git subrepo clone (merge) https://github.com/kubernetes-incubator/metrics-server.git metrics-server
subrepo:
subdir: "metrics-server"
merged: "92d8412"
upstream:
origin: "https://github.com/kubernetes-incubator/metrics-server.git"
branch: "master"
commit: "92d8412"
git-subrepo:
version: "0.4.0"
origin: "???"
commit: "???"
diff --git a/metrics-server/vendor/github.com/NYTimes/gziphandler/gzip.go b/metrics-server/vendor/github.com/NYTimes/gziphandler/gzip.go
new file mode 100644
index 0000000..f91dcfa
--- /dev/null
+++ b/metrics-server/vendor/github.com/NYTimes/gziphandler/gzip.go
@@ -0,0 +1,429 @@
+package gziphandler
+
+import (
+ "bufio"
+ "compress/gzip"
+ "fmt"
+ "io"
+ "net"
+ "net/http"
+ "strconv"
+ "strings"
+ "sync"
+)
+
+const (
+ vary = "Vary"
+ acceptEncoding = "Accept-Encoding"
+ contentEncoding = "Content-Encoding"
+ contentType = "Content-Type"
+ contentLength = "Content-Length"
+)
+
+type codings map[string]float64
+
+const (
+ // DefaultQValue is the default qvalue to assign to an encoding if no explicit qvalue is set.
+ // This is actually kind of ambiguous in RFC 2616, so hopefully it's correct.
+ // The examples seem to indicate that it is.
+ DefaultQValue = 1.0
+
+ // 1500 bytes is the MTU size for the internet since that is the largest size allowed at the network layer.
+ // If you take a file that is 1300 bytes and compress it to 800 bytes, it’s still transmitted in that same 1500 byte packet regardless, so you’ve gained nothing.
+ // That being the case, you should restrict the gzip compression to files with a size greater than a single packet, 1400 bytes (1.4KB) is a safe value.
+ DefaultMinSize = 1400
+)
+
+// gzipWriterPools stores a sync.Pool for each compression level for reuse of
+// gzip.Writers. Use poolIndex to covert a compression level to an index into
+// gzipWriterPools.
+var gzipWriterPools [gzip.BestCompression - gzip.BestSpeed + 2]*sync.Pool
+
+func init() {
+ for i := gzip.BestSpeed; i <= gzip.BestCompression; i++ {
+ addLevelPool(i)
+ }
+ addLevelPool(gzip.DefaultCompression)
+}
+
+// poolIndex maps a compression level to its index into gzipWriterPools. It
+// assumes that level is a valid gzip compression level.
+func poolIndex(level int) int {
+ // gzip.DefaultCompression == -1, so we need to treat it special.
+ if level == gzip.DefaultCompression {
+ return gzip.BestCompression - gzip.BestSpeed + 1
+ }
+ return level - gzip.BestSpeed
+}
+
+func addLevelPool(level int) {
+ gzipWriterPools[poolIndex(level)] = &sync.Pool{
+ New: func() interface{} {
+ // NewWriterLevel only returns error on a bad level, we are guaranteeing
+ // that this will be a valid level so it is okay to ignore the returned
+ // error.
+ w, _ := gzip.NewWriterLevel(nil, level)
+ return w
+ },
+ }
+}
+
+// GzipResponseWriter provides an http.ResponseWriter interface, which gzips
+// bytes before writing them to the underlying response. This doesn't close the
+// writers, so don't forget to do that.
+// It can be configured to skip response smaller than minSize.
+type GzipResponseWriter struct {
+ http.ResponseWriter
+ index int // Index for gzipWriterPools.
+ gw *gzip.Writer
+
+ code int // Saves the WriteHeader value.
+
+ minSize int // Specifed the minimum response size to gzip. If the response length is bigger than this value, it is compressed.
+ buf []byte // Holds the first part of the write before reaching the minSize or the end of the write.
+
+ contentTypes []string // Only compress if the response is one of these content-types. All are accepted if empty.
+}
+
+type GzipResponseWriterWithCloseNotify struct {
+ *GzipResponseWriter
+}
+
+func (w GzipResponseWriterWithCloseNotify) CloseNotify() <-chan bool {
+ return w.ResponseWriter.(http.CloseNotifier).CloseNotify()
+}
+
+// Write appends data to the gzip writer.
+func (w *GzipResponseWriter) Write(b []byte) (int, error) {
+ // If content type is not set.
+ if _, ok := w.Header()[contentType]; !ok {
+ // It infer it from the uncompressed body.
+ w.Header().Set(contentType, http.DetectContentType(b))
+ }
+
+ // GZIP responseWriter is initialized. Use the GZIP responseWriter.
+ if w.gw != nil {
+ n, err := w.gw.Write(b)
+ return n, err
+ }
+
+ // Save the write into a buffer for later use in GZIP responseWriter (if content is long enough) or at close with regular responseWriter.
+ // On the first write, w.buf changes from nil to a valid slice
+ w.buf = append(w.buf, b...)
+
+ // If the global writes are bigger than the minSize and we're about to write
+ // a response containing a content type we want to handle, enable
+ // compression.
+ if len(w.buf) >= w.minSize && handleContentType(w.contentTypes, w) && w.Header().Get(contentEncoding) == "" {
+ err := w.startGzip()
+ if err != nil {
+ return 0, err
+ }
+ }
+
+ return len(b), nil
+}
+
+// startGzip initialize any GZIP specific informations.
+func (w *GzipResponseWriter) startGzip() error {
+
+ // Set the GZIP header.
+ w.Header().Set(contentEncoding, "gzip")
+
+ // if the Content-Length is already set, then calls to Write on gzip
+ // will fail to set the Content-Length header since its already set
+ // See: https://github.com/golang/go/issues/14975.
