Class: ActiveRecordApi::Request::TokenCache

Inherits:
Object
  • Object
show all
Includes:
ActiveAttr::Model
Defined in:
lib/active_record_api/request/token_cache.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#debug ⇒ Object

Returns the value of attribute debug.



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# File 'lib/active_record_api/request/token_cache.rb', line 6

def debug
  @debug
end

Instance Method Details

#acquire_lock ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 88

def acquire_lock
  @redis_client.set 'auth_token_lock', unique_key, nx: true, ex: 8
  current_lock_value = @redis_client.get 'auth_token_lock'
  debug_log "#{current_lock_value} == #{unique_key}"
  current_lock_value == unique_key
end

#debug_log(message) ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 84

def debug_log(message)
  Rails.logger.info message if debug && defined? Rails
end

#fetch_token(token_proc) ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 19

def fetch_token(token_proc)
  retrieve_token_from_redis(token_proc)
end

#flush ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 8

def flush
  return unless defined? AUTH_REDIS_POOL
  debug_log 'flushing token cache'
  AUTH_REDIS_POOL.with do |client|
    @redis_client = client
    @redis_client.del('auth_token')
    release_lock
  end
  debug_log 'token cache has been flushed'
end

#redis_session ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 67

def redis_session
  if redis_session_impossible?
    debug_log 'Redis session environment variables not present.'
    return nil
  end

  @redis_session ||= Redis.new({ url: "redis://#{ENV['REDIS_SESSION_HOST']}", db: ENV['REDIS_SESSION'] })
end

#redis_session_impossible? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record_api/request/token_cache.rb', line 62

def redis_session_impossible?
  return true unless defined? Redis
  ENV['REDIS_SESSION_HOST'].nil? || ENV['REDIS_SESSION'].nil?
end

#release_lock ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 95

def release_lock
  @redis_client.del 'auth_token_lock'
end

#retrieve_token_from_redis(token_proc) ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 23

def retrieve_token_from_redis(token_proc)
  debug_log 'looking for token in cache'
  unless defined? AUTH_REDIS_POOL
    debug_log 'no auth redis pool. getting new token'
    token = token_proc.call
    raise "no token returned! #{token}" if token.nil?
    return token
  end
  AUTH_REDIS_POOL.with do |client|
    @redis_client = client
    @token = nil
    @retry = 0
    while @token.nil? && @retry < 5
      @token = @redis_client.get('auth_token')
      debug_log "retry ##{@retry}"
      debug_log "found token: #{@token}"
      @retry += 1
      if @token.nil? || session_missing_for?(@token)
        if acquire_lock
          begin
            debug_log 'acquired lock and fetching token for cache'
            @token = token_proc.call
            raise "no token returned! #{@token}" if @token.nil?
            @redis_client.set 'auth_token', @token
          ensure
            debug_log 'releasing lock'
            release_lock
          end
        else
          debug_log 'waiting for token to be cached'
          sleep 3
        end
      end
    end
  end
  raise "no token found after waiting #{@retry} times" if @token.nil?
  @token
end

#session_missing_for?(token) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/active_record_api/request/token_cache.rb', line 76

def session_missing_for?(token)
  return false if redis_session.nil?
  session = (redis_session.send(:get, token) if redis_session.respond_to?(:get))
  debug_log("Session located for token #{token}") unless session.nil?
  debug_log("Session could not be located for token #{token}") if session.nil?
  session.nil?
end

#unique_key ⇒ Object 



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# File 'lib/active_record_api/request/token_cache.rb', line 99

def unique_key
  @unique_key ||= rand.to_s
end