Check java versioning

Fixes #3452

lib/logstash/runner.rb

@@ -16,6 +16,7 @@ class LogStash::Runner
 
   def main(args)
     require "logstash/util"
+    require "logstash/util/java_version"
     require "stud/trap"
     require "stud/task"
     @startup_interruption_trap = Stud::trap("INT") { puts "Interrupted"; exit 0 }
@@ -27,6 +28,9 @@ class LogStash::Runner
       return 1
     end
 
+    # Print a warning to STDERR for bad java versions
+    LogStash::Util::JavaVersion.warn_on_bad_java_version
+
     Stud::untrap("INT", @startup_interruption_trap)
 
     task = run(args)

lib/logstash/util/java_version.rb

@@ -0,0 +1,50 @@
+module LogStash::Util::JavaVersion
+  # Print a warning if we're on a bad version of java
+  def self.warn_on_bad_java_version
+    if self.bad_java_version?(self.version)
+      STDERR.puts("Please upgrade your java version, the current version '#{self.version}' may cause problems. We recommend a minimum version of 1.7.0_51")
+    end
+  end
+
+  # Check to see if this is a recommended java version, print a warning to stdout if this is a bad version
+  # Returns the current java version
+  def self.version
+    return nil if RUBY_ENGINE != "jruby"
+
+    require 'java'
+    java_import "java.lang.System"
+
+    System.getProperties["java.runtime.version"]
+  end
+
+  def self.parse_java_version(version_string)
+    return nil if version_string.nil?
+
+    # Crazy java versioning rules @ http://www.oracle.com/technetwork/java/javase/versioning-naming-139433.html
+    # The regex below parses this all correctly http://rubular.com/r/sInQc3Nc7f
+
+    match = version_string.match(/\A(\d+)\.(\d+)\.(\d+)(_(\d+))?(-(.+))?\Z/)
+    major, minor, patch, ufull, update, bfull, build = match.captures
+
+    return {
+      :full => version_string,
+      :major => major.to_i,
+      :minor => minor.to_i,
+      :patch => patch.to_i,
+      :update => update.to_i, # this is always coerced to an int (a nil will be zero) to make comparisons easier
+      :build => build # not an integer, could be b06 for instance!,
+    }
+  end
+
+  def self.bad_java_version?(version_string)
+    return nil if version_string.nil?
+
+    parsed = parse_java_version(version_string)
+
+    if parsed[:major] >= 1 && parsed[:minor] == 7 && parsed[:patch] == 0 && parsed[:update] < 51
+      return true
+    elsif parsed[:major] >= 1 && parsed[:minor] < 7
+      return true
+    end
+  end
+end

spec/util/java_version_spec.rb

@@ -0,0 +1,64 @@
+require 'spec_helper'
+require 'logstash/util/java_version'
+
+describe "LogStash::Util::JavaVersion" do
+  let(:mod) { LogStash::Util::JavaVersion }
+  it "should get the current java version if we're on Java" do
+    if RUBY_ENGINE == "jruby"
+      expect(LogStash::Util::JavaVersion.version).to be_a(String)
+    end
+  end
+
+  it "should mark a bad java version as bad" do
+    expect(mod.bad_java_version?("1.7.0_45-beta")).to be_truthy
+    expect(mod.bad_java_version?("1.6.0")).to be_truthy
+  end
+
+  it "should mark a good java version as good" do
+    expect(mod.bad_java_version?("1.7.0_51")).to be_falsey
+    expect(mod.bad_java_version?("1.8.0-beta")).to be_falsey
+  end
+
+  describe "parsing java versions" do
+    it "should return nil on a nil version" do
+      expect(mod.parse_java_version(nil)).to be_nil
+    end
+
+    it "should parse a plain version" do
+      parsed = mod.parse_java_version("1.3.0")
+      expect(parsed[:major]).to eql(1)
+      expect(parsed[:minor]).to eql(3)
+      expect(parsed[:patch]).to eql(0)
+      expect(parsed[:update]).to eql(0)
+      expect(parsed[:build]).to be_nil
+    end
+
+    it "should parse an update" do
+      parsed = mod.parse_java_version("1.4.0_03")
+      expect(parsed[:major]).to eql(1)
+      expect(parsed[:minor]).to eql(4)
+      expect(parsed[:patch]).to eql(0)
+      expect(parsed[:update]).to eql(3)
+      expect(parsed[:build]).to be_nil
+    end
+
+    it "should parse a version with just a build" do
+      parsed = mod.parse_java_version("1.4.0-beta")
+      expect(parsed[:major]).to eql(1)
+      expect(parsed[:minor]).to eql(4)
+      expect(parsed[:patch]).to eql(0)
+      expect(parsed[:update]).to eql(0)
+      expect(parsed[:build]).to eql("beta")
+    end
+
+    it "should parse a version with an update and a build" do
+      parsed = mod.parse_java_version("1.4.0_03-beta")
+      expect(parsed[:major]).to eql(1)
+      expect(parsed[:minor]).to eql(4)
+      expect(parsed[:patch]).to eql(0)
+      expect(parsed[:update]).to eql(3)
+      expect(parsed[:build]).to eql("beta")
+    end
+  end
+
+end