grafana/pkg/plugins/manager/process/process.go

package process

import (
	"context"
	"errors"
	"time"

	"github.com/grafana/grafana/pkg/plugins"
)

type Service struct{}

func ProvideService() *Service {
	return &Service{}
}

func (*Service) Start(ctx context.Context, p *plugins.Plugin) error {
	if !p.IsManaged() || !p.Backend || p.SignatureError != nil {
		return nil
	}

	if err := startPluginAndRestartKilledProcesses(ctx, p); err != nil {
		return err
	}

	p.Logger().Debug("Successfully started backend plugin process")
	return nil
}

func (*Service) Stop(ctx context.Context, p *plugins.Plugin) error {
	p.Logger().Debug("Stopping plugin process")
	if err := p.Decommission(); err != nil {
		return err
	}

	if err := p.Stop(ctx); err != nil {
		return err
	}

	return nil
}

func startPluginAndRestartKilledProcesses(ctx context.Context, p *plugins.Plugin) error {
	if err := p.Start(ctx); err != nil {
		return err
	}

	if p.IsCorePlugin() {
		return nil
	}

	go func(ctx context.Context, p *plugins.Plugin) {
		if err := restartKilledProcess(ctx, p); err != nil {
			p.Logger().Error("Attempt to restart killed plugin process failed", "error", err)
		}
	}(ctx, p)

	return nil
}

func restartKilledProcess(ctx context.Context, p *plugins.Plugin) error {
	ticker := time.NewTicker(time.Second * 1)

	for {
		select {
		case <-ctx.Done():
			if err := ctx.Err(); err != nil && !errors.Is(err, context.Canceled) {
				return err
			}
			return p.Stop(ctx)
		case <-ticker.C:
			if p.IsDecommissioned() {
				p.Logger().Debug("Plugin decommissioned")
				return nil
			}

			if !p.Exited() {
				continue
			}

			p.Logger().Debug("Restarting plugin")
			if err := p.Start(ctx); err != nil {
				p.Logger().Error("Failed to restart plugin", "error", err)
				continue
			}
			p.Logger().Debug("Plugin restarted")
		}
	}
}