Rename LOG_LEVEL to MISTRAL_LOG_LEVEL

Ports mistralai/client-python#86

.env.example

@@ -1,3 +1,3 @@
 # Get this from https://console.mistral.ai/api-keys/
 MISTRAL_API_KEY=
-LOG_LEVEL=ERROR
+MISTRAL_LOG_LEVEL=ERROR

PYTHON_CLIENT_COMPARISON.md

@@ -182,3 +182,14 @@ coverage and using RSpec, which is usually what I do.
 
 The `function_calling.rb` example omits the unnecessary `n_rows = data['transaction_id'].length` line present in
 the Python version.
+
+## Logging
+
+Python has a global logger:
+
+```python
+self._logger = logging.getLogger(__name__)
+```
+
+Ruby doesn't. Thus, in order to allow users to customize the logging level, they can set the environment variable
+`MISTRAL_LOG_LEVEL` to `DEBUG`, `INFO`, `WARN`, `ERROR` or `FATAL`.

lib/mistral/client_base.rb

@@ -9,7 +9,6 @@ def initialize(endpoint:, api_key: nil, max_retries: 5, timeout: 120)
       @api_key = api_key
       @max_retries = max_retries
       @timeout = timeout
-
       @logger = config_logger
 
       # For azure endpoints, we default to the mistral model
@@ -115,7 +114,7 @@ def process_line(line)
 
     def config_logger
       Logger.new($stdout).tap do |logger|
-        logger.level = ENV.fetch('LOG_LEVEL', 'ERROR')
+        logger.level = ENV.fetch('MISTRAL_LOG_LEVEL', 'ERROR')
 
         logger.formatter = proc do |severity, datetime, progname, msg|
           "#{datetime.strftime("%Y-%m-%d %H:%M:%S")} #{severity} #{progname}: #{msg}\n"