clair/worker/detectors/os.go

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2015-11-13 19:11:28 +00:00
// Copyright 2015 clair authors
//
// 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 detectors exposes functions to register and use container
// information extractors.
package detectors
import (
"fmt"
"sync"
)
// The OSDetector interface defines a way to detect an Operating System and
// its version from input data
type OSDetector interface {
// Detect detects an Operating System and its version from input data
Detect(map[string][]byte) (string, string)
// GetRequiredFiles returns the list of files required for Detect, without
// leading /
GetRequiredFiles() []string
}
var (
osDetectorsLock sync.Mutex
osDetectors = make(map[string]OSDetector)
)
// RegisterOSDetector provides a way to dynamically register an implementation of a
// OSDetector.
//
// If RegisterOSDetector is called twice with the same name if OSDetector is nil,
// or if the name is blank, it panics.
func RegisterOSDetector(name string, f OSDetector) {
if name == "" {
panic("Could not register a OSDetector with an empty name")
}
if f == nil {
panic("Could not register a nil OSDetector")
}
osDetectorsLock.Lock()
defer osDetectorsLock.Unlock()
if _, alreadyExists := osDetectors[name]; alreadyExists {
panic(fmt.Sprintf("Detector '%s' is already registered", name))
}
osDetectors[name] = f
}
// DetectOS finds the OS of the layer by using every registered OSDetector
func DetectOS(data map[string][]byte) string {
for _, detector := range osDetectors {
OS, version := detector.Detect(data)
if OS != "" && version != "" {
return OS + ":" + version
}
}
return ""
}
// GetRequiredFilesOS returns the list of files required for Detect for every
// registered OSDetector, without leading /
func GetRequiredFilesOS() (files []string) {
for _, detector := range osDetectors {
files = append(files, detector.GetRequiredFiles()...)
}
return
}