Extract load_yaml_config from setup_logging and add tests

backend/entityservice/logger_setup.py

@@ -1,10 +1,10 @@
 import logging.config
 import os
 from pathlib import Path
+
 import structlog
-import yaml
 
-from entityservice.errors import InvalidConfiguration
+from entityservice.utils import load_yaml_config
 
 
 def setup_logging(
@@ -15,14 +15,8 @@ def setup_logging(
     Setup logging configuration
     """
     path = os.getenv(env_key, Path(__file__).parent / default_path)
-    try:
-        with open(path, 'rt') as f:
-            config = yaml.safe_load(f)
-        logging.config.dictConfig(config)
-    except yaml.YAMLError as e:
-        raise InvalidConfiguration("Parsing YAML logging config failed") from e
-    except FileNotFoundError as e:
-        raise InvalidConfiguration(f"Logging config YAML file '{path}' doesn't exist.") from e
+    config = load_yaml_config(path)
+    logging.config.dictConfig(config)
 
     # Configure Structlog wrapper for client use
     setup_structlog()

backend/entityservice/tests/test_utils.py

@@ -0,0 +1,64 @@
+import textwrap
+
+import pytest
+
+from entityservice.errors import InvalidConfiguration
+from entityservice.utils import load_yaml_config
+from entityservice.tests.util import generate_bytes, temp_file_containing
+
+
+class TestYamlLoader:
+
+    def test_empty(self):
+        with temp_file_containing(b'') as fp:
+            filename = fp.name
+            assert None == load_yaml_config(filename)
+
+    def test_list(self):
+        with temp_file_containing(b'[1,2,3]') as fp:
+            filename = fp.name
+            assert [1,2,3] == load_yaml_config(filename)
+
+    def test_missing_file(self):
+        filename = 'unlikely a valid file'
+        with pytest.raises(InvalidConfiguration):
+            load_yaml_config(filename)
+
+    def test_random_bytes(self):
+        with temp_file_containing(generate_bytes(128)) as fp:
+            filename = fp.name
+            with pytest.raises(InvalidConfiguration):
+                load_yaml_config(filename)
+
+    def test_valid_yaml(self):
+        yamldata = textwrap.dedent("""
+        api:
+          number: 42
+          ingress:
+            enabled: true
+            host: example.com
+        """)
+        self._check_valid_yaml(yamldata)
+
+    def _check_valid_yaml(self, yamldata:str):
+        with temp_file_containing(yamldata.encode()) as fp:
+            filename = fp.name
+            loaded = load_yaml_config(filename)
+        assert 'api' in loaded
+        assert 'number' in loaded['api']
+        assert loaded['api']['number'] == 42
+        assert loaded['api']['ingress']['enabled']
+        return loaded
+
+    def test_valid_yaml_with_comments(self):
+        yamldata = textwrap.dedent("""
+        ## Api is a thing
+        api:
+          number: 42
+          ingress:
+            enabled: true
+            # host: example.com
+        """)
+        loaded = self._check_valid_yaml(yamldata)
+        assert 'host' not in loaded['api']['ingress']
+

backend/entityservice/tests/util.py

@@ -5,6 +5,7 @@
 import os
 import random
 import time
+import tempfile
 from contextlib import contextmanager
 from enum import IntEnum
 
@@ -14,6 +15,15 @@
 from entityservice.tests.config import url
 
 
+@contextmanager
+def temp_file_containing(data):
+    # Code to acquire resource, e.g.:
+    with tempfile.NamedTemporaryFile('wb') as fp:
+        fp.write(data)
+        fp.seek(0)
+        yield fp
+
+
 def serialize_bytes(hash_bytes):
     """ Serialize bloomfilter bytes
 

backend/entityservice/utils.py

@@ -8,15 +8,36 @@
 
 import binascii
 import bitmath
-from flask import request
 from connexion import ProblemException
+from flask import request
 from structlog import get_logger
+import yaml
 
+from entityservice.errors import InvalidConfiguration
 from entityservice.database import DBConn, get_number_parties_uploaded, get_number_parties_ready, get_project_column
 
 logger = get_logger()
 
 
+def load_yaml_config(filename):
+    """
+    Load a yaml file as a Python object.
+
+    :param filename: a Path or String object
+    :raises InvalidConfiguration if the file isn't found or the yaml isn't valid.
+    :return: Python representation of yaml file's contents (usually Dict), or None if empty.
+    """
+    try:
+        with open(filename, 'rt') as f:
+            return yaml.safe_load(f)
+    except UnicodeDecodeError as e:
+        raise InvalidConfiguration("YAML file appears corrupt") from e
+    except yaml.YAMLError as e:
+        raise InvalidConfiguration("Parsing YAML config failed") from e
+    except FileNotFoundError as e:
+        raise InvalidConfiguration(f"Logging config YAML file '{filename}' doesn't exist.") from e
+
+
 def fmt_bytes(num_bytes):
     """
     Displays an integer number of bytes in a human friendly form.