68 lines
2.6 KiB
Go
68 lines
2.6 KiB
Go
// Copyright 2015 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 node
|
|
|
|
import (
|
|
"path/filepath"
|
|
|
|
"github.com/ethereum/go-ethereum/ethdb"
|
|
"github.com/ethereum/go-ethereum/event"
|
|
"github.com/ethereum/go-ethereum/p2p"
|
|
)
|
|
|
|
// ServiceContext is a collection of service independent options inherited from
|
|
// the protocol stack, that is passed to all constructors to be optionally used;
|
|
// as well as utility methods to operate on the service environment.
|
|
type ServiceContext struct {
|
|
dataDir string // Data directory for protocol persistence
|
|
EventMux *event.TypeMux // Event multiplexer used for decoupled notifications
|
|
}
|
|
|
|
// Database opens an existing database with the given name (or creates one if no
|
|
// previous can be found) from within the node's data directory. If the node is
|
|
// an ephemeral one, a memory database is returned.
|
|
func (ctx *ServiceContext) Database(name string, cache int) (ethdb.Database, error) {
|
|
if ctx.dataDir == "" {
|
|
return ethdb.NewMemDatabase()
|
|
}
|
|
return ethdb.NewLDBDatabase(filepath.Join(ctx.dataDir, name), cache)
|
|
}
|
|
|
|
// ServiceConstructor is the function signature of the constructors needed to be
|
|
// registered for service instantiation.
|
|
type ServiceConstructor func(ctx *ServiceContext) (Service, error)
|
|
|
|
// Service is an individual protocol that can be registered into a node.
|
|
//
|
|
// Notes:
|
|
// - Service life-cycle management is delegated to the node. The service is
|
|
// allowed to initialize itself upon creation, but no goroutines should be
|
|
// spun up outside of the Start method.
|
|
// - Restart logic is not required as the node will create a fresh instance
|
|
// every time a service is started.
|
|
type Service interface {
|
|
// Protocol retrieves the P2P protocols the service wishes to start.
|
|
Protocols() []p2p.Protocol
|
|
|
|
// Start spawns any goroutines required by the service.
|
|
Start() error
|
|
|
|
// Stop terminates all goroutines belonging to the service, blocking until they
|
|
// are all terminated.
|
|
Stop() error
|
|
}
|