X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/45cc809dfeab1d603e80cec3d44770d7f5a7c8ae..a8be45a3ff557e879c8ad2d749b3cfbd6d9510fe:/services/keep-web/s3.go diff --git a/services/keep-web/s3.go b/services/keep-web/s3.go index 7fb90789a5..f98efd8fdf 100644 --- a/services/keep-web/s3.go +++ b/services/keep-web/s3.go @@ -2,17 +2,21 @@ // // SPDX-License-Identifier: AGPL-3.0 -package main +package keepweb import ( "crypto/hmac" "crypto/sha256" + "encoding/base64" + "encoding/json" "encoding/xml" "errors" "fmt" "hash" "io" + "mime" "net/http" + "net/textproto" "net/url" "os" "path/filepath" @@ -33,6 +37,42 @@ const ( s3MaxClockSkew = 5 * time.Minute ) +type commonPrefix struct { + Prefix string +} + +type listV1Resp struct { + XMLName string `xml:"http://s3.amazonaws.com/doc/2006-03-01/ ListBucketResult"` + s3.ListResp + // s3.ListResp marshals an empty tag when + // CommonPrefixes is nil, which confuses some clients. + // Fix by using this nested struct instead. + CommonPrefixes []commonPrefix + // Similarly, we need omitempty here, because an empty + // tag confuses some clients (e.g., + // github.com/aws/aws-sdk-net never terminates its + // paging loop). + NextMarker string `xml:"NextMarker,omitempty"` + // ListObjectsV2 has a KeyCount response field. + KeyCount int +} + +type listV2Resp struct { + XMLName string `xml:"http://s3.amazonaws.com/doc/2006-03-01/ ListBucketResult"` + IsTruncated bool + Contents []s3.Key + Name string + Prefix string + Delimiter string + MaxKeys int + CommonPrefixes []commonPrefix + EncodingType string `xml:",omitempty"` + KeyCount int + ContinuationToken string `xml:",omitempty"` + NextContinuationToken string `xml:",omitempty"` + StartAfter string `xml:",omitempty"` +} + func hmacstring(msg string, key []byte) []byte { h := hmac.New(sha256.New, key) io.WriteString(h, msg) @@ -75,6 +115,8 @@ func s3querystring(u *url.URL) string { return strings.Join(keys, "&") } +var reMultipleSlashChars = regexp.MustCompile(`//+`) + func s3stringToSign(alg, scope, signedHeaders string, r *http.Request) (string, error) { timefmt, timestr := "20060102T150405Z", r.Header.Get("X-Amz-Date") if timestr == "" { @@ -97,11 +139,39 @@ func s3stringToSign(alg, scope, signedHeaders string, r *http.Request) (string, } } - canonicalRequest := fmt.Sprintf("%s\n%s\n%s\n%s\n%s\n%s", r.Method, r.URL.EscapedPath(), s3querystring(r.URL), canonicalHeaders, signedHeaders, r.Header.Get("X-Amz-Content-Sha256")) + normalizedPath := normalizePath(r.URL.Path) + ctxlog.FromContext(r.Context()).Debugf("normalizedPath %q", normalizedPath) + canonicalRequest := fmt.Sprintf("%s\n%s\n%s\n%s\n%s\n%s", r.Method, normalizedPath, s3querystring(r.URL), canonicalHeaders, signedHeaders, r.Header.Get("X-Amz-Content-Sha256")) ctxlog.FromContext(r.Context()).Debugf("s3stringToSign: canonicalRequest %s", canonicalRequest) return fmt.Sprintf("%s\n%s\n%s\n%s", alg, r.Header.Get("X-Amz-Date"), scope, hashdigest(sha256.New(), canonicalRequest)), nil } +func normalizePath(s string) string { + // (url.URL).EscapedPath() would be incorrect here. AWS + // documentation specifies the URL path should be normalized + // according to RFC 3986, i.e., unescaping ALPHA / DIGIT / "-" + // / "." / "_" / "~". The implication is that everything other + // than those chars (and "/") _must_ be percent-encoded -- + // even chars like ";" and "," that are not normally + // percent-encoded in paths. + out := "" + for _, c := range []byte(reMultipleSlashChars.ReplaceAllString(s, "/")) { + if (c >= 'a' && c <= 'z') || + (c >= 'A' && c <= 'Z') || + (c >= '0' && c <= '9') || + c == '-' || + c == '.' || + c == '_' || + c == '~' || + c == '/' { + out += string(c) + } else { + out += fmt.Sprintf("%%%02X", c) + } + } + return out +} + func s3signature(secretKey, scope, signedHeaders, stringToSign string) (string, error) { // scope is {datestamp}/{region}/{service}/aws4_request drs := strings.Split(scope, "/") @@ -153,8 +223,8 @@ func (h *handler) checks3signature(r *http.Request) (string, error) { } client := (&arvados.Client{ - APIHost: h.Config.cluster.Services.Controller.ExternalURL.Host, - Insecure: h.Config.cluster.TLS.Insecure, + APIHost: h.Cluster.Services.Controller.ExternalURL.Host, + Insecure: h.Cluster.TLS.Insecure, }).WithRequestID(r.Header.Get("X-Request-Id")) var aca arvados.APIClientAuthorization var secret string @@ -162,7 +232,7 @@ func (h *handler) checks3signature(r *http.Request) (string, error) { if len(key) == 27 && key[5:12] == "-gj3su-" { // Access key is the UUID of an Arvados token, secret // key is the secret part. - ctx := arvados.ContextWithAuthorization(r.Context(), "Bearer "+h.Config.cluster.SystemRootToken) + ctx := arvados.ContextWithAuthorization(r.Context(), "Bearer "+h.Cluster.SystemRootToken) err = client.RequestAndDecodeContext(ctx, &aca, "GET", "arvados/v1/api_client_authorizations/"+key, nil, nil) secret = aca.APIToken } else { @@ -216,6 +286,8 @@ var UnauthorizedAccess = "UnauthorizedAccess" var InvalidRequest = "InvalidRequest" var SignatureDoesNotMatch = "SignatureDoesNotMatch" +var reRawQueryIndicatesAPI = regexp.MustCompile(`^[a-z]+(&|$)`) + // serveS3 handles r and returns true if r is a request from an S3 // client, otherwise it returns false. func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { @@ -238,25 +310,33 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { return false } - _, kc, client, release, err := h.getClients(r.Header.Get("X-Request-Id"), token) + fs, sess, tokenUser, err := h.Cache.GetSession(token) if err != nil { - s3ErrorResponse(w, InternalError, "Pool failed: "+h.clientPool.Err().Error(), r.URL.Path, http.StatusInternalServerError) + s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusInternalServerError) return true } - defer release() - - fs := client.SiteFileSystem(kc) - fs.ForwardSlashNameSubstitution(h.Config.cluster.Collections.ForwardSlashNameSubstitution) + readfs := fs + if writeMethod[r.Method] { + // Create a FileSystem for this request, to avoid + // exposing incomplete write operations to concurrent + // requests. + client := sess.client.WithRequestID(r.Header.Get("X-Request-Id")) + fs = client.SiteFileSystem(sess.keepclient) + fs.ForwardSlashNameSubstitution(h.Cluster.Collections.ForwardSlashNameSubstitution) + } var objectNameGiven bool + var bucketName string fspath := "/by_id" - if id := parseCollectionIDFromDNSName(r.Host); id != "" { + if id := arvados.CollectionIDFromDNSName(r.Host); id != "" { fspath += "/" + id + bucketName = id objectNameGiven = strings.Count(strings.TrimSuffix(r.URL.Path, "/"), "/") > 0 } else { + bucketName = strings.SplitN(strings.TrimPrefix(r.URL.Path, "/"), "/", 2)[0] objectNameGiven = strings.Count(strings.TrimSuffix(r.URL.Path, "/"), "/") > 1 } - fspath += r.URL.Path + fspath += reMultipleSlashChars.ReplaceAllString(r.URL.Path, "/") switch { case r.Method == http.MethodGet && !objectNameGiven: @@ -266,16 +346,36 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { w.Header().Set("Content-Type", "application/xml") io.WriteString(w, xml.Header) fmt.Fprintln(w, ``) + } else if _, ok = r.URL.Query()["location"]; ok { + // GetBucketLocation + w.Header().Set("Content-Type", "application/xml") + io.WriteString(w, xml.Header) + fmt.Fprintln(w, ``+ + h.Cluster.ClusterID+ + ``) + } else if reRawQueryIndicatesAPI.MatchString(r.URL.RawQuery) { + // GetBucketWebsite ("GET /bucketid/?website"), GetBucketTagging, etc. + s3ErrorResponse(w, InvalidRequest, "API not supported", r.URL.Path+"?"