Fixes logstash-plugins#25: Implement environment inheritance

lib/logstash/inputs/exec.rb

@@ -21,6 +21,9 @@ class LogStash::Inputs::Exec < LogStash::Inputs::Base
   # Command to run. For example : `uptime`
   config :command, :validate => :string, :required => true
 
+  # Whether logstash's environment variables should be passed to the command
+  config :inherit_environment, :validate => :boolean, :default => false
+
   # Interval to run the command. Value is in seconds.
   # Either `interval` or `schedule` option must be defined.
   config :interval, :validate => :number
@@ -34,7 +37,7 @@ def register
     @logger.info("Registering Exec Input", :type => @type, :command => @command, :interval => @interval, :schedule => @schedule)
     @hostname = Socket.gethostname
     @io       = nil
-    
+
     if (@interval.nil? && @schedule.nil?) || (@interval && @schedule)
       raise LogStash::ConfigurationError, "exec input: either 'interval' or 'schedule' option must be defined."
     end
@@ -94,7 +97,11 @@ def execute(queue)
   private
 
   def run_command
-    @io = IO.popen(@command)
+    if @inherit_environment
+      @io = IO.popen(ENV, @command)
+    else
+      @io = IO.popen(@command)
+    end
     output = @io.read
     @io.close # required in order to read $?
     exit_status = $?.exitstatus # should be threadsafe as per rb_thread_save_context

spec/inputs/exec_spec.rb

@@ -25,7 +25,7 @@
     let(:loggr) { double('loggr') }
 
     before :each do
-      expect(described_class).to receive(:logger).and_return(loggr).exactly(7).times
+      expect(described_class).to receive(:logger).and_return(loggr).exactly(8).times
       allow(loggr).to receive(:info)
       allow(loggr).to receive(:info?)
       allow(loggr).to receive(:warn)
@@ -69,6 +69,37 @@
 
   end
 
+  context "when inheriting environment" do
+    let(:input) { described_class.new("command" => "env | grep '^FOO='", "interval" => 0) }
+    let(:queue) { [] }
+
+    let(:input_env) { described_class.new("command" => "env | grep '^FOO='", "inherit_environment" => true, "interval" => 0) }
+    let(:queue_env) { [] }
+
+    before do
+      ENV["FOO"] = "BAR"
+
+      input.register
+      input.execute(queue)
+
+      input_env.register
+      input_env.execute(queue_env)
+    end
+
+    after do
+      input.stop
+      input_env.stop
+    end
+
+    it "didn't inherit the environment" do
+      expect(queue.pop.get('message')).to eq "\n"
+    end
+
+    it "inherited the environment" do
+      expect(queue_env.pop.get('message')).to eq "FOO=BAR\n"
+    end
+  end
+
   context "when scheduling" do
     let(:input) { described_class.new("command" => "ls", "schedule" => "* * * * * UTC") }
     let(:queue) { [] }