Allow lock Redis from global detached context. #350
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Sometimes we need to perfrom operation on Redis from a background thread, for this we need to lock Redis. We can use `ThreadSafeContext` but we might prefer not to for the following reasons: 1. Creating a `ThreadSafeContext` is costly. 2. `ThreadSafeContext` which is not attached to a client do not have the module pointer and this could cause some operations to fail. The PR adds the ability to lock Redis using the global detached context. After locking, we will get `DetachedContextGuard` object which will automatically unlock Redis when dispose. `DetachedContextGuard` implements `Deref<Context>` so it can be used just like a regular `Context` to perform operations. **Notice: This context should not be use to return any replies!!!** Future improvement is to seperate contexts for command invocation and replies so those can not be accidently misstaken, notice that this PR do not introduce any regression regarding this topic because we already have this issue with `ThreadSafeContext`.
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I like the idea of having separate contexts that can never be used mistakenly. |
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Issue opened: #351 |
iddm
reviewed
Jun 20, 2023
iddm
approved these changes
Jun 20, 2023
1 task
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Sometimes we need to perform operation on Redis from a background thread, for this we need to lock Redis. We can use
ThreadSafeContextbut we might prefer not to for the following reasons:ThreadSafeContextis costly.ThreadSafeContextwhich is not attached to a client do not have the module pointer and this could cause some operations to fail.The PR adds the ability to lock Redis using the global detached context. After locking, we will get
DetachedContextGuardobject which will automatically unlock Redis when dispose.DetachedContextGuardimplementsDeref<Context>so it can be used just like a regularContextto perform operations.Notice: This context should not be use to return any replies!!!
Notice: Locking Redis by a thread that already owns the Redis lock is considered undefined behaviour!!!
Future improvement is to separate contexts for command invocation and replies so those can not be accidentally mistaken, notice that this PR do not introduce any regression regarding this topic because we already have this issue with
ThreadSafeContext.