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/latest.go

@@ -0,0 +1,93 @@
+/*
+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"
+)
+
+// Latest is the latest version of a kind of resource.
+type Latest struct {
+	// Ref is the branch name this latest version belongs to.
+	Ref string `json:"ref,omitempty"`
+	// Stream is stream name this latest version belongs to.
+	Stream string `json:"stream,omitempty"`
+	// Kind is the kind of resource this latest version is for.
+	Kind VersionKind `json:"kind,omitempty"`
+	// Version is the latest version for this ref, stream and kind.
+	Version string `json:"version,omitempty"`
+}
+
+// JSONPath returns the S3 JSON path for this object.
+func (l Latest) JSONPath() string {
+	return path.Join(
+		constants.CDNAPIPrefix,
+		"ref", l.Ref,
+		"stream", l.Stream,
+		"versions",
+		"latest",
+		l.Kind.String()+".json",
+	)
+}
+
+// URL returns the URL for this object.
+func (l Latest) 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
+}
+
+// Validate checks if this latest version is valid.
+func (l Latest) 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.Kind == VersionKindUnknown {
+		retErr = errors.Join(retErr, fmt.Errorf("version of kind %q is not supported", l.Kind))
+	}
+	if !semver.IsValid(l.Version) {
+		retErr = errors.Join(retErr, fmt.Errorf("version %q is not a valid semver", l.Version))
+	}
+
+	return retErr
+}
+
+// ValidateRequest checks if this latest version beside values that are fetched.
+func (l Latest) 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.Kind == VersionKindUnknown {
+		retErr = errors.Join(retErr, fmt.Errorf("version of kind %q is not supported", l.Kind))
+	}
+	if l.Version != "" {
+		retErr = errors.Join(retErr, fmt.Errorf("version %q must be empty for request", l.Version))
+	}
+	return retErr
+}
+
+// ShortPath returns the short path of the latest version.
+func (l Latest) ShortPath() string {
+	return shortPath(l.Ref, l.Stream, l.Version)
+}