+r.URL.RawQuery, http.StatusBadRequest) } else { // ListObjects - h.s3list(w, r, fs) + h.s3list(bucketName, w, r, fs) } return true case r.Method == http.MethodGet || r.Method == http.MethodHead: + if reRawQueryIndicatesAPI.MatchString(r.URL.RawQuery) { + // GetObjectRetention ("GET /bucketid/objectid?retention&versionID=..."), etc. + s3ErrorResponse(w, InvalidRequest, "API not supported", r.URL.Path+"?"+r.URL.RawQuery, http.StatusBadRequest) + return true + } fi, err := fs.Stat(fspath) if r.Method == "HEAD" && !objectNameGiven { // HeadBucket if err == nil && fi.IsDir() { + err = setFileInfoHeaders(w.Header(), fs, fspath) + if err != nil { + s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusBadGateway) + return true + } w.WriteHeader(http.StatusOK) } else if os.IsNotExist(err) { s3ErrorResponse(w, NoSuchBucket, "The specified bucket does not exist.", r.URL.Path, http.StatusNotFound) @@ -284,7 +384,12 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { } return true } - if err == nil && fi.IsDir() && objectNameGiven && strings.HasSuffix(fspath, "/") && h.Config.cluster.Collections.S3FolderObjects { + if err == nil && fi.IsDir() && objectNameGiven && strings.HasSuffix(fspath, "/") && h.Cluster.Collections.S3FolderObjects { + err = setFileInfoHeaders(w.Header(), fs, fspath) + if err != nil { + s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusBadGateway) + return true + } w.Header().Set("Content-Type", "application/x-directory") w.WriteHeader(http.StatusOK) return true @@ -295,19 +400,36 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { s3ErrorResponse(w, NoSuchKey, "The specified key does not exist.", r.URL.Path, http.StatusNotFound) return true } + + if !h.userPermittedToUploadOrDownload(r.Method, tokenUser) { + http.Error(w, "Not permitted", http.StatusForbidden) + return true + } + h.logUploadOrDownload(r, sess.arvadosclient, fs, fspath, nil, tokenUser) + // shallow copy r, and change URL path r := *r r.URL.Path = fspath + err = setFileInfoHeaders(w.Header(), fs, fspath) + if err != nil { + s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusBadGateway) + return true + } http.FileServer(fs).ServeHTTP(w, &r) return true case r.Method == http.MethodPut: + if reRawQueryIndicatesAPI.MatchString(r.URL.RawQuery) { + // PutObjectAcl ("PUT /bucketid/objectid?acl&versionID=..."), etc. + s3ErrorResponse(w, InvalidRequest, "API not supported", r.URL.Path+"?"+r.URL.RawQuery, http.StatusBadRequest) + return true + } if !objectNameGiven { s3ErrorResponse(w, InvalidArgument, "Missing object name in PUT request.", r.URL.Path, http.StatusBadRequest) return true } var objectIsDir bool if strings.HasSuffix(fspath, "/") { - if !h.Config.cluster.Collections.S3FolderObjects { + if !h.Cluster.Collections.S3FolderObjects { s3ErrorResponse(w, InvalidArgument, "invalid object name: trailing slash", r.URL.Path, http.StatusBadRequest) return true } @@ -349,7 +471,7 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { return true } err = fs.Mkdir(dir, 0755) - if err == arvados.ErrInvalidArgument { + if errors.Is(err, arvados.ErrInvalidArgument) || errors.Is(err, arvados.ErrInvalidOperation) { // Cannot create a directory // here. err = fmt.Errorf("mkdir %q failed: %w", dir, err) @@ -373,6 +495,13 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { