feat: implement basic librarian configure command

.generator/cli.py

@@ -45,6 +45,7 @@
 
 BUILD_REQUEST_FILE = "build-request.json"
 GENERATE_REQUEST_FILE = "generate-request.json"
+CONFIGURE_REQUEST_FILE = "configure-request.json"
 RELEASE_INIT_REQUEST_FILE = "release-init-request.json"
 STATE_YAML_FILE = "state.yaml"
 
@@ -114,6 +115,103 @@ def _write_json_file(path: str, updated_content: Dict):
         json.dump(updated_content, f, indent=2)
         f.write("\n")
 
+def _add_new_library_source_roots(library_config: Dict, library_id: str) -> None:
+    """Adds the default source_roots to the library configuration if not present.
+
+    Args:
+        library_config(Dict): The library configuration.
+        library_id(str): The id of the library.
+    """
+    if library_config["source_roots"] is None:
+        library_config["source_roots"] = [f"packages/{library_id}"]
+
+
+def _add_new_library_preserve_regex(library_config: Dict, library_id: str) -> None:
+    """Adds the default preserve_regex to the library configuration if not present.
+
+    Args:
+        library_config(Dict): The library configuration.
+        library_id(str): The id of the library.
+    """
+    if library_config["preserve_regex"] is None:
+        library_config["preserve_regex"] = [
+            f"packages/{library_id}/CHANGELOG.md",
+            "docs/CHANGELOG.md",
+            "docs/README.rst",
+            "samples/README.txt",
+            "tar.gz",
+            "gapic_version.py",
+            "scripts/client-post-processing",
+            "samples/snippets/README.rst",
+            "tests/system",
+        ]
+
+
+def _add_new_library_remove_regex(library_config: Dict, library_id: str) -> None:
+    """Adds the default remove_regex to the library configuration if not present.
+
+    Args:
+        library_config(Dict): The library configuration.
+        library_id(str): The id of the library.
+    """
+    if library_config["remove_regex"] is None:
+        library_config["remove_regex"] = [f"packages/{library_id}"]
+
+
+def _add_new_library_tag_format(library_config: Dict) -> None:
+    """Adds the default tag_format to the library configuration if not present.
+
+    Args:
+        library_config(Dict): The library configuration.
+    """
+    if "tag_format" not in library_config:
+        library_config["tag_format"] = "{{id}}-v{{version}}"
+
+
+def _get_new_library_config(request_data: Dict) -> Dict:
+    """Finds and returns the configuration for a new library.
+
+    Args:
+        request_data(Dict): The request data from which to extract the new
+        library config.
+
+    Returns:
+        Dict: The unmodified configuration of a new library, or an empty
+        dictionary if not found.
+    """
+    for library_config in request_data.get("libraries", []):
+        all_apis = library_config.get("apis", [])
+        for api in all_apis:
+            if api.get("status") == "new":
+                return library_config
+    return {}
+
+
+def _prepare_new_library_config(library_config: Dict) -> Dict:
+    """
+    Prepares the new library's configuration by removing temporary keys and
+    adding default values.
+
+    Args:
+        library_config (Dict): The raw library configuration.
+
+    Returns:
+        Dict: The prepared library configuration.
+    """
+    # remove status key from new library config.
+    all_apis = library_config.get("apis", [])
+    for api in all_apis:
+        if "status" in api:
+            del api["status"]
+
+    library_id = _get_library_id(library_config)
+    _add_new_library_source_roots(library_config, library_id)
+    _add_new_library_preserve_regex(library_config, library_id)
+    _add_new_library_remove_regex(library_config, library_id)
+    _add_new_library_tag_format(library_config)
+
+    return library_config
+
 
 def handle_configure(
     librarian: str = LIBRARIAN_DIR,
@@ -144,7 +242,17 @@ def handle_configure(
     Raises:
         ValueError: If configuring a new library fails.
     """
-    # TODO(https://github.com/googleapis/librarian/issues/466): Implement configure command and update docstring.
+    try:
+        # configure-request.json contains the library definitions.
+        request_data = _read_json_file(f"{librarian}/{CONFIGURE_REQUEST_FILE}")
+        new_library_config = _get_new_library_config(request_data)
+        prepared_config = _prepare_new_library_config(new_library_config)
+
+        # Write the new library configuration to configure-response.json.
+        _write_json_file(f"{librarian}/configure-response.json", prepared_config)
+
+    except Exception as e:
+        raise ValueError("Configuring a new library failed.") from e
     logger.info("'configure' command executed.")
 
 

.generator/test_cli.py

@@ -28,6 +28,7 @@
 from cli import (
     GENERATE_REQUEST_FILE,
     BUILD_REQUEST_FILE,
+    CONFIGURE_REQUEST_FILE,
     RELEASE_INIT_REQUEST_FILE,
     SOURCE_DIR,
     STATE_YAML_FILE,
@@ -43,7 +44,9 @@
     _get_library_dist_name,
     _get_library_id,
     _get_libraries_to_prepare_for_release,
+    _get_new_library_config,
     _get_previous_version,
+    _prepare_new_library_config,
     _process_changelog,
     _process_version_file,
     _read_bazel_build_py_rule,
@@ -160,6 +163,35 @@ def mock_build_request_file(tmp_path, monkeypatch):
     return request_file
 
