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Diffstat (limited to 'node/node_example_test.go')
| -rw-r--r-- | node/node_example_test.go | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/node/node_example_test.go b/node/node_example_test.go new file mode 100644 index 000000000..f2bd014b0 --- /dev/null +++ b/node/node_example_test.go @@ -0,0 +1,87 @@ +// 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/p2p/discover" +) + +// 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 +// - 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) Start() error { fmt.Println("Sample service starting..."); return nil } +func (s *SampleService) Stop() error { fmt.Println("Sample service stopping..."); return nil } + +func ExampleUsage() { + // Create a network node to run protocols with the default values. The below list + // is only used to display each of the configuration options. All of these could + // have been ommited if the default behavior is desired. + nodeConfig := &node.Config{ + DataDir: "", // Empty uses ephemeral storage + PrivateKey: nil, // Nil generates a node key on the fly + Name: "", // Any textual node name is allowed + NoDiscovery: false, // Can disable discovering remote nodes + BootstrapNodes: []*discover.Node{}, // List of bootstrap nodes to use + ListenAddr: ":0", // Network interface to listen on + NAT: nil, // UPnP port mapper to use for crossing firewalls + Dialer: nil, // Custom dialer to use for establishing peer connections + NoDial: false, // Can prevent this node from dialing out + MaxPeers: 0, // Number of peers to allow + MaxPendingPeers: 0, // Number of peers allowed to handshake concurrently + } + stack, err := node.New(nodeConfig) + 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("my sample service", 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: + // Sample service starting... + // Sample service stopping... + // Sample service starting... + // Sample service stopping... +} |