return true } defer f.Close() + + if !h.userPermittedToUploadOrDownload(r.Method, tokenUser) { + http.Error(w, "Not permitted", http.StatusForbidden) + return true + } + h.logUploadOrDownload(r, sess.arvadosclient, fs, fspath, nil, tokenUser) + _, err = io.Copy(f, r.Body) if err != nil { err = fmt.Errorf("write to %q failed: %w", r.URL.Path, err) @@ -386,7 +515,7 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { return true } } - err = fs.Sync() + err = h.syncCollection(fs, readfs, fspath) if err != nil { err = fmt.Errorf("sync failed: %w", err) s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusInternalServerError) @@ -395,6 +524,11 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { w.WriteHeader(http.StatusOK) return true case r.Method == http.MethodDelete: + if reRawQueryIndicatesAPI.MatchString(r.URL.RawQuery) { + // DeleteObjectTagging ("DELETE /bucketid/objectid?tagging&versionID=..."), etc. + s3ErrorResponse(w, InvalidRequest, "API not supported", r.URL.Path+"?"+r.URL.RawQuery, http.StatusBadRequest) + return true + } if !objectNameGiven || r.URL.Path == "/" { s3ErrorResponse(w, InvalidArgument, "missing object name in DELETE request", r.URL.Path, http.StatusBadRequest) return true @@ -433,7 +567,7 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { s3ErrorResponse(w, InvalidArgument, err.Error(), r.URL.Path, http.StatusBadRequest) return true } - err = fs.Sync() + err = h.syncCollection(fs, readfs, fspath) if err != nil { err = fmt.Errorf("sync failed: %w", err) s3ErrorResponse(w, InternalError, err.Error(), r.URL.Path, http.StatusInternalServerError) @@ -443,11 +577,92 @@ func (h *handler) serveS3(w http.ResponseWriter, r *http.Request) bool { return true default: s3ErrorResponse(w, InvalidRequest, "method not allowed", r.URL.Path, http.StatusMethodNotAllowed) - return true } } +// Save modifications to the indicated collection in srcfs, then (if +// successful) ensure they are also reflected in dstfs. +func (h *handler) syncCollection(srcfs, dstfs arvados.CustomFileSystem, path string) error { + coll, _ := h.determineCollection(srcfs, path) + if coll == nil || coll.UUID == "" { + return errors.New("could not determine collection to sync") + } + d, err := srcfs.OpenFile("by_id/"+coll.UUID, os.O_RDWR, 0777) + if err != nil { + return err + } + defer d.Close() + err = d.Sync() + if err != nil { + return err + } + snap, err := d.Snapshot() + if err != nil { + return err + } + dstd, err := dstfs.OpenFile("by_id/"+coll.UUID, os.O_RDWR, 0777) + if err != nil { + return err + } + defer dstd.Close() + return dstd.Splice(snap) +} + +func setFileInfoHeaders(header http.Header, fs arvados.CustomFileSystem, path string) error { + maybeEncode := func(s string) string { + for _, c := range s { + if c > '\u007f' || c < ' ' { + return mime.BEncoding.Encode("UTF-8", s) + } + } + return s + } + path = strings.TrimSuffix(path, "/") + var props map[string]interface{} + for { + fi, err := fs.Stat(path) + if err != nil { + return err + } + switch src := fi.Sys().(type) { + case *arvados.Collection: + props = src.Properties + case *arvados.Group: + props = src.Properties + default: + if err, ok := src.(error); ok { + return err + } + // Try parent + cut := strings.LastIndexByte(path, '/') + if cut < 0 { + return nil + } + path = path[:cut] + continue + } + break + } + for k, v := range props { + if !validMIMEHeaderKey(k) { + continue + } + k = "x-amz-meta-" + k + if s, ok := v.