feat(cli): improve renku run error messages (#2915)

Author: Panaetius

renku/command/run.py

@@ -178,7 +178,10 @@ def parse_explicit_definition(entries, type):
                 )
             except FileNotFoundError:
                 command = " ".join(factory.base_command)
-                raise errors.ParameterError(f"Cannot execute command '{command}'")
+                raise errors.ParameterError(
+                    f"Cannot execute command '{command}': "
+                    "This is likely because the executable doesn't exist or has the wrong permissions set."
+                )
 
             ended_at_time = local_now()
 

renku/core/errors.py

@@ -17,7 +17,6 @@
 # limitations under the License.
 """Renku exceptions."""
 
-import os
 from pathlib import Path
 from typing import List, Union
 
@@ -212,28 +211,16 @@ class InvalidOutputPath(RenkuException):
 class OutputsNotFound(RenkuException):
     """Raise when there are not any detected outputs in the repository."""
 
-    def __init__(self, repository, inputs):
+    def __init__(self):
         """Build a custom message."""
-        from pathlib import Path
-
-        msg = "There are not any detected outputs in the repository."
-
-        paths = [
-            os.path.relpath(input_.default_value)  # relative to cur path
-            for input_ in inputs
-            if Path(input_.default_value).is_dir()
-        ]
-
-        if paths:
-            msg += (
-                '\n  (use "git rm <file>..." to remove them first)'
-                "\n\n" + "\n".join("\t" + click.style(path, fg="yellow") for path in paths) + "\n\n"
-                "Once you have removed files that should be used as outputs,\n"
-                "you can safely rerun the previous command."
-                "\nYou can use --output flag to specify outputs explicitly."
-            )
-        else:
-            msg += "\n\nIf you want to track the command anyway use " "--no-output option."
+
+        msg = (
+            "There are not any detected outputs in the repository. This can be due to your command not creating "
+            "any new files or due to files that get created already existing before the command was run. In the "
+            "latter case, you can remove those files prior to running your command.\nIf you want to track the command"
+            "without outputs, use the use --no-output option.\nYou can also use the --output flag to track outputs"
+            "manually."
+        )
 
         super(OutputsNotFound, self).__init__(msg)
 

renku/core/workflow/plan_factory.py

@@ -79,19 +79,23 @@ def __init__(
         self.no_output_detection = no_output_detection
 
         if not command_line:
-            raise errors.UsageError("Command line can not be empty.")
+            raise errors.UsageError("Command line can not be empty. Please specify a command to execute.")
 
         if not directory:
             directory = os.getcwd()
         self.directory = Path(directory)
         if not self.directory.exists():
-            raise errors.UsageError("Directory must exist.")
+            raise errors.UsageError(
+                f"Directory '{self.directory}' doesn't exist. Please make sure you are inside an existing directory."
+            )
 
         if not working_dir:
             working_dir = os.getcwd()
         self.working_dir = Path(working_dir)
         if not self.working_dir.exists():
-            raise errors.UsageError("Working Directory must exist.")
+            raise errors.UsageError(
+                f"Repository path '{self.working_dir}' doesn't exist. Make sure you are inside a Renku repository."
+            )
 
         if isinstance(command_line, (list, tuple)):
             self.command_line = list(command_line)
@@ -298,7 +302,7 @@ def add_outputs(self, candidates: Set[Tuple[Union[Path, str], Optional[str]]]):
             candidate = self._resolve_existing_subpath(self.working_dir / candidate_path)
 
             if candidate is None:
-                raise errors.UsageError('Path "{0}" does not exist.'.format(candidate_path))
+                raise errors.UsageError('Path "{0}" does not exist inside the current project.'.format(candidate_path))
 
             glob = str(candidate.relative_to(self.working_dir))
 
@@ -324,17 +328,17 @@ def _check_potential_output_directory(
             preexisting_paths = content - subpaths
             if preexisting_paths:
                 raise errors.InvalidOutputPath(
-                    'The output directory "{0}" is not empty. \n\n'
-                    "Delete existing files before running the "
-                    "command:"
-                    '\n  (use "git rm <file>..." to remove them '
-                    "first)"
-                    "\n\n".format(input_path)
+                    f"The output directory '{input_path}' is not empty. \n\n"
+                    "As renku treats whole directory outputs as generated by renku,"
+                    "those directories have to be empty before being tracked by renku.\n\n"
+                    "You can solve this by:\n"
+                    f"- Deleting the existing files in the directory (use 'git rm -r {input_path}')\n"
+                    "- Using a different output folder\n"
+                    "- Using a new empty subfolder inside the output folder\n\n"
+                    "Output directories with existing files:\n\n"
                     + "\n".join("\t" + click.style(path, fg="yellow") for path in preexisting_paths)
                     + "\n\n"
-                    "Once you have removed files that should be used "
-                    "as outputs,\n"
-                    "you can safely rerun the previous command."
+                    "Once you have resolved the issues above, you can safely rerun the previous command."
                 )
 
         # Remove files from the input directory
@@ -590,8 +594,6 @@ def watch(self, client_dispatcher: IClientDispatcher, no_output=False):
             # List of all output paths.
             output_paths = []
 
-            inputs = {input.id: input for input in self.inputs}
-
             # Keep track of unmodified output files.
             unmodified = set()
 
@@ -639,7 +641,7 @@ def watch(self, client_dispatcher: IClientDispatcher, no_output=False):
                 raise errors.UnmodifiedOutputs(repository, unmodified)
 
             if not no_output and not output_paths:
-                raise errors.OutputsNotFound(repository, inputs.values())
+                raise errors.OutputsNotFound()
 
             if client.check_external_storage():
                 client.track_paths_in_storage(*output_paths)
@@ -725,7 +727,7 @@ def read_files_list(files_list: Path):
     data = yaml.safe_load(files_list.read_text())
 
     if not isinstance(data, dict):
-        raise errors.OperationError("Inputs/outputs files list must be a YAML dictionary.")
+        raise errors.OperationError("Explicit Inputs/Outputs/Parameters files list must be a YAML dictionary.")
 
     return data