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-rw-r--r--node/node.go124
-rw-r--r--node/node_example_test.go12
-rw-r--r--node/node_test.go54
-rw-r--r--node/service.go35
-rw-r--r--node/service_test.go54
5 files changed, 223 insertions, 56 deletions
diff --git a/node/node.go b/node/node.go
index ad4e69414..023f77403 100644
--- a/node/node.go
+++ b/node/node.go
@@ -21,6 +21,7 @@ import (
"errors"
"os"
"path/filepath"
+ "reflect"
"sync"
"syscall"
@@ -40,14 +41,17 @@ var (
// Node represents a P2P node into which arbitrary services might be registered.
type Node struct {
- datadir string // Path to the currently used data directory
- config *p2p.Server // Configuration of the underlying P2P networking layer
- stack map[string]ServiceConstructor // Protocol stack registered into this node
- emux *event.TypeMux // Event multiplexer used between the services of a stack
+ datadir string // Path to the currently used data directory
+ eventmux *event.TypeMux // Event multiplexer used between the services of a stack
- running *p2p.Server // Currently running P2P networking layer
- services map[string]Service // Currently running services
+ serverConfig *p2p.Server // Configuration of the underlying P2P networking layer
+ server *p2p.Server // Currently running P2P networking layer
+ serviceIndex map[string]ServiceConstructor // Set of services currently registered in the node
+ serviceOrder []string // Service construction order to handle dependencies
+ services map[string]Service // Currently running services
+
+ stop chan struct{} // Channel to wait for termination notifications
lock sync.RWMutex
}
@@ -66,7 +70,7 @@ func New(conf *Config) (*Node, error) {
}
return &Node{
datadir: conf.DataDir,
- config: &p2p.Server{
+ serverConfig: &p2p.Server{
PrivateKey: conf.NodeKey(),
Name: conf.Name,
Discovery: !conf.NoDiscovery,
@@ -81,8 +85,9 @@ func New(conf *Config) (*Node, error) {
MaxPeers: conf.MaxPeers,
MaxPendingPeers: conf.MaxPendingPeers,
},
- stack: make(map[string]ServiceConstructor),
- emux: new(event.TypeMux),
+ serviceIndex: make(map[string]ServiceConstructor),
+ serviceOrder: []string{},
+ eventmux: new(event.TypeMux),
}, nil
}
@@ -92,14 +97,15 @@ func (n *Node) Register(id string, constructor ServiceConstructor) error {
defer n.lock.Unlock()
// Short circuit if the node is running or if the id is taken
- if n.running != nil {
+ if n.server != nil {
return ErrNodeRunning
}
- if _, ok := n.stack[id]; ok {
+ if _, ok := n.serviceIndex[id]; ok {
return ErrServiceRegistered
}
// Otherwise register the service and return
- n.stack[id] = constructor
+ n.serviceOrder = append(n.serviceOrder, id)
+ n.serviceIndex[id] = constructor
return nil
}
@@ -111,14 +117,20 @@ func (n *Node) Unregister(id string) error {
defer n.lock.Unlock()
// Short circuit if the node is running, or if the service is unknown
- if n.running != nil {
+ if n.server != nil {
return ErrNodeRunning
}
- if _, ok := n.stack[id]; !ok {
+ if _, ok := n.serviceIndex[id]; !ok {
return ErrServiceUnknown
}
// Otherwise drop the service and return
- delete(n.stack, id)
+ delete(n.serviceIndex, id)
+ for i, service := range n.serviceOrder {
+ if service == id {
+ n.serviceOrder = append(n.serviceOrder[:i], n.serviceOrder[i+1:]...)
