Adds a basic CLI for converting recipe files

- Usage: `percy convert [-o output] FILE`
- Error and warning messages dump to `STDERR` by default (like `curl` does)
- By default the converted recipe is dumped to `STDOUT`. The `-o` option allows
  the user to specify an output file.

.pytest.ini

@@ -1,6 +1,5 @@
 # This surpresses deprecation `pytest` warnings related to using `conda.*` packages.
-# TODO Future: remove/upgrade deprecated packages
 [pytest]
 filterwarnings =
-    ignore:conda.* is pending deprecation:PendingDeprecationWarning
-    ignore:conda.* is deprecated:DeprecationWarning
+    ignore::DeprecationWarning
+    ignore::PendingDeprecationWarning

percy/commands/convert.py

@@ -0,0 +1,69 @@
+"""
+File:           convert.py
+Description:    CLI for converting an old recipe file to the "new" format.
+"""
+from __future__ import annotations
+
+import os
+import sys
+from typing import Final
+
+import click
+
+from percy.parser.recipe_parser import RecipeParser
+from percy.parser.types import MessageCategory, MessageTable
+
+# Required file name for the recipe, specified in CEP-13
+NEW_FORMAT_RECIPE_FILE_NAME: Final[str] = "recipe.yaml"
+
+
+def print_out(*args, **kwargs):
+    """
+    Convenience wrapper that prints to STDOUT
+    """
+    print(*args, file=sys.stdout, **kwargs)
+
+
+def print_err(*args, **kwargs):
+    """
+    Convenience wrapper that prints to STDERR
+    """
+    print(*args, file=sys.stderr, **kwargs)
+
+
+def print_messages(category: MessageCategory, msg_tbl: MessageTable):
+    """
+    Convenience function for dumping a series of messages of a certain category
+    :param category: Category of messages to print
+    :param msg_tbl: `MessageTable` instance containing the messages to print
+    """
+    msgs: Final[list[str]] = msg_tbl.get_messages(category)
+    for msg in msgs:
+        print_err(f"[{category.upper()}]: {msg}")
+
+
+@click.command(short_help="Converts a `meta.yaml` formatted-recipe file to the new `recipe.yaml` format")
+@click.argument("file", type=click.File("r", encoding="utf-8"))
+@click.option("--output", "-o", type=click.Path(exists=False), default=None, help="File to dump a new recipe to.")
+def convert(file: click.File, output: click.Path) -> None:  # pylint: disable=redefined-outer-name
+    """
+    Recipe conversion CLI utility. By default, recipes print to STDOUT. Messages always print to STDERR.
+    """
+    recipe_content: Final[str] = file.read()
+
+    parser = RecipeParser(recipe_content)
+    result, msg_tbl = parser.render_to_new_recipe_format()
+
+    if output is None:
+        print_out(result)
+    else:
+        if not os.path.basename(output) == "recipe.yaml":
+            print_err("WARNING: File is not called `recipe.yaml`.")
+        with open(output, "w", encoding="utf-8") as fptr:
+            fptr.write(result)
+
+    summary: Final[str] = msg_tbl.get_totals_message()
+    if summary:
+        print_messages(MessageCategory.WARNING, msg_tbl)
+        print_messages(MessageCategory.ERROR, msg_tbl)
+        print_err(summary)

percy/commands/main.py

@@ -9,6 +9,7 @@
 import click
 
 from percy.commands.aggregate import aggregate
+from percy.commands.convert import convert
 from percy.commands.recipe import recipe
 
 
@@ -21,6 +22,7 @@ def cli() -> None:
 # add subcommands
 cli.add_command(recipe)
 cli.add_command(aggregate)
+cli.add_command(convert)
 
 
 @cli.command()

percy/tests/commands/test_convert_cli.py

@@ -0,0 +1,22 @@
+"""
+File:           test_convert_cli.py
+Description:    Tests the `convert` CLI
+"""
+from click.testing import CliRunner
+
+from percy.commands.convert import convert
+
+
+def test_usage() -> None:
+    """
+    Ensure failure to provide a sub-command results in rendering the help menu
+    """
+    runner = CliRunner()
+    # No commands are provided
+    result = runner.invoke(convert, [])
+    assert result.exit_code != 0
+    assert result.output.startswith("Usage:")
+    # Help is specified
+    result = runner.invoke(convert, ["--help"])
+    assert result.exit_code == 0
+    assert result.output.startswith("Usage:")