warn on EOL ruby version (#110)

CHANGELOG.md

@@ -1,4 +1,8 @@
-## 0.9.0 (2018-08-16)
+## 0.9.1 (2018-08-29)
+* Warn on EOL ruby versions.
+* Fix DateTime normalization.
+
+## 0.9.0 (2018-08-20)
 * Add RemoteServerError class for 5xx level errors.
 * Allow to_json to be called with arguments
 * Expires_in now sets and reflects current expires_at value

README.md

@@ -57,3 +57,12 @@ client.fetch_access_token!
 `gem install signet`
 
 Be sure `https://rubygems.org` is in your gem sources.
+
+## Supported Ruby Versions
+This library is currently supported on Ruby 1.9+.  
+However, Ruby 2.4 or later is strongly recommended, as earlier releases have
+reached or are nearing end-of-life. After March 31, 2019, Google will provide
+official support only for Ruby versions that are considered current and
+supported by Ruby Core (that is, Ruby versions that are either in normal
+maintenance or in security maintenance).
+See https://www.ruby-lang.org/en/downloads/branches/ for further details.

lib/signet/version.rb

@@ -18,10 +18,71 @@ module Signet
     module VERSION
       MAJOR = 0
       MINOR = 9
-      TINY  = 0
+      TINY  = 1
       PRE   = nil
 
       STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
+
+      # On March 31, 2019, set supported version to 2.4 and recommended to 2.6.
+      # Thereafter, follow the MRI support schedule: supported means non-EOL,
+      # and recommended means in normal (rather than security) maintenance.
+      # See https://www.ruby-lang.org/en/downloads/branches/
+      ##
+      # Minimum "supported" Ruby version (non-EOL)
+      # @private
+      #
+      SUPPORTED_VERSION_THRESHOLD = '1.9'.freeze
+      ##
+      # Minimum "recommended" Ruby version (normal maintenance)
+      # @private
+      #
+      RECOMMENDED_VERSION_THRESHOLD = '2.4'.freeze
+      ##
+      # Check Ruby version and emit a warning if it is old
+      # @private
+      #
+      def self.warn_on_old_ruby_version
+        return if ENV['GOOGLE_CLOUD_SUPPRESS_RUBY_WARNINGS']
+        cur_version = Gem::Version.new RUBY_VERSION
+        if cur_version < Gem::Version.new(SUPPORTED_VERSION_THRESHOLD)
+          warn_unsupported_ruby cur_version, RECOMMENDED_VERSION_THRESHOLD
+        elsif cur_version < Gem::Version.new(RECOMMENDED_VERSION_THRESHOLD)
+          warn_nonrecommended_ruby cur_version, RECOMMENDED_VERSION_THRESHOLD
+        end
+      rescue ArgumentError
+        'Unable to determine current Ruby version.'
+      end
+
+      ##
+      # Print a warning for an EOL version of Ruby
+      # @private
+      #
+      def self.warn_unsupported_ruby cur_version, recommended_version
+        "WARNING: You are running Ruby #{cur_version}, which has reached" + 
+        " end-of-life and is no longer supported by Ruby Core.\n" + 
+        'Signet works best on supported versions of' + 
+        ' Ruby. It is strongly recommended that you upgrade to Ruby' + 
+        " #{recommended_version} or later. \n" +
+        'See https://www.ruby-lang.org/en/downloads/branches/ for more' +
+        " info on the Ruby maintenance schedule.\n" + 
+        'To suppress this message, set the' + 
+        ' GOOGLE_CLOUD_SUPPRESS_RUBY_WARNINGS environment variable.'
+      end
+
+      ##
+      # Print a warning for a supported but nearing EOL version of Ruby
+      # @private
+      #
+      def self.warn_nonrecommended_ruby cur_version, recommended_version
+        "WARNING: You are running Ruby #{cur_version}, which is nearing" + 
+        " end-of-life.\n" + 
+        'Signet works best on supported versions of' +
+        " Ruby. Consider upgrading to Ruby #{recommended_version} or later.\n" +
+        'See https://www.ruby-lang.org/en/downloads/branches/ for more' +
+        " info on the Ruby maintenance schedule.\n" +
+        'To suppress this message, set the' + 
+        ' GOOGLE_CLOUD_SUPPRESS_RUBY_WARNINGS environment variable.'
+      end
     end
   end
 end

signet.gemspec

@@ -35,4 +35,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'launchy', '~> 2.4'
   s.add_development_dependency 'kramdown', '~> 1.5'
   s.add_development_dependency 'simplecov', '~> 0.9'
+
+  s.post_install_message = Signet::VERSION::warn_on_old_ruby_version
 end