Merge pull request #17 from lifeomic/FLDM-390/json-child-logger

Add JsonLogger which supports child loggers

.gitignore

@@ -129,3 +129,4 @@ dmypy.json
 # Pyre type checker
 .pyre/
 .idea
+.tool-versions

CHANGELOG.md

@@ -0,0 +1,30 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
+and this project adheres to
+[Semantic Versioning](http://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [0.4.0] - 2024-10-11
+
+### Added
+
+- Added a new `JsonLogger` class that logs messages in JSON format. Supports
+  child loggers as well. The logger inherits from builtin `logging.Logger` and
+  the log methods have the same API as the builtin as well. Example usage:
+
+  ```python
+  from lifeomic_logging import JsonLogger
+
+  # Create a logger with a name and optional context that will be included
+  # on all log messages.
+  logger = JsonLogger("my-logger", {"foo": "bar"})
+  logger.info({"msg": "message", "isTrue": True})
+  # >>> {"name": "my-logger", "foo": "bar", "level": "INFO", "msg": "message", "isTrue": true}
+  child_logger = logger.child({"fizz": "buzz"})
+  child.info("message")
+  # >>> {"name": "my-logger", "foo": "bar", "fizz": "buzz", "level": "INFO", "msg": "message"}
+  ```

README.md

@@ -11,19 +11,23 @@
 
 ### Dependencies
 
-* [Python 3](https://www.python.org/download/releases/3.0/) version >= 3.6
+- [Python 3](https://www.python.org/download/releases/3.0/) version >= 3.6
 
 ### Getting the Source
 
-This project is [hosted on GitHub](https://github.com/lifeomic/logging-py). You can clone this project directly using this command:
+This project is [hosted on GitHub](https://github.com/lifeomic/logging-py). You
+can clone this project directly using this command:
 
 ```bash
 git clone git@github.com:lifeomic/logging-py.git
 ```
 
 ### Development
 
-Python environments are managed using [virtualenv](https://virtualenv.pypa.io/en/latest/).  Be sure to have this installed first `pip install virtualenv`.  The makefile will setup the environment for the targets listed below.
+Python environments are managed using
+[virtualenv](https://virtualenv.pypa.io/en/latest/). Be sure to have this
+installed first `pip install virtualenv`. The makefile will setup the
+environment for the targets listed below.
 
 #### Running tests
 
@@ -54,20 +58,31 @@ with scoped_logger(__name__, { "bar": "foo" }) as log:
 
 ## Release Process
 
-[Releases](https://github.com/lifeomic/logging-py/releases) are generally created with each merged PR. Packages for each release are published to [PyPi](https://pypi.org/project/phc/). See [CHANGELOG.md](CHANGELOG.md) for release notes.
+[Releases](https://github.com/lifeomic/logging-py/releases) are generally
+created with each merged PR. Packages for each release are published to
+[PyPi](https://pypi.org/project/phc/). See [CHANGELOG.md](CHANGELOG.md) for
+release notes.
+
+To release a new version of the package, update the version number in
+`lifeomic_logging/version.py` as a part of your change, and the new version will
+be released automatically to PyPi on merge.
 
 ### Versioning
 
 This project uses [Semantic Versioning](http://semver.org/).
 
 ## Contributing
 
-We encourage public contributions! Please review [CONTRIBUTING.md](CONTRIBUTING.md) and [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md) for details on our code of conduct and development process.
+We encourage public contributions! Please review
+[CONTRIBUTING.md](CONTRIBUTING.md) and [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md)
+for details on our code of conduct and development process.
 
 ## License
 
-This project is licensed under the MIT License - see [LICENSE](LICENSE) file for details.
+This project is licensed under the MIT License - see [LICENSE](LICENSE) file for
+details.
 
 ## Authors
 
-See the list of [contributors](https://github.com/lifeomic/cli/contributors) who participate in this project.
+See the list of [contributors](https://github.com/lifeomic/cli/contributors) who
+participate in this project.

lifeomic_logging/logger.py

@@ -7,6 +7,7 @@
 from logging import Formatter, Filter, StreamHandler, getLogger, INFO, Logger
 from json import dumps
 from contextlib import contextmanager
+from typing import Generator, Optional
 
 thread_local_storage = threading.local()
 
@@ -36,14 +37,46 @@
 )
 
 
+class JsonLogger(Logger):
+    """
+    A logger that logs in JSON format. Supports creating child loggers with
+    expanded context, similar to the NodeJS Bunyan logger.
+    """
+
+    def __init__(
+        self,
+        name: str,
+        context: Optional[dict] = None,
+        level: int = INFO,
+    ):
+        super().__init__(name, level)
+        self.context = context if context is not None else {}
+        handler = StreamHandler()
+        handler.setFormatter(_JSONFormatter())
+        self.addHandler(handler)
+
+    def child(self, additional_context: dict):
+        child_context = {**self.context, **additional_context}
+        child_logger = self.__class__(
+            name=self.name, level=self.level, context=child_context
+        )
+        return child_logger
+
+    def _log(self, level, msg, args, exc_info=None, extra=None, stack_info=False):
+        if extra is None:
+            extra = {}
+        extra.update(self.context)
+        super()._log(level, msg, args, exc_info, extra, stack_info)
+
+
 @contextmanager
 def scoped_logger(
     logname: str,
-    normal_context: dict = None,
-    error_context: dict = None,
+    normal_context: Optional[dict] = None,
+    error_context: Optional[dict] = None,
     stream=None,
     level: int = INFO,
-) -> Logger:
+) -> Generator[Logger, None, None]:
     """Creates a scopped logger
 
     Parameters
@@ -84,7 +117,7 @@ def scoped_logger(
         )
 
 
-def get_request_context(lambda_context: dict) -> dict:
+def get_request_context(lambda_context: dict) -> Optional[dict]:
     """Helper method to retrieve our most pertinent header information.
         These are stored from the passed in lambda_context
         object. Please see

lifeomic_logging/version.py

@@ -1 +1 @@
-__version__ = "0.3.2"
+__version__ = "0.4.0"