Add a stdin option to ShellCommandAgent

Author: knu

app/models/agents/shell_command_agent.rb

@@ -11,7 +11,7 @@ def self.should_run?
     description <<-MD
       The Shell Command Agent will execute commands on your local system, returning the output.
 
-      `command` specifies the command (either a shell command line string or an array of command line arguments) to be executed, and `path` will tell ShellCommandAgent in what directory to run this command.
+      `command` specifies the command (either a shell command line string or an array of command line arguments) to be executed, and `path` will tell ShellCommandAgent in what directory to run this command.  The content of `stdin` will be fed to the command via the standard input.
 
       `expected_update_period_in_days` is used to determine if the Agent is working.
 
@@ -50,6 +50,12 @@ def validate_options
         errors.add(:base, "The path, command, and expected_update_period_in_days fields are all required.")
       end
 
+      case options['stdin']
+      when String, nil
+      else
+        errors.add(:base, "stdin must be a string.")
+      end
+
       unless Array(options['command']).all? { |o| o.is_a?(String) }
         errors.add(:base, "command must be a shell command line string or an array of command line arguments.")
       end
@@ -79,8 +85,9 @@ def handle(opts, event = nil)
       if Agents::ShellCommandAgent.should_run?
         command = opts['command']
         path = opts['path']
+        stdin = opts['stdin']
 
-        result, errors, exit_status = run_command(path, command)
+        result, errors, exit_status = run_command(path, command, stdin)
 
         vals = {"command" => command, "path" => path, "exit_status" => exit_status, "errors" => errors, "output" => result}
         created_event = create_event :payload => vals
@@ -91,15 +98,22 @@ def handle(opts, event = nil)
       end
     end
 
-    def run_command(path, command)
+    def run_command(path, command, stdin)
       begin
         rout, wout = IO.pipe
         rerr, werr = IO.pipe
+        rin,  win = IO.pipe
 
-        pid = spawn(*command, chdir: path, out: wout, err: werr)
+        pid = spawn(*command, chdir: path, out: wout, err: werr, in: rin)
 
         wout.close
         werr.close
+        rin.close
+
+        if stdin
+          win.write stdin
+          win.close
+        end
 
         (result = rout.read).strip!
         (errors = rerr.read).strip!

spec/models/agents/shell_command_agent_spec.rb

@@ -12,7 +12,8 @@
 
     @valid_params2 = {
       path: @valid_path,
-      command: [RbConfig.ruby, '-e', 'puts "hello, world."; STDERR.puts "warning!"'],
+      command: [RbConfig.ruby, '-e', 'puts "hello, #{STDIN.eof? ? "world" : STDIN.read.strip}."; STDERR.puts "warning!"'],
+      stdin: "{{name}}",
       expected_update_period_in_days: '1',
     }
 
@@ -27,7 +28,8 @@
     @event = Event.new
     @event.agent = agents(:jane_weather_agent)
     @event.payload = {
-      :cmd => "ls"
+      'name' => 'Huginn',
+      'cmd' => 'ls',
     }
     @event.save!
 
@@ -58,7 +60,7 @@
 
   describe "#working?" do
     it "generating events as scheduled" do
-      stub(@checker).run_command(@valid_path, 'pwd') { ["fake pwd output", "", 0] }
+      stub(@checker).run_command(@valid_path, 'pwd', nil) { ["fake pwd output", "", 0] }
 
       expect(@checker).not_to be_working
       @checker.check
@@ -71,7 +73,7 @@
 
   describe "#check" do
     before do
-      stub(@checker).run_command(@valid_path, 'pwd') { ["fake pwd output", "", 0] }
+      stub(@checker).run_command(@valid_path, 'pwd', nil) { ["fake pwd output", "", 0] }
     end
 
     it "should create an event when checking" do
@@ -84,7 +86,7 @@
     it "should create an event when checking (unstubbed)" do
       expect { @checker2.check }.to change { Event.count }.by(1)
       expect(Event.last.payload[:path]).to eq(@valid_path)
-      expect(Event.last.payload[:command]).to eq([RbConfig.ruby, '-e', 'puts "hello, world."; STDERR.puts "warning!"'])
+      expect(Event.last.payload[:command]).to eq([RbConfig.ruby, '-e', 'puts "hello, #{STDIN.eof? ? "world" : STDIN.read.strip}."; STDERR.puts "warning!"'])
       expect(Event.last.payload[:output]).to eq('hello, world.')
       expect(Event.last.payload[:errors]).to eq('warning!')
     end
@@ -97,7 +99,7 @@
 
   describe "#receive" do
     before do
-      stub(@checker).run_command(@valid_path, @event.payload[:cmd]) { ["fake ls output", "", 0] }
+      stub(@checker).run_command(@valid_path, @event.payload[:cmd], nil) { ["fake ls output", "", 0] }
     end
 
     it "creates events" do
@@ -108,6 +110,13 @@
       expect(Event.last.payload[:output]).to eq("fake ls output")
     end
 
+    it "creates events (unstubbed)" do
+      @checker2.receive([@event])
+      expect(Event.last.payload[:path]).to eq(@valid_path)
+      expect(Event.last.payload[:output]).to eq('hello, Huginn.')
+      expect(Event.last.payload[:errors]).to eq('warning!')
+    end
+
     it "does not run when should_run? is false" do
       stub(Agents::ShellCommandAgent).should_run? { false }