From fd4aa814443b847f3f3c6b2124adee7781b6c4b7 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Thu, 6 Aug 2020 09:03:03 +0200
Subject: [PATCH 01/20] chore: uppercase env var log level value

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 101cbc6ac5..110e2d7834 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -118,7 +118,7 @@ def __init__(
     ):
         self.service = service or os.getenv("POWERTOOLS_SERVICE_NAME") or "service_undefined"
         self.sampling_rate = sampling_rate or os.getenv("POWERTOOLS_LOGGER_SAMPLE_RATE") or 0.0
-        self.log_level = level or os.getenv("LOG_LEVEL") or logging.INFO
+        self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
         self.handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
         self.log_keys = copy.copy(self._default_log_keys)

From 261ec2b42ad047b400abf9b060eeb4a983829201 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:05:25 +0200
Subject: [PATCH 02/20] feat: add keys to existing formatter

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/formatter.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/aws_lambda_powertools/logging/formatter.py b/aws_lambda_powertools/logging/formatter.py
index 7b38524b6d..cb3bb39734 100644
--- a/aws_lambda_powertools/logging/formatter.py
+++ b/aws_lambda_powertools/logging/formatter.py
@@ -56,6 +56,9 @@ def __init__(self, **kwargs):
         self.format_dict.update(kwargs)
         self.default_json_formatter = kwargs.pop("json_default", json_formatter)
 
+    def update_formatter(self, **kwargs):
+        self.format_dict.update(kwargs)
+
     def format(self, record):  # noqa: A003
         record_dict = record.__dict__.copy()
         record_dict["asctime"] = self.formatTime(record, self.datefmt)

From 114a0acbb1f0c648d220ed4b5324e5cbb981a106 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:07:13 +0200
Subject: [PATCH 03/20] chore: remove duplicate parameters docstring

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 110e2d7834..10102330bf 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -89,19 +89,6 @@ class Logger(logging.Logger):
                 logger.structure_logs(append=True, payment_id=event["payment_id"])
                 logger.info("Hello")
 
-    Parameters
-    ----------
-    logging : logging.Logger
-        Inherits Logger
-    service: str
-        name of the service to create the logger for, "service_undefined" by default
-    level: str, int
-        log level, INFO by default
-    sampling_rate: float
-        debug log sampling rate, 0.0 by default
-    stream: sys.stdout
-        log stream, stdout by default
-
     Raises
     ------
     InvalidLoggerSamplingRateError

From 26f7336121dedcdc8b05550802605ce4e18fbb29 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:15:48 +0200
Subject: [PATCH 04/20] feat: add name parameter

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 10102330bf..bd6ee2a830 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -55,6 +55,8 @@ class Logger(logging.Logger):
         service name to be appended in logs, by default "service_undefined"
     level : str, optional
         logging.level, by default "INFO"
+    name: str
+        Logger name, "{service}" by default
     sample_rate: float, optional
         sample rate for debug calls within execution context defaults to 0.0
     stream: sys.stdout, optional
@@ -80,7 +82,7 @@ class Logger(logging.Logger):
         >>> def handler(event, context):
                 logger.info("Hello")
 
-    **Append payment_id to previously setup structured log logger**
+    **Append payment_id to previously setup logger**
 
         >>> from aws_lambda_powertools import Logger
         >>> logger = Logger(service="payment")
@@ -89,6 +91,16 @@ class Logger(logging.Logger):
                 logger.structure_logs(append=True, payment_id=event["payment_id"])
                 logger.info("Hello")
 
+    **Create child Logger using logging inheritance via name param**
+
+        >>> # app.py
+        >>> from aws_lambda_powertools import Logger
+        >>> logger = Logger(name="payment")
+        >>>
+        >>> # another_file.py
+        >>> from aws_lambda_powertools import Logger
+        >>> logger = Logger(name="payment.child)
+
     Raises
     ------
     InvalidLoggerSamplingRateError
@@ -99,18 +111,20 @@ def __init__(
         self,
         service: str = None,
         level: Union[str, int] = None,
+        name: str = None,
         sampling_rate: float = None,
         stream: sys.stdout = None,
         **kwargs,
     ):
         self.service = service or os.getenv("POWERTOOLS_SERVICE_NAME") or "service_undefined"
+        self.name = name or self.service
         self.sampling_rate = sampling_rate or os.getenv("POWERTOOLS_LOGGER_SAMPLE_RATE") or 0.0
         self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
         self.handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
         self.log_keys = copy.copy(self._default_log_keys)
 
-        super().__init__(name=self.service, level=self.log_level)
+        super().__init__(name=self.name, level=self.log_level)
 
         try:
             if self.sampling_rate and random.random() <= float(self.sampling_rate):

From b0678e3ed3d8c0d4c04c569aa18140e399044b95 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:37:44 +0200
Subject: [PATCH 05/20] feat: support logging inheritance

---
 aws_lambda_powertools/logging/logger.py | 56 +++++++++++++++++--------
 1 file changed, 39 insertions(+), 17 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index bd6ee2a830..021df17b39 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -1,4 +1,3 @@
-import copy
 import functools
 import logging
 import os
@@ -34,7 +33,7 @@ def _is_cold_start() -> bool:
     return cold_start
 
 
-class Logger(logging.Logger):
+class Logger:
     """Creates and setups a logger to format statements in JSON.
 