+ break
+ }
+ }
return nil
}
@@ -128,19 +140,27 @@ func (n *Node) Start() error {
defer n.lock.Unlock()
// Short circuit if the node's already running
- if n.running != nil {
+ if n.server != nil {
return ErrNodeRunning
}
// Otherwise copy and specialize the P2P configuration
running := new(p2p.Server)
- *running = *n.config
+ *running = *n.serverConfig
- ctx := &ServiceContext{
- dataDir: n.datadir,
- EventMux: n.emux,
- }
services := make(map[string]Service)
- for id, constructor := range n.stack {
+ for _, id := range n.serviceOrder {
+ constructor := n.serviceIndex[id]
+
+ // Create a new context for the particular service
+ ctx := &ServiceContext{
+ datadir: n.datadir,
+ services: make(map[string]Service),
+ EventMux: n.eventmux,
+ }
+ for id, s := range services { // copy needed for threaded access
+ ctx.services[id] = s
+ }
+ // Construct and save the service
service, err := constructor(ctx)
if err != nil {
return err
@@ -161,10 +181,12 @@ func (n *Node) Start() error {
started := []string{}
for id, service := range services {
// Start the next service, stopping all previous upon failure
- if err := service.Start(); err != nil {
+ if err := service.Start(running); err != nil {
for _, id := range started {
services[id].Stop()
}
+ running.Stop()
+
return err
}
// Mark the service started for potential cleanup
@@ -172,7 +194,8 @@ func (n *Node) Start() error {
}
// Finish initializing the startup
n.services = services
- n.running = running
+ n.server = running
+ n.stop = make(chan struct{})
return nil
}
@@ -184,7 +207,7 @@ func (n *Node) Stop() error {
defer n.lock.Unlock()
// Short circuit if the node's not running
- if n.running == nil {
+ if n.server == nil {
return ErrNodeStopped
}
// Otherwise terminate all the services and the P2P server too
@@ -196,10 +219,11 @@ func (n *Node) Stop() error {
failure.Services[id] = err
}
}
- n.running.Stop()
+ n.server.Stop()
n.services = nil
- n.running = nil
+ n.server = nil
+ close(n.stop)
if len(failure.Services) > 0 {
return failure
@@ -207,6 +231,19 @@ func (n *Node) Stop() error {
return nil
}
+// Wait blocks the thread until the node is stopped. If the node is not running
+// at the time of invocation, the method immediately returns.
+func (n *Node) Wait() {
+ n.lock.RLock()
+ if n.server == nil {
+ return
+ }
+ stop := n.stop
+ n.lock.RUnlock()
+
+ <-stop
+}
+
// Restart terminates a running node and boots up a new one in its place. If the
// node isn't running, an error is returned.
func (n *Node) Restart() error {
@@ -226,20 +263,45 @@ func (n *Node) Server() *p2p.Server {
n.lock.RLock()
defer n.lock.RUnlock()
- return n.running
+ return n.server
}
-// Service retrieves a currently running services registered under a given id.
+// Service retrieves a currently running service registered under a given id.
func (n *Node) Service(id string) Service {
n.lock.RLock()
defer n.lock.RUnlock()
- if n.services == nil {
+ // Short circuit if the node's not running
+ if n.server == nil {
return nil
}
return n.services[id]
}
+// SingletonService retrieves a currently running service using a specific type
+// implementing the Service interface. This is a utility function for scenarios
+// where it is known that only one instance of a given service type is running,
+// allowing to access services without needing to know their specific id with
+// which they were registered. Note, this method uses reflection, so do not run
+// in a tight loop.
