guests: make CentOS/RHEL flavor detection more dynamic

Instead of having to update these flavor.rb files every time a
new version of CentOS/RHEL come out let's dynamically pick up
the version (7,8,9) from the machine.

This was inspired slightly by the Rocky Linux guest flavor.rb.

plugins/guests/centos/cap/flavor.rb

@@ -3,21 +3,24 @@ module VagrantPlugins
     module Cap
       class Flavor
         def self.flavor(machine)
-          # Read the version file
+          # Pick up version info from `/etc/os-release`. This file started to exist
-          output = ""
+          # in CentOS 7. For versions before that (i.e. CentOS 6) just plain `:centos`
-          machine.communicate.sudo("cat /etc/centos-release") do |_, data|
+          # should do.
-            output = data
+          version = nil
+          if machine.communicate.test("test -f /etc/os-release")
+            begin
+              machine.communicate.execute("source /etc/os-release && printf $VERSION_ID") do |type, data|
+                if type == :stdout
+                  version = data.split(".").first.to_i
+                end
+              end
+            rescue
+            end
           end
-
+          if version.nil? || version < 1
-          # Detect various flavors we care about
-          if output =~ /(CentOS)( .+)? 7/i
-            return :centos_7
-          elsif output =~ /(CentOS)( .+)? 8/i
-            return :centos_8
-          elsif output =~ /(CentOS)( .+)? 9/i
-            return :centos_9
-          else
             return :centos
+          else
+            return "centos_#{version}".to_sym
           end
         end
       end

plugins/guests/redhat/cap/flavor.rb

@@ -3,21 +3,24 @@ module VagrantPlugins
     module Cap
       class Flavor
         def self.flavor(machine)
-          # Read the version file
+          # Pick up version info from `/etc/os-release`. This file started to exist
-          output = ""
+          # in RHEL 7. For versions before that (i.e. RHEL 6) just plain `:rhel`
-          machine.communicate.sudo("cat /etc/redhat-release") do |_, data|
+          # should do.
-            output = data
+          version = nil
+          if machine.communicate.test("test -f /etc/os-release")
+            begin
+              machine.communicate.execute("source /etc/os-release && printf $VERSION_ID") do |type, data|
+                if type == :stdout
+                  version = data.split(".").first.to_i
+                end
+              end
+            rescue
+            end
           end
-
+          if version.nil? || version < 1
-          # Detect various flavors we care about
-          if output =~ /(Red Hat Enterprise|Scientific|Cloud|Virtuozzo)\s*Linux( .+)? release 7/i
-            return :rhel_7
-          elsif output =~ /(Red Hat Enterprise|Scientific|Cloud|Virtuozzo)\s*Linux( .+)? release 8/i
-            return :rhel_8
-          elsif output =~ /(Red Hat Enterprise|Scientific|Cloud|Virtuozzo)\s*Linux( .+)? release 9/i
-            return :rhel_9
-          else
             return :rhel
+          else
+            return "rhel_#{version}".to_sym
           end
         end
       end

test/unit/plugins/guests/centos/cap/flavor_test.rb

@@ -21,16 +21,31 @@ describe "VagrantPlugins::GuestCentos::Cap::Flavor" do
   describe ".flavor" do
     let(:cap) { caps.get(:flavor) }
 
-    {
+    # /etc/os-release was added in EL7+
-      "CentOS Linux 2.4 release 7" => :centos_7,
+    context "without /etc/os-release file" do
-      "CentOS Linux release 8.1.1911 (Core)" => :centos_8,
+      {
-
+        "" => :centos
-      "CentOS" => :centos,
+      }.each do |str, expected|
-      "banana" => :centos,
+        it "returns #{expected} for #{str}" do
-    }.each do |str, expected|
+          comm.stub_command("test -f /etc/os-release", exit_code: 1)
-      it "returns #{expected} for #{str}" do
+          expect(cap.flavor(machine)).to be(expected)
-        comm.stub_command("cat /etc/centos-release", stdout: str)
+        end
-        expect(cap.flavor(machine)).to be(expected)
+      end
+    end
+    context "with /etc/os-release file" do
+      {
+        "7" => :centos_7,
+        "8" => :centos_8,
+        "9.0" => :centos_9,
+        "9.1" => :centos_9,
+        "" => :centos,
+        "banana" => :centos,
+      }.each do |str, expected|
+        it "returns #{expected} for #{str}" do
+          comm.stub_command("test -f /etc/os-release", exit_code: 0)
+          comm.stub_command("source /etc/os-release && printf $VERSION_ID", stdout: str)
+          expect(cap.flavor(machine)).to be(expected)
+        end
       end
     end
   end

test/unit/plugins/guests/redhat/cap/flavor_test.rb

@@ -21,22 +21,31 @@ describe "VagrantPlugins::GuestRedHat::Cap::Flavor" do
   describe ".flavor" do
     let(:cap) { caps.get(:flavor) }
 
-    {
+    # /etc/os-release was added in EL7+
-      "Red Hat Enterprise Linux 2.4 release 7" => :rhel_7,
+    context "without /etc/os-release file" do
-      "Red Hat Enterprise Linux release 7" => :rhel_7,
+      {
-      "Scientific Linux release 7" => :rhel_7,
+        "" => :rhel
-      "CloudLinux release 7.2 (Valeri Kubasov)" => :rhel_7,
+      }.each do |str, expected|
-
+        it "returns #{expected} for #{str}" do
-      "CloudLinux release 8.1.1911 (Valeri Kubasov)" => :rhel_8,
+          comm.stub_command("test -f /etc/os-release", exit_code: 1)
-      "Red Hat Enterprise Linux release 8" => :rhel_8,
+          expect(cap.flavor(machine)).to be(expected)
-
+        end
-      "Red Hat Enterprise Linux" => :rhel,
+      end
-      "RHEL 6" => :rhel,
+    end
-      "banana" => :rhel,
+    context "with /etc/os-release file" do
-    }.each do |str, expected|
+      {
-      it "returns #{expected} for #{str}" do
+        "7" => :rhel_7,
-        comm.stub_command("cat /etc/redhat-release", stdout: str)
+        "8" => :rhel_8,
-        expect(cap.flavor(machine)).to be(expected)
+        "9.0" => :rhel_9,
+        "9.1" => :rhel_9,
+        "" => :rhel,
+        "banana" => :rhel,
+      }.each do |str, expected|
+        it "returns #{expected} for #{str}" do
+          comm.stub_command("test -f /etc/os-release", exit_code: 0)
+          comm.stub_command("source /etc/os-release && printf $VERSION_ID", stdout: str)
+          expect(cap.flavor(machine)).to be(expected)
+        end
       end
     end
   end