api: rename /api/versions to versionsapi and /api/attestationcfig to attestationconfigapi (#1876)

* rename to attestationconfigapi + put client and fetcher inside pkg

* rename api/version to versionsapi and put fetcher + client inside pkg

* rename AttestationConfigAPIFetcher to Fetcher

internal/api/versionsapi/list.go

@@ -0,0 +1,173 @@
+/*
+Copyright (c) Edgeless Systems GmbH
+
+SPDX-License-Identifier: AGPL-3.0-only
+*/
+
+package versionsapi
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"path"
+
+	"github.com/edgelesssys/constellation/v2/internal/constants"
+	"golang.org/x/mod/semver"
+)
+
+// List represents a list of versions for a kind of resource.
+// It has a granularity of either "major" or "minor".
+//
+// For example, a List with granularity "major" could contain
+// the base version "v1" and a list of minor versions "v1.0", "v1.1", "v1.2" etc.
+// A List with granularity "minor" could contain the base version
+// "v1.0" and a list of patch versions "v1.0.0", "v1.0.1", "v1.0.2" etc.
+type List struct {
+	// Ref is the branch name the list belongs to.
+	Ref string `json:"ref,omitempty"`
+	// Stream is the update stream of the list.
+	Stream string `json:"stream,omitempty"`
+	// Granularity is the granularity of the base version of this list.
+	// It can be either "major" or "minor".
+	Granularity Granularity `json:"granularity,omitempty"`
+	// Base is the base version of the list.
+	// Every version in the list is a finer-grained version of this base version.
+	Base string `json:"base,omitempty"`
+	// Kind is the kind of resource this list is for.
+	Kind VersionKind `json:"kind,omitempty"`
+	// Versions is a list of all versions in this list.
+	Versions []string `json:"versions,omitempty"`
+}
+
+// JSONPath returns the S3 JSON path for this object.
+func (l List) JSONPath() string {
+	return path.Join(
+		constants.CDNAPIPrefix,
+		"ref", l.Ref,
+		"stream", l.Stream,
+		"versions", l.Granularity.String(), l.Base,
+		l.Kind.String()+".json",
+	)
+}
+
+// URL returns the URL for this object.
+func (l List) URL() (string, error) {
+	url, err := url.Parse(constants.CDNRepositoryURL)
+	if err != nil {
+		return "", fmt.Errorf("parsing CDN URL: %w", err)
+	}
+	url.Path = l.JSONPath()
+	return url.String(), nil
+}
+
+// ValidateRequest validates the request parameters of the list.
+// The versions field must be empty.
+func (l List) ValidateRequest() error {
+	var retErr error
+	if err := ValidateRef(l.Ref); err != nil {
+		retErr = errors.Join(retErr, err)
+	}
+	if err := ValidateStream(l.Ref, l.Stream); err != nil {
+		retErr = errors.Join(retErr, err)
+	}
+	if l.Granularity != GranularityMajor && l.Granularity != GranularityMinor {
+		retErr = errors.Join(retErr, fmt.Errorf("granularity %q is not supported", l.Granularity))
+	}
+	if l.Kind == VersionKindUnknown {
+		retErr = errors.Join(retErr, fmt.Errorf("kind %q is not supported", l.Kind))
+	}
+	if !semver.IsValid(l.Base) {
+		retErr = errors.Join(retErr, fmt.Errorf("base version %q is not a valid semantic version", l.Base))
+	}
+	var normalizeFunc func(string) string
+	switch l.Granularity {
+	case GranularityMajor:
+		normalizeFunc = semver.Major
+	case GranularityMinor:
+		normalizeFunc = semver.MajorMinor
+	default:
+		normalizeFunc = func(s string) string { return s }
+	}
+	if normalizeFunc(l.Base) != l.Base {
+		retErr = errors.Join(retErr, fmt.Errorf("base version %q does not match granularity %q", l.Base, l.Granularity))
+	}
+	if len(l.Versions) != 0 {
+		retErr = errors.Join(retErr, fmt.Errorf("versions must be empty for request"))
+	}
+	return retErr
+}
+
+// Validate checks if the list is valid.
+// This performs the following checks:
+// - The ref is set.
+// - The stream is supported.
+// - The granularity is "major" or "minor".
+// - The kind is supported.
+// - The base version is a valid semantic version that matches the granularity.
+// - All versions in the list are valid semantic versions that are finer-grained than the base version.
+func (l List) Validate() error {
+	var retErr error
+	if err := ValidateRef(l.Ref); err != nil {
+		retErr = errors.Join(retErr, err)
+	}
+	if err := ValidateStream(l.Ref, l.Stream); err != nil {
+		retErr = errors.Join(retErr, err)
+	}
+	if l.Granularity != GranularityMajor && l.Granularity != GranularityMinor {
+		retErr = errors.Join(retErr, fmt.Errorf("granularity %q is not supported", l.Granularity))
+	}
+	if l.Kind == VersionKindUnknown {
+		retErr = errors.Join(retErr, fmt.Errorf("kind %q is not supported", l.Kind))
+	}
+	if !semver.IsValid(l.Base) {
+		retErr = errors.Join(retErr, fmt.Errorf("base version %q is not a valid semantic version", l.Base))
+	}
+	var normalizeFunc func(string) string
+	switch l.Granularity {
+	case GranularityMajor:
+		normalizeFunc = semver.Major
+	case GranularityMinor:
+		normalizeFunc = semver.MajorMinor
+	default:
+		normalizeFunc = func(s string) string { return s }
+	}
+	if normalizeFunc(l.Base) != l.Base {
+		retErr = errors.Join(retErr, fmt.Errorf("base version %q does not match granularity %q", l.Base, l.Granularity))
+	}
+	for _, ver := range l.Versions {
+		if !semver.IsValid(ver) {
+			retErr = errors.Join(retErr, fmt.Errorf("version %q is not a valid semantic version", ver))
+		}
+		if normalizeFunc(ver) != l.Base || normalizeFunc(ver) == ver {
+			retErr = errors.Join(retErr, fmt.Errorf("version %q is not finer-grained than base version %q", ver, l.Base))
+		}
+	}
+
+	return retErr
+}
+
+// Contains returns true if the list contains the given version.
+func (l List) Contains(version string) bool {
+	for _, v := range l.Versions {
+		if v == version {
+			return true
+		}
+	}
+	return false
+}
+
+// StructuredVersions returns the versions of the list as slice of
+// Version structs.
+func (l List) StructuredVersions() []Version {
+	versions := make([]Version, len(l.Versions))
+	for i, v := range l.Versions {
+		versions[i] = Version{
+			Ref:     l.Ref,
+			Stream:  l.Stream,
+			Version: v,
+			Kind:    l.Kind,
+		}
+	}
+	return versions
+}