     Includes service name and any additional key=value into logs
@@ -122,10 +121,37 @@ def __init__(
         self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
         self.handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
-        self.log_keys = copy.copy(self._default_log_keys)
-
-        super().__init__(name=self.name, level=self.log_level)
-
+        self._logger = logging.getLogger(self.name)
+
+        self._init_logger(**kwargs)
+
+    def __getattr__(self, name):
+        # Proxy attributes not found to actual logger to support backward compatibility
+        # https://github.com/awslabs/aws-lambda-powertools-python/issues/97
+        return getattr(self._logger, name)
+
+    def _init_logger(self, **kwargs):
+        """Configures new logger"""
+        # Ensure logger children remains independent
+        self._logger.propagate = False
+
+        # Skip configuration if it's a child logger, or a handler is already present
+        # to prevent multiple Loggers with the same name or its children having different sampling mechanisms
+        # and multiple messages from being logged as handlers can be duplicated
+        if self._logger.parent.name == "root" and not self._logger.handlers:
+            self._configure_sampling()
+            self._logger.setLevel(self.log_level)
+            self._logger.addHandler(self.handler)
+            self.structure_logs(**kwargs)
+
+    def _configure_sampling(self):
+        """Dynamically set log level based on sampling rate
+
+        Raises
+        ------
+        InvalidLoggerSamplingRateError
+            When sampling rate provided is not a float
+        """
         try:
             if self.sampling_rate and random.random() <= float(self.sampling_rate):
                 logger.debug("Setting log level to Debug due to sampling rate")
@@ -135,10 +161,6 @@ def __init__(
                 f"Expected a float value ranging 0 to 1, but received {self.sampling_rate} instead. Please review POWERTOOLS_LOGGER_SAMPLE_RATE environment variable."  # noqa E501
             )
 
-        self.setLevel(self.log_level)
-        self.structure_logs(**kwargs)
-        self.addHandler(self.handler)
-
     def inject_lambda_context(self, lambda_handler: Callable[[Dict, Any], Any] = None, log_event: bool = False):
         """Decorator to capture Lambda contextual info and inject into struct logging
 
@@ -217,13 +239,13 @@ def structure_logs(self, append: bool = False, **kwargs):
         append : bool, optional
             [description], by default False
         """
-        self.handler.setFormatter(JsonFormatter(**self._default_log_keys, **kwargs))
-
-        if append:
-            new_keys = {**self.log_keys, **kwargs}
-            self.handler.setFormatter(JsonFormatter(**new_keys))
-
-        self.log_keys.update(**kwargs)
+        for handler in self._logger.handlers:
+            if append:
+                # Update existing formatter in an existing logger handler
+                handler.formatter.update_formatter(**kwargs)
+            else:
+                # Set a new formatter for a logger handler
+                handler.setFormatter(JsonFormatter(**self._default_log_keys, **kwargs))
 
 
 def set_package_logger(

From fa58fd8bd900a7aa352fb803f536841233dfa0bf Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:39:54 +0200
Subject: [PATCH 06/20] chore: spelling

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 021df17b39..9bf9996bea 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -162,7 +162,7 @@ def _configure_sampling(self):
             )
 
     def inject_lambda_context(self, lambda_handler: Callable[[Dict, Any], Any] = None, log_event: bool = False):
-        """Decorator to capture Lambda contextual info and inject into struct logging
+        """Decorator to capture Lambda contextual info and inject into logger
 
         Parameters
         ----------
@@ -253,7 +253,7 @@ def set_package_logger(
 ):
     """Set an additional stream handler, formatter, and log level for aws_lambda_powertools package logger.
 
-    **Package log by default is supressed (NullHandler), this should only used for debugging.
+    **Package log by default is suppressed (NullHandler), this should only used for debugging.
     This is separate from application Logger class utility**
 
     Example

From 4327dec5f4f924e5db49a04dd44ba5ab4a82b915 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 06:42:58 +0200
Subject: [PATCH 07/20] improv: make handler prop private

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 9bf9996bea..50b75f2420 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -119,7 +119,7 @@ def __init__(
         self.name = name or self.service
         self.sampling_rate = sampling_rate or os.getenv("POWERTOOLS_LOGGER_SAMPLE_RATE") or 0.0
         self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
-        self.handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
+        self._handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
         self._logger = logging.getLogger(self.name)
 
@@ -141,7 +141,7 @@ def _init_logger(self, **kwargs):
         if self._logger.parent.name == "root" and not self._logger.handlers:
             self._configure_sampling()
             self._logger.setLevel(self.log_level)
-            self._logger.addHandler(self.handler)
+            self._logger.addHandler(self._handler)
             self.structure_logs(**kwargs)
 
     def _configure_sampling(self):

From e420b052cec02229f6a3160d07937252610cc1c6 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Sun, 9 Aug 2020 07:40:53 +0200
Subject: [PATCH 08/20] feat: fetch random logger; remove dead loc

---
 tests/functional/test_aws_lambda_logging.py | 48 ++++++---------------
 tests/functional/test_logger.py             | 40 +++++++----------
 tests/functional/utility_functions.py       |  8 ++++
 3 files changed, 36 insertions(+), 60 deletions(-)
 create mode 100644 tests/functional/utility_functions.py

diff --git a/tests/functional/test_aws_lambda_logging.py b/tests/functional/test_aws_lambda_logging.py
index 9d61c16e2d..5c7856d0f1 100644
--- a/tests/functional/test_aws_lambda_logging.py
+++ b/tests/functional/test_aws_lambda_logging.py
@@ -1,11 +1,10 @@
 """aws_lambda_logging tests."""
 import io
 import json
-import logging
 
 import pytest
 
-from aws_lambda_powertools import Logger
+from .utility_functions import get_random_logger
 
