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node: refactor package node (#21105)

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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.
This commit is contained in:
rene
2020-08-03 19:40:46 +02:00
committed by GitHub
parent b2b14e6ce3
commit c0c01612e9
63 changed files with 2606 additions and 2887 deletions
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39
node/node_example_test.go
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@ -21,26 +21,20 @@ import (
"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
// 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.Service:
// - Protocols() []p2p.Protocol - devp2p protocols the service can communicate on
// - APIs() []rpc.API - api methods the service wants to expose on rpc channels
// 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 SampleService struct{}
type SampleLifecycle 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 (s *SampleLifecycle) Start() error { fmt.Println("Service starting..."); return nil }
func (s *SampleLifecycle) Stop() error { fmt.Println("Service stopping..."); return nil }
func ExampleService() {
func ExampleLifecycle() {
// Create a network node to run protocols with the default values.
stack, err := node.New(&node.Config{})
if err != nil {
@ -48,29 +42,18 @@ func ExampleService() {
}
defer stack.Close()
// 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)
}
// 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.Restart(); err != nil {
log.Fatalf("Failed to restart the protocol stack: %v", err)
}
if err := stack.Stop(); err != nil {
if err := stack.Close(); err != nil {
log.Fatalf("Failed to stop the protocol stack: %v", err)
}
// Output:
// Service starting...
// Service stopping...
// Service starting...
// Service stopping...
}