clair/ext/imagefmt/driver.go
Sida Chen fb32dcfa58 Clair Logic, Extensions: updated mock tests, extensions, basic logic
Main Clair logic is changed in worker, updater, notifier for better adapting
ancestry schema. Extensions are updated with the new model and feature lister
 and namespace detector drivers are able to specify the specific listers and
detectors used to process layer's content. InRange and GetFixedIn interfaces
are added to Version format for adapting ranged affected features and next
available fixed in in the future. Tests for worker, updater and extensions
are fixed.
2017-08-10 11:24:40 -04:00

165 lines
4.7 KiB
Go

// Copyright 2017 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 notification fetches notifications from the database and informs the
// specified remote handler about their existences, inviting the third party to
// actively query the API about it.
// Package imagefmt exposes functions to dynamically register methods to
// detect different types of container image formats.
package imagefmt
import (
"crypto/tls"
"fmt"
"io"
"math"
"net/http"
"os"
"strings"
"sync"
log "github.com/sirupsen/logrus"
"github.com/coreos/clair/pkg/commonerr"
"github.com/coreos/clair/pkg/tarutil"
)
var (
// ErrCouldNotFindLayer is returned when we could not download or open the layer file.
ErrCouldNotFindLayer = commonerr.NewBadRequestError("could not find layer from given path")
// insecureTLS controls whether TLS server's certificate chain and hostname are verified
// when pulling layers, verified in default.
insecureTLS = false
extractorsM sync.RWMutex
extractors = make(map[string]Extractor)
)
// Extractor represents an ability to extract files from a particular container
// image format.
type Extractor interface {
// ExtractFiles produces a tarutil.FilesMap from a image layer.
ExtractFiles(layer io.ReadCloser, filenames []string) (tarutil.FilesMap, error)
}
// RegisterExtractor makes an extractor available by the provided name.
//
// If called twice with the same name, the name is blank, or if the provided
// Extractor is nil, this function panics.
func RegisterExtractor(name string, d Extractor) {
extractorsM.Lock()
defer extractorsM.Unlock()
if name == "" {
panic("imagefmt: could not register an Extractor with an empty name")
}
if d == nil {
panic("imagefmt: could not register a nil Extractor")
}
// Enforce lowercase names, so that they can be reliably be found in a map.
name = strings.ToLower(name)
if _, dup := extractors[name]; dup {
panic("imagefmt: RegisterExtractor called twice for " + name)
}
extractors[name] = d
}
// Extractors returns the list of the registered extractors.
func Extractors() map[string]Extractor {
extractorsM.RLock()
defer extractorsM.RUnlock()
ret := make(map[string]Extractor)
for k, v := range extractors {
ret[k] = v
}
return ret
}
// UnregisterExtractor removes a Extractor with a particular name from the list.
func UnregisterExtractor(name string) {
extractorsM.Lock()
defer extractorsM.Unlock()
delete(extractors, name)
}
// Extract streams an image layer from disk or over HTTP, determines the
// image format, then extracts the files specified.
func Extract(format, path string, headers map[string]string, toExtract []string) (tarutil.FilesMap, error) {
var layerReader io.ReadCloser
if strings.HasPrefix(path, "http://") || strings.HasPrefix(path, "https://") {
// Create a new HTTP request object.
request, err := http.NewRequest("GET", path, nil)
if err != nil {
return nil, ErrCouldNotFindLayer
}
// Set any provided HTTP Headers.
if headers != nil {
for k, v := range headers {
request.Header.Set(k, v)
}
}
// Send the request and handle the response.
tr := &http.Transport{
TLSClientConfig: &tls.Config{InsecureSkipVerify: insecureTLS},
}
client := &http.Client{Transport: tr}
r, err := client.Do(request)
if err != nil {
log.WithError(err).Warning("could not download layer")
return nil, ErrCouldNotFindLayer
}
// Fail if we don't receive a 2xx HTTP status code.
if math.Floor(float64(r.StatusCode/100)) != 2 {
log.WithField("status code", r.StatusCode).Warning("could not download layer: expected 2XX")
return nil, ErrCouldNotFindLayer
}
layerReader = r.Body
} else {
var err error
layerReader, err = os.Open(path)
if err != nil {
return nil, ErrCouldNotFindLayer
}
}
defer layerReader.Close()
if extractor, exists := Extractors()[strings.ToLower(format)]; exists {
files, err := extractor.ExtractFiles(layerReader, toExtract)
if err != nil {
return nil, err
}
return files, nil
}
return nil, commonerr.NewBadRequestError(fmt.Sprintf("unsupported image format '%s'", format))
}
// SetInsecureTLS sets the insecureTLS to control whether TLS server's certificate chain
// and hostname are verified when pulling layers.
func SetInsecureTLS(insecure bool) {
insecureTLS = insecure
}