commit 74cd1e48fa0e5207940cdec4556d9eb0d358c47b
author Sapan Bhatia <sapan@opennetworking.org> Mon Aug 14 02:00:04 2017 -0400
committer Sapan Bhatia <sapan@opennetworking.org> Mon Aug 21 14:31:08 2017 -0400
tree 7bbca7f3b6716aac4027566298c8b4dee5b61732
parent f81a5fc607bfa15d3e0d5fb792b4489dad346794

CORD-1743: Support reloads for logging module + Bugfix in setup.py

Change-Id: I055d8a1eb5b4dfe233e68624a7ebecd1acb49061

multistructlog.py

diff --git a/multistructlog.py b/multistructlog.py
index a92753e..8896cf2 100644
--- a/multistructlog.py
+++ b/multistructlog.py
@@ -32,7 +32,7 @@
 
 Each handler depends on a specific renderer (e.g. Logstash needs JSON and
 stdout needs ConsoleRenderer) but a structlog instance can enchain only one
-renderer. For this reason, we apply the renderer at the logging layer, as
+renderer. For this reason, we apply renderers at the logging layer, as
 logging formatters.
 """
 
@@ -71,6 +71,7 @@
 
     def __call__(self):
         base_logger = logging.getLogger()
+        base_logger.handlers = []
         for h in self.handlers:
             formatter = FormatterFactory(h.__class__.__name__)()
             h.setFormatter(formatter)
@@ -86,14 +87,17 @@
     - config is the root xos configuration
     - overrides override elements of that config, e.g. level=logging.INFO would cause debug messages to be dropped
     - overrides can contain a 'processors' element, which lets you add processors to structlogs chain 
+    - overrides can also contain force_create = True which returns a previously created logger. Multiple threads 
+      will overwrite the shared logger. 
 
     The use of structlog in Chameleon was used as a reference when writing this code.
 """
 
+CURRENT_LOGGER = None
+CURRENT_LOGGER_PARMS = (None, None)
 
 def create_logger(_config, **overrides):
-    first_entry_elts = ['Starting']
-    first_entry_struct = {}
+    first_entry_elts = []
 
     """Inherit base options from config"""
     try:
@@ -102,6 +106,17 @@
         first_entry_elts.append('Config is empty')
         logging_config = {}
 
+    """Check if a logger with this configuration has already been created, if so, return that logger 
+       instead of creating a new one"""
+    global CURRENT_LOGGER
+    global CURRENT_LOGGER_PARMS
+
+    if CURRENT_LOGGER and CURRENT_LOGGER_PARMS == (logging_config, overrides) and not overrides.get('force_create'):
+        return CURRENT_LOGGER
+    
+    first_entry_elts.append('Starting')
+    first_entry_struct = {}
+
     if overrides:
         first_entry_struct['overrides'] = overrides
 
@@ -136,4 +151,10 @@
     first_entry = '. '.join(first_entry_elts)
     log.info(first_entry, **first_entry_struct)
 
+    CURRENT_LOGGER = log
+    CURRENT_LOGGER_PARMS = (logging_config, overrides)
     return log
+
+if __name__ == '__main__':
+    l = create_logger({'logging': {'version': 2, 'loggers':{'':{'level': 'INFO'}}}}, level="INFO")
+    l.info("Test OK")

setup.py

diff --git a/setup.py b/setup.py
index 5913f8a..6ff2a91 100644
--- a/setup.py
+++ b/setup.py
@@ -33,7 +33,7 @@
       ],
       copyright='Open Networking Foundation',
       include_package_data=True,
-      install_requires=['structlog', 'logstash', 'colorama'],
+      install_requires=['structlog', 'python-logstash', 'colorama'],
       keywords=['multistructlog', 'structlog',
                 'multiple backends', 'xos logging']
       )