vmpooler/lib/vmpooler/api/rate_limiter.rb

116 lines
3.9 KiB
Ruby

# frozen_string_literal: true
module Vmpooler
class API
# Rate limiter middleware to protect against abuse
# Uses Redis to track request counts per IP and token
class RateLimiter
DEFAULT_LIMITS = {
global_per_ip: { limit: 100, period: 60 }, # 100 requests per minute per IP
authenticated: { limit: 500, period: 60 }, # 500 requests per minute with token
vm_creation: { limit: 20, period: 60 }, # 20 VM creations per minute
vm_deletion: { limit: 50, period: 60 } # 50 VM deletions per minute
}.freeze
def initialize(app, redis, config = {})
@app = app
@redis = redis
@config = DEFAULT_LIMITS.merge(config[:rate_limits] || {})
@enabled = config.fetch(:rate_limiting_enabled, true)
end
def call(env)
return @app.call(env) unless @enabled
request = Rack::Request.new(env)
client_id = identify_client(request)
endpoint_type = classify_endpoint(request)
# Check rate limits
return rate_limit_response(client_id, endpoint_type) if rate_limit_exceeded?(client_id, endpoint_type, request)
# Track the request
increment_request_count(client_id, endpoint_type)
@app.call(env)
end
private
def identify_client(request)
# Prioritize token-based identification for authenticated requests
token = request.env['HTTP_X_AUTH_TOKEN']
return "token:#{token}" if token && !token.empty?
# Fall back to IP address
ip = request.ip || request.env['REMOTE_ADDR'] || 'unknown'
"ip:#{ip}"
end
def classify_endpoint(request)
path = request.path
method = request.request_method
return :vm_creation if method == 'POST' && path.include?('/vm')
return :vm_deletion if method == 'DELETE' && path.include?('/vm')
return :authenticated if request.env['HTTP_X_AUTH_TOKEN']
:global_per_ip
end
def rate_limit_exceeded?(client_id, endpoint_type, _request)
limit_config = @config[endpoint_type] || @config[:global_per_ip]
key = "vmpooler__ratelimit__#{endpoint_type}__#{client_id}"
current_count = @redis.get(key).to_i
current_count >= limit_config[:limit]
rescue StandardError => e
# If Redis fails, allow the request through (fail open)
warn "Rate limiter Redis error: #{e.message}"
false
end
def increment_request_count(client_id, endpoint_type)
limit_config = @config[endpoint_type] || @config[:global_per_ip]
key = "vmpooler__ratelimit__#{endpoint_type}__#{client_id}"
@redis.pipelined do |pipeline|
pipeline.incr(key)
pipeline.expire(key, limit_config[:period])
end
rescue StandardError => e
# Log error but don't fail the request
warn "Rate limiter increment error: #{e.message}"
end
def rate_limit_response(client_id, endpoint_type)
limit_config = @config[endpoint_type] || @config[:global_per_ip]
key = "vmpooler__ratelimit__#{endpoint_type}__#{client_id}"
begin
ttl = @redis.ttl(key)
rescue StandardError
ttl = limit_config[:period]
end
headers = {
'Content-Type' => 'application/json',
'X-RateLimit-Limit' => limit_config[:limit].to_s,
'X-RateLimit-Remaining' => '0',
'X-RateLimit-Reset' => (Time.now.to_i + ttl).to_s,
'Retry-After' => ttl.to_s
}
body = JSON.pretty_generate({
'ok' => false,
'error' => 'Rate limit exceeded',
'limit' => limit_config[:limit],
'period' => limit_config[:period],
'retry_after' => ttl
})
[429, headers, [body]]
end
end
end
end