[SNOW-1039218] feat: add hidden app list-templates command

src/snowflake/cli/plugins/nativeapp/commands.py

@@ -7,9 +7,17 @@
     with_project_definition,
 )
 from snowflake.cli.api.commands.snow_typer import SnowTyper
-from snowflake.cli.api.output.types import CommandResult, MessageResult
+from snowflake.cli.api.output.types import (
+    CollectionResult,
+    CommandResult,
+    MessageResult,
+)
+from snowflake.cli.api.secure_path import SecurePath
 from snowflake.cli.plugins.nativeapp.common_flags import ForceOption, InteractiveOption
-from snowflake.cli.plugins.nativeapp.init import nativeapp_init
+from snowflake.cli.plugins.nativeapp.init import (
+    OFFICIAL_TEMPLATES_GITHUB_URL,
+    nativeapp_init,
+)
 from snowflake.cli.plugins.nativeapp.manager import NativeAppManager
 from snowflake.cli.plugins.nativeapp.policy import (
     AllowAlwaysPolicy,
@@ -20,7 +28,11 @@
 from snowflake.cli.plugins.nativeapp.teardown_processor import (
     NativeAppTeardownProcessor,
 )
-from snowflake.cli.plugins.nativeapp.utils import is_tty_interactive
+from snowflake.cli.plugins.nativeapp.utils import (
+    get_first_paragraph_from_markdown_file,
+    is_tty_interactive,
+    shallow_git_clone,
+)
 from snowflake.cli.plugins.nativeapp.version.commands import app as versions_app
 
 app = SnowTyper(
@@ -69,6 +81,39 @@ def app_init(
     )
 
 
+@app.command("list-templates", hidden=True)
+def app_list_templates(**options) -> CommandResult:
+    """
+    Prints information regarding templates that can be used with snow app init.
+    """
+    with SecurePath.temporary_directory() as temp_path:
+        repo = shallow_git_clone(OFFICIAL_TEMPLATES_GITHUB_URL, temp_path.path)
+
+        # Mark a directory as a template if a project definition jinja template is inside
+        template_directories = [
+            entry.name
+            for entry in repo.head.commit.tree
+            if (temp_path / entry.name / "snowflake.yml.jinja").exists()
+        ]
+
+        # get the template descriptions from the README.md in its directory
+        template_descriptions = [
+            get_first_paragraph_from_markdown_file(
+                (temp_path / directory / "README.md").path
+            )
+            for directory in template_directories
+        ]
+
+        result = (
+            {"template": directory, "description": description}
+            for directory, description in zip(
+                template_directories, template_descriptions
+            )
+        )
+
+        return CollectionResult(result)
+
+
 @app.command("bundle", hidden=True)
 @with_project_definition("native_app")
 def app_bundle(

src/snowflake/cli/plugins/nativeapp/init.py

@@ -220,18 +220,10 @@ def _init_from_template(
 
     try:
         with SecurePath.temporary_directory() as temp_path:
-            from git import Repo
             from git import rmtree as git_rmtree
+            from snowflake.cli.plugins.nativeapp.utils import shallow_git_clone
 
-            # Clone the repository in the temporary directory with options.
-            repo = Repo.clone_from(
-                url=git_url,
-                to_path=temp_path.path,
-                filter=["tree:0"],
-                depth=1,
-            )
-            # Close repo to avoid issues with permissions on Windows
-            repo.close()
+            shallow_git_clone(git_url, temp_path.path)
 
             if use_whole_repo_as_template:
                 # the template is the entire git repository

src/snowflake/cli/plugins/nativeapp/utils.py

@@ -1,4 +1,7 @@
+from os import PathLike
+from pathlib import Path
 from sys import stdin, stdout
+from typing import Optional, Union
 
 
 def needs_confirmation(needs_confirm: bool, auto_yes: bool) -> bool:
@@ -7,3 +10,55 @@ def needs_confirmation(needs_confirm: bool, auto_yes: bool) -> bool:
 
 def is_tty_interactive():
     return stdin.isatty() and stdout.isatty()
+
+
+def get_first_paragraph_from_markdown_file(file_path: Path) -> Optional[str]:
+    """
+    Reads a Markdown file at the given file path and finds the first paragraph
+
+    Parameters:
+        file_path (Path): Path to Markdown file
+
+    Returns:
+        Optional[str]: the first paragraph as a string, or None
+        if no paragraph could be found, or the path was invalid
+    """
+    if not file_path.exists():
+        return None
+
+    with open(file_path, "r") as markdown_file:
+        paragraph_text = None
+
+        for line in markdown_file:
+            stripped_line = line.strip()
+            if not stripped_line.startswith("#") and stripped_line:
+                paragraph_text = stripped_line
+                break
+
+        return paragraph_text
+
+
+def shallow_git_clone(url: Union[str, PathLike], to_path: Union[str, PathLike]):
+    """
+    Performs a shallow clone of the repository at the provided url to the path specified
+
+    Parameters:
+        url (str | PathLike): Valid git url.
+        to_path (str | PathLike): Path to which the repository should be cloned to.
+
+    Returns:
+        Repo: the repository that was cloned
+    """
+    from git import Repo
+
+    # Clone the repository in the directory with options.
+    repo = Repo.clone_from(
+        url=url,
+        to_path=to_path,
+        filter=["tree:0"],
+        depth=1,
+    )
+    # Close repo to avoid issues with permissions on Windows
+    repo.close()
+
+    return repo

tests/__snapshots__/test_help_messages.ambr

@@ -113,6 +113,30 @@
   ╰──────────────────────────────────────────────────────────────────────────────╯
 
