An advanced set of semaphore Nodes for Node RED, with a dynamic fail-safe.
This is a set of Nodes for Node RED, that allows messages to be queued, and signalled to pass, once a message has reached the end of the flow. But at the same time, allowing an optional fail-safe, that can be controlled dynamically.
Furthermore, messages can be flagged to bypass the semaphore and 'sneak' past the messages waiting for the lock to be released.
This is achieved with either a single messge property, or a JSONata expression.
| Node | What's it for? |
|---|---|
| Semaphore Take | Queues and passes a message through when signalled (or when the optional fail-safe triggers) |
| Semaphore Release | Raises the signal to allow a message to pass |
| Semaphore FS Reset | Alters the current fail-safe time |
Semaphore Take and Semaphore FS Reset Optional Properties
| Property | What's it for? |
|---|---|
| smp_failsafeTimeout (number) (IN) | Overrides the default fail-safe time |
| smp_appliedFailsafe (number) (OUT) | The fail-safe time that was applied |
| smp_isFailsafe (boolean) (Semaphore Take only) (OUT) | If the release was due to a fail-safe condition |
Semaphore Release Optional Properties
| Property | What's it for? |
|---|---|
| reset (boolean) (IN) | Resets the queue state, and does not pass on the incoming msg |
| smp_reset (boolean) (IN) | Resets the queue state, and passes on the incoming msg |
Working in an enterprise environment, where strict API access is enforced/monitored, I needed to come up with a way to control processing. Having tried various nodes to accomplish this, i was either creating messy flows to try and emulate this approach, or using no longer maintained or buggy nodes.
MIT License
Copyright (c) 2023 Marcus Davies
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