Shared LRU TTL Cache for NetBox Custom Scripts #710

New Issue

MrUnknownDE · 2026-04-05T17:16:38+02:00

MrUnknownDE commented

2026-04-05 17:16:38 +02:00

Originally created by @SaschaSchwarzK on 12/18/2025

NetBox version

v4.4.8

Feature type

New functionality

Proposed functionality

Introduce a built‑in LRU‑style cache with TTL support that is accessible from custom scripts, event rules, and background worker processes in NetBox.
The cache should:

Use NetBox’s configured Django cache backend (django.core.cache).
Be shared across all worker processes and app instances.
Support:
- LRU eviction policy
- TTL (time‑to‑live) per entry
- Namespacing
- Stampede protection via Redis locking
Provide a Python API/decorator, e.g.:

@cache_function(namespace="vault", ttl=300)
def get_secret(device_id): ...

Use case

Custom scripts triggered via event rules often make external API calls—such as retrieving secrets from Vault or querying external inventory/monitoring systems.

In high‑volume environments with multiple workers, the same script may run simultaneously for many devices, causing:

Duplicate external API calls
Rate‑limit violations
Higher latency and unnecessary load on workers

A shared cross‑worker TTL cache prevents these issues by letting the first worker compute and cache a value, while all others reuse the cached data.

Database changes

No changes to PostgreSQL are required.
All cached data remains ephemeral and stored only in the configured cache backend.

External dependencies

A Django‑compatible cache backend (Redis/Valkey recommended)
Shared access for all app and worker instances
Redis locking support for stampede protection

*Originally created by @SaschaSchwarzK on 12/18/2025* ### NetBox version v4.4.8 ### Feature type New functionality ### Proposed functionality Introduce a built‑in **LRU‑style cache with TTL support** that is accessible from **custom scripts, event rules, and background worker processes** in NetBox. The cache should: - Use NetBox’s configured **Django cache backend** (`django.core.cache`). - Be **shared across all worker processes and app instances**. - Support: - **LRU eviction policy** - **TTL (time‑to‑live)** per entry - **Namespacing** - **Stampede protection** via Redis locking - Provide a Python API/decorator, e.g.: ```python @cache_function(namespace="vault", ttl=300) def get_secret(device_id): ... ``` ### Use case Custom scripts triggered via event rules often make external API calls—such as retrieving secrets from Vault or querying external inventory/monitoring systems. In high‑volume environments with multiple workers, the same script may run simultaneously for many devices, causing: - Duplicate external API calls - Rate‑limit violations - Higher latency and unnecessary load on workers A shared cross‑worker TTL cache prevents these issues by letting the first worker compute and cache a value, while all others reuse the cached data. ### Database changes No changes to PostgreSQL are required. All cached data remains ephemeral and stored only in the configured cache backend. ### External dependencies - A Django‑compatible cache backend (Redis/Valkey recommended) - Shared access for all app and worker instances - Redis locking support for stampede protection

MrUnknownDE closed this issue

2026-04-05 17:16:38 +02:00

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Reference: github/netbox#710