OpenCensus Runtime Context
The OpenCensus Runtime Context provides in-process context propagation. By default, thread local storage is used for Python 2.7, 3.4 and 3.5; contextvars is used for Python >= 3.6, which provides asyncio support.
This library is installed by default with opencensus, there is no need to install it explicitly.
In most cases context propagation happens automatically within a process, following the control flow of threads and asynchronous coroutines. The runtime context is a dictionary stored in a context variable when available, and in thread local storage otherwise.
There are cases where you may want to propagate the context explicitly:
Explicit Thread Creation
from threading import Thread from opencensus.common.runtime_context import RuntimeContext def work(name): # here you will get the context from the parent thread print(RuntimeContext) thread = Thread( # propagate context explicitly target=RuntimeContext.with_current_context(work), args=('foobar',), ) thread.start() thread.join()
from multiprocessing.dummy import Pool as ThreadPool from opencensus.common.runtime_context import RuntimeContext def work(name): # here you will get the context from the parent thread print(RuntimeContext) pool = ThreadPool(2) # propagate context explicitly pool.map(RuntimeContext.with_current_context(work), [ 'bear', 'cat', 'dog', 'horse', 'rabbit', ]) pool.close() pool.join()