Official Go implementation of the Ethereum protocol
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go-ethereum/node/node_example_test.go

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// 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_test
import (
"fmt"
"log"
"github.com/ethereum/go-ethereum/node"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rpc"
)
// SampleService is a trivial network service that can be attached to a node for
// life cycle management.
//
// The following methods are needed to implement a node.Service:
// - Protocols() []p2p.Protocol - devp2p protocols the service can communicate on
// - APIs() []rpc.API - api methods the service wants to expose on rpc channels
// - Start() error - method invoked when the node is ready to start the service
// - Stop() error - method invoked when the node terminates the service
type SampleService struct{}
func (s *SampleService) Protocols() []p2p.Protocol { return nil }
func (s *SampleService) APIs() []rpc.API { return nil }
func (s *SampleService) Start(*p2p.Server) error { fmt.Println("Service starting..."); return nil }
func (s *SampleService) Stop() error { fmt.Println("Service stopping..."); return nil }
func ExampleService() {
cmd/geth: add --config file flag (#13875) * p2p/discover, p2p/discv5: add marshaling methods to Node * p2p/netutil: make Netlist decodable from TOML * common/math: encode nil HexOrDecimal256 as 0x0 * cmd/geth: add --config file flag * cmd/geth: add missing license header * eth: prettify Config again, fix tests * eth: use gasprice.Config instead of duplicating its fields * eth/gasprice: hide nil default from dumpconfig output * cmd/geth: hide genesis block in dumpconfig output * node: make tests compile * console: fix tests * cmd/geth: make TOML keys look exactly like Go struct fields * p2p: use discovery by default This makes the zero Config slightly more useful. It also fixes package node tests because Node detects reuse of the datadir through the NodeDatabase. * cmd/geth: make ethstats URL settable through config file * cmd/faucet: fix configuration * cmd/geth: dedup attach tests * eth: add comment for DefaultConfig * eth: pass downloader.SyncMode in Config This removes the FastSync, LightSync flags in favour of a more general SyncMode flag. * cmd/utils: remove jitvm flags * cmd/utils: make mutually exclusive flag error prettier It now reads: Fatal: flags --dev, --testnet can't be used at the same time * p2p: fix typo * node: add DefaultConfig, use it for geth * mobile: add missing NoDiscovery option * cmd/utils: drop MakeNode This exposed a couple of places that needed to be updated to use node.DefaultConfig. * node: fix typo * eth: make fast sync the default mode * cmd/utils: remove IPCApiFlag (unused) * node: remove default IPC path Set it in the frontends instead. * cmd/geth: add --syncmode * cmd/utils: make --ipcdisable and --ipcpath mutually exclusive * cmd/utils: don't enable WS, HTTP when setting addr * cmd/utils: fix --identity
8 years ago
// Create a network node to run protocols with the default values.
stack, err := node.New(&node.Config{})
if err != nil {
log.Fatalf("Failed to create network node: %v", err)
}
// Create and register a simple network service. This is done through the definition
// of a node.ServiceConstructor that will instantiate a node.Service. The reason for
// the factory method approach is to support service restarts without relying on the
// individual implementations' support for such operations.
constructor := func(context *node.ServiceContext) (node.Service, error) {
return new(SampleService), nil
}
if err := stack.Register(constructor); err != nil {
log.Fatalf("Failed to register service: %v", err)
}
// Boot up the entire protocol stack, do a restart and terminate
if err := stack.Start(); err != nil {
log.Fatalf("Failed to start the protocol stack: %v", err)
}
if err := stack.Restart(); err != nil {
log.Fatalf("Failed to restart the protocol stack: %v", err)
}
if err := stack.Stop(); err != nil {
log.Fatalf("Failed to stop the protocol stack: %v", err)
}
// Output:
// Service starting...
// Service stopping...
// Service starting...
// Service stopping...
}