docs: add new example for web custom log and update readme

Author: Bob Bui

README.md

@@ -211,8 +211,10 @@ json_logging.config_root_logger()
 ```
 
 ## 2.6 Custom log formatter
-Customer JSON log formatter can be passed to init method. see example for more detail: 
-https://github.com/thangbn/json-logging-python/blob/master/example/custom_log_format.py
+Customer JSON log formatter can be passed to init method. see examples for more detail: [non web](https://github.com/thangbn/json-logging-python/blob/master/example/custom_log_format.py), 
+[web](https://github.com/thangbn/json-logging-python/blob/master/example/custom_log_format_request.py)
+
+
 
 ## 2.7 Exclude certain URl from request instrumentation
 Certain URL can be excluded from request instrumentation by specifying a list of regex into **init_request_instrument** method like below:

example/custom_log_format.py

@@ -1,71 +1,37 @@
 # This example shows how the logger can be set up to use a custom JSON format.
-import logging
 import json
-import traceback
-from datetime import datetime
-import copy
-import json_logging
+import logging
 import sys
 
-json_logging.ENABLE_JSON_LOGGING = True
+import json_logging
 
 
 def extra(**kw):
     '''Add the required nested props layer'''
     return {'extra': {'props': kw}}
 
 
-class CustomJSONLog(logging.Formatter):
+class CustomJSONLog(json_logging.JSONLogFormatter):
     """
     Customized logger
     """
 
-    def get_exc_fields(self, record):
-        if record.exc_info:
-            exc_info = self.format_exception(record.exc_info)
-        else:
-            exc_info = record.exc_text
-        return {'python.exc_info': exc_info}
-
-    @classmethod
-    def format_exception(cls, exc_info):
-        return ''.join(traceback.format_exception(*exc_info)) if exc_info else ''
-
     def format(self, record):
-        json_log_object = {"@timestamp": datetime.utcnow().isoformat(),
-                           "level": record.levelname,
-                           "message": record.getMessage(),
-                           "caller": record.filename + '::' + record.funcName
-                           }
-        json_log_object['data'] = {
-            "python.logger_name": record.name,
-            "python.module": record.module,
-            "python.funcName": record.funcName,
-            "python.filename": record.filename,
-            "python.lineno": record.lineno,
-            "python.thread": record.threadName,
-            "python.pid": record.process
-        }
-        if hasattr(record, 'props'):
-            json_log_object['data'].update(record.props)
-
-        if record.exc_info or record.exc_text:
-            json_log_object['data'].update(self.get_exc_fields(record))
+        json_customized_log_object = ({
+            "customized_prop": "customized value",
+            "message": record.getMessage()
+        })
 
-        return json.dumps(json_log_object)
+        return json.dumps(json_customized_log_object)
 
 
 # You would normally import logger_init and setup the logger in your main module - e.g.
 # main.py
 
-json_logging.init_non_web(custom_formatter=CustomJSONLog)
+json_logging.init_non_web(custom_formatter=CustomJSONLog, enable_json=True)
 
 logger = logging.getLogger(__name__)
 logger.setLevel(logging.DEBUG)
 logger.addHandler(logging.StreamHandler(sys.stderr))
 
-logger.info('Starting')
-try:
-    1 / 0
-except:  # noqa pylint: disable=bare-except
-    logger.exception('You can\'t divide by zero')
+logger.info('sample log message')

example/custom_log_format_request.py

@@ -0,0 +1,59 @@
+import json
+import logging
+import sys
+
+import flask
+
+import json_logging
+
+
+class CustomRequestJSONLog(json_logging.JSONLogWebFormatter):
+    """
+    Customized logger
+    """
+
+    def format(self, record):
+        json_customized_log_object = ({
+            "customized_prop": "customized value",
+            "correlation_id": json_logging.get_correlation_id(),
+        })
+        return json.dumps(json_customized_log_object)
+
+
+app = flask.Flask(__name__)
+json_logging.init_flask(enable_json=True)
+json_logging.init_request_instrument(app, exclude_url_patterns=[r'/exclude_from_request_instrumentation'],
+                                     custom_formatter=CustomRequestJSONLog)
+
+# init the logger as usual
+logger = logging.getLogger("test logger")
+logger.setLevel(logging.DEBUG)
+logger.addHandler(logging.StreamHandler(sys.stdout))
+
+
+@app.route('/')
+def home():
+    logger.info("test log statement")
+    logger.info("test log statement with extra props", extra={'props': {"extra_property": 'extra_value'}})
+    correlation_id = json_logging.get_correlation_id()
+    return "hello world" \
+           "\ncorrelation_id                    : " + correlation_id
+
+
+@app.route('/exception')
+def exception():
+    try:
+        raise RuntimeError
+    except BaseException as e:
+        logger.error("Error occurred", exc_info=e)
+        logger.exception("Error occurred", exc_info=e)
+    return "Error occurred, check log for detail"
+
+
+@app.route('/exclude_from_request_instrumentation')
+def exclude_from_request_instrumentation():
+    return "this request wont log request instrumentation information"
+
+
+if __name__ == "__main__":
+    app.run(host='0.0.0.0', port=int(5000), use_reloader=False)