Merge pull request #67 from bcdev/forman-64-console_logging

Simplify logging configuration

Author: forman

CHANGES.md

@@ -2,6 +2,10 @@
 
 ### Enhancements
 
+* Simplified logging to console. You can now set configuration setting `logging`
+  to a log level which will implicitly enable console logging with given log
+  level. [#64]
+
 * Added a section in the notebook `examples/zappend-demo.ipynb`
   that demonstrates transaction rollbacks.
 

docs/guide.md

@@ -691,14 +691,28 @@ the [Configuration Reference](config.md) for more details.
 ## Logging
 
 The `zappend` logging output is configured using the `logging` setting.
-Its configuration follows exactly the 
-[dictionary schema](https://docs.python.org/3/library/logging.config.html#logging-config-dictschema)
-of the Python module `logging.config`. The logger used by the `zappend` tool is named 
-`zappend`. Note that you can also configure the logger of other Python modules, e.g.,
-`xarray` or `dask` using an entry in the `loggers` setting.
+In the simplest case, if you just want logging output from `zappend` to the console:
 
+```json
+{
+    "logging": true
+}
+```
+
+The above uses log level `INFO`. If you want a different log level, 
+just provide its name:
+
+```json
+{
+    "logging": "DEBUG"
+}
+```
+
+If you also want logging output in a file or using a different format or if you want to
+see logging output of other Python modules, you can configure Python's logging 
+system following the [logging dictionary schema](https://docs.python.org/3/library/logging.config.html#logging-config-dictschema).
 Given here is an example that logs `zappend`'s output to the console using 
-the INFO level:
+the `INFO` level (same as `"logging": true`):
 
 ```json
 {
@@ -726,3 +740,5 @@ the INFO level:
 }
 ```
 
+Using the `loggers` entry you can configure the logger of other Python modules, e.g.,
+`xarray` or `dask`. The logger used by the `zappend` tool is named `zappend`. 

tests/test_log.py

@@ -11,12 +11,27 @@
 
 
 class LogTest(unittest.TestCase):
+    old_level = None
+    old_handlers = None
+
+    @classmethod
+    def setUpClass(cls):
+        cls.old_level = logger.level
+        cls.old_handlers = list(logger.handlers)
+        for h in cls.old_handlers:
+            logger.removeHandler(h)
+
+    def tearDown(self):
+        logger.setLevel(self.old_level)
+        for h in self.old_handlers:
+            logger.addHandler(h)
+
     def test_logger(self):
         self.assertIsInstance(logger, logging.Logger)
         self.assertEqual(logging.NOTSET, logger.level)
         self.assertEqual(1, len(logger.handlers))
 
-    def test_configure_logging(self):
+    def test_configure_logging_dict(self):
         logging_config = {
             "version": 1,
             "formatters": {
@@ -31,19 +46,31 @@ def test_configure_logging(self):
             "loggers": {"zappend": {"level": "INFO", "handlers": ["console"]}},
         }
 
-        old_level = logger.level
-        old_handlers = list(logger.handlers)
-        for h in old_handlers:
-            logger.removeHandler(h)
+        configure_logging(logging_config)
+        self.assertEqual(logging.INFO, logger.level)
+        self.assertEqual(1, len(logger.handlers))
+        self.assertIsInstance(logger.handlers[0], logging.StreamHandler)
 
-        try:
-            configure_logging(logging_config)
-            self.assertEqual(logging.INFO, logger.level)
-            self.assertEqual(1, len(logger.handlers))
-        finally:
-            logger.setLevel(old_level)
-            for h in old_handlers:
-                logger.addHandler(h)
+    def test_configure_logging_false(self):
+        logging_config = False
+        configure_logging(logging_config)
+        self.assertEqual(logging.NOTSET, logger.level)
+        self.assertEqual(1, len(logger.handlers))
+        self.assertIsInstance(logger.handlers[0], logging.StreamHandler)
+
+    def test_configure_logging_true(self):
+        logging_config = True
+        configure_logging(logging_config)
+        self.assertEqual(logging.INFO, logger.level)
+        self.assertEqual(1, len(logger.handlers))
+        self.assertIsInstance(logger.handlers[0], logging.StreamHandler)
+
+    def test_configure_logging_level(self):
+        logging_config = "WARNING"
+        configure_logging(logging_config)
+        self.assertEqual(logging.WARNING, logger.level)
+        self.assertEqual(1, len(logger.handlers))
+        self.assertIsInstance(logger.handlers[0], logging.StreamHandler)
 
     def test_get_log_level(self):
         self.assertEqual(logging.DEBUG, get_log_level("DEBUG"))

zappend/config/schema.py

@@ -297,9 +297,9 @@
 }
 
 
-LOGGING_SCHEMA = {
+DETAILED_LOGGING_SCHEMA = {
     "description": (
-        f"Logging configuration. For details refer to the"
+        f"Detailed logging configuration. For details refer to the"
         f" [dictionary schema]({LOG_REF_URL})"
         f" of the Python module `logging.config`."
     ),
@@ -441,6 +441,27 @@
     "additionalProperties": True,
 }
 
+LOGGING_SCHEMA = {
+    "description": "Logging configuration.",
+    "oneOf": [
+        {
+            "description": (
+                "Shortform that enables logging to the console"
+                ' using log level `"INFO"`.'
+            ),
+            "type": "boolean",
+        },
+        {
+            "description": (
+                "Shortform that enables logging to the console"
+                " using the specified log level."
+            ),
+            "enum": LOG_LEVELS,
+        },
+        DETAILED_LOGGING_SCHEMA,
+    ],
+}
+
 CONFIG_SCHEMA_V1 = {
     "title": "Configuration Reference",
     "type": "object",

zappend/log.py

@@ -25,6 +25,26 @@ def get_log_level(level_name: str) -> int:
     return _nameToLevel.get(level_name, logging.NOTSET)
 
 
-def configure_logging(logging_config: dict[str, Any] | None):
-    if logging_config:
-        logging.config.dictConfig(logging_config)
+def configure_logging(logging_config: dict[str, Any] | str | bool | None):
+    if not logging_config:
+        return
+    if isinstance(logging_config, (str, bool)):
+        logging_config = {
+            "version": 1,
+            "formatters": {
+                "normal": {
+                    "format": "%(asctime)s %(levelname)s %(message)s",
+                    "style": "%",
+                }
+            },
+            "handlers": {
+                "console": {"class": "logging.StreamHandler", "formatter": "normal"}
+            },
+            "loggers": {
+                "zappend": {
+                    "level": _nameToLevel.get(logging_config, logging.INFO),
+                    "handlers": ["console"],
+                }
+            },
+        }
+    logging.config.dictConfig(logging_config)