 
 @pytest.fixture
@@ -13,26 +12,9 @@ def stdout():
     return io.StringIO()
 
 
-@pytest.fixture
-def handler(stdout):
-    return logging.StreamHandler(stdout)
-
-
-@pytest.fixture
-def logger():
-    return logging.getLogger(__name__)
-
-
-@pytest.fixture
-def root_logger(handler):
-    logging.root.addHandler(handler)
-    yield logging.root
-    logging.root.removeHandler(handler)
-
-
 @pytest.mark.parametrize("level", ["DEBUG", "WARNING", "ERROR", "INFO", "CRITICAL"])
-def test_setup_with_valid_log_levels(root_logger, stdout, level):
-    logger = Logger(level=level, stream=stdout, request_id="request id!", another="value")
+def test_setup_with_valid_log_levels(stdout, level):
+    logger = get_random_logger(level=level, stream=stdout, request_id="request id!", another="value")
     msg = "This is a test"
     log_command = {
         "INFO": logger.info,
@@ -55,8 +37,8 @@ def test_setup_with_valid_log_levels(root_logger, stdout, level):
     assert "exception" not in log_dict
 
 
-def test_logging_exception_traceback(root_logger, stdout):
-    logger = Logger(level="DEBUG", stream=stdout, request_id="request id!", another="value")
+def test_logging_exception_traceback(stdout):
+    logger = get_random_logger(level="DEBUG", stream=stdout, request_id="request id!", another="value")
 
     try:
         raise Exception("Boom")
@@ -69,9 +51,9 @@ def test_logging_exception_traceback(root_logger, stdout):
     assert "exception" in log_dict
 
 
-def test_setup_with_invalid_log_level(root_logger, logger, stdout):
+def test_setup_with_invalid_log_level(stdout):
     with pytest.raises(ValueError) as e:
-        Logger(level="not a valid log level")
+        get_random_logger(level="not a valid log level")
         assert "Unknown level" in e.value.args[0]
 
 
@@ -82,12 +64,8 @@ def check_log_dict(log_dict):
     assert "message" in log_dict
 
 
-def test_setup_with_bad_level_does_not_fail():
-    Logger("DBGG", request_id="request id!", another="value")
-
-
-def test_with_dict_message(root_logger, stdout):
-    logger = Logger(level="DEBUG", stream=stdout)
+def test_with_dict_message(stdout):
+    logger = get_random_logger(level="DEBUG", stream=stdout)
 
     msg = {"x": "isx"}
     logger.critical(msg)
@@ -97,8 +75,8 @@ def test_with_dict_message(root_logger, stdout):
     assert msg == log_dict["message"]
 
 
-def test_with_json_message(root_logger, stdout):
-    logger = Logger(stream=stdout)
+def test_with_json_message(stdout):
+    logger = get_random_logger(stream=stdout)
 
     msg = {"x": "isx"}
     logger.info(json.dumps(msg))
@@ -108,8 +86,8 @@ def test_with_json_message(root_logger, stdout):
     assert msg == log_dict["message"]
 
 
-def test_with_unserialisable_value_in_message(root_logger, stdout):
-    logger = Logger(level="DEBUG", stream=stdout)
+def test_with_unserialisable_value_in_message(stdout):
+    logger = get_random_logger(level="DEBUG", stream=stdout)
 
     class X:
         pass
diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index e402a3d0f2..d5a46c7034 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -9,24 +9,14 @@
 from aws_lambda_powertools.logging.exceptions import InvalidLoggerSamplingRateError
 from aws_lambda_powertools.logging.logger import set_package_logger
 
+from .utility_functions import get_random_logger
+
 
 @pytest.fixture
 def stdout():
     return io.StringIO()
 
 
-@pytest.fixture
-def handler(stdout):
-    return logging.StreamHandler(stdout)
-
-
-@pytest.fixture
-def root_logger(handler):
-    logging.root.addHandler(handler)
-    yield logging.root
-    logging.root.removeHandler(handler)
-
-
 @pytest.fixture
 def lambda_context():
     lambda_context = {
@@ -45,14 +35,14 @@ def lambda_event():
 
 
 def capture_logging_output(stdout):
-    return json.loads(stdout.getvalue())
+    return json.loads(stdout.getvalue().strip())
 
 
 def capture_multiple_logging_statements_output(stdout):
     return [json.loads(line.strip()) for line in stdout.getvalue().split("\n") if line]
 
 
-def test_setup_service_name(root_logger, stdout):
+def test_setup_service_name(stdout):
     service_name = "payment"
     # GIVEN Logger is initialized
     # WHEN service is explicitly defined
@@ -68,7 +58,7 @@ def test_setup_service_name(root_logger, stdout):
 def test_setup_no_service_name(stdout):
     # GIVEN Logger is initialized
     # WHEN no service is explicitly defined
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     logger.info("Hello")
 
@@ -82,7 +72,7 @@ def test_setup_service_env_var(monkeypatch, stdout):
     # GIVEN Logger is initialized
     # WHEN service is explicitly defined via POWERTOOLS_SERVICE_NAME env
     monkeypatch.setenv("POWERTOOLS_SERVICE_NAME", service_name)
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     logger.info("Hello")
 
@@ -96,7 +86,7 @@ def test_setup_sampling_rate_env_var(monkeypatch, stdout):
     # WHEN samping rate is explicitly set to 100% via POWERTOOLS_LOGGER_SAMPLE_RATE env
     sampling_rate = "1"
     monkeypatch.setenv("POWERTOOLS_LOGGER_SAMPLE_RATE", sampling_rate)
-    logger = Logger(stream=stdout, level="INFO")
+    logger = get_random_logger(stream=stdout)
     logger.debug("I am being sampled")
 
