chore: add doc comment to server API (#215)

server/callbacks.go

@@ -7,19 +7,25 @@ import (
 	"github.com/open-telemetry/opamp-go/server/types"
 )
 
+// CallbacksStruct is a struct that implements Callbacks interface and allows
+// to override only the methods that are needed. If a method is not overridden then it will
+// accept all connections.
 type CallbacksStruct struct {
 	OnConnectingFunc func(request *http.Request) types.ConnectionResponse
 }
 
 var _ types.Callbacks = (*CallbacksStruct)(nil)
 
+// OnConnecting implements Callbacks.interface.
 func (c CallbacksStruct) OnConnecting(request *http.Request) types.ConnectionResponse {
 	if c.OnConnectingFunc != nil {
 		return c.OnConnectingFunc(request)
 	}
 	return types.ConnectionResponse{Accept: true}
 }
 
+// ConnectionCallbacksStruct is a struct that implements ConnectionCallbacks interface and allows
+// to override only the methods that are needed.
 type ConnectionCallbacksStruct struct {
 	OnConnectedFunc       func(conn types.Connection)
 	OnMessageFunc         func(conn types.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent
@@ -28,12 +34,15 @@ type ConnectionCallbacksStruct struct {
 
 var _ types.ConnectionCallbacks = (*ConnectionCallbacksStruct)(nil)
 
+// OnConnected implements ConnectionCallbacks.OnConnected.
 func (c ConnectionCallbacksStruct) OnConnected(conn types.Connection) {
 	if c.OnConnectedFunc != nil {
 		c.OnConnectedFunc(conn)
 	}
 }
 
+// OnMessage implements ConnectionCallbacks.OnMessage.
+// If OnMessageFunc is nil then it will send an empty response to the agent
 func (c ConnectionCallbacksStruct) OnMessage(conn types.Connection, message *protobufs.AgentToServer) *protobufs.ServerToAgent {
 	if c.OnMessageFunc != nil {
 		return c.OnMessageFunc(conn, message)
@@ -45,6 +54,7 @@ func (c ConnectionCallbacksStruct) OnMessage(conn types.Connection, message *pro
 	}
 }
 
+// OnConnectionClose implements ConnectionCallbacks.OnConnectionClose.
 func (c ConnectionCallbacksStruct) OnConnectionClose(conn types.Connection) {
 	if c.OnConnectionCloseFunc != nil {
 		c.OnConnectionCloseFunc(conn)

server/server.go

@@ -9,6 +9,7 @@ import (
 	"github.com/open-telemetry/opamp-go/server/types"
 )
 
+// Settings contains the settings for attaching an OpAMP Server.
 type Settings struct {
 	// Callbacks that the Server will call after successful Attach/Start.
 	Callbacks types.Callbacks
@@ -19,6 +20,7 @@ type Settings struct {
 	EnableCompression bool
 }
 
+// StartSettings contains the settings for starting an OpAMP Server.
 type StartSettings struct {
 	Settings
 
@@ -37,6 +39,7 @@ type HTTPHandlerFunc func(http.ResponseWriter, *http.Request)
 
 type ConnContext func(ctx context.Context, c net.Conn) context.Context
 
+// OpAMPServer is an interface representing the server side of the OpAMP protocol.
 type OpAMPServer interface {
 	// Attach prepares the OpAMP Server to begin handling requests from an existing
 	// http.Server. The returned HTTPHandlerFunc and ConnContext should be added as a

server/serverimpl.go

@@ -44,6 +44,7 @@ type server struct {
 
 var _ OpAMPServer = (*server)(nil)
 
+// New creates a new OpAMP Server.
 func New(logger types.Logger) *server {
 	if logger == nil {
 		logger = &internal.NopLogger{}