go-pulse/node/node_example_test.go
rene c0c01612e9
node: refactor package node (#21105)
This PR significantly changes the APIs for instantiating Ethereum nodes in
a Go program. The new APIs are not backwards-compatible, but we feel that
this is made up for by the much simpler way of registering services on
node.Node. You can find more information and rationale in the design
document: https://gist.github.com/renaynay/5bec2de19fde66f4d04c535fd24f0775.

There is also a new feature in Node's Go API: it is now possible to
register arbitrary handlers on the user-facing HTTP server. In geth, this
facility is used to enable GraphQL.

There is a single minor change relevant for geth users in this PR: The
GraphQL API is no longer available separately from the JSON-RPC HTTP
server. If you want GraphQL, you need to enable it using the
./geth --http --graphql flag combination.

The --graphql.port and --graphql.addr flags are no longer available.
2020-08-03 19:40:46 +02:00

60 lines
2.1 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_test
import (
"fmt"
"log"
"github.com/ethereum/go-ethereum/node"
)
// SampleLifecycle 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.Lifecycle:
// - Start() error - method invoked when the node is ready to start the service
// - Stop() error - method invoked when the node terminates the service
type SampleLifecycle struct{}
func (s *SampleLifecycle) Start() error { fmt.Println("Service starting..."); return nil }
func (s *SampleLifecycle) Stop() error { fmt.Println("Service stopping..."); return nil }
func ExampleLifecycle() {
// 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)
}
defer stack.Close()
// Create and register a simple network Lifecycle.
service := new(SampleLifecycle)
stack.RegisterLifecycle(service)
// 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.Close(); err != nil {
log.Fatalf("Failed to stop the protocol stack: %v", err)
}
// Output:
// Service starting...
// Service stopping...
}