     # THEN sampling rate should be equals POWERTOOLS_LOGGER_SAMPLE_RATE value
@@ -110,7 +100,7 @@ def test_setup_sampling_rate_env_var(monkeypatch, stdout):
 
 def test_inject_lambda_context(lambda_context, stdout):
     # GIVEN Logger is initialized
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger
     @logger.inject_lambda_context
@@ -133,7 +123,7 @@ def handler(event, context):
 
 def test_inject_lambda_context_log_event_request(lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger instructed to log event
     @logger.inject_lambda_context(log_event=True)
@@ -150,7 +140,7 @@ def handler(event, context):
 def test_inject_lambda_context_log_event_request_env_var(monkeypatch, lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
     monkeypatch.setenv("POWERTOOLS_LOGGER_LOG_EVENT", "true")
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger instructed to log event
     # via POWERTOOLS_LOGGER_LOG_EVENT env
@@ -167,7 +157,7 @@ def handler(event, context):
 
 def test_inject_lambda_context_log_no_request_by_default(monkeypatch, lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger
     @logger.inject_lambda_context
@@ -190,7 +180,7 @@ def test_inject_lambda_cold_start(lambda_context, stdout):
     logger.is_cold_start = True
 
     # GIVEN Logger is initialized
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger, and called twice
     @logger.inject_lambda_context
@@ -238,7 +228,7 @@ def test_package_logger_format(capsys):
 
 def test_logger_append_duplicated(stdout):
     # GIVEN Logger is initialized with request_id field
-    logger = Logger(stream=stdout, request_id="value")
+    logger = get_random_logger(stream=stdout, request_id="value")
 
     # WHEN `request_id` is appended to the existing structured log
     # using a different value
@@ -255,12 +245,12 @@ def test_logger_invalid_sampling_rate():
     # WHEN sampling_rate non-numeric value
     # THEN we should raise InvalidLoggerSamplingRateError
     with pytest.raises(InvalidLoggerSamplingRateError):
-        Logger(sampling_rate="TEST")
+        get_random_logger(stream=stdout, sampling_rate="TEST")
 
 
 def test_inject_lambda_context_with_structured_log(lambda_context, stdout):
     # GIVEN Logger is initialized
-    logger = Logger(stream=stdout)
+    logger = get_random_logger(stream=stdout)
 
     # WHEN structure_logs has been used to add an additional key upfront
     # and a lambda function is decorated with logger.inject_lambda_context
diff --git a/tests/functional/utility_functions.py b/tests/functional/utility_functions.py
new file mode 100644
index 0000000000..0838fb9a01
--- /dev/null
+++ b/tests/functional/utility_functions.py
@@ -0,0 +1,8 @@
+import secrets
+
+from aws_lambda_powertools import Logger
+
+
+def get_random_logger(**kwargs):
+    """Return vanilla logger w/ random name"""
+    return Logger(name=secrets.token_urlsafe(), **kwargs)

From e4b8e9617b44eacdcd68c2e49f8456298bbed2ed Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Mon, 10 Aug 2020 10:36:15 +0200
Subject: [PATCH 09/20] improv: cover child logger independence

---
 tests/functional/test_logger.py | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index d5a46c7034..c167c97cb2 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -46,7 +46,7 @@ def test_setup_service_name(stdout):
     service_name = "payment"
     # GIVEN Logger is initialized
     # WHEN service is explicitly defined
-    logger = Logger(service=service_name, stream=stdout)
+    logger = get_random_logger(service=service_name, stream=stdout)
 
     logger.info("Hello")
 
@@ -273,3 +273,24 @@ def handler(event, context):
     )
     for key in expected_logger_context_keys:
         assert key in log
+
+
+def test_logger_children_do_not_propagate_changes(stdout):
+    # GIVEN Loggers are initialized
+    # mimick importing logger from another module/file
+    # as loggers are created in global scope
+    child = Logger(stream=stdout, name="order.warehouse")
+    parent = Logger(stream=stdout, name="order")
+
+    # WHEN a child Logger adds an additional key
+    child.structure_logs(append=True, customer_id="value")
+
+    # THEN child Logger changes should not propagate to parent
+    # and subsequent log statements should have the latest value
+    parent.info("Hello parent")
+    child.info("Hello child")
+
+    parent_log, child_log = capture_multiple_logging_statements_output(stdout)
+    assert "customer_id" not in parent_log
+    assert "customer_id" in child_log
+    assert child.parent.name == "order"

From eb99d8e14d8d9018744124e0b210046170b4ece5 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Mon, 10 Aug 2020 22:14:22 +0200
Subject: [PATCH 10/20] improv: addresses nico feedback on missing test

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 tests/functional/test_logger.py | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index c167c97cb2..0bd08f1e5c 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -294,3 +294,19 @@ def test_logger_children_do_not_propagate_changes(stdout):
     assert "customer_id" not in parent_log
     assert "customer_id" in child_log
     assert child.parent.name == "order"
+
+
+def test_logger_name_not_set(stdout):
+    # GIVEN Logger is initialized
+    # WHEN name isn't set
+    logger = Logger(stream=stdout, service="something")
+
+    # THEN Logger should function just as fine
+    # and access to its properties should be
+    # proxied to the inner Logger
+    logger.info("Hello")
+
+    log = capture_logging_output(stdout)
+    assert "Hello" == log["message"]
+    assert logger.parent.name == "root"
+    assert logger.name == "something"