 
+@pytest.fixture
+def mock_configure_request_data():
+    """Returns mock data for configure-request.json."""
+    return {
+        "libraries": [
+            {
+                "id": "google-cloud-language",
+                "apis": [{"path": "google/cloud/language/v1", "status": "new"}],
+            }
+        ]
+    }
+
+
+@pytest.fixture
+def mock_configure_request_file(tmp_path, monkeypatch, mock_configure_request_data):
+    """Creates the mock request file at the correct path inside a temp dir."""
+    # Create the path as expected by the script: .librarian/configure-request.json
+    request_path = f"{LIBRARIAN_DIR}/{CONFIGURE_REQUEST_FILE}"
+    request_dir = tmp_path / os.path.dirname(request_path)
+    request_dir.mkdir(parents=True, exist_ok=True)
+    request_file = request_dir / os.path.basename(request_path)
+
+    request_file.write_text(json.dumps(mock_configure_request_data))
+
+    # Change the current working directory to the temp path for the test.
+    monkeypatch.chdir(tmp_path)
+    return request_file
+
+
 @pytest.fixture
 def mock_build_bazel_file(tmp_path, monkeypatch):
     """Creates the mock BUILD.bazel file at the correct path inside a temp dir."""
@@ -236,6 +268,98 @@ def mock_state_file(tmp_path, monkeypatch):
     return request_file
 
 
+def test_handle_configure_success(mock_configure_request_file, mocker):
+    """Tests the successful execution path of handle_configure."""
+    mock_write_json = mocker.patch("cli._write_json_file")
+    mock_prepare_config = mocker.patch(
+        "cli._prepare_new_library_config", return_value={"id": "prepared"}
+    )
+
+    handle_configure()
+
+    mock_prepare_config.assert_called_once()
+    mock_write_json.assert_called_once_with(
+        f"{LIBRARIAN_DIR}/configure-response.json", {"id": "prepared"}
+    )
+
+
+def test_handle_configure_no_new_library(mocker):
+    """Tests that handle_configure fails if no new library is found."""
+    mocker.patch("cli._read_json_file", return_value={"libraries": []})
+    # The call to _prepare_new_library_config with an empty dict will raise a ValueError
+    # because _get_library_id will fail.
+    with pytest.raises(ValueError, match="Configuring a new library failed."):
+        handle_configure()
+
+
+def test_get_new_library_config_found(mock_configure_request_data):
+    """Tests that the new library configuration is returned when found."""
+    config = _get_new_library_config(mock_configure_request_data)
+    assert config["id"] == "google-cloud-language"
+    # Assert that the config is NOT modified
+    assert "status" in config["apis"][0]
+
+
+def test_get_new_library_config_not_found():
+    """Tests that an empty dictionary is returned when no new library is found."""
+    request_data = {
+        "libraries": [
+            {"id": "existing-library", "apis": [{"path": "path/v1", "status": "existing"}]},
+        ]
+    }
+    config = _get_new_library_config(request_data)
+    assert config == {}
+
+
+def test_get_new_library_config_empty_input():
+    """Tests that an empty dictionary is returned for empty input."""
+    config = _get_new_library_config({})
+    assert config == {}
+
+
+def test_prepare_new_library_config():
+    """Tests the preparation of a new library's configuration."""
+    raw_config = {
+        "id": "google-cloud-language",
+        "apis": [{"path": "google/cloud/language/v1", "status": "new"}],
+        "source_roots": None,
+        "preserve_regex": None,
+        "remove_regex": None,
+    }
+
+    prepared_config = _prepare_new_library_config(raw_config)
+
+    # Check that status is removed
+    assert "status" not in prepared_config["apis"][0]
+    # Check that defaults are added
+    assert prepared_config["source_roots"] == ["packages/google-cloud-language"]
+    assert "packages/google-cloud-language/CHANGELOG.md" in prepared_config["preserve_regex"]
+    assert prepared_config["remove_regex"] == ["packages/google-cloud-language"]
+    assert prepared_config["tag_format"] == "{{id}}-v{{version}}"
+
+
+def test_prepare_new_library_config_preserves_existing_values():
+    """Tests that existing values in the config are not overwritten."""
+    raw_config = {
+        "id": "google-cloud-language",
+        "apis": [{"path": "google/cloud/language/v1", "status": "new"}],
+        "source_roots": ["packages/google-cloud-language-custom"],
+        "preserve_regex": ["custom/regex"],
+        "remove_regex": ["custom/remove"],
+        "tag_format": "custom-format-{{version}}",
+    }
+
+    prepared_config = _prepare_new_library_config(raw_config)
+
+    # Check that status is removed
+    assert "status" not in prepared_config["apis"][0]
+    # Check that existing values are preserved
+    assert prepared_config["source_roots"] == ["packages/google-cloud-language-custom"]
+    assert prepared_config["preserve_regex"] == ["custom/regex"]
+    assert prepared_config["remove_regex"] == ["custom/remove"]
+    assert prepared_config["tag_format"] == "custom-format-{{version}}"
+
+
 def test_get_library_id_success():
     """Tests that _get_library_id returns the correct ID when present."""
     request_data = {"id": "test-library", "name": "Test Library"}
@@ -261,17 +385,6 @@ def test_get_library_id_empty_id():
         _get_library_id(request_data)
 
 
-def test_handle_configure_success(caplog, mock_generate_request_file):
-    """
-    Tests the successful execution path of handle_configure.
-    """
-    caplog.set_level(logging.INFO)
-
-    handle_configure()
-
-    assert "'configure' command executed." in caplog.text
-
-
 def test_run_post_processor_success(mocker, caplog):
     """
     Tests that the post-processor helper calls the correct command.