumulus_version
@@ -94,6 +100,8 @@ Ohai.plugin(:Platform) do
   #
   # Determines the platform version for F5 Big-IP systems
   #
+  # @deprecated
+  #
   # @returns [String] bigip Linux version from /etc/f5-release
   #
   def bigip_version
@@ -107,6 +115,8 @@ Ohai.plugin(:Platform) do
   #
   # Determines the platform version for Debian based systems
   #
+  # @deprecated
+  #
   # @returns [String] version of the platform
   #
   def debian_platform_version
@@ -120,11 +130,13 @@ Ohai.plugin(:Platform) do
   #
   # Determines the platform_family based on the platform
   #
+  # @param plat [String] the platform name
+  #
   # @returns [String] platform_family value
   #
-  def determine_platform_family
-    case platform
-    when /debian/, /ubuntu/, /linuxmint/, /raspbian/, /cumulus/
+  def platform_family_from_platform(plat)
+    case plat
+    when /debian/, /ubuntu/, /linuxmint/, /raspbian/, /cumulus/, /kali/
       # apt-get+dpkg almost certainly goes here
       "debian"
     when /oracle/, /centos/, /redhat/, /scientific/, /enterpriseenterprise/, /xenserver/, /cloudlinux/, /ibm_powerkvm/, /parallels/, /nexus_centos/, /clearos/, /bigip/ # Note that 'enterpriseenterprise' is oracle's LSB "distributor ID"
@@ -139,7 +151,7 @@ Ohai.plugin(:Platform) do
       "amazon"
     when /suse/, /sles/, /opensuse/
       "suse"
-    when /fedora/, /pidora/, /arista_eos/
+    when /fedora/, /pidora/, /arista_eos/, /arista_eos/
       # In the broadest sense:  RPM-based, fedora-derived distributions which are not strictly re-compiled RHEL (if it uses RPMs, and smells more like redhat and less like
       # SuSE it probably goes here).
       "fedora"
@@ -149,7 +161,7 @@ Ohai.plugin(:Platform) do
       "gentoo"
     when /slackware/
       "slackware"
-    when /arch/
+    when /arch/, /manjaro/
       "arch"
     when /exherbo/
       "exherbo"
@@ -160,7 +172,13 @@ Ohai.plugin(:Platform) do
     end
   end
 
-  collect_data(:linux) do
+  # modern linux distros include a /etc/os-release file, which we now rely on for
+  # OS detection. For older distros that do not include that file we fall back to
+  # our pre-Ohai 15 detection logic, which is the method below. No new functionality
+  # should be added to this logic.
+  #
+  # @deprecated
+  def legacy_platform_detection
     # platform [ and platform_version ? ] should be lower case to avoid dealing with RedHat/Redhat/redhat matching
     if File.exist?("/etc/oracle-release")
       contents = File.read("/etc/oracle-release").chomp
@@ -227,7 +245,6 @@ Ohai.plugin(:Platform) do
     elsif File.exist?("/etc/Eos-release")
       platform "arista_eos"
       platform_version File.read("/etc/Eos-release").strip.split[-1]
-      platform_family "fedora"
     elsif os_release_file_is_cisco?
       raise "unknown Cisco /etc/os-release or /etc/cisco-release ID_LIKE field" if
         os_release_info["ID_LIKE"].nil? || ! os_release_info["ID_LIKE"].include?("wrlinux")
@@ -241,7 +258,6 @@ Ohai.plugin(:Platform) do
         raise "unknown Cisco /etc/os-release or /etc/cisco-release ID field"
       end
 
