Class: ThrottleMachines::Storage::Redis

Inherits:
Base
  • Object
show all
Defined in:
lib/throttle_machines/storage/redis.rb

Constant Summary collapse

LUA_SCRIPTS_DIR =

Load Lua scripts from files

File.expand_path('redis', __dir__)
GCRA_SCRIPT = 
File.read(File.join(LUA_SCRIPTS_DIR, 'gcra.lua'))
TOKEN_BUCKET_SCRIPT = 
File.read(File.join(LUA_SCRIPTS_DIR, 'token_bucket.lua'))
PEEK_GCRA_SCRIPT = 
File.read(File.join(LUA_SCRIPTS_DIR, 'peek_gcra.lua'))
PEEK_TOKEN_BUCKET_SCRIPT = 
File.read(File.join(LUA_SCRIPTS_DIR, 'peek_token_bucket.lua'))
INCREMENT_COUNTER_SCRIPT = 
File.read(File.join(LUA_SCRIPTS_DIR, 'increment_counter.lua'))

Instance Method Summary collapse

Methods inherited from Base

#with_timeout

Constructor Details

#initialize(options = {}) ⇒ Redis

Breaker scripts removed: breaker state is owned by BreakerMachines



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# File 'lib/throttle_machines/storage/redis.rb', line 16

def initialize(options = {})
  super
  @redis = options[:redis] || options[:client] || options[:pool]
  @prefix = options[:prefix] || 'throttle:'

  # Cache scripts to avoid repeated script loads
  @gcra_sha = nil
  @token_bucket_sha = nil
  @peek_gcra_sha = nil
  @peek_token_bucket_sha = nil

  # Validate Redis connection
  validate_redis_connection!
end

Instance Method Details

#check_gcra_limit(key, emission_interval, delay_tolerance, ttl) ⇒ Object

GCRA operations (atomic via Lua)



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# File 'lib/throttle_machines/storage/redis.rb', line 58

def check_gcra_limit(key, emission_interval, delay_tolerance, ttl)
  ensure_gcra_script_loaded!

  result = with_redis do |redis|
    redis.evalsha(
      @gcra_sha,
      keys: [prefixed(key)],
      argv: [emission_interval, delay_tolerance, ttl, current_time]
    )
  end

  allowed = result[0] == 1
  tat = result[1]
  now = current_time

  {
    allowed: allowed,
    retry_after: allowed ? 0 : (tat - now - delay_tolerance),
    tat: tat
  }
rescue ::Redis::CommandError => e
  raise unless e.message.include?('NOSCRIPT')

  @gcra_sha = nil
  retry
end

#check_token_bucket(key, capacity, refill_rate, ttl) ⇒ Object

Token bucket operations (atomic via Lua)



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# File 'lib/throttle_machines/storage/redis.rb', line 86

def check_token_bucket(key, capacity, refill_rate, ttl)
  ensure_token_bucket_script_loaded!

  result = with_redis do |redis|
    redis.evalsha(
      @token_bucket_sha,
      keys: [prefixed(key)],
      argv: [capacity, refill_rate, ttl, current_time]
    )
  end

  allowed = result[0] == 1
  tokens = result[1]

  {
    allowed: allowed,
    retry_after: allowed ? 0 : (1 - tokens) / refill_rate,
    tokens_remaining: tokens.floor
  }
rescue ::Redis::CommandError => e
  raise unless e.message.include?('NOSCRIPT')

  @token_bucket_sha = nil
  retry
end

#clear(pattern = nil) ⇒ Object

Utility operations



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# File 'lib/throttle_machines/storage/redis.rb', line 169

def clear(pattern = nil)
  # Use SCAN instead of KEYS to avoid blocking in production
  cursor = '0'
  scan_pattern = pattern ? prefixed(pattern) : "#{@prefix}*"

  with_redis do |redis|
    loop do
      cursor, keys = redis.scan(cursor, match: scan_pattern, count: 100)
      redis.del(*keys) unless keys.empty?
      break if cursor == '0'
    end
  end
end

#get_counter(key, window) ⇒ Object 



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# File 'lib/throttle_machines/storage/redis.rb', line 41

def get_counter(key, window)
  window_key = prefixed("#{key}:#{window}")
  with_redis { |r| (r.get(window_key) || 0).to_i }
end

#get_counter_ttl(key, window) ⇒ Object 



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# File 'lib/throttle_machines/storage/redis.rb', line 46

def get_counter_ttl(key, window)
  window_key = prefixed("#{key}:#{window}")
  ttl = with_redis { |r| r.ttl(window_key) }
  [ttl, 0].max
end

#healthy? ⇒ Boolean

Returns:



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# File 'lib/throttle_machines/storage/redis.rb', line 183

def healthy?
  with_redis { |r| r.ping == 'PONG' }
rescue StandardError
  false
end

#increment_counter(key, window, amount = 1) ⇒ Object

Rate limiting operations



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# File 'lib/throttle_machines/storage/redis.rb', line 32

def increment_counter(key, window, amount = 1)
  window_key = prefixed("#{key}:#{window}")

  # Use Lua script for atomic increment with TTL
  with_redis do |redis|
    redis.eval(INCREMENT_COUNTER_SCRIPT, keys: [window_key], argv: [amount, window.to_i])
  end
end

#peek_gcra_limit(key, emission_interval, delay_tolerance) ⇒ Object

Peek methods for non-consuming checks



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# File 'lib/throttle_machines/storage/redis.rb', line 113

def peek_gcra_limit(key, emission_interval, delay_tolerance)
  ensure_peek_gcra_script_loaded!

  result = with_redis do |redis|
    redis.evalsha(
      @peek_gcra_sha,
      keys: [prefixed(key)],
      argv: [emission_interval, delay_tolerance, current_time]
    )
  end

  allowed = result[0] == 1
  tat = result[1]
  now = current_time

  {
    allowed: allowed,
    retry_after: allowed ? 0 : (tat - now - delay_tolerance),
    tat: tat
  }
rescue ::Redis::CommandError => e
  raise unless e.message.include?('NOSCRIPT')

  @peek_gcra_sha = nil
  retry
end

#peek_token_bucket(key, capacity, refill_rate) ⇒ Object 



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# File 'lib/throttle_machines/storage/redis.rb', line 140

def peek_token_bucket(key, capacity, refill_rate)
  ensure_peek_token_bucket_script_loaded!

  result = with_redis do |redis|
    redis.evalsha(
      @peek_token_bucket_sha,
      keys: [prefixed(key)],
      argv: [capacity, refill_rate, current_time]
    )
  end

  allowed = result[0] == 1
  tokens_remaining = result[1]

  {
    allowed: allowed,
    retry_after: allowed ? 0 : (1 - tokens_remaining) / refill_rate,
    tokens_remaining: tokens_remaining.floor
  }
rescue ::Redis::CommandError => e
  raise unless e.message.include?('NOSCRIPT')

  @peek_token_bucket_sha = nil
  retry
end

#reset_counter(key, window) ⇒ Object 



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# File 'lib/throttle_machines/storage/redis.rb', line 52

def reset_counter(key, window)
  window_key = prefixed("#{key}:#{window}")
  with_redis { |r| r.del(window_key) }
end