path: root/p2p/simulations/events.go

// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package simulations

import (
    "fmt"
    "time"
)

// EventType is the type of event emitted by a simulation network
type EventType string

const (
    // EventTypeNode is the type of event emitted when a node is either
    // created, started or stopped
    EventTypeNode EventType = "node"

    // EventTypeConn is the type of event emitted when a connection is
    // is either established or dropped between two nodes
    EventTypeConn EventType = "conn"

    // EventTypeMsg is the type of event emitted when a p2p message it
    // sent between two nodes
    EventTypeMsg EventType = "msg"
)

// Event is an event emitted by a simulation network
type Event struct {
    // Type is the type of the event
    Type EventType `json:"type"`

    // Time is the time the event happened
    Time time.Time `json:"time"`

    // Control indicates whether the event is the result of a controlled
    // action in the network
    Control bool `json:"control"`

    // Node is set if the type is EventTypeNode
    Node *Node `json:"node,omitempty"`

    // Conn is set if the type is EventTypeConn
    Conn *Conn `json:"conn,omitempty"`

    // Msg is set if the type is EventTypeMsg
    Msg *Msg `json:"msg,omitempty"`

    //Optionally provide data (currently for simulation frontends only)
    Data interface{} `json:"data"`
}

// NewEvent creates a new event for the given object which should be either a
// Node, Conn or Msg.
//
// The object is copied so that the event represents the state of the object
// when NewEvent is called.
func NewEvent(v interface{}) *Event {
    event := &Event{Time: time.Now()}
    switch v := v.(type) {
    case *Node:
        event.Type = EventTypeNode
        node := *v
        event.Node = &node
    case *Conn:
        event.Type = EventTypeConn
        conn := *v
        event.Conn = &conn
    case *Msg:
        event.Type = EventTypeMsg
        msg := *v
        event.Msg = &msg
    default:
        panic(fmt.Sprintf("invalid event type: %T", v))
    }
    return event
}

// ControlEvent creates a new control event
func ControlEvent(v interface{}) *Event {
    event := NewEvent(v)
    event.Control = true
    return event
}

// String returns the string representation of the event
func (e *Event) String() string {
    switch e.Type {
    case EventTypeNode:
        return fmt.Sprintf("<node-event> id: %s up: %t", e.Node.ID().TerminalString(), e.Node.Up())
    case EventTypeConn:
        return fmt.Sprintf("<conn-event> nodes: %s->%s up: %t", e.Conn.One.TerminalString(), e.Conn.Other.TerminalString(), e.Conn.Up)
    case EventTypeMsg:
        return fmt.Sprintf("<msg-event> nodes: %s->%s proto: %s, code: %d, received: %t", e.Msg.One.TerminalString(), e.Msg.Other.TerminalString(), e.Msg.Protocol, e.Msg.Code, e.Msg.Received)
    default:
        return ""
    }
}