Class: DeadBro::RedisSubscriber

Inherits:
Object
  • Object
show all
Defined in:
lib/dead_bro/redis_subscriber.rb

Constant Summary collapse

THREAD_LOCAL_KEY = 
:dead_bro_redis_events
MAX_TRACKED_EVENTS = 
1000

Class Method Summary collapse

Class Method Details

.build_event(name, data, duration_ms, start_offset_ms = nil) ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 256

def self.build_event(name, data, duration_ms, start_offset_ms = nil)
  cmd = extract_command(data)
  {
    event: name.to_s,
    command: cmd[:command],
    key: cmd[:key],
    args_count: cmd[:args_count],
    duration_ms: duration_ms,
    start_offset_ms: start_offset_ms,
    db: safe_db(data[:db])
  }
rescue
  nil
end

.extract_command(data) ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 271

def self.extract_command(data)
  return {command: nil, key: nil, args_count: nil} unless data.is_a?(Hash)

  parts = if data[:command]
    Array(data[:command]).map(&:to_s)
  elsif data[:commands]
    Array(data[:commands]).flatten.map(&:to_s)
  elsif data[:cmd]
    Array(data[:cmd]).map(&:to_s)
  else
    []
  end

  command_name = parts.first&.upcase
  key = parts[1]
  args_count = parts.length - 1 if parts.any?

  {
    command: safe_command(command_name),
    key: safe_key(key),
    args_count: args_count
  }
rescue
  {command: nil, key: nil, args_count: nil}
end

.install_notifications_subscription! ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 208

def self.install_notifications_subscription!
  # Try to subscribe to ActiveSupport::Notifications if available
  # This covers cases where other libraries emit redis.* events
  if defined?(ActiveSupport::Notifications)
    begin
      ActiveSupport::Notifications.subscribe(/\Aredis\..+\z/) do |name, started, finished, _unique_id, data|
        next unless Thread.current[THREAD_LOCAL_KEY]
        duration_ms = ((finished - started) * 1000.0).round(2)
        tracking_start = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
        start_offset_ms = tracking_start ? ((started - tracking_start) * 1000.0).round(2) : nil
        event = build_event(name, data, duration_ms, start_offset_ms)
        if event && should_continue_tracking?
          Thread.current[THREAD_LOCAL_KEY] << event
        end
      end
    rescue
    end
  end
end

.install_redis_client! ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 25

def self.install_redis_client!
  # Only instrument if Redis::Client actually has the call method
  # Check both public and private methods
  has_call = ::Redis::Client.method_defined?(:call, false) ||
    ::Redis::Client.private_method_defined?(:call, false)
  return unless has_call

  mod = Module.new do
    # Use method_missing alternative or alias_method pattern
    # We'll use prepend but make the method signature as flexible as possible
    def call(*args, &block)
      # Extract command from args - first arg is typically the command array
      command = args.first
      # Only track if thread-local storage is set up
      if Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] && !command.nil?
        record_redis_command(command) do
          super(*args, &block)
        end
      else
        # If not tracking, just pass through unchanged
        super
      end
    end

    def call_pipeline(pipeline)
      record_redis_pipeline(pipeline) do
        super
      end
    end

    def call_multi(multi)
      record_redis_multi(multi) do
        super
      end
    end

    private

    def record_redis_command(command)
      return yield unless Thread.current[RedisSubscriber::THREAD_LOCAL_KEY]

      wall_start = Time.now
      start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      error = nil
      begin
        result = yield
        result
      rescue Exception => e
        error = e
        raise
      ensure
        finish_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        duration_ms = ((finish_time - start_time) * 1000.0).round(2)

        begin
          cmd_info = extract_command_info(command)
          tracking_start = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
          start_offset_ms = tracking_start ? ((wall_start - tracking_start) * 1000.0).round(2) : nil
          event = {
            event: "redis.command",
            command: cmd_info[:command],
            key: cmd_info[:key],
            args_count: cmd_info[:args_count],
            duration_ms: duration_ms,
            start_offset_ms: start_offset_ms,
            db: safe_db(@db),
            error: error ? error.class.name : nil
          }

          if Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] && RedisSubscriber.should_continue_tracking?
            Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] << event
          end
        rescue
        end
      end
    end

    def record_redis_pipeline(pipeline)
      return yield unless Thread.current[RedisSubscriber::THREAD_LOCAL_KEY]

      wall_start = Time.now
      start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      begin
        result = yield
        result
      ensure
        finish_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        duration_ms = ((finish_time - start_time) * 1000.0).round(2)

