fix: make the input location optional in the run command

The run command always required an input location, so pipelines that do
not take any input could only be started by passing an empty string.

The input location is now optional. The trailing positional value is only
treated as an input when it is not an available pipeline name, and the
input options are only built when a location was provided.

Signed-off-by: NoiceHax <yashasprakash021@gmail.com>

Author: NoiceHax

docs/command-line-interface.rst

@@ -759,8 +759,8 @@ Optional arguments:
 
 .. _cli_run:
 
-`$ run PIPELINE_NAME [PIPELINE_NAME ...] input_location`
---------------------------------------------------------
+`$ run PIPELINE_NAME [PIPELINE_NAME ...] [input_location]`
+----------------------------------------------------------
 
 A ``run`` command is available for executing pipelines and printing the results
 without providing any configuration. This can be useful for running a pipeline to get
@@ -770,6 +770,9 @@ review the results.
 .. tip:: You can run multiple pipelines by providing their names, space-separated,
   such as `pipeline1 pipeline2`.
 
+The ``input_location`` is optional, so pipelines that do not take any input can be
+run without it.
+
 Optional arguments:
 
 - ``--project PROJECT_NAME``: Provide a project name; otherwise, a random value is

scanpipe/management/commands/run.py

@@ -23,6 +23,7 @@
 from collections import defaultdict
 from pathlib import Path
 
+from django.apps import apps
 from django.core.management import call_command
 from django.core.management.base import BaseCommand
 from django.core.management.base import CommandError
@@ -31,6 +32,8 @@
 from scanpipe.management.commands import extract_tag_from_input_file
 from scanpipe.pipes.fetch import SCHEME_TO_FETCHER_MAPPING
 
+scanpipe_app = apps.get_app_config("scanpipe")
+
 
 class Command(BaseCommand):
     help = "Run a pipeline and print the results."
@@ -50,9 +53,11 @@ def add_arguments(self, parser):
         )
         parser.add_argument(
             "input_location",
+            nargs="?",
             help=(
                 "Input location: file, directory, and URL supported."
-                'Multiple values can be provided using the "input1,input2" syntax.'
+                'Multiple values can be provided using the "input1,input2" syntax. '
+                "Optional, as some pipelines do not require any input."
             ),
         )
         parser.add_argument("--project", required=False, help="Project name.")
@@ -64,8 +69,14 @@ def add_arguments(self, parser):
         )
 
     def handle(self, *args, **options):
+        # The ``input_location`` positional is declared for the command usage, but
+        # argparse collects every positional value in ``pipelines``. The trailing
+        # value is the input location unless it is an available pipeline name.
         pipelines = options["pipelines"]
-        input_location = options["input_location"]
+        input_location = None
+        if len(pipelines) > 1 and not self.is_pipeline_name(pipelines[-1]):
+            input_location = pipelines.pop()
+
         output_format = options["format"]
         # Generate a random name for the project if not provided
         project_name = options["project"] or get_random_string(10)
@@ -74,8 +85,9 @@ def handle(self, *args, **options):
             "pipeline": pipelines,
             "execute": True,
             "verbosity": 0,
-            **self.get_input_options(input_location),
         }
+        if input_location:
+            create_project_options.update(self.get_input_options(input_location))
 
         # Run the database migrations in case the database is not created or outdated.
         call_command("migrate", verbosity=0, interactive=False)
@@ -84,6 +96,13 @@ def handle(self, *args, **options):
         # Print the results for the specified format on stdout
         call_command("output", project=project_name, format=[output_format], print=True)
 
+    @staticmethod
+    def is_pipeline_name(value):
+        """Return True when the provided ``value`` is an available pipeline name."""
+        pipeline_name, _ = scanpipe_app.extract_group_from_pipeline(value)
+        pipeline_name = scanpipe_app.get_new_pipeline_name(pipeline_name)
+        return pipeline_name in scanpipe_app.pipelines
+
     @staticmethod
     def get_input_options(input_location):
         """

scanpipe/tests/test_commands.py

@@ -1007,9 +1007,7 @@ def test_scanpipe_management_command_create_user_admin_superuser(self):
         self.assertTrue(user.is_superuser)
 
     def test_scanpipe_management_command_run(self):
-        expected = (
-            "Error: the following arguments are required: PIPELINE_NAME, input_location"
-        )
+        expected = "Error: the following arguments are required: PIPELINE_NAME"
         with self.assertRaisesMessage(CommandError, expected):
             call_command("run")
 
@@ -1047,6 +1045,29 @@ def test_scanpipe_management_command_run(self):
         self.assertEqual("do_nothing", runs[1]["pipeline_name"])
         self.assertEqual(["Group1", "Group2"], runs[1]["selected_groups"])
 
+    def test_scanpipe_management_command_run_without_input_location(self):
+        out = StringIO()
+        with redirect_stdout(out):
+            call_command("run", "do_nothing")
+
+        json_data = json.loads(out.getvalue())
+        self.assertEqual([], json_data["files"])
+        runs = json_data["headers"][0]["runs"]
+        self.assertEqual(1, len(runs))
+        self.assertEqual("do_nothing", runs[0]["pipeline_name"])
+        self.assertEqual("success", runs[0]["status"])
+
+        # A trailing pipeline name is not mistaken for an input location
+        out = StringIO()
+        with redirect_stdout(out):
+            call_command("run", "do_nothing", "profile_step")
+
+        json_data = json.loads(out.getvalue())
+        runs = json_data["headers"][0]["runs"]
+        self.assertEqual(2, len(runs))
+        self.assertEqual("do_nothing", runs[0]["pipeline_name"])
+        self.assertEqual("profile_step", runs[1]["pipeline_name"])
+
     @mock.patch("scanpipe.pipes.fetch.is_safe_url", return_value=True)
     @mock.patch("scanpipe.pipes.fetch.check_url")
     @mock.patch("requests.sessions.Session.get")