Invoke Function Without Parameters

samcli/commands/local/invoke/cli.py

@@ -26,41 +26,50 @@
 Invoking a Lambda function using input from stdin
 $ echo '{"message": "Hey, are you there?" }' | sam local invoke "HelloWorldFunction" \n
 """
+STDIN_FILE_NAME = "-"
 
 
 @click.command("invoke", help=HELP_TEXT, short_help="Invokes a local Lambda function once.")
 @click.option("--event", '-e',
               type=click.Path(),
-              default="-",  # Defaults to stdin
+              default=STDIN_FILE_NAME,  # Defaults to stdin
               help="JSON file containing event data passed to the Lambda function during invoke. If this option "
                    "is not specified, we will default to reading JSON from stdin")
+@click.option("--no-event", is_flag=True, default=False, help="Invoke Function with an empty event")
 @invoke_common_options
 @cli_framework_options
 @click.argument('function_identifier', required=False)
 @pass_context
-def cli(ctx, function_identifier, template, event, env_vars, debug_port, debug_args, debugger_path,
+def cli(ctx, function_identifier, template, event, no_event, env_vars, debug_port, debug_args, debugger_path,
         docker_volume_basedir, docker_network, log_file, skip_pull_image, profile, region):
 
     # All logic must be implemented in the ``do_cli`` method. This helps with easy unit testing
 
-    do_cli(ctx, function_identifier, template, event, env_vars, debug_port, debug_args, debugger_path,
+    do_cli(ctx, function_identifier, template, event, no_event, env_vars, debug_port, debug_args, debugger_path,
            docker_volume_basedir, docker_network, log_file, skip_pull_image, profile, region)  # pragma: no cover
 
 
-def do_cli(ctx, function_identifier, template, event, env_vars, debug_port, debug_args,  # pylint: disable=R0914
-           debugger_path, docker_volume_basedir, docker_network, log_file, skip_pull_image, profile, region):
+def do_cli(ctx, function_identifier, template, event, no_event, env_vars, debug_port,  # pylint: disable=R0914
+           debug_args, debugger_path, docker_volume_basedir, docker_network, log_file, skip_pull_image, profile,
+           region):
     """
     Implementation of the ``cli`` method, just separated out for unit testing purposes
     """
 
     LOG.debug("local invoke command is called")
 
-    event_data = _get_event(event)
+    if no_event and event != STDIN_FILE_NAME:
+        # Do not know what the user wants. no_event and event both passed in.
+        raise UserException("no_event and event cannot be used together. Please provide only one.")
+
+    if no_event:
+        event_data = "{}"
+    else:
+        event_data = _get_event(event)
 
     # Pass all inputs to setup necessary context to invoke function locally.
     # Handler exception raised by the processor for invalid args and print errors
     try:
-
         with InvokeContext(template_file=template,
                            function_identifier=function_identifier,
                            env_vars_file=env_vars,
@@ -94,7 +103,7 @@ def _get_event(event_file_name):
     :return string: Contents of the event file or stdin
     """
 
-    if event_file_name == "-":
+    if event_file_name == STDIN_FILE_NAME:
         # If event is empty, listen to stdin for event data until EOF
         LOG.info("Reading invoke payload from stdin (you can also pass it from file with --event)")
 

tests/integration/local/invoke/test_integrations_cli.py

@@ -94,3 +94,25 @@ def test_invoke_when_function_writes_stderr(self):
         process_stderr = b"".join(process.stderr.readlines()).strip()
 
         self.assertIn("Docker Lambda is writing to stderr", process_stderr.decode('utf-8'))
+
+    def test_invoke_returns_expected_result_when_no_event_given(self):
+        command_list = self.get_command_list("EchoEventFunction", template_path=self.template_path)
+        command_list.append("--no-event")
+        process = Popen(command_list, stdout=PIPE)
+        return_code = process.wait()
+        process_stdout = b"".join(process.stdout.readlines()).strip()
+
+        self.assertEquals(return_code, 0)
+        self.assertEquals("{}", process_stdout.decode('utf-8'))
+
+    def test_invoke_raises_exception_with_noargs_and_event(self):
+        command_list = self.get_command_list("HelloWorldLambdaFunction",
+                                             template_path=self.template_path,
+                                             event_path=self.event_path)
+        command_list.append("--no-event")
+        process = Popen(command_list, stderr=PIPE)
+        process.wait()
+
+        process_stderr = b"".join(process.stderr.readlines()).strip()
+        error_output = process_stderr.decode('utf-8')
+        self.assertIn("no_event and event cannot be used together. Please provide only one.", error_output)

tests/unit/commands/local/invoke/test_cli.py

@@ -11,6 +11,8 @@
 from samcli.commands.exceptions import UserException
 from samcli.commands.local.invoke.cli import do_cli as invoke_cli, _get_event as invoke_cli_get_event
 
+STDIN_FILE_NAME = "-"
+
 
 class TestCli(TestCase):
 
@@ -27,6 +29,7 @@ def setUp(self):
         self.log_file = "logfile"
         self.skip_pull_image = True
         self.profile = "profile"
+        self.no_event = False
         self.region = "region"
 