From 8ddd7a3db962329dd4271ddb1734ced67c188696 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Mon, 10 Aug 2020 22:16:30 +0200
Subject: [PATCH 11/20] fix: docstring name parameter short description

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 50b75f2420..d4ac924a4c 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -54,7 +54,7 @@ class Logger:
         service name to be appended in logs, by default "service_undefined"
     level : str, optional
         logging.level, by default "INFO"
-    name: str
+    name: str, optional
         Logger name, "{service}" by default
     sample_rate: float, optional
         sample rate for debug calls within execution context defaults to 0.0

From 052121a4014f1b700800a0cd217cfad2b1cd042f Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Tue, 11 Aug 2020 18:27:27 +0200
Subject: [PATCH 12/20] improv: logger inheritance via child param

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 50 ++++++++++++++++++-------
 1 file changed, 36 insertions(+), 14 deletions(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index d4ac924a4c..495e8b751d 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -1,4 +1,5 @@
 import functools
+import inspect
 import logging
 import os
 import random
@@ -54,8 +55,8 @@ class Logger:
         service name to be appended in logs, by default "service_undefined"
     level : str, optional
         logging.level, by default "INFO"
-    name: str, optional
-        Logger name, "{service}" by default
+    child: bool, optional
+        create a child Logger named <service>.<caller_file_name>, False by default
     sample_rate: float, optional
         sample rate for debug calls within execution context defaults to 0.0
     stream: sys.stdout, optional
@@ -90,15 +91,16 @@ class Logger:
                 logger.structure_logs(append=True, payment_id=event["payment_id"])
                 logger.info("Hello")
 
-    **Create child Logger using logging inheritance via name param**
+    **Create child Logger using logging inheritance via child param**
 
         >>> # app.py
+        >>> import another_file
         >>> from aws_lambda_powertools import Logger
-        >>> logger = Logger(name="payment")
+        >>> logger = Logger(service="payment")
         >>>
         >>> # another_file.py
         >>> from aws_lambda_powertools import Logger
-        >>> logger = Logger(name="payment.child)
+        >>> logger = Logger(service="payment", child=True)
 
     Raises
     ------
@@ -110,18 +112,18 @@ def __init__(
         self,
         service: str = None,
         level: Union[str, int] = None,
-        name: str = None,
+        child: bool = False,
         sampling_rate: float = None,
         stream: sys.stdout = None,
         **kwargs,
     ):
         self.service = service or os.getenv("POWERTOOLS_SERVICE_NAME") or "service_undefined"
-        self.name = name or self.service
         self.sampling_rate = sampling_rate or os.getenv("POWERTOOLS_LOGGER_SAMPLE_RATE") or 0.0
         self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
+        self.child = child
         self._handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
-        self._logger = logging.getLogger(self.name)
+        self._logger = self._get_logger()
 
         self._init_logger(**kwargs)
 
@@ -130,15 +132,32 @@ def __getattr__(self, name):
         # https://github.com/awslabs/aws-lambda-powertools-python/issues/97
         return getattr(self._logger, name)
 
+    def _get_logger(self):
+        """ Returns a Logger named {self.service}, or {service.filename} for child loggers"""
+        logger_name = self.service
+        if self.child:
+            logger_name = f"{self.service}.{self._get_caller_filename()}"
+
+        return logging.getLogger(logger_name)
+
+    def _get_caller_filename(self):
+        """ Return caller filename by finding the caller frame """
+        # Current frame         => _get_logger()
+        # Previous frame        => logger.py
+        # Before previous frame => Caller
+        frame = inspect.currentframe()
+        caller_frame = frame.f_back.f_back.f_back
+        filename = caller_frame.f_globals["__name__"]
+
+        return filename
+
     def _init_logger(self, **kwargs):
         """Configures new logger"""
-        # Ensure logger children remains independent
-        self._logger.propagate = False
 
-        # Skip configuration if it's a child logger, or a handler is already present
-        # to prevent multiple Loggers with the same name or its children having different sampling mechanisms
+        # Skip configuration if it's a child logger to prevent
+        # multiple handlers being attached as well as different sampling mechanisms
         # and multiple messages from being logged as handlers can be duplicated
-        if self._logger.parent.name == "root" and not self._logger.handlers:
+        if not self.child:
             self._configure_sampling()
             self._logger.setLevel(self.log_level)
             self._logger.addHandler(self._handler)
@@ -239,7 +258,10 @@ def structure_logs(self, append: bool = False, **kwargs):
         append : bool, optional
             [description], by default False
         """
-        for handler in self._logger.handlers:
+
+        # Child loggers don't have handlers attached, use its parent handlers
+        handlers = self._logger.parent.handlers if self.child else self._logger.handlers
+        for handler in handlers:
             if append:
                 # Update existing formatter in an existing logger handler
                 handler.formatter.update_formatter(**kwargs)

From 9345dbd8b52e64064564f8861ed525d05e7d87e8 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Tue, 11 Aug 2020 18:28:16 +0200
Subject: [PATCH 13/20] improv: update tests

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 tests/functional/test_logger.py | 62 +++++++++++++++------------------
 1 file changed, 29 insertions(+), 33 deletions(-)

diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index 0bd08f1e5c..63183b05e4 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -9,8 +9,6 @@
 from aws_lambda_powertools.logging.exceptions import InvalidLoggerSamplingRateError
 from aws_lambda_powertools.logging.logger import set_package_logger
 