+func (n *Node) SingletonService(service interface{}) (string, error) {
+ n.lock.RLock()
+ defer n.lock.RUnlock()
+
+ // Short circuit if the node's not running
+ if n.server == nil {
+ return "", ErrServiceUnknown
+ }
+ // Otherwise try to find the service to return
+ for id, running := range n.services {
+ if reflect.TypeOf(running) == reflect.ValueOf(service).Elem().Type() {
+ reflect.ValueOf(service).Elem().Set(reflect.ValueOf(running))
+ return id, nil
+ }
+ }
+ return "", ErrServiceUnknown
+}
+
// DataDir retrieves the current datadir used by the protocol stack.
func (n *Node) DataDir() string {
return n.datadir
@@ -248,5 +310,5 @@ func (n *Node) DataDir() string {
// EventMux retrieves the event multiplexer used by all the network services in
// the current protocol stack.
func (n *Node) EventMux() *event.TypeMux {
- return n.emux
+ return n.eventmux
}
diff --git a/node/node_example_test.go b/node/node_example_test.go
index f2bd014b0..898d4f5bc 100644
--- a/node/node_example_test.go
+++ b/node/node_example_test.go
@@ -35,8 +35,8 @@ import (
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 (s *SampleService) Start(*p2p.Server) error { fmt.Println("Service starting..."); return nil }
+func (s *SampleService) Stop() error { fmt.Println("Service stopping..."); return nil }
func ExampleUsage() {
// Create a network node to run protocols with the default values. The below list
@@ -80,8 +80,8 @@ func ExampleUsage() {
log.Fatalf("Failed to stop the protocol stack: %v", err)
}
// Output:
- // Sample service starting...
- // Sample service stopping...
- // Sample service starting...
- // Sample service stopping...
+ // Service starting...
+ // Service stopping...
+ // Service starting...
+ // Service stopping...
}
diff --git a/node/node_test.go b/node/node_test.go
index 7201276b5..1d5570e42 100644
--- a/node/node_test.go
+++ b/node/node_test.go
@@ -102,7 +102,7 @@ func TestNodeUsedDataDir(t *testing.T) {
type NoopService struct{}
func (s *NoopService) Protocols() []p2p.Protocol { return nil }
-func (s *NoopService) Start() error { return nil }
+func (s *NoopService) Start(*p2p.Server) error { return nil }
func (s *NoopService) Stop() error { return nil }
func NewNoopService(*ServiceContext) (Service, error) { return new(NoopService), nil }
@@ -148,7 +148,7 @@ type InstrumentedService struct {
stop error
protocolsHook func()
- startHook func()
+ startHook func(*p2p.Server)
stopHook func()
}
@@ -159,9 +159,9 @@ func (s *InstrumentedService) Protocols() []p2p.Protocol {
return s.protocols
}
-func (s *InstrumentedService) Start() error {
+func (s *InstrumentedService) Start(server *p2p.Server) error {
if s.startHook != nil {
- s.startHook()
+ s.startHook(server)
}
return s.start
}
@@ -189,7 +189,7 @@ func TestServiceLifeCycle(t *testing.T) {
id := id // Closure for the constructor
constructor := func(*ServiceContext) (Service, error) {
return &InstrumentedService{
- startHook: func() { started[id] = true },
+ startHook: func(*p2p.Server) { started[id] = true },
stopHook: func() { stopped[id] = true },
}, nil
}
@@ -241,7 +241,7 @@ func TestServiceRestarts(t *testing.T) {
running = false
return &InstrumentedService{
- startHook: func() {
+ startHook: func(*p2p.Server) {
if running {
panic("already running")
}
@@ -288,7 +288,7 @@ func TestServiceConstructionAbortion(t *testing.T) {
id := id // Closure for the constructor
constructor := func(*ServiceContext) (Service, error) {
return &InstrumentedService{
- startHook: func() { started[id] = true },
+ startHook: func(*p2p.Server) { started[id] = true },
}, nil
}
if err := stack.Register(id, constructor); err != nil {
@@ -334,7 +334,7 @@ func TestServiceStartupAbortion(t *testing.T) {
id := id // Closure for the constructor
constructor := func(*ServiceContext) (Service, error) {
return &InstrumentedService{
- startHook: func() { started[id] = true },
+ startHook: func(*p2p.Server) { started[id] = true },
stopHook: func() { stopped[id] = true },
}, nil
}
@@ -384,7 +384,7 @@ func TestServiceTerminationGuarantee(t *testing.T) {
id := id // Closure for the constructor
constructor := func(*ServiceContext) (Service, error) {
return &InstrumentedService{
- startHook: func() { started[id] = true },
+ startHook: func(*p2p.Server) { started[id] = true },
stopHook: func() { stopped[id] = true },
}, nil
}
@@ -438,6 +438,42 @@ func TestServiceTerminationGuarantee(t *testing.T) {
}
}
+// TestSingletonServiceRetrieval tests that singleton services can be retrieved.
