DMAC/internal/pkg/server/reactormanager.go

package server

import (
	pb "FRMS/internal/pkg/grpc"
	"FRMS/internal/pkg/logging"
	"FRMS/internal/pkg/manager"
	"time"

	"context"

	"github.com/spf13/viper"
)

// MaxConnectionAttempts is the max number of tries to allow
// when connecting to a reactor.
const MaxConnectionAttempts = 10

// Manager is an interface requiring a structure that can be started
// and stopped as well as provide timeouts in milliseconds.
type Manager interface {
	Start() error // status checks
	Stop() error
	Timeout() (time.Duration, error) // TO Generator
}

// NewManager returns a manager fulfilling the Manager interface as well as
// any potential errors.
func NewManager(max int) (Manager, error) {
	return manager.New(max)
}

// ReactorManager contains a base manager, client, global
// config, and error channel.
// The ReactorManager can be started/stopped as clients connect/disconnect.
// Also serves as handler for gRPC requests from reactors.
// Can be extended to write changes to config.
type ReactorManager struct {
	Manager // base manager interface
	*Client
	Config *viper.Viper // global config to maintain
	Err    chan error
}

// NewReactorManager takes in a client, config and channel to pass errors on.
// Returns a new reactor manager as well as any errors that occured during
// creation.
// Uses MaxConnectionAttempts which defaults to 10 to prevent
// unnessecary network load and/or timeout lengths.
func NewReactorManager(
	cl *Client,
	config *viper.Viper,
	errCh chan error,
) (*ReactorManager, error) {

	m, err := NewManager(MaxConnectionAttempts)

	if err != nil {
		return &ReactorManager{}, err
	}

	r := &ReactorManager{
		Manager: m,
		Client:  cl,
		Config:  config,
		Err:     errCh,
	}

	return r, err
}

// Start logs the start and calls start on the embedded manager.
func (r *ReactorManager) Start() error {
	logging.Debug(logging.DStart, "RMA %v starting", r.Id)
	return r.Manager.Start()
}

// Stop logs the stop and calls stop on the embedded manager.
func (r *ReactorManager) Stop() error {
	logging.Debug(logging.DExit, "RMA %v stopping", r.Id)
	return r.Manager.Stop()
}

// UpdateClient is used to change the underlying manager client if there
// changes to its data.
//
// BUG(Keegan): Client is not protected by a lock and may lead to races
func (r *ReactorManager) UpdateClient(cl *Client) error {
	logging.Debug(logging.DClient, "RMA %v updating client", r.Id)
	r.Client = cl
	return nil
}

// ReactorStatusHandler implements a gRPC handler that is called by reactors.
// Takes in a context and request which has reactor and device information.
// For now, loops over devices and logs information about their status.
func (r *ReactorManager) ReactorStatusHandler(
	ctx context.Context,
	req *pb.ReactorStatusPing,
) (*pb.ReactorStatusResponse, error) {

	logging.Debug(logging.DClient, "RMA %v recieved ping", r.Id)

	for _, dev := range req.GetDevices() {
		logging.Debug(
			logging.DClient,
			"RMA %v device %v is %v",
			r.Id,
			dev.GetAddr(),
			dev.GetStatus().String(),
		)
	}

	return &pb.ReactorStatusResponse{Id: int32(r.Id)}, nil
}