mirror of
https://github.com/edgelesssys/constellation.git
synced 2024-10-01 01:36:09 -04:00
153 lines
4.1 KiB
Go
153 lines
4.1 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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/*
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Package imagefetcher provides helping wrappers around a versionsapi fetcher.
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It also enables local image overrides and download of raw images.
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*/
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package imagefetcher
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import (
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io/fs"
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"regexp"
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"github.com/edgelesssys/constellation/v2/internal/api/fetcher"
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"github.com/edgelesssys/constellation/v2/internal/api/versionsapi"
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"github.com/edgelesssys/constellation/v2/internal/cloud/cloudprovider"
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"github.com/edgelesssys/constellation/v2/internal/variant"
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"github.com/spf13/afero"
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)
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// Fetcher fetches image references using a lookup table.
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type Fetcher struct {
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fetcher versionsAPIImageInfoFetcher
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fs *afero.Afero
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}
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// New returns a new image fetcher.
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func New() *Fetcher {
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return &Fetcher{
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fetcher: fetcher.NewVersionAPIFetcher(),
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fs: &afero.Afero{Fs: afero.NewOsFs()},
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}
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}
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// FetchReference fetches the image reference for a given image version uid, CSP and image variant.
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func (f *Fetcher) FetchReference(ctx context.Context,
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provider cloudprovider.Provider, attestationVariant variant.Variant,
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image, region string,
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) (string, error) {
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ver, err := versionsapi.NewVersionFromShortPath(image, versionsapi.VersionKindImage)
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if err != nil {
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return "", fmt.Errorf("parsing config image short path: %w", err)
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}
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imgInfoReq := versionsapi.ImageInfo{
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Ref: ver.Ref,
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Stream: ver.Stream,
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Version: ver.Version,
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}
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url, err := imgInfoReq.URL()
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if err != nil {
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return "", err
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}
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imgInfo, err := getFromFile(f.fs, imgInfoReq)
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if err != nil && errors.Is(err, fs.ErrNotExist) {
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imgInfo, err = f.fetcher.FetchImageInfo(ctx, imgInfoReq)
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}
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var notFoundErr *fetcher.NotFoundError
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switch {
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case errors.As(err, ¬FoundErr):
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overridePath := imageInfoFilename(imgInfoReq)
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return "", fmt.Errorf("image info file not found locally at %q or remotely at %s", overridePath, url)
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case err != nil:
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return "", err
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}
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if err := imgInfo.Validate(); err != nil {
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return "", fmt.Errorf("validating image info file: %w", err)
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}
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return getReferenceFromImageInfo(provider, attestationVariant.String(), imgInfo, filters(provider, region)...)
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}
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func filters(provider cloudprovider.Provider, region string) []filter {
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var filters []filter
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switch provider {
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case cloudprovider.AWS:
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filters = append(filters, func(i versionsapi.ImageInfoEntry) bool {
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return i.Region == region
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})
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}
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return filters
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}
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func getFromFile(fs *afero.Afero, imgInfo versionsapi.ImageInfo) (versionsapi.ImageInfo, error) {
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fileName := imageInfoFilename(imgInfo)
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raw, err := fs.ReadFile(fileName)
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if err != nil {
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return versionsapi.ImageInfo{}, err
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}
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var newInfo versionsapi.ImageInfo
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if err := json.Unmarshal(raw, &newInfo); err != nil {
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return versionsapi.ImageInfo{}, fmt.Errorf("decoding image info file: %w", err)
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}
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return newInfo, nil
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}
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var filenameReplaceRegexp = regexp.MustCompile(`([^a-zA-Z0-9.-])`)
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func imageInfoFilename(imgInfo versionsapi.ImageInfo) string {
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path := imgInfo.JSONPath()
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return filenameReplaceRegexp.ReplaceAllString(path, "_")
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}
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// getReferenceFromImageInfo returns the image reference for a given CSP and image variant.
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func getReferenceFromImageInfo(provider cloudprovider.Provider,
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attestationVariant string, imgInfo versionsapi.ImageInfo,
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filt ...filter,
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) (string, error) {
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var correctVariant versionsapi.ImageInfoEntry
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var found bool
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variantLoop:
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for _, variant := range imgInfo.List {
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gotCSP := cloudprovider.FromString(variant.CSP)
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if gotCSP != provider || variant.AttestationVariant != attestationVariant {
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continue
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}
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for _, f := range filt {
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if !f(variant) {
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continue variantLoop
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}
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}
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correctVariant = variant
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found = true
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break
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}
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if !found {
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return "", fmt.Errorf("image not available in image info for CSP %q, variant %q and other filters", provider.String(), attestationVariant)
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}
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return correctVariant.Reference, nil
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}
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type versionsAPIImageInfoFetcher interface {
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FetchImageInfo(ctx context.Context, imageInfo versionsapi.ImageInfo) (versionsapi.ImageInfo, error)
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}
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type filter func(versionsapi.ImageInfoEntry) bool
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