Intermediate LevelSystem Design & Architecture
How does the Leaky Bucket algorithm smooth traffic spikes in API Gateways?
❓ Interview Prompt: Explain Leaky Bucket Rate Limiting Algorithm, fixed output rate, FIFO queue buffer, smoothing bursty traffic, and HTTP 429 responses.
The Leaky Bucket Algorithm processes bursty incoming traffic to produce a smooth, constant output rate:
How It Works:
1
Incoming requests enter a FIFO queue (the "bucket").
2
Requests leak out of the bucket at a fixed, constant rate (e.g. 10 requests per second).
3
If the bucket overflows its maximum queue capacity, excess incoming requests are immediately rejected with '429 Too Many Requests'.
Code Implementation Example
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Leaky Bucket Traffic Smoothing Diagram:
[Bursty Requests: 100/sec] ──> ┌───────────────┐
│ Leaky Bucket │
└───────┬───────┘
│ (Fixed Leak Rate: 10/sec)
▼
[Backend Web Servers]💡Leaky Bucket converting bursty inputs into smooth constant outputs.
🎯 Interview Key Takeaway
Use the Leaky Bucket algorithm in API Gateways when downstream services require a smooth, non-bursty traffic flow.
#System Design#Leaky Bucket#Rate Limiting#Traffic Smoothing#Intermediate
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