// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.

// SPDX-License-Identifier: Apache-2.0

package agents

import (

"fmt"

"io"

"io/ioutil"

"os/exec"

"path"

"syscall"

log "github.com/sirupsen/logrus"

)

// AgentProcess is the common interface exposed by both internal and external agent processes

type AgentProcess interface {

Name() string

}

// ExternalAgentProcess represents an external agent process

type ExternalAgentProcess struct {

cmd *exec.Cmd

}

// NewExternalAgentProcess returns a new external agent process

func NewExternalAgentProcess(path string, env []string, stdoutWriter io.Writer, stderrWriter io.Writer) ExternalAgentProcess {

command := exec.Command(path)

command.Env = env

command.Stdout = NewNewlineSplitWriter(stdoutWriter)

command.Stderr = NewNewlineSplitWriter(stderrWriter)

command.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}

return ExternalAgentProcess{

cmd: command,

}

}

// Name returns the name of the agent

// For external agents is the executable name

func (a *ExternalAgentProcess) Name() string {

return path.Base(a.cmd.Path)

}

func (a *ExternalAgentProcess) Pid() int {

return a.cmd.Process.Pid

}

// Start starts an external agent process

func (a *ExternalAgentProcess) Start() error {

return a.cmd.Start()

}

// Wait waits for the external agent process to exit

func (a *ExternalAgentProcess) Wait() error {

return a.cmd.Wait()

}

// String is used to print values passed as an operand to any format that accepts a string or to an unformatted printer such as Print.

func (a *ExternalAgentProcess) String() string {

return fmt.Sprintf("%s (%s)", a.Name(), a.cmd.Path)

}

// ListExternalAgentPaths return a list of external agents found in a given directory

func ListExternalAgentPaths(root string) []string {

var agentPaths []string

files, err := ioutil.ReadDir(root)

if err != nil {

log.WithError(err).Warning("Cannot list external agents")

return agentPaths

}

for _, file := range files {

if !file.IsDir() {

agentPaths = append(agentPaths, path.Join(root, file.Name()))

}

}

return agentPaths

}