cmd/examples/basic_plugin/service.go

//  Copyright 2024 Google LLC
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.

package main

import (
	"context"

	"github.com/GoogleCloudPlatform/galog"
	"google.golang.org/grpc"

	pb "github.com/GoogleCloudPlatform/google-guest-agent/pkg/proto/plugin_comm"
)

// PluginServer implements the plugin RPC server interface.
type PluginServer struct {
	pb.UnimplementedGuestAgentPluginServer
	server *grpc.Server
}

// Apply applies the config sent or performs the work defined in the message.
// ApplyRequest is opaque to the agent and is expected to be well known contract
// between Plugin and the server itself. For e.g. service might want to update
// plugin config to enable/disable feature here plugins can react to such requests.
func (ps *PluginServer) Apply(ctx context.Context, msg *pb.ApplyRequest) (*pb.ApplyResponse, error) {
	galog.Infof("Received apply request: %+v", msg)
	return &pb.ApplyResponse{}, nil
}

// Start starts the plugin and initiates the plugin functionality.
// Until plugin receives Start request plugin is expected to be not functioning
// and just listening on the address handed off waiting for the request.
func (ps *PluginServer) Start(ctx context.Context, msg *pb.StartRequest) (*pb.StartResponse, error) {
	galog.Infof("Received start request: %+v", msg)
	return &pb.StartResponse{}, nil
}

// Stop is the stop hook and implements any cleanup if required.
// Stop maybe called if plugin revision is being changed.
// For e.g. if plugins want to stop some task it was performing or remove some
// state before exiting it can be done on this request.
func (ps *PluginServer) Stop(ctx context.Context, msg *pb.StopRequest) (*pb.StopResponse, error) {
	galog.Infof("Received stop request: %+v", msg)
	return &pb.StopResponse{}, nil
}

// GetStatus is the health check agent would perform to make sure plugin process
// is alive. If request fails process is considered dead and relaunched. Plugins
// can share any additional information to report it to the service. For e.g. if
// plugins detect some non-fatal errors causing it unable to offer some features
// it can reported in status which is sent back to the service by agent.
func (ps *PluginServer) GetStatus(ctx context.Context, msg *pb.GetStatusRequest) (*pb.Status, error) {
	galog.Infof("Received get status request: %+v", msg)
	return &pb.Status{Code: 0, Results: []string{"Plugin is running ok"}}, nil
}