        begin
          commands_count = pipeline.commands&.length || 0
          tracking_start = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
          start_offset_ms = tracking_start ? ((wall_start - tracking_start) * 1000.0).round(2) : nil
          event = {
            event: "redis.pipeline",
            commands_count: commands_count,
            duration_ms: duration_ms,
            start_offset_ms: start_offset_ms,
            db: safe_db(@db)
          }

          if Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] && RedisSubscriber.should_continue_tracking?
            Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] << event
          end
        rescue
        end
      end
    end

    def record_redis_multi(multi)
      return yield unless Thread.current[RedisSubscriber::THREAD_LOCAL_KEY]

      wall_start = Time.now
      start_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
      begin
        result = yield
        result
      ensure
        finish_time = Process.clock_gettime(Process::CLOCK_MONOTONIC)
        duration_ms = ((finish_time - start_time) * 1000.0).round(2)

        begin
          commands_count = multi.commands&.length || 0
          tracking_start = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
          start_offset_ms = tracking_start ? ((wall_start - tracking_start) * 1000.0).round(2) : nil
          event = {
            event: "redis.multi",
            commands_count: commands_count,
            duration_ms: duration_ms,
            start_offset_ms: start_offset_ms,
            db: safe_db(@db)
          }

          if Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] && RedisSubscriber.should_continue_tracking?
            Thread.current[RedisSubscriber::THREAD_LOCAL_KEY] << event
          end
        rescue
        end
      end
    end

    def extract_command_info(command)
      parts = Array(command).map(&:to_s)
      command_name = parts.first&.upcase
      key = parts[1]
      args_count = (parts.length > 1) ? parts.length - 1 : 0

      {
        command: safe_command(command_name),
        key: safe_key(key),
        args_count: args_count
      }
    rescue
      {command: nil, key: nil, args_count: nil}
    end

    def safe_command(cmd)
      return nil if cmd.nil?
      cmd.to_s[0, 20]
    rescue
      nil
    end

    def safe_key(key)
      return nil if key.nil?
      s = key.to_s
      (s.length > 200) ? s[0, 200] + "…" : s
    rescue
      nil
    end

    def safe_db(db)
      Integer(db)
    rescue
      nil
    end
  end

  ::Redis::Client.prepend(mod) unless ::Redis::Client.ancestors.include?(mod)
rescue
  # Redis::Client may not be available or may have different structure
end

.install_redis_instrumentation! ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 14

def self.install_redis_instrumentation!
  # Only instrument Redis::Client - this is where commands actually execute
  # Don't instrument Redis class as it has public methods with different signatures
  if defined?(::Redis::Client)
    install_redis_client!
  end

  # Also try ActiveSupport::Notifications if events are available
  install_notifications_subscription!
end

.safe_command(cmd) ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 297

def self.safe_command(cmd)
  return nil if cmd.nil?
  cmd.to_s[0, 20]
rescue
  nil
end

.safe_db(db) ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 312

def self.safe_db(db)
  Integer(db)
rescue
  nil
end

.safe_key(key) ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 304

def self.safe_key(key)
  return nil if key.nil?
  s = key.to_s
  (s.length > 200) ? s[0, 200] + "…" : s
rescue
  nil
end

.should_continue_tracking? ⇒ Boolean

Check if we should continue tracking based on count and time limits

Returns:

  • (Boolean) 


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# File 'lib/dead_bro/redis_subscriber.rb', line 239

def self.should_continue_tracking?
  events = Thread.current[THREAD_LOCAL_KEY]
  return false unless events

  # Check count limit
  return false if events.length >= MAX_TRACKED_EVENTS

  # Check time limit
  start_time = Thread.current[DeadBro::TRACKING_START_TIME_KEY]
  if start_time
    elapsed_seconds = Time.now - start_time
    return false if elapsed_seconds >= DeadBro::MAX_TRACKING_DURATION_SECONDS
  end

  true
end

.start_request_tracking ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 228

def self.start_request_tracking
  Thread.current[THREAD_LOCAL_KEY] = []
end

.stop_request_tracking ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 232

def self.stop_request_tracking
  events = Thread.current[THREAD_LOCAL_KEY]
  Thread.current[THREAD_LOCAL_KEY] = nil
  events || []
end

.subscribe! ⇒ Object 



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# File 'lib/dead_bro/redis_subscriber.rb', line 8

def self.subscribe!
  install_redis_instrumentation!
rescue
  # Never raise from instrumentation install
end