-from .utility_functions import get_random_logger
-
 
 @pytest.fixture
 def stdout():
@@ -46,7 +44,7 @@ def test_setup_service_name(stdout):
     service_name = "payment"
     # GIVEN Logger is initialized
     # WHEN service is explicitly defined
-    logger = get_random_logger(service=service_name, stream=stdout)
+    logger = Logger(service=service_name, stream=stdout)
 
     logger.info("Hello")
 
@@ -58,7 +56,7 @@ def test_setup_service_name(stdout):
 def test_setup_no_service_name(stdout):
     # GIVEN Logger is initialized
     # WHEN no service is explicitly defined
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     logger.info("Hello")
 
@@ -72,7 +70,7 @@ def test_setup_service_env_var(monkeypatch, stdout):
     # GIVEN Logger is initialized
     # WHEN service is explicitly defined via POWERTOOLS_SERVICE_NAME env
     monkeypatch.setenv("POWERTOOLS_SERVICE_NAME", service_name)
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     logger.info("Hello")
 
@@ -86,7 +84,7 @@ def test_setup_sampling_rate_env_var(monkeypatch, stdout):
     # WHEN samping rate is explicitly set to 100% via POWERTOOLS_LOGGER_SAMPLE_RATE env
     sampling_rate = "1"
     monkeypatch.setenv("POWERTOOLS_LOGGER_SAMPLE_RATE", sampling_rate)
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
     logger.debug("I am being sampled")
 
     # THEN sampling rate should be equals POWERTOOLS_LOGGER_SAMPLE_RATE value
@@ -100,7 +98,7 @@ def test_setup_sampling_rate_env_var(monkeypatch, stdout):
 
 def test_inject_lambda_context(lambda_context, stdout):
     # GIVEN Logger is initialized
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger
     @logger.inject_lambda_context
@@ -123,7 +121,7 @@ def handler(event, context):
 
 def test_inject_lambda_context_log_event_request(lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger instructed to log event
     @logger.inject_lambda_context(log_event=True)
@@ -140,7 +138,7 @@ def handler(event, context):
 def test_inject_lambda_context_log_event_request_env_var(monkeypatch, lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
     monkeypatch.setenv("POWERTOOLS_LOGGER_LOG_EVENT", "true")
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger instructed to log event
     # via POWERTOOLS_LOGGER_LOG_EVENT env
@@ -157,7 +155,7 @@ def handler(event, context):
 
 def test_inject_lambda_context_log_no_request_by_default(monkeypatch, lambda_context, stdout, lambda_event):
     # GIVEN Logger is initialized
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger
     @logger.inject_lambda_context
@@ -180,7 +178,7 @@ def test_inject_lambda_cold_start(lambda_context, stdout):
     logger.is_cold_start = True
 
     # GIVEN Logger is initialized
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN a lambda function is decorated with logger, and called twice
     @logger.inject_lambda_context
@@ -228,7 +226,7 @@ def test_package_logger_format(capsys):
 
 def test_logger_append_duplicated(stdout):
     # GIVEN Logger is initialized with request_id field
-    logger = get_random_logger(stream=stdout, request_id="value")
+    logger = Logger(stream=stdout, request_id="value")
 
     # WHEN `request_id` is appended to the existing structured log
     # using a different value
@@ -245,12 +243,12 @@ def test_logger_invalid_sampling_rate():
     # WHEN sampling_rate non-numeric value
     # THEN we should raise InvalidLoggerSamplingRateError
     with pytest.raises(InvalidLoggerSamplingRateError):
-        get_random_logger(stream=stdout, sampling_rate="TEST")
+        Logger(stream=stdout, sampling_rate="TEST")
 
 
 def test_inject_lambda_context_with_structured_log(lambda_context, stdout):
     # GIVEN Logger is initialized
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     # WHEN structure_logs has been used to add an additional key upfront
     # and a lambda function is decorated with logger.inject_lambda_context
@@ -275,38 +273,36 @@ def handler(event, context):
         assert key in log
 
 
-def test_logger_children_do_not_propagate_changes(stdout):
+def test_logger_children_propagate_changes(stdout):
     # GIVEN Loggers are initialized
-    # mimick importing logger from another module/file
+    # create child logger before parent to mimick
+    # importing logger from another module/file
     # as loggers are created in global scope
-    child = Logger(stream=stdout, name="order.warehouse")
-    parent = Logger(stream=stdout, name="order")
+    child = Logger(stream=stdout, service="order", child=True)
+    parent = Logger(stream=stdout, service="order")
 
     # WHEN a child Logger adds an additional key
     child.structure_logs(append=True, customer_id="value")
 
-    # THEN child Logger changes should not propagate to parent
+    # THEN child Logger changes should propagate to parent
     # and subsequent log statements should have the latest value
     parent.info("Hello parent")
     child.info("Hello child")
 
     parent_log, child_log = capture_multiple_logging_statements_output(stdout)
-    assert "customer_id" not in parent_log
+    assert "customer_id" in parent_log
     assert "customer_id" in child_log
     assert child.parent.name == "order"
 
 
-def test_logger_name_not_set(stdout):
-    # GIVEN Logger is initialized
-    # WHEN name isn't set
-    logger = Logger(stream=stdout, service="something")
+def test_logger_child_not_set(stdout):
+    # GIVEN two Loggers are initialized
+    # WHEN child param isn't set
+    logger_one = Logger(service="something")
+    logger_two = Logger(service="something")
 
