status: add status server implementation

Author: ellemouton

status/log.go

@@ -0,0 +1,24 @@
+package status
+
+import (
+	"github.com/btcsuite/btclog"
+	"github.com/lightningnetwork/lnd/build"
+)
+
+const Subsystem = "STAT"
+
+// log is a logger that is initialized with no output filters. This means the
+// package will not perform any logging by default until the caller requests it.
+var log btclog.Logger
+
+// The default amount of logging is none.
+func init() {
+	UseLogger(build.NewSubLogger(Subsystem, nil))
+}
+
+// UseLogger uses a specified Logger to output package logging info.
+// This should be used in preference to SetLogWriter if the caller is also
+// using btclog.
+func UseLogger(logger btclog.Logger) {
+	log = logger
+}

status/manager.go

@@ -0,0 +1,191 @@
+package status
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+
+	"github.com/lightninglabs/lightning-terminal/litrpc"
+)
+
+// SubServerStatus represents the status of a sub-server.
+type SubServerStatus struct {
+	// Disabled is true if the sub-server is available in the LiT bundle but
+	// has explicitly been disabled by the user.
+	Disabled bool
+
+	// Running is true if the sub-server is enabled and has successfully
+	// been started.
+	Running bool
+
+	// Err will be a non-empty string if the sub-server failed to start.
+	Err string
+}
+
+// newSubServerStatus constructs a new SubServerStatus.
+func newSubServerStatus() *SubServerStatus {
+	return &SubServerStatus{
+		Disabled: true,
+	}
+}
+
+// Manager manages the status of any sub-server registered to it. It is also an
+// implementation of the litrpc.StatusServer which can be queried for the status
+// of various LiT sub-servers.
+type Manager struct {
+	litrpc.UnimplementedStatusServer
+
+	subServers map[string]*SubServerStatus
+	mu         sync.RWMutex
+}
+
+// NewStatusManager constructs a new Manager.
+func NewStatusManager() *Manager {
+	return &Manager{
+		subServers: make(map[string]*SubServerStatus),
+	}
+}
+
+// SubServerStatus queries the current status of a given sub-server.
+//
+// NOTE: this is part of the litrpc.StatusServer interface.
+func (s *Manager) SubServerStatus(_ context.Context,
+	_ *litrpc.SubServerStatusReq) (*litrpc.SubServerStatusResp,
+	error) {
+
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	resp := make(map[string]*litrpc.SubServerStatus, len(s.subServers))
+	for server, status := range s.subServers {
+		resp[server] = &litrpc.SubServerStatus{
+			Disabled: status.Disabled,
+			Running:  status.Running,
+			Error:    status.Err,
+		}
+	}
+
+	return &litrpc.SubServerStatusResp{
+		SubServers: resp,
+	}, nil
+}
+
+// RegisterSubServer will create a new sub-server entry for the Manager to
+// keep track of.
+func (s *Manager) RegisterSubServer(name string) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	s.subServers[name] = newSubServerStatus()
+}
+
+// RegisterAndEnableSubServer will create a new sub-server entry for the
+// Manager to keep track of and will set it as enabled.
+func (s *Manager) RegisterAndEnableSubServer(name string) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	ss := newSubServerStatus()
+	ss.Disabled = false
+
+	s.subServers[name] = ss
+
+}
+
+// GetStatus returns the current status of a given sub-server. This will
+// silently fail if the referenced sub-server has not yet been registered.
+func (s *Manager) GetStatus(name string) (*SubServerStatus, error) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+
+	status, ok := s.subServers[name]
+	if !ok {
+		return nil, errors.New("a sub-server with name %s has not " +
+			"yet been registered")
+	}
+
+	return status, nil
+}
+
+// SetEnabled marks the sub-server with the given name as enabled.
+//
+// NOTE: This will silently fail if the referenced sub-server has not yet been
+// registered.
+func (s *Manager) SetEnabled(name string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	log.Debugf("Setting the %s sub-server as enabled", name)
+
+	ss, ok := s.subServers[name]
+	if !ok {
+		return
+	}
+
+	ss.Disabled = false
+}
+
+// SetRunning can be used to set the status of a sub-server as Running
+// with no errors.
+//
+// NOTE: This will silently fail if the referenced sub-server has not yet been
+// registered.
+func (s *Manager) SetRunning(name string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	log.Debugf("Setting the %s sub-server as running", name)
+
+	ss, ok := s.subServers[name]
+	if !ok {
+		return
+	}
+
+	ss.Running = true
+}
+
+// SetStopped can be used to set the status of a sub-server as not Running and
+// with no errors.
+//
+// NOTE: This will silently fail if the referenced sub-server has not yet been
+// registered.
+func (s *Manager) SetStopped(name string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	log.Debugf("Setting the %s sub-server as stopped", name)
+
+	ss, ok := s.subServers[name]
+	if !ok {
+		return
+	}
+
+	ss.Running = false
+	ss.Err = ""
+}
+
+// SetErrored can be used to set the status of a sub-server as not Running
+// and also to set an error message for the sub-server.
+//
+// NOTE: This will silently fail if the referenced sub-server has not yet been
+// registered.
+func (s *Manager) SetErrored(name string, errStr string,
+	params ...interface{}) {
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	log.Debugf("Setting the %s sub-server as errored: %s", name, errStr)
+
+	ss, ok := s.subServers[name]
+	if !ok {
+		return
+	}
+
+	err := fmt.Sprintf(errStr, params...)
+	log.Errorf("could not start the %s sub-server: %s", name, err)
+
+	ss.Running = false
+	ss.Err = err
+}