Added four new internal signals: STOP_FABRIC_SIGNAL, STOP_ACTIVE_OBJECT_SIGNAL, SUBSCRIBE_META_SIGNAL, PUBLISH_META_SIGNAL. These signals used to be created by the active object, but they have been moved into the event.py class, so that signal catching globs can be supported by miros.
Writes to Python print are not thread safe. Before this release the default behavior of live_spy and live_trace wrote out to python's print function directly. This live instrumentation could cause an io-block and a resulting run time error. I fixed this threading issue by changing the miros active objects to write their live stream messages through a dedicated instrumentation thread. This thread ensures that only one thing gets to print at a time. Also, the active object now provides a thread safe version of print which uses the instrumentation thread.
Miros provides the user with a way to over-write how their live trace and live spy streams are written. The thread managing the live stream watches a queue, which contains 0 or more Instrumentation named tuples. An Instrumentation named tuple has a fn and a content element. The fn describes the way the content is intended to be printed, so that the register_live_spy_callback and register_live_trace_callback features will continue to work. The user can change "how" their instrumentation stream will be represented, but the function-they-provide-to-do-this-with: fn, must be protected within a thread.
Since there can be many active objects which all want to print their live instrumentation information at the same time, but only one instrumentation thread handler, I made the class which provides the instrumentation threading a singleton. The class which provides the instrumentation threading is called InstrumentationWriterClass, and it is turned into the singleton InstrumentationWriter by the SingletonDectorator class. When an active object is being constructed it creates an InstrumentationWriter. If a previously build active object has already done this, a reference to the previously created InstrumentedWriter is returned. Then the instrumentation writing thread is started if it hasn't been started already.