-    # THEN Logger should function just as fine
-    # and access to its properties should be
-    # proxied to the inner Logger
-    logger.info("Hello")
-
-    log = capture_logging_output(stdout)
-    assert "Hello" == log["message"]
-    assert logger.parent.name == "root"
-    assert logger.name == "something"
+    # THEN we should have two Logger instances
+    # however inner logger wise should be the same
+    assert id(logger_one) != id(logger_two)
+    assert logger_one._logger is logger_two._logger
+    assert logger_one.name is logger_two.name

From 5860e7e8eed06ed53311824b4332772184414512 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Tue, 11 Aug 2020 18:28:49 +0200
Subject: [PATCH 14/20] improv: logger test utility no longer necessary

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 tests/functional/utility_functions.py | 8 --------
 1 file changed, 8 deletions(-)
 delete mode 100644 tests/functional/utility_functions.py

diff --git a/tests/functional/utility_functions.py b/tests/functional/utility_functions.py
deleted file mode 100644
index 0838fb9a01..0000000000
--- a/tests/functional/utility_functions.py
+++ /dev/null
@@ -1,8 +0,0 @@
-import secrets
-
-from aws_lambda_powertools import Logger
-
-
-def get_random_logger(**kwargs):
-    """Return vanilla logger w/ random name"""
-    return Logger(name=secrets.token_urlsafe(), **kwargs)

From 8e02dc40f1c3aebf7c9ba3afb9b65a406f6f1ae7 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Tue, 11 Aug 2020 18:30:04 +0200
Subject: [PATCH 15/20] improv: make test name more descriptive

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 tests/functional/test_logger.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index 63183b05e4..fd58410dd6 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -295,8 +295,8 @@ def test_logger_children_propagate_changes(stdout):
     assert child.parent.name == "order"
 
 
-def test_logger_child_not_set(stdout):
-    # GIVEN two Loggers are initialized
+def test_logger_child_not_set_returns_same_logger(stdout):
+    # GIVEN two Loggers are initialized with the same service name
     # WHEN child param isn't set
     logger_one = Logger(service="something")
     logger_two = Logger(service="something")

From 28140ad55b6543dcc9887253add30d5b24824fe9 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Tue, 11 Aug 2020 18:44:55 +0200
Subject: [PATCH 16/20] fix: remove logger utility as it's no longer used

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 tests/functional/test_aws_lambda_logging.py | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/tests/functional/test_aws_lambda_logging.py b/tests/functional/test_aws_lambda_logging.py
index 5c7856d0f1..cf4782d1d2 100644
--- a/tests/functional/test_aws_lambda_logging.py
+++ b/tests/functional/test_aws_lambda_logging.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from .utility_functions import get_random_logger
+from aws_lambda_powertools import Logger
 
 
 @pytest.fixture
@@ -14,7 +14,7 @@ def stdout():
 
 @pytest.mark.parametrize("level", ["DEBUG", "WARNING", "ERROR", "INFO", "CRITICAL"])
 def test_setup_with_valid_log_levels(stdout, level):
-    logger = get_random_logger(level=level, stream=stdout, request_id="request id!", another="value")
+    logger = Logger(level=level, stream=stdout, request_id="request id!", another="value")
     msg = "This is a test"
     log_command = {
         "INFO": logger.info,
@@ -38,7 +38,7 @@ def test_setup_with_valid_log_levels(stdout, level):
 
 
 def test_logging_exception_traceback(stdout):
-    logger = get_random_logger(level="DEBUG", stream=stdout, request_id="request id!", another="value")
+    logger = Logger(level="DEBUG", stream=stdout, request_id="request id!", another="value")
 
     try:
         raise Exception("Boom")
@@ -53,7 +53,7 @@ def test_logging_exception_traceback(stdout):
 
 def test_setup_with_invalid_log_level(stdout):
     with pytest.raises(ValueError) as e:
-        get_random_logger(level="not a valid log level")
+        Logger(level="not a valid log level")
         assert "Unknown level" in e.value.args[0]
 
 
@@ -65,7 +65,7 @@ def check_log_dict(log_dict):
 
 
 def test_with_dict_message(stdout):
-    logger = get_random_logger(level="DEBUG", stream=stdout)
+    logger = Logger(level="DEBUG", stream=stdout)
 
     msg = {"x": "isx"}
     logger.critical(msg)
@@ -76,7 +76,7 @@ def test_with_dict_message(stdout):
 
 
 def test_with_json_message(stdout):
-    logger = get_random_logger(stream=stdout)
+    logger = Logger(stream=stdout)
 
     msg = {"x": "isx"}
     logger.info(json.dumps(msg))
@@ -87,7 +87,7 @@ def test_with_json_message(stdout):
 
 
 def test_with_unserialisable_value_in_message(stdout):
-    logger = get_random_logger(level="DEBUG", stream=stdout)
+    logger = Logger(level="DEBUG", stream=stdout)
 
     class X:
         pass

From 728e464cf968fd28606b68d6ba5ad995789749e1 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Wed, 12 Aug 2020 09:22:52 +0200
Subject: [PATCH 17/20] fix: address feedback on consistency

Signed-off-by: heitorlessa <lessa@amazon.co.uk>
---
 aws_lambda_powertools/logging/logger.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index 495e8b751d..f6d37e562d 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -133,7 +133,7 @@ def __getattr__(self, name):
         return getattr(self._logger, name)
 
     def _get_logger(self):
-        """ Returns a Logger named {self.service}, or {service.filename} for child loggers"""
+        """ Returns a Logger named {self.service}, or {self.service.filename} for child loggers"""
         logger_name = self.service
         if self.child:
             logger_name = f"{self.service}.{self._get_caller_filename()}"

