Rate Limiter

gistfile1.txt

#!/bin/bash

#class RateLimiter {
# public:
#     // rate is an integer num requests per second
#     RateLimiter(int rate) {
#     }
 
#     bool IsAllowed() {
#       //implement this
#     }
# }
# Allows 100/sec but also allows bursts of requests up to 150/sec
# Optimal solution: Use Token Bucket Alg https://en.wikipedia.org/wiki/Token_bucket
# This is not that:

MAX_THRESHOLD=100
BURST_THRESHOLD=150
STATE="./state.txt"
USER_PREV=0




is_allowed() {
  # if [ -z "$1" ]; then
  #   echo "missing arg"
  #   exit 1
  # fi


  NUMBER_OF_REQUESTS=$(cat "$STATE" | wc -l)
  NUMBER_OF_REQUESTS=$((NUMBER_OF_REQUESTS - USER_PREV))
  # echo "$NUMBER_OF_REQUESTS"
  if [[ "$NUMBER_OF_REQUESTS" -lt "$BURST_THRESHOLD" ]]; then
    if [ "$NUMBER_OF_REQUESTS"  -lt "$MAX_THRESHOLD" ]; then
      USER_PREV=0
    fi
    USER_PREV=$((NUMBER_OF_REQUESTS - MAX_THRESHOLD)) 
    echo "1"
    exit 0
  else
    echo "0"
  fi



  USER_PREV=0
}
# token bucket alg

for req in $(seq 1 100); do

  # echo "$RANDOM"
  MAX=$((1 + RANDOM % 150))
  echo "Req: $MAX"
  rm -rf "$STATE"
  touch "$STATE"
  for req in $(seq 1 $MAX); do
    echo "$req" >> "$STATE"
  done

  isAllowed=$(is_allowed)

  echo "is Allowed: $isAllowed"

done