     @patch("samcli.commands.local.invoke.cli.InvokeContext")
@@ -43,6 +46,7 @@ def test_cli_must_setup_context_and_invoke(self, get_event_mock, InvokeContextMo
                    function_identifier=self.function_id,
                    template=self.template,
                    event=self.eventfile,
+                   no_event=self.no_event,
                    env_vars=self.env_vars,
                    debug_port=self.debug_port,
                    debug_args=self.debug_args,
@@ -73,6 +77,74 @@ def test_cli_must_setup_context_and_invoke(self, get_event_mock, InvokeContextMo
                                                                    stderr=context_mock.stderr)
         get_event_mock.assert_called_with(self.eventfile)
 
+    @patch("samcli.commands.local.invoke.cli.InvokeContext")
+    @patch("samcli.commands.local.invoke.cli._get_event")
+    def test_cli_must_invoke_with_no_event(self, get_event_mock, InvokeContextMock):
+        self.no_event = True
+        # Mock the __enter__ method to return a object inside a context manager
+        context_mock = Mock()
+        InvokeContextMock.return_value.__enter__.return_value = context_mock
+        invoke_cli(ctx=None,
+                   function_identifier=self.function_id,
+                   template=self.template,
+                   event=STDIN_FILE_NAME,
+                   no_event=self.no_event,
+                   env_vars=self.env_vars,
+                   debug_port=self.debug_port,
+                   debug_args=self.debug_args,
+                   debugger_path=self.debugger_path,
+                   docker_volume_basedir=self.docker_volume_basedir,
+                   docker_network=self.docker_network,
+                   log_file=self.log_file,
+                   skip_pull_image=self.skip_pull_image,
+                   profile=self.profile,
+                   region=self.region)
+
+        InvokeContextMock.assert_called_with(template_file=self.template,
+                                             function_identifier=self.function_id,
+                                             env_vars_file=self.env_vars,
+                                             docker_volume_basedir=self.docker_volume_basedir,
+                                             docker_network=self.docker_network,
+                                             log_file=self.log_file,
+                                             skip_pull_image=self.skip_pull_image,
+                                             aws_profile=self.profile,
+                                             debug_port=self.debug_port,
+                                             debug_args=self.debug_args,
+                                             debugger_path=self.debugger_path,
+                                             aws_region=self.region)
+
+        context_mock.local_lambda_runner.invoke.assert_called_with(context_mock.function_name,
+                                                                   event="{}",
+                                                                   stdout=context_mock.stdout,
+                                                                   stderr=context_mock.stderr)
+        get_event_mock.assert_not_called()
+
+    @patch("samcli.commands.local.invoke.cli.InvokeContext")
+    @patch("samcli.commands.local.invoke.cli._get_event")
+    def test_must_raise_user_exception_on_no_event_and_event(self, get_event_mock, InvokeContextMock):
+        self.no_event = True
+
+        with self.assertRaises(UserException) as ex_ctx:
+
+            invoke_cli(ctx=None,
+                       function_identifier=self.function_id,
+                       template=self.template,
+                       event=self.eventfile,
+                       no_event=self.no_event,
+                       env_vars=self.env_vars,
+                       debug_port=self.debug_port,
+                       debug_args=self.debug_args,
+                       debugger_path=self.debugger_path,
+                       docker_volume_basedir=self.docker_volume_basedir,
+                       docker_network=self.docker_network,
+                       log_file=self.log_file,
+                       skip_pull_image=self.skip_pull_image,
+                       profile=self.profile,
+                       region=self.region)
+
+        msg = str(ex_ctx.exception)
+        self.assertEquals(msg, "no_event and event cannot be used together. Please provide only one.")
+
     @patch("samcli.commands.local.invoke.cli.InvokeContext")
     @patch("samcli.commands.local.invoke.cli._get_event")
     def test_must_raise_user_exception_on_function_not_found(self, get_event_mock, InvokeContextMock):
@@ -91,6 +163,7 @@ def test_must_raise_user_exception_on_function_not_found(self, get_event_mock, I
                        function_identifier=self.function_id,
                        template=self.template,
                        event=self.eventfile,
+                       no_event=self.no_event,
                        env_vars=self.env_vars,
                        debug_port=self.debug_port,
                        debug_args=self.debug_args,
@@ -119,6 +192,7 @@ def test_must_raise_user_exception_on_invalid_sam_template(self, get_event_mock,
                        function_identifier=self.function_id,
                        template=self.template,
                        event=self.eventfile,
+                       no_event=self.no_event,
                        env_vars=self.env_vars,
                        debug_port=self.debug_port,
                        debug_args=self.debug_args,
@@ -137,7 +211,7 @@ def test_must_raise_user_exception_on_invalid_sam_template(self, get_event_mock,
 class TestGetEvent(TestCase):
 
     @parameterized.expand([
-        param("-"),
+        param(STDIN_FILE_NAME),
         param("somefile")
     ])
     @patch("samcli.commands.local.invoke.cli.click")