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clair/ext/featurens/driver.go

142 lines
4.0 KiB

// 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 featurens exposes functions to dynamically register methods for
// determining a namespace for features present in an image layer.
package featurens
import (
"sync"
"testing"
log "github.com/sirupsen/logrus"
"github.com/stretchr/testify/assert"
"github.com/coreos/clair/database"
"github.com/coreos/clair/pkg/tarutil"
)
var (
detectorsM sync.RWMutex
detectors = make(map[string]Detector)
)
// Detector represents an ability to detect a namespace used for organizing
// features present in an image layer.
type Detector interface {
// Detect attempts to determine a Namespace from a FilesMap of an image
// layer.
Detect(tarutil.FilesMap) (*database.Namespace, error)
// RequiredFilenames returns the list of files required to be in the FilesMap
// provided to the Detect method.
//
// Filenames must not begin with "/".
RequiredFilenames() []string
}
// RegisterDetector makes a detector available by the provided name.
//
// If called twice with the same name, the name is blank, or if the provided
// Detector is nil, this function panics.
func RegisterDetector(name string, d Detector) {
if name == "" {
panic("namespace: could not register a Detector with an empty name")
}
if d == nil {
panic("namespace: could not register a nil Detector")
}
detectorsM.Lock()
defer detectorsM.Unlock()
if _, dup := detectors[name]; dup {
panic("namespace: RegisterDetector called twice for " + name)
}
detectors[name] = d
}
// Detect iterators through all registered Detectors and returns all non-nil detected namespaces
func Detect(files tarutil.FilesMap, detectorNames []string) ([]database.Namespace, error) {
detectorsM.RLock()
defer detectorsM.RUnlock()
namespaces := map[string]*database.Namespace{}
for _, name := range detectorNames {
if detector, ok := detectors[name]; ok {
namespace, err := detector.Detect(files)
if err != nil {
log.WithError(err).WithField("name", name).Warning("failed while attempting to detect namespace")
return nil, err
}
if namespace != nil {
log.WithFields(log.Fields{"name": name, "namespace": namespace.Name}).Debug("detected namespace")
namespaces[namespace.Name] = namespace
}
} else {
log.WithField("Name", name).Warn("Unknown namespace detector")
}
}
nslist := []database.Namespace{}
for _, ns := range namespaces {
nslist = append(nslist, *ns)
}
return nslist, nil
}
// RequiredFilenames returns the total list of files required for all
// registered Detectors.
func RequiredFilenames(detectorNames []string) (files []string) {
detectorsM.RLock()
defer detectorsM.RUnlock()
for _, detector := range detectors {
files = append(files, detector.RequiredFilenames()...)
}
return
}
// ListDetectors returns the names of all registered namespace detectors.
func ListDetectors() []string {
r := []string{}
for name := range detectors {
r = append(r, name)
}
return r
}
// TestData represents the data used to test an implementation of Detector.
type TestData struct {
Files tarutil.FilesMap
ExpectedNamespace *database.Namespace
}
// TestDetector runs a Detector on each provided instance of TestData and
// asserts the output to be equal to the expected output.
func TestDetector(t *testing.T, d Detector, testData []TestData) {
for _, td := range testData {
namespace, err := d.Detect(td.Files)
assert.Nil(t, err)
if namespace == nil {
assert.Equal(t, td.ExpectedNamespace, namespace)
} else {
assert.Equal(t, td.ExpectedNamespace.Name, namespace.Name)
}
}
}