-      platform_family "wrlinux"
       platform_version os_release_info["VERSION"]
     elsif File.exist?("/etc/gentoo-release")
       platform "gentoo"
@@ -286,25 +302,50 @@ Ohai.plugin(:Platform) do
     elsif lsb[:id] # LSB can provide odd data that changes between releases, so we currently fall back on it rather than dealing with its subtleties
       platform lsb[:id].downcase
       platform_version lsb[:release]
-    # Use os-release (present on all modern linux distros) BUT use old *-release files as fallback.
-    # os-release will only be used if no other *-release file is present.
-    # We have to do this for compatibility reasons, or older OS releases might get different
-    # "platform" or "platform_version" attributes (e.g. SLES12, RHEL7).
-    elsif File.exist?("/etc/os-release")
-      case os_release_info["ID"]
-      when "sles"
-        platform "suse" # SLES is wrong. We call it SUSE
-      when "opensuse-leap"
-        platform "opensuseleap"
-      else
-        platform os_release_info["ID"]
-      end
-      platform_version os_release_info["VERSION_ID"]
-      # platform_family also does not need to be hardcoded anymore.
-      # This would be the correct way, but we stick with "determine_platform_family" for compatibility reasons.
-      # platform_family os_release_info["ID_LIKE"]
+    end
+  end
+
+  # our platform names don't match os-release. given a time machine they would but ohai
+  # came before the os-release file. This method remaps the os-release names to
+  # the ohai names
+  #
+  # @param id [String] the platform ID from /etc/os-release
+  #
+  # @returns [String] the platform name to use in Ohai
+  #
+  def platform_id_remap(id)
+    case id
+    when "rhel"
+      "redhat"
+    when "amzn"
+      "amazon"
+    when "ol"
+      "oracle"
+    when "sles"
+      "suse"
+    when "opensuse-leap"
+      "opensuseleap"
+    when "xenenterprise"
+      "xenserver"
+    else
+      id
+    end
+  end
+
+  collect_data(:linux) do
+    if ::File.exist?("/etc/os-release")
+      logger.trace("Plugin platform: Using /etc/os-release for platform detection")
+
+      # fixup os-release names to ohai platform names
+      platform platform_id_remap(os_release_info["ID"])
+
+      # unless we already set it in a specific way above set the plaform_version from os-release file
+      platform_version os_release_info["VERSION_ID"] if platform_version.nil?
+    else # we're on an old Linux distro
+      legacy_platform_detection
     end
 
-    platform_family determine_platform_family if platform_family.nil?
+    # unless we set it in a specific way with the platform logic above set based on platform data
+    platform_family platform_family_from_platform(platform) if platform_family.nil?
   end
 end
diff --git a/spec/unit/plugins/linux/platform_spec.rb b/spec/unit/plugins/linux/platform_spec.rb
index bc486396..b8aa898a 100644
--- a/spec/unit/plugins/linux/platform_spec.rb
+++ b/spec/unit/plugins/linux/platform_spec.rb
@@ -474,6 +474,14 @@ OS_RELEASE
         expect(@plugin[:platform_version].to_f).to eq(2)
       end
 
+      it "should read the platform as amazon and version as 2 when codename is in the release string" do
+        expect(File).to receive(:read).with("/etc/redhat-release").and_return("Amazon Linux release 2 (Karoo)")
+        @plugin.run
+        expect(@plugin[:platform]).to eq("amazon")
+        expect(@plugin[:platform_family]).to eq("amazon")
+        expect(@plugin[:platform_version].to_f).to eq(2)
+      end
+
       # https://github.com/chef/ohai/issues/560
       # Issue is seen on EL7, so that's what we're testing.
       context "on versions that have /etc/os-release" do
@@ -819,14 +827,6 @@ OS_RELEASE
           expect(@plugin[:platform_family]).to eq("suse")
         end
 
-        it "should read the version as 10.1 for bogus SLES 10" do
-          expect(File).to receive(:read).with("/etc/SuSE-release").and_return("SUSE Linux Enterprise Server 10 (i586)\nVERSION = 10\nPATCHLEVEL = 1\n")
-          @plugin.run
-          expect(@plugin[:platform]).to eq("suse")
-          expect(@plugin[:platform_version]).to eq("10.1")
-          expect(@plugin[:platform_family]).to eq("suse")
-        end
-
         it "should read the version as 11.2" do
           expect(File).to receive(:read).with("/etc/SuSE-release").and_return("SUSE Linux Enterprise Server 11.2 (i586)\nVERSION = 11\nPATCHLEVEL = 2\n")
           @plugin.run
@@ -843,14 +843,6 @@ OS_RELEASE
           expect(@plugin[:platform_family]).to eq("suse")
         end
 
-        it "[OHAI-272] should read the version as 9.1" do
-          expect(File).to receive(:read).with("/etc/SuSE-release").exactly(1).times.and_return("SuSE Linux 9.1 (i586)\nVERSION = 9.1")
-          @plugin.run
-          expect(@plugin[:platform]).to eq("suse")
-          expect(@plugin[:platform_version]).to eq("9.1")
-          expect(@plugin[:platform_family]).to eq("suse")
-        end
-
         it "[OHAI-272] should read the version as 11.4" do
           expect(File).to receive(:read).with("/etc/SuSE-release").exactly(1).times.and_return("openSUSE 11.4 (i586)\nVERSION = 11.4\nCODENAME = Celadon")
           @plugin.run