+func TestSingletonServiceRetrieval(t *testing.T) {
+ // Create a simple stack and register two service types
+ stack, err := New(testNodeConfig)
+ if err != nil {
+ t.Fatalf("failed to create protocol stack: %v", err)
+ }
+ if err := stack.Register("noop", func(*ServiceContext) (Service, error) { return new(NoopService), nil }); err != nil {
+ t.Fatalf("noop service registration failed: %v", err)
+ }
+ if err := stack.Register("instrumented", func(*ServiceContext) (Service, error) { return new(InstrumentedService), nil }); err != nil {
+ t.Fatalf("instrumented service registration failed: %v", err)
+ }
+ // Make sure none of the services can be retrieved until started
+ var noopServ *NoopService
+ if id, err := stack.SingletonService(&noopServ); id != "" || err != ErrServiceUnknown {
+ t.Fatalf("noop service retrieval mismatch: have %v/%v, want %v/%v", id, err, "", ErrServiceUnknown)
+ }
+ var instServ *InstrumentedService
+ if id, err := stack.SingletonService(&instServ); id != "" || err != ErrServiceUnknown {
+ t.Fatalf("instrumented service retrieval mismatch: have %v/%v, want %v/%v", id, err, "", ErrServiceUnknown)
+ }
+ // Start the stack and ensure everything is retrievable now
+ if err := stack.Start(); err != nil {
+ t.Fatalf("failed to start stack: %v", err)
+ }
+ defer stack.Stop()
+
+ if id, err := stack.SingletonService(&noopServ); id != "noop" || err != nil {
+ t.Fatalf("noop service retrieval mismatch: have %v/%v, want %v/%v", id, err, "noop", nil)
+ }
+ if id, err := stack.SingletonService(&instServ); id != "instrumented" || err != nil {
+ t.Fatalf("instrumented service retrieval mismatch: have %v/%v, want %v/%v", id, err, "instrumented", nil)
+ }
+}
+
// Tests that all protocols defined by individual services get launched.
func TestProtocolGather(t *testing.T) {
stack, err := New(testNodeConfig)
diff --git a/node/service.go b/node/service.go
index ec838dbe8..28fc34764 100644
--- a/node/service.go
+++ b/node/service.go
@@ -18,6 +18,7 @@ package node
import (
"path/filepath"
+ "reflect"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
@@ -28,18 +29,39 @@ import (
// 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
+ datadir string // Data directory for protocol persistence
+ services map[string]Service // Index of the already constructed services
+ 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 == "" {
+ if ctx.datadir == "" {
return ethdb.NewMemDatabase()
}
- return ethdb.NewLDBDatabase(filepath.Join(ctx.dataDir, name), cache)
+ return ethdb.NewLDBDatabase(filepath.Join(ctx.datadir, name), cache)
+}
+
+// Service retrieves an already constructed service registered under a given id.
+func (ctx *ServiceContext) Service(id string) Service {
+ return ctx.services[id]
+}
+
+// SingletonService retrieves an already constructed service using a specific type
+// implementing the Service interface. This is a utility function for scenarios
+// where it is known that only one instance of a given service type is running,
+// allowing to access services without needing to know their specific id with
+// which they were registered.