(string); ok { + header.Set(k, maybeEncode(s)) + } else if j, err := json.Marshal(v); err == nil { + header.Set(k, maybeEncode(string(j))) + } + } + return nil +} + +func validMIMEHeaderKey(k string) bool { + check := "z-" + k + return check != textproto.CanonicalMIMEHeaderKey(check) +} + // Call fn on the given path (directory) and its contents, in // lexicographic order. // @@ -504,25 +719,54 @@ func walkFS(fs arvados.CustomFileSystem, path string, isRoot bool, fn func(path var errDone = errors.New("done") -func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.CustomFileSystem) { +func (h *handler) s3list(bucket string, w http.ResponseWriter, r *http.Request, fs arvados.CustomFileSystem) { var params struct { - bucket string - delimiter string - marker string - maxKeys int - prefix string + v2 bool + delimiter string + maxKeys int + prefix string + marker string // decoded continuationToken (v2) or provided by client (v1) + startAfter string // v2 + continuationToken string // v2 + encodingTypeURL bool // v2 } - params.bucket = strings.SplitN(r.URL.Path[1:], "/", 2)[0] params.delimiter = r.FormValue("delimiter") - params.marker = r.FormValue("marker") if mk, _ := strconv.ParseInt(r.FormValue("max-keys"), 10, 64); mk > 0 && mk < s3MaxKeys { params.maxKeys = int(mk) } else { params.maxKeys = s3MaxKeys } params.prefix = r.FormValue("prefix") + switch r.FormValue("list-type") { + case "": + case "2": + params.v2 = true + default: + http.Error(w, "invalid list-type parameter", http.StatusBadRequest) + return + } + if params.v2 { + params.continuationToken = r.FormValue("continuation-token") + marker, err := base64.StdEncoding.DecodeString(params.continuationToken) + if err != nil { + http.Error(w, "invalid continuation token", http.StatusBadRequest) + return + } + params.marker = string(marker) + params.startAfter = r.FormValue("start-after") + switch r.FormValue("encoding-type") { + case "": + case "url": + params.encodingTypeURL = true + default: + http.Error(w, "invalid encoding-type parameter", http.StatusBadRequest) + return + } + } else { + params.marker = r.FormValue("marker") + } - bucketdir := "by_id/" + params.bucket + bucketdir := "by_id/" + bucket // walkpath is the directory (relative to bucketdir) we need // to walk: the innermost directory that is guaranteed to // contain all paths that have the requested prefix. Examples: @@ -537,33 +781,16 @@ func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.Cust walkpath = "" } - type commonPrefix struct { - Prefix string - } - type listResp struct { - XMLName string `xml:"http://s3.amazonaws.com/doc/2006-03-01/ ListBucketResult"` - s3.ListResp - // s3.ListResp marshals an empty tag when - // CommonPrefixes is nil, which confuses some clients. - // Fix by using this nested struct instead. - CommonPrefixes []commonPrefix - // Similarly, we need omitempty here, because an empty - // tag confuses some clients (e.g., - // github.com/aws/aws-sdk-net never terminates its - // paging loop). - NextMarker string `xml:"NextMarker,omitempty"` - // ListObjectsV2 has a KeyCount response field. - KeyCount int - } - resp := listResp{ - ListResp: s3.ListResp{ - Name: strings.SplitN(r.URL.Path[1:], "/", 2)[0], - Prefix: params.prefix, - Delimiter: params.delimiter, - Marker: params.marker, - MaxKeys: params.maxKeys, - }, - } + resp := listV2Resp{ + Name: bucket, + Prefix: params.prefix, + Delimiter: params.delimiter, + MaxKeys: params.maxKeys, + ContinuationToken: r.FormValue("continuation-token"), + StartAfter: params.startAfter, + } + nextMarker := "" + commonPrefixes := map[string]bool{} err := walkFS(fs, strings.TrimSuffix(bucketdir+"/"+walkpath, "/"), true, func(path string, fi os.FileInfo) error { if path == bucketdir { @@ -603,10 +830,10 @@ func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.Cust return errDone } } - if path < params.marker || path < params.prefix { + if path < params.marker || path < params.prefix || path <= params.startAfter { return nil } - if fi.IsDir() && !h.Config.cluster.Collections.S3FolderObjects { + if fi.IsDir() && !h.Cluster.Collections.S3FolderObjects { // Note we don't add anything to // commonPrefixes here even if delimiter is // "/". We descend into the directory, and @@ -614,6 +841,13 @@ func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.Cust // finding a regular file inside it. return nil } + if len(resp.Contents)+len(commonPrefixes) >= params.maxKeys { + resp.IsTruncated = true + if params.delimiter != "" || params.v2 { + nextMarker = path + } + return errDone + } if params.delimiter != "" { idx := strings.Index(path[len(params.prefix):], params.delimiter) if idx >= 0 { @@ -625,13 +859,6 @@ func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.Cust return filepath.SkipDir } } - if len(resp.Contents)+len(commonPrefixes) >= params.maxKeys { - resp.IsTruncated = true - if params.delimiter != "" { - resp.NextMarker = path - } - return errDone - } resp.Contents = append(resp.Contents, s3.Key{ Key: path, LastModified: fi.ModTime().UTC().Format("2006-01-02T15:04:05.999") + "Z", @@ -651,9 +878,66 @@ func (h *handler) s3list(w http.ResponseWriter, r *http.Request, fs arvados.Cust sort.Slice(resp.CommonPrefixes, func(i, j int) bool { return resp.CommonPrefixes[i].Prefix < resp.CommonPrefixes[j].Prefix }) } resp.KeyCount = len(resp.Contents) + var respV1orV2 interface{} + + if params.encodingTypeURL { + // https://docs.aws.amazon.com/AmazonS3/latest/API/API_ListObjectsV2.html + // "If you specify the encoding-type request + // parameter, Amazon S3 includes this element in the + // response, and returns encoded key name values in + // the following response elements: + // + // Delimiter, Prefix, Key, and StartAfter. + // + // Type: String + // + // Valid Values: url" + // + // This is somewhat vague but in practice it appears + // to mean x-www-form-urlencoded as in RFC1866 8.2.1 + // para 1 (encode space as "+") rather than straight + // percent-encoding as in RFC1738 2.2. Presumably, + // the intent is to allow the client to decode XML and + // then paste the strings directly into another URI + // query or POST form like "https://host/path?foo=" + + // foo + "&bar=" + bar. + resp.EncodingType = "url" + resp.Delimiter = url.QueryEscape(resp.Delimiter) + resp.Prefix = url.QueryEscape(resp.Prefix) + resp.StartAfter = url.QueryEscape(resp.StartAfter) + for i, ent := range resp.Contents { + ent.Key = url.QueryEscape(ent.Key) + resp.Contents[i] = ent + } + for i, ent := range resp.CommonPrefixes { + ent.Prefix = url.QueryEscape(ent.Prefix) + resp.CommonPrefixes[i] = ent + } + } + + if params.v2 { + resp.NextContinuationToken = base64.StdEncoding.EncodeToString([]byte(nextMarker)) + respV1orV2 = resp + } else { + respV1orV2 = listV1Resp{ + CommonPrefixes: resp.CommonPrefixes, + NextMarker: nextMarker, + KeyCount: resp.KeyCount, + ListResp: s3.ListResp{ + IsTruncated: resp.IsTruncated, + Name: bucket, + Prefix: params.prefix, + Delimiter: params.delimiter, + Marker: params.marker, + MaxKeys: params.maxKeys, + Contents: resp.Contents, + }, + } + } + w.Header().Set("Content-Type", "application/xml") io.WriteString(w, xml.Header) - if err := xml.NewEncoder(w).Encode(resp); err != nil { + if err := xml.NewEncoder(w).Encode(respV1orV2); err != nil { ctxlog.FromContext(r.Context()).WithError(err).Error("error writing xml response") } }