swarm

swarm is a simple benchmarking framework built upon gevent. It can be used to generate massive simultaneous and persistent TCP connections to a server, while each connection interacts with the server using your custom protocol.

swarm does not create any connections on startup, you have to telnet to it to control its behavior.

How to install

python setup.py install

How to use

1. Implement the protocol module for your server. This module should be consist of functions you want to use in the script descripted in step 2. swarm provides several examples in examples/protocol:

    # examples/protocols/durian.py
    from swarm.protocol import reply_parser_crlf
   
   
    def heartbeat(client):
        def make_request():
            return "heartbeat\r\n"
   
        client.send_for_reply(make_request(), reply_parser_crlf())
   
   
    def enter_chatroom(client):
        def make_request():
            return "enter_chatroom\r\n"
   
        client.send_for_reply(make_request(), reply_parser_crlf())
   
   
    def leave_chatroom(client):
        def make_request():
            return "leave_chatroom\r\n"
   
        client.send_for_reply(make_request(), reply_parser_crlf())
   
   
    def close_connection(client):
        client.close_connection()
   

2. Write a script (in yaml) that defines actions for each connection to perform in order. This script will be executed by every connection repeatedly. Also, under the examples directory, an example script using above custom protocol is provided.

    # examples/scripts/example.yml
    
    protocol: durian
    actions:
      - command: heartbeat
        args:
          uid: 123 
        rounds: [2, 10] 
        sleep_between_rounds: [1, 5]
        sleep_after_action: [1, 5]
   
      - command: create_chatroom
        args:
          uid: 123 
          rid: 7
        rounds: 1
        sleep_between_rounds: 0
        sleep_after_action: [1, 5]
   

3. Run swarm with your script (Check out swarm --help first).

    swarm --listen 127.0.0.1:8400 --server 127.0.0.1:8080 \
        --script /path/to/examples/scripts/example.yml \
        --protocol-dir /path/to/examples/protocols/
   

4. Use your favorite TCP client (nc, telnet etc.) to connect to swarm listening address, and then you will see what to do next.

    % telnet 127.0.0.1 8400
    laptop:notes:% telnet 127.0.0.1 8412
    Trying 127.0.0.1...
    Connected to 127.0.0.1.
    Escape character is '^]'.
   
        ===============================
        Welcome to Swarm Remote Console
        ===============================
        
    Usage:
    incr 1000\n -- Start 1000 new connections
    decr 100\n  -- Close 100 random connections
    stop\n      -- Stop swarm benchmarker remotely
    quit\n      -- Close this control session
    help\n      -- Help
   

5. Checkout the output of swarm. The running state will be printed periodically.

API

In order to provide the ability to communicate with your server though TCP connection for your protocol's implementation, swarm executes each action (the function defined in protocol module) with a instance of FakeClient as the first argument, which has the following network-relative methods:

• send_for_reply(request, reply_parser) - Send the request and wait for the reply.

  • request should be a string (binary or not) containing the whole request.

  • reply_parser should be a function object which is used to parse the reply. It tells swarm how much bytes of data left to read for this reply though its return value.

• send_noreply(request) - Send the request and no reply needed.

  • request should be a string (binary or not) containing the whole request.

• close_connection() - Just close the underlying TCP connection. swarm will create a new connection and start a new iteration for the script.

###Notice

• Don't do any blocking operations gevent does not support in your protocol. You've been warned.

Directives

Once your protocol module is ready, you can tell every connection how to act by writing a script.

You have to learn some yaml first, and then you can use the directives provided by swarm to make up your benchmark plan:

• protocol - protocol module name. The location of its parent directory is specified with command line option --protocol-dir of swarm.

• actions - array of actions. Each action object is consist of:

  • command - One of the functions from the protocol module.

  • args - Extra arguments (beside the instance of FakeClient) this command can accept.

  • rounds - How many rounds to execute for this action per iteration. This directive accepts both integer and two-elements array (swarm takes it as a range and select a integer in it randomly).

  • sleep_between_rounds - How many seconds to sleep between every round. This directive accepts both integer and two-elements array (swarm takes it as a range and select a integer in it randomly).

  • sleep_after_action - How many seconds to sleep when current action completed. This directive accepts both integer and two-elements array (swarm taks it as a range and select a integer in it randomly).

Tuning your OS

To reduce memory usage, swarm configures every connection with minimum value for send/receve buffer by default.

To increase concurrency of swarm, you still have to

• raise the open files limit,

• increase the system port range,

or swarm will fail you at some point. :)

TODO

Please do tell me what you need, my goddess.