cli[minor]: Add langgraph new command (#2369)

Adds a "new" command to create langgraph application from a template.

libs/cli/tests/unit_tests/cli/test_cli.py

@@ -0,0 +1,133 @@
+import pathlib
+
+from click.testing import CliRunner
+
+from langgraph_cli.cli import cli, prepare_args_and_stdin
+from langgraph_cli.config import Config, validate_config
+from langgraph_cli.docker import DEFAULT_POSTGRES_URI, DockerCapabilities, Version
+from langgraph_cli.util import clean_empty_lines
+
+DEFAULT_DOCKER_CAPABILITIES = DockerCapabilities(
+    version_docker=Version(26, 1, 1),
+    version_compose=Version(2, 27, 0),
+    healthcheck_start_interval=True,
+)
+
+
+def test_prepare_args_and_stdin():
+    # this basically serves as an end-to-end test for using config and docker helpers
+    config_path = pathlib.Path("./langgraph.json")
+    config = validate_config(
+        Config(dependencies=["."], graphs={"agent": "agent.py:graph"})
+    )
+    port = 8000
+    debugger_port = 8001
+    debugger_graph_url = f"http://127.0.0.1:{port}"
+
+    actual_args, actual_stdin = prepare_args_and_stdin(
+        capabilities=DEFAULT_DOCKER_CAPABILITIES,
+        config_path=config_path,
+        config=config,
+        docker_compose="custom-docker-compose.yml",
+        port=port,
+        debugger_port=debugger_port,
+        debugger_base_url=debugger_graph_url,
+        watch=True,
+    )
+
+    expected_args = [
+        "--project-directory",
+        ".",
+        "-f",
+        "custom-docker-compose.yml",
+        "-f",
+        "-",
+    ]
+    expected_stdin = f"""volumes:
+    langgraph-data:
+        driver: local
+services:
+    langgraph-redis:
+        image: redis:6
+        healthcheck:
+            test: redis-cli ping
+            interval: 5s
+            timeout: 1s
+            retries: 5
+    langgraph-postgres:
+        image: postgres:16
+        ports:
+            - "5433:5432"
+        environment:
+            POSTGRES_DB: postgres
+            POSTGRES_USER: postgres
+            POSTGRES_PASSWORD: postgres
+        volumes:
+            - langgraph-data:/var/lib/postgresql/data
+        healthcheck:
+            test: pg_isready -U postgres
+            start_period: 10s
+            timeout: 1s
+            retries: 5
+            interval: 60s
+            start_interval: 1s
+    langgraph-debugger:
+        image: langchain/langgraph-debugger
+        restart: on-failure
+        depends_on:
+            langgraph-postgres:
+                condition: service_healthy
+        ports:
+            - "{debugger_port}:3968"
+        environment:
+            VITE_STUDIO_LOCAL_GRAPH_URL: {debugger_graph_url}
+    langgraph-api:
+        ports:
+            - "8000:8000"
+        depends_on:
+            langgraph-redis:
+                condition: service_healthy
+            langgraph-postgres:
+                condition: service_healthy
+        environment:
+            REDIS_URI: redis://langgraph-redis:6379
+            POSTGRES_URI: {DEFAULT_POSTGRES_URI}
+        healthcheck:
+            test: python /api/healthcheck.py
+            interval: 60s
+            start_interval: 1s
+            start_period: 10s
+        
+        pull_policy: build
+        build:
+            context: .
+            dockerfile_inline: |
+                FROM langchain/langgraph-api:3.11
+                ADD . /deps/
+                RUN PYTHONDONTWRITEBYTECODE=1 pip install --no-cache-dir -c /api/constraints.txt -e /deps/*
+                ENV LANGSERVE_GRAPHS='{{"agent": "agent.py:graph"}}'
+                WORKDIR /deps/
+        
+        develop:
+            watch:
+                - path: langgraph.json
+                  action: rebuild
+                - path: .
+                  action: rebuild\
+"""
+    assert actual_args == expected_args
+    assert clean_empty_lines(actual_stdin) == expected_stdin
+
+
+def test_version_option() -> None:
+    """Test the --version option of the CLI."""
+    runner = CliRunner()
+    result = runner.invoke(cli, ["--version"])
+
+    # Verify that the command executed successfully
+    assert result.exit_code == 0, "Expected exit code 0 for --version option"
+
+    # Check that the output contains the correct version information
+    assert (
+        "LangGraph CLI, version" in result.output
+    ), "Expected version information in output"

libs/cli/tests/unit_tests/cli/test_templates.py

@@ -0,0 +1,70 @@
+"""Unit tests for the 'new' CLI command.
+
+This command creates a new LangGraph project using a specified template.
+"""
+
+import os
+from io import BytesIO
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from unittest.mock import MagicMock, patch
+from urllib import request
+from zipfile import ZipFile
+
+from click.testing import CliRunner
+
+from langgraph_cli.cli import cli
+from langgraph_cli.templates import TEMPLATE_ID_TO_CONFIG
+
+
+@patch.object(request, "urlopen")
+def test_create_new_with_mocked_download(mock_urlopen: MagicMock) -> None:
+    """Test the 'new' CLI command with a mocked download response using urllib."""
+    # Mock the response content to simulate a ZIP file
+    mock_zip_content = BytesIO()
+    with ZipFile(mock_zip_content, "w") as mock_zip:
+        mock_zip.writestr("test-file.txt", "Test content.")
+
+    # Create a mock response that behaves like a context manager
+    mock_response = MagicMock()
+    mock_response.read.return_value = mock_zip_content.getvalue()
+    mock_response.__enter__.return_value = mock_response  # Setup enter context
+    mock_response.status = 200
+
+    mock_urlopen.return_value = mock_response
+
+    with TemporaryDirectory() as temp_dir:
+        runner = CliRunner()
+        template = next(
+            iter(TEMPLATE_ID_TO_CONFIG)
+        )  # Select the first template for the test
+        result = runner.invoke(cli, ["new", temp_dir, "--template", template])
+
+        # Verify CLI command execution and success
+        assert result.exit_code == 0, result.output
+        assert (
+            "New project created" in result.output
+        ), "Expected success message in output."
+
+        # Verify that the directory is not empty
+        assert os.listdir(temp_dir), "Expected files to be created in temp directory."
+
+        # Check for a known file in the extracted content
+        extracted_files = [f.name for f in Path(temp_dir).glob("*")]
+        assert (
+            "test-file.txt" in extracted_files
+        ), "Expected 'test-file.txt' in the extracted content."
+
+
+def test_invalid_template_id() -> None:
+    """Test that an invalid template ID passed via CLI results in a graceful error."""
+    runner = CliRunner()
+    result = runner.invoke(
+        cli, ["new", "dummy_path", "--template", "invalid-template-id"]
+    )
+
+    # Verify the command failed and proper message is displayed
+    assert result.exit_code != 0, "Expected non-zero exit code for invalid template."
+    assert (
+        "Template 'invalid-template-id' not found" in result.output
+    ), "Expected error message in output."