cli: image info (v2)

internal/imagefetcher/imagefetcher.go

@@ -0,0 +1,152 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+/*
+Package imagefetcher provides helping wrappers around a versionsapi fetcher.
+
+It also enables local image overrides and download of raw images.
+*/
+package imagefetcher
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"regexp"
+
+	"github.com/edgelesssys/constellation/v2/internal/cloud/cloudprovider"
+	"github.com/edgelesssys/constellation/v2/internal/variant"
+	"github.com/edgelesssys/constellation/v2/internal/versionsapi"
+	"github.com/edgelesssys/constellation/v2/internal/versionsapi/fetcher"
+	"github.com/spf13/afero"
+)
+
+// Fetcher fetches image references using a lookup table.
+type Fetcher struct {
+	fetcher versionsAPIImageInfoFetcher
+	fs      *afero.Afero
+}
+
+// New returns a new image fetcher.
+func New() *Fetcher {
+	return &Fetcher{
+		fetcher: fetcher.NewFetcher(),
+		fs:      &afero.Afero{Fs: afero.NewOsFs()},
+	}
+}
+
+// FetchReference fetches the image reference for a given image version uid, CSP and image variant.
+func (f *Fetcher) FetchReference(ctx context.Context,
+	provider cloudprovider.Provider, attestationVariant variant.Variant,
+	image, region string,
+) (string, error) {
+	ver, err := versionsapi.NewVersionFromShortPath(image, versionsapi.VersionKindImage)
+	if err != nil {
+		return "", fmt.Errorf("parsing config image short path: %w", err)
+	}
+
+	imgInfoReq := versionsapi.ImageInfo{
+		Ref:     ver.Ref,
+		Stream:  ver.Stream,
+		Version: ver.Version,
+	}
+
+	url, err := imgInfoReq.URL()
+	if err != nil {
+		return "", err
+	}
+
+	imgInfo, err := getFromFile(f.fs, imgInfoReq)
+	if err != nil && errors.Is(err, fs.ErrNotExist) {
+		imgInfo, err = f.fetcher.FetchImageInfo(ctx, imgInfoReq)
+	}
+
+	var notFoundErr *fetcher.NotFoundError
+	switch {
+	case errors.As(err, &notFoundErr):
+		overridePath := imageInfoFilename(imgInfoReq)
+		return "", fmt.Errorf("image info file not found locally at %q or remotely at %s", overridePath, url)
+	case err != nil:
+		return "", err
+	}
+
+	if err := imgInfo.Validate(); err != nil {
+		return "", fmt.Errorf("validating image info file: %w", err)
+	}
+
+	return getReferenceFromImageInfo(provider, attestationVariant.String(), imgInfo, filters(provider, region)...)
+}
+
+func filters(provider cloudprovider.Provider, region string) []filter {
+	var filters []filter
+	switch provider {
+	case cloudprovider.AWS:
+		filters = append(filters, func(i versionsapi.ImageInfoEntry) bool {
+			return i.Region == region
+		})
+	}
+	return filters
+}
+
+func getFromFile(fs *afero.Afero, imgInfo versionsapi.ImageInfo) (versionsapi.ImageInfo, error) {
+	fileName := imageInfoFilename(imgInfo)
+
+	raw, err := fs.ReadFile(fileName)
+	if err != nil {
+		return versionsapi.ImageInfo{}, err
+	}
+
+	var newInfo versionsapi.ImageInfo
+	if err := json.Unmarshal(raw, &newInfo); err != nil {
+		return versionsapi.ImageInfo{}, fmt.Errorf("decoding image info file: %w", err)
+	}
+
+	return newInfo, nil
+}
+
+var filenameReplaceRegexp = regexp.MustCompile(`([^a-zA-Z0-9.-])`)
+
+func imageInfoFilename(imgInfo versionsapi.ImageInfo) string {
+	path := imgInfo.JSONPath()
+	return filenameReplaceRegexp.ReplaceAllString(path, "_")
+}
+
+// getReferenceFromImageInfo returns the image reference for a given CSP and image variant.
+func getReferenceFromImageInfo(provider cloudprovider.Provider,
+	attestationVariant string, imgInfo versionsapi.ImageInfo,
+	filt ...filter,
+) (string, error) {
+	var correctVariant versionsapi.ImageInfoEntry
+	var found bool
+variantLoop:
+	for _, variant := range imgInfo.List {
+		gotCSP := cloudprovider.FromString(variant.CSP)
+		if gotCSP != provider || variant.AttestationVariant != attestationVariant {
+			continue
+		}
+		for _, f := range filt {
+			if !f(variant) {
+				continue variantLoop
+			}
+		}
+		correctVariant = variant
+		found = true
+		break
+	}
+	if !found {
+		return "", fmt.Errorf("image not available in image info for CSP %q, variant %q and other filters", provider.String(), attestationVariant)
+	}
+
+	return correctVariant.Reference, nil
+}
+
+type versionsAPIImageInfoFetcher interface {
+	FetchImageInfo(ctx context.Context, imageInfo versionsapi.ImageInfo) (versionsapi.ImageInfo, error)
+}
+
+type filter func(versionsapi.ImageInfoEntry) bool