Thread local example

thread_local.py

# solom/__init__.py
THREAD_LOCAL = threading.local()


# In some pecan helper module...
def before_hook(self):
    # Use thread-local storage so we don't have to 
    # add two extra params to virtuall every single 
    # function in our app!
    solum.THREAD_LOCAL.ctx = context.RequestContext(...)
    solum.THREAD_LOCAL.trace = ApiTrace()


# Meanwhile...
def my_cool_function(self):
      # We can add utils to reduce the amount of 
      # typing you have to do, but this would be 
      # the underlying interface...

      trace = solum.THREAD_LOCAL.trace

    # Stores under { ... "my_cool_function" : { "pulled_hash": github_hash } ... }
    trace.user(pulled_hash=github_hash)
    trace.support(useful={...}, json_serializable=[...])

    #....

    # We can consider creating a very thin adapter on top of oslo logging to DRY this up.
    LOG.info('Doing this and that now...', 
             context=solum.THREAD_LOCAL.ctx, extra=solum.THREAD_LOCAL.trace)

    # Another possibility
    LOG.info('Doing this and that now...', *solum.log_kwargs())


def another_function(self):
    try:
        # ...
    except Exception as ex:
        # Yah, I get the trace info from my_cool_function here. In the case
        # that this error was in part caused by a side-affect of something
        # that my_cool_function did, we will want that other info.
        LOG.exception(ex, *solum.log_kwargs())