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

// SPDX-License-Identifier: Apache-2.0

package agents

import (

"os"

"path"

"path/filepath"

log "github.com/sirupsen/logrus"

)

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

func ListExternalAgentPaths(dir string, root string) []string {

var agentPaths []string

if !isCanonical(dir) || !isCanonical(root) {

log.Warningf("Agents base paths are not absolute and in canonical form: %s, %s", dir, root)

return agentPaths

}

fullDir := path.Join(root, dir)

files, err := os.ReadDir(fullDir)

if err != nil {

if os.IsNotExist(err) {

log.Infof("The extension's directory %q does not exist, assuming no extensions to be loaded.", fullDir)

} else {

// TODO - Should this return an error rather than ignore failing to load?

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

}

return agentPaths

}

for _, file := range files {

if !file.IsDir() {

// The returned path is absolute wrt to `root`. This allows

// to exec the agents in their own mount namespace

p := path.Join("/", dir, file.Name())

agentPaths = append(agentPaths, p)

}

}

return agentPaths

}

func isCanonical(path string) bool {

absPath, err := filepath.Abs(path)

return err == nil && absPath == path

}