wehub-resource-sync
31 lines
1.3 KiB
ReStructuredText
31 lines
1.3 KiB
ReStructuredText
Anti-pattern: Using global variables to share state between tasks and actors
|
||
============================================================================
|
||
|
||
**TLDR:** Don't use global variables to share state with tasks and actors. Instead, encapsulate the global variables in an actor and pass the actor handle to other tasks and actors.
|
||
|
||
Ray drivers, tasks and actors are running in
|
||
different processes, so they don’t share the same address space.
|
||
This means that if you modify global variables
|
||
in one process, changes are not reflected in other processes.
|
||
|
||
The solution is to use an actor's instance variables to hold the global state and pass the actor handle to places where the state needs to be modified or accessed.
|
||
Note that using class variables to manage state between instances of the same class is not supported.
|
||
Each actor instance is instantiated in its own process, so each actor will have its own copy of the class variables.
|
||
|
||
Code example
|
||
------------
|
||
|
||
**Anti-pattern:**
|
||
|
||
.. literalinclude:: ../doc_code/anti_pattern_global_variables.py
|
||
:language: python
|
||
:start-after: __anti_pattern_start__
|
||
:end-before: __anti_pattern_end__
|
||
|
||
**Better approach:**
|
||
|
||
.. literalinclude:: ../doc_code/anti_pattern_global_variables.py
|
||
:language: python
|
||
:start-after: __better_approach_start__
|
||
:end-before: __better_approach_end__
|