From dc4b2044b65ba31c57616bcb3486b30510b95543 Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Wed, 12 Aug 2020 09:49:50 +0200
Subject: [PATCH 18/20] improv: turn log_level input case insensitive

---
 aws_lambda_powertools/logging/logger.py |  9 ++++++++-
 tests/functional/test_logger.py         | 18 ++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/aws_lambda_powertools/logging/logger.py b/aws_lambda_powertools/logging/logger.py
index f6d37e562d..1b4f3d8bcf 100644
--- a/aws_lambda_powertools/logging/logger.py
+++ b/aws_lambda_powertools/logging/logger.py
@@ -119,7 +119,7 @@ def __init__(
     ):
         self.service = service or os.getenv("POWERTOOLS_SERVICE_NAME") or "service_undefined"
         self.sampling_rate = sampling_rate or os.getenv("POWERTOOLS_LOGGER_SAMPLE_RATE") or 0.0
-        self.log_level = level or os.getenv("LOG_LEVEL".upper()) or logging.INFO
+        self.log_level = self._get_log_level(level)
         self.child = child
         self._handler = logging.StreamHandler(stream) if stream is not None else logging.StreamHandler(sys.stdout)
         self._default_log_keys = {"service": self.service, "sampling_rate": self.sampling_rate}
@@ -132,6 +132,13 @@ def __getattr__(self, name):
         # https://github.com/awslabs/aws-lambda-powertools-python/issues/97
         return getattr(self._logger, name)
 
+    def _get_log_level(self, level: str):
+        """ Returns preferred log level set by the customer in upper case """
+        log_level: str = level or os.getenv("LOG_LEVEL")
+        log_level = log_level.upper() if log_level is not None else logging.INFO
+
+        return log_level
+
     def _get_logger(self):
         """ Returns a Logger named {self.service}, or {self.service.filename} for child loggers"""
         logger_name = self.service
diff --git a/tests/functional/test_logger.py b/tests/functional/test_logger.py
index fd58410dd6..21f2512528 100644
--- a/tests/functional/test_logger.py
+++ b/tests/functional/test_logger.py
@@ -306,3 +306,21 @@ def test_logger_child_not_set_returns_same_logger(stdout):
     assert id(logger_one) != id(logger_two)
     assert logger_one._logger is logger_two._logger
     assert logger_one.name is logger_two.name
+
+
+def test_logger_level_case_insensitive(stdout):
+    # GIVEN a Loggers is initialized
+    # WHEN log level is set as "info" instead of "INFO"
+    logger = Logger(level="info")
+
+    # THEN we should correctly set log level as INFO
+    assert logger.level == logging.INFO
+
+
+def test_logger_level_not_set(stdout):
+    # GIVEN a Loggers is initialized
+    # WHEN no log level was passed
+    logger = Logger(level="info")
+
+    # THEN we should default to INFO
+    assert logger.level == logging.INFO

From 5d29ef7895220d72b742076be7c04ddd2a78437a Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Fri, 14 Aug 2020 17:13:44 +0200
Subject: [PATCH 19/20] chore: add unreleased changes to Logger

---
 CHANGELOG.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e3f64eca58..b139896e10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,11 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- **Logger**: Support for logger inheritance with `child` parameter
+
+### Fixed
+- **Logger**: Log level is now case insensitive via params and env var
 
 ## [1.0.2] - 2020-07-16
 ### Fixed

From 490119fc6cc33a8477d26e5743e91f6122ae3e4e Mon Sep 17 00:00:00 2001
From: heitorlessa <lessa@amazon.co.uk>
Date: Fri, 14 Aug 2020 17:39:10 +0200
Subject: [PATCH 20/20] docs: adds reusing logger across your code section

Documents new Logger feature to support logging inheritance using the new `child` parameter.
---
 docs/content/core/logger.mdx | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/docs/content/core/logger.mdx b/docs/content/core/logger.mdx
index e12c2b7c63..225fb401cf 100644
--- a/docs/content/core/logger.mdx
+++ b/docs/content/core/logger.mdx
@@ -183,6 +183,41 @@ def handler(event, context):
 ```
 </details>
 
+## Reusing Logger across your code
+
+Logger supports inheritance via `child` parameter. This allows you to create multiple Loggers across your code base, and propagate changes such as new keys to all Loggers.
+
+```python:title=collect.py
+# POWERTOOLS_SERVICE_NAME: "payment"
+import shared # Creates a child logger named "payment.shared"
+from aws_lambda_powertools import Logger
+
+logger = Logger()
+
+def handler(event, context):
+  shared.inject_payment_id(event) # highlight-line
+  logger.structure_logs(append=True, order_id=event["order_id"]) # highlight-line
+      ...
+```
+
+```python:title=shared.py
+# POWERTOOLS_SERVICE_NAME: "payment"
+from aws_lambda_powertools import Logger
+
+logger = Logger(child=True) # highlight-line
+
+def inject_payment_id(event):
+    logger.structure_logs(append=True, payment_id=event["payment_id"])
+```
+
+In this example, `Logger` will create a parent logger named `payment` and a child logger named `payment.shared`. Any changes in the parent and child `Loggers` will be propagated among them.
+
+If you ever forget to use `child` param, we will return an existing `Logger` with the same `service` name.
+
+<Note type="info">
+	Child loggers will be named after the following convention <code>service.filename</code>.
+</Note><br/>
+
 ## Sampling debug logs
 
 You can dynamically set a percentage of your logs to **DEBUG** level using `sample_rate` param or via env var `POWERTOOLS_LOGGER_SAMPLE_RATE`.