 
+  '''
+# ---
+# name: test_help_messages[app.list-templates]
+  '''
+
+   Usage: default app list-templates [OPTIONS]                                    
+
+   Prints information regarding templates that can be used with snow app init.    
+
+  ╭─ Options ────────────────────────────────────────────────────────────────────╮
+  │ --help  -h        Show this message and exit.                                │
+  ╰──────────────────────────────────────────────────────────────────────────────╯
+  ╭─ Global configuration ───────────────────────────────────────────────────────╮
+  │ --format           [TABLE|JSON]  Specifies the output format.                │
+  │                                  [default: TABLE]                            │
+  │ --verbose  -v                    Displays log entries for log levels `info`  │
+  │                                  and higher.                                 │
+  │ --debug                          Displays log entries for log levels `debug` │
+  │                                  and higher; debug logs contains additional  │
+  │                                  information.                                │
+  │ --silent                         Turns off intermediate output to console.   │
+  ╰──────────────────────────────────────────────────────────────────────────────╯
+
+
   '''
 # ---
 # name: test_help_messages[app.open]

tests/nativeapp/__snapshots__/test_commands.ambr

@@ -358,3 +358,28 @@
 
   '''
 # ---
+# name: test_list_templates_no_options_success
+  '''
+  +------------------------------------------------------------------------------+
+  | template         | description                                               |
+  |------------------+-----------------------------------------------------------|
+  | basic            | This is the basic project template for a Snowflake Native |
+  |                  | App project. It contains minimal code meant to help you   |
+  |                  | set up your first application object in your account      |
+  |                  | quickly.                                                  |
+  | streamlit-java   | This is an example template for a Snowflake Native App    |
+  |                  | project which demonstrates the use of Java extension code |
+  |                  | and adding Streamlit code. This template is meant to      |
+  |                  | guide developers towards a possible project structure on  |
+  |                  | the basis of functionality, as well as to indicate the    |
+  |                  | contents of some common and useful files.                 |
+  | streamlit-python | This is an example template for a Snowflake Native App    |
+  |                  | project which demonstrates the use of Python extension    |
+  |                  | code and adding Streamlit code. This template is meant to |
+  |                  | guide developers towards a possible project structure on  |
+  |                  | the basis of functionality, as well as to indicate the    |
+  |                  | contents of some common and useful files.                 |
+  +------------------------------------------------------------------------------+
+
+  '''
+# ---

tests/nativeapp/test_commands.py

@@ -109,3 +109,11 @@ def test_init_no_template_failure(
 
     assert result.exit_code == 1
     assert result.output == snapshot
+
+
+def test_list_templates_no_options_success(runner, temp_dir, snapshot):
+    args = ["app", "list-templates"]
+    result = runner.invoke(args)
+
+    assert result.exit_code == 0
+    assert result.output == snapshot

tests/nativeapp/test_utils.py

@@ -0,0 +1,57 @@
+from textwrap import dedent
+
+import pytest
+from snowflake.cli.api.secure_path import SecurePath
+from snowflake.cli.plugins.nativeapp.utils import get_first_paragraph_from_markdown_file
+
+
+@pytest.mark.parametrize(
+    "file_content, expected_paragraph",
+    [
+        (
+            dedent(
+                """
+            ## Introduction
+
+            This is an example template for a Snowflake Native App project which demonstrates the use of Python extension code and adding Streamlit code. This template is meant to guide developers towards a possible project structure on the basis of functionality, as well as to indicate the contents of some common and useful files. 
+
+            Since this template contains Python files only, you do not need to perform any additional steps to build the source code. You can directly go to the next section. However, if there were any source code that needed to be built, you must manually perform the build steps here before proceeding to the next section. 
+
+            Similarly, you can also use your own build steps for any other languages supported by Snowflake that you wish to write your code in. For more information on supported languages, visit [docs](https://docs.snowflake.com/en/developer-guide/stored-procedures-vs-udfs#label-sp-udf-languages).
+            """
+            ),
+            "This is an example template for a Snowflake Native App project which demonstrates the use of Python extension code and adding Streamlit code. This template is meant to guide developers towards a possible project structure on the basis of functionality, as well as to indicate the contents of some common and useful files.",
+        ),
+        (
+            dedent(
+                """
+            # Just a Heading
+
+            ## And some whitespace.
+            """
+            ),
+            None,
+        ),
+    ],
+)
+def test_get_first_paragraph_from_markdown_file_with_valid_path(
+    file_content, expected_paragraph
+):
+    with SecurePath.temporary_directory() as temp_path:
+        temp_readme_path = (temp_path / "README.md").path
+
+        with open(temp_readme_path, "w+") as temp_readme_file:
+            temp_readme_file.write(file_content)
+
+        actual_paragraph = get_first_paragraph_from_markdown_file(temp_readme_path)
+
+        assert actual_paragraph == expected_paragraph
+
+
+def test_get_first_paragraph_from_markdown_file_with_invalid_path():
+    with SecurePath.temporary_directory() as temp_path:
+        temp_readme_path = (temp_path / "README.md").path
+
+        actual_paragraph = get_first_paragraph_from_markdown_file(temp_readme_path)
+
+        assert actual_paragraph is None