Merge branch 'docs/logging_dev' into chore_improve_logs_api

Author: davidgamez

docs/Logs.md

@@ -0,0 +1,48 @@
+# How to use the logging framework
+Al our services runs in GCP. To get the best out of the log traces, we should use a common pattern acrosss all functions and services. This documents describes how to use the shared logging functions.
+
+## Python functions
+
+### Logging level
+The logging level is by default [INFO](https://github.com/MobilityData/mobility-feed-api/blob/a857ca794b5991aa8b6e7ecedb197914ae1eca04/api/src/shared/common/logging_utils.py#L5).
+The logging level can be changed at runtime by setting the function variable `LOGGING_LEVEL` to the desired value, example DEBUG
+
+### Initialize logging
+ On the main file initialize the logging client by calling the following function:
+```
+init_logger()
+```
+The [init_logger](https://github.com/MobilityData/mobility-feed-api/blob/a857ca794b5991aa8b6e7ecedb197914ae1eca04/functions-python/helpers/logger.py#L49) will set the right logging level and initialize the GCP cloud client if it's not running in local environment. 
+
+### Logging messages
+There are two ways to log messages:
+
+ 1. Logs messages without specific stable_id.
+
+```
+ import logging
+
+ logging.info("Total feeds: %s", total_feeds)
+
+```
+
+2. Using a stable id
+```
+ import logging
+
+ logger = logging.get_logger("my logger name", "mdb-001")
+ logging.info("Total feeds: %s", total_feeds) # This will output the following format for total_feeds equals to 10: [mdb-001] Total feeds: 10
+
+```
+
+Use log parameters instead of string interpolation. String interpolation always creates a string concatenation even if the log is not send due to the environment log level settings.
+Example:
+```
+# Avoid string interpolation.
+logging.info(f"Total of feeds: {total}")
+
+# Use this optimized version
+logging.info(f"Total of feeds: %s", total)
+```
+
+