+func (ctx *ServiceContext) SingletonService(service interface{}) (string, error) {
+ for id, running := range ctx.services {
+ if reflect.TypeOf(running) == reflect.ValueOf(service).Elem().Type() {
+ reflect.ValueOf(service).Elem().Set(reflect.ValueOf(running))
+ return id, nil
+ }
+ }
+ return "", ErrServiceUnknown
}
// ServiceConstructor is the function signature of the constructors needed to be
@@ -58,8 +80,9 @@ 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
+ // Start is called after all services have been constructed and the networking
+ // layer was also initialized to spawn any goroutines required by the service.
+ Start(server *p2p.Server) error
// Stop terminates all goroutines belonging to the service, blocking until they
// are all terminated.
diff --git a/node/service_test.go b/node/service_test.go
index 50a4f9715..921a1a012 100644
--- a/node/service_test.go
+++ b/node/service_test.go
@@ -17,14 +17,16 @@
package node
import (
+ "fmt"
"io/ioutil"
"os"
"path/filepath"
"testing"
)
-// Tests that service context methods work properly.
-func TestServiceContext(t *testing.T) {
+// Tests that databases are correctly created persistent or ephemeral based on
+// the configured service context.
+func TestContextDatabases(t *testing.T) {
// Create a temporary folder and ensure no database is contained within
dir, err := ioutil.TempDir("", "")
if err != nil {
@@ -36,7 +38,7 @@ func TestServiceContext(t *testing.T) {
t.Fatalf("non-created database already exists")
}
// Request the opening/creation of a database and ensure it persists to disk
- ctx := &ServiceContext{dataDir: dir}
+ ctx := &ServiceContext{datadir: dir}
db, err := ctx.Database("persistent", 0)
if err != nil {
t.Fatalf("failed to open persistent database: %v", err)
@@ -47,7 +49,7 @@ func TestServiceContext(t *testing.T) {
t.Fatalf("persistent database doesn't exists: %v", err)
}
// Request th opening/creation of an ephemeral database and ensure it's not persisted
- ctx = &ServiceContext{dataDir: ""}
+ ctx = &ServiceContext{datadir: ""}
db, err = ctx.Database("ephemeral", 0)
if err != nil {
t.Fatalf("failed to open ephemeral database: %v", err)
@@ -58,3 +60,47 @@ func TestServiceContext(t *testing.T) {
t.Fatalf("ephemeral database exists")
}
}
+
+// Tests that already constructed services can be retrieves by later ones.
+func TestContextServices(t *testing.T) {
+ stack, err := New(testNodeConfig)
+ if err != nil {
+ t.Fatalf("failed to create protocol stack: %v", err)
+ }
+ // Define a set of services, constructed before/after a verifier
+ formers := []string{"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"}
+ latters := []string{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"}
+
+ verifier := func(ctx *ServiceContext) (Service, error) {
+ for i, id := range formers {
+ if ctx.Service(id) == nil {
+ return nil, fmt.Errorf("former %d: service not found", i)
+ }
+ }
+ for i, id := range latters {
+ if ctx.Service(id) != nil {
+ return nil, fmt.Errorf("latters %d: service found", i)
+ }
+ }
+ return new(NoopService), nil
+ }
+ // Register the collection of services
+ for i, id := range formers {
+ if err := stack.Register(id, NewNoopService); err != nil {
+ t.Fatalf("former #%d: failed to register service: %v", i, err)
+ }
+ }
+ if err := stack.Register("verifier", verifier); err != nil {
+ t.Fatalf("failed to register service verifier: %v", err)
+ }
+ for i, id := range latters {
+ if err := stack.Register(id, NewNoopService); err != nil {
+ t.Fatalf("latter #%d: failed to register service: %v", i, err)
+ }
+ }
+ // Start the protocol stack and ensure services are constructed in order
+ if err := stack.Start(); err != nil {
+ t.Fatalf("failed to start stack: %v", err)
+ }
+ defer stack.Stop()
+}
generated by cgit (git 2.34.1) at 2024-11-12 15:55:34 +0800