feat: read content of generate request

Author: ohmayr

.generator/cli.py

@@ -14,13 +14,44 @@
 
 import argparse
 import sys
+import json
+import os
+import logging
+
+logger = logging.getLogger()
+
+LIBRARIAN = "/librarian"
+
+# Helper function that reads a json file path and returns the loaded json content.
+def _read_json_file(path):
+    if not os.path.exists(path):
+        raise FileNotFoundError(f"Request file not found at '{path}'")
+    try:
+        with open(path, 'r') as f:
+            return json.load(f)
+    except json.JSONDecodeError:
+        raise ValueError(f"Invalid JSON in request file '{path}'")
+    except IOError as e:
+        raise IOError(f"Invalid JSON in request file '{path}': {e}")
+
 
 def handle_configure(dry_run=False):
     # TODO(https://github.com/googleapis/librarian/issues/466): Implement configure command.
     print("'configure' command executed.")
 
 def handle_generate(dry_run=False):
     # TODO(https://github.com/googleapis/librarian/issues/448): Implement generate command.
+
+    # Read a generate-request.json file
+    request_path = f"{LIBRARIAN}/generate-request.json"
+    try:
+        request_data = _read_json_file(request_path)
+    except Exception as e:
+        logger.error(e)
+        sys.exit(1)
+
+    # Print the data:
+    print(json.dumps(request_data, indent=2))
     print("'generate' command executed.")
 
 def handle_build(dry_run=False):

.generator/requirements-test.in

@@ -0,0 +1,16 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+pytest
+pytest-mock

.generator/test_cli.py

@@ -26,3 +26,41 @@ def test_handle_generate_dry_run():
 def test_handle_build_dry_run():
     # This is a simple test to ensure that the dry run command succeeds.
     handle_build(dry_run=True)
+import pytest
+import json
+
+from cli import _read_json_file
+
+def test_read_valid_json(mocker):
+    """Tests reading a valid JSON file."""
+    mock_content = '{"key": "value"}'
+    mocker.patch("os.path.exists", return_value=True)
+    mocker.patch("builtins.open", mocker.mock_open(read_data=mock_content))
+    result = _read_json_file("fake/path.json")
+    assert result == {"key": "value"}
+
+def test_file_not_found(mocker):
+    """Tests behavior when the file does not exist."""
+    mocker.patch("os.path.exists", return_value=False)
+
+    with pytest.raises(FileNotFoundError):
+        _read_json_file("non/existent/path.json")
+
+def test_invalid_json(mocker):
+    """Tests reading a file with malformed JSON."""
+    mock_content = '{"key": "value",}'
+    mocker.patch("os.path.exists", return_value=True)
+    mocker.patch("builtins.open", mocker.mock_open(read_data=mock_content))
+
+    with pytest.raises(ValueError, match="Invalid JSON"):
+        _read_json_file("fake/path.json")
+
+def test_io_error_on_read(mocker):
+    """Tests for a generic IOError."""
+    mocker.patch("os.path.exists", return_value=True)
+    mocked_open = mocker.mock_open()
+    mocked_open.side_effect = IOError("Permission denied")
+    mocker.patch("builtins.open", mocked_open)
+
+    with pytest.raises(IOError, match="Permission denied"):
+        _read_json_file("fake/path.json")

.librarian/generate-request.json

@@ -0,0 +1,10 @@
+{
+    "id": "google-cloud-language",
+    "apis": [
+      {
+        "path": "google/cloud/language/v1",
+        "service_config": "language.yaml"
+      }
+    ]
+  }
+