+ w.Header().Del(contentLength)
+
+ // Write the header to gzip response.
+ if w.code != 0 {
+ w.ResponseWriter.WriteHeader(w.code)
+ }
+
+ // Initialize the GZIP response.
+ w.init()
+
+ // Flush the buffer into the gzip response.
+ n, err := w.gw.Write(w.buf)
+
+ // This should never happen (per io.Writer docs), but if the write didn't
+ // accept the entire buffer but returned no specific error, we have no clue
+ // what's going on, so abort just to be safe.
+ if err == nil && n < len(w.buf) {
+ return io.ErrShortWrite
+ }
+
+ w.buf = nil
+ return err
+}
+
+// WriteHeader just saves the response code until close or GZIP effective writes.
+func (w *GzipResponseWriter) WriteHeader(code int) {
+ if w.code == 0 {
+ w.code = code
+ }
+}
+
+// init graps a new gzip writer from the gzipWriterPool and writes the correct
+// content encoding header.
+func (w *GzipResponseWriter) init() {
+ // Bytes written during ServeHTTP are redirected to this gzip writer
+ // before being written to the underlying response.
+ gzw := gzipWriterPools[w.index].Get().(*gzip.Writer)
+ gzw.Reset(w.ResponseWriter)
+ w.gw = gzw
+}
+
+// Close will close the gzip.Writer and will put it back in the gzipWriterPool.
+func (w *GzipResponseWriter) Close() error {
+ if w.gw == nil {
+ // Gzip not trigged yet, write out regular response.
+ if w.code != 0 {
+ w.ResponseWriter.WriteHeader(w.code)
+ }
+ if w.buf != nil {
+ _, writeErr := w.ResponseWriter.Write(w.buf)
+ // Returns the error if any at write.
+ if writeErr != nil {
+ return fmt.Errorf("gziphandler: write to regular responseWriter at close gets error: %q", writeErr.Error())
+ }
+ }
+ return nil
+ }
+
+ err := w.gw.Close()
+ gzipWriterPools[w.index].Put(w.gw)
+ w.gw = nil
+ return err
+}
+
+// Flush flushes the underlying *gzip.Writer and then the underlying
+// http.ResponseWriter if it is an http.Flusher. This makes GzipResponseWriter
+// an http.Flusher.
+func (w *GzipResponseWriter) Flush() {
+ if w.gw == nil {
+ // Only flush once startGzip has been called.
+ //
+ // Flush is thus a no-op until the written body
+ // exceeds minSize.
+ return
+ }
+
+ w.gw.Flush()
+
+ if fw, ok := w.ResponseWriter.(http.Flusher); ok {
+ fw.Flush()
+ }
+}
+
+// Hijack implements http.Hijacker. If the underlying ResponseWriter is a
+// Hijacker, its Hijack method is returned. Otherwise an error is returned.
+func (w *GzipResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+ if hj, ok := w.ResponseWriter.(http.Hijacker); ok {
+ return hj.Hijack()
+ }
+ return nil, nil, fmt.Errorf("http.Hijacker interface is not supported")
+}
+
+// verify Hijacker interface implementation
+var _ http.Hijacker = &GzipResponseWriter{}
+
+// MustNewGzipLevelHandler behaves just like NewGzipLevelHandler except that in
+// an error case it panics rather than returning an error.
+func MustNewGzipLevelHandler(level int) func(http.Handler) http.Handler {
+ wrap, err := NewGzipLevelHandler(level)
+ if err != nil {
+ panic(err)
+ }
+ return wrap
+}
+
+// NewGzipLevelHandler returns a wrapper function (often known as middleware)
+// which can be used to wrap an HTTP handler to transparently gzip the response
+// body if the client supports it (via the Accept-Encoding header). Responses will
+// be encoded at the given gzip compression level. An error will be returned only
+// if an invalid gzip compression level is given, so if one can ensure the level
+// is valid, the returned error can be safely ignored.
+func NewGzipLevelHandler(level int) (func(http.Handler) http.Handler, error) {
+ return NewGzipLevelAndMinSize(level, DefaultMinSize)
+}
+
+// NewGzipLevelAndMinSize behave as NewGzipLevelHandler except it let the caller
+// specify the minimum size before compression.
+func NewGzipLevelAndMinSize(level, minSize int) (func(http.Handler) http.Handler, error) {
+ return GzipHandlerWithOpts(CompressionLevel(level), MinSize(minSize))
+}
+
+func GzipHandlerWithOpts(opts ...option) (func(http.Handler) http.Handler, error) {
+ c := &config{
+ level: gzip.DefaultCompression,
+ minSize: DefaultMinSize,
+ }
+
+ for _, o := range opts {
+ o(c)
+ }
+
+ if err := c.validate(); err != nil {
+ return nil, err
+ }
+
+ return func(h http.Handler) http.Handler {
+ index := poolIndex(c.level)
+
+ return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+ w.Header().Add(vary, acceptEncoding)
+ if acceptsGzip(r) {
+ gw := &GzipResponseWriter{
+ ResponseWriter: w,
+ index: index,
+ minSize: c.minSize,
+ contentTypes: c.contentTypes,
+ }
+ defer gw.Close()
+
+ if _, ok := w.(http.CloseNotifier); ok {
+ gwcn := GzipResponseWriterWithCloseNotify{gw}
+ h.ServeHTTP(gwcn, r)
+ } else {
+ h.ServeHTTP(gw, r)
+ }
+
+ } else {
+ h.ServeHTTP(w, r)
+ }
+ })
+ }, nil
+}
+
+// Used for functional configuration.
+type config struct {
+ minSize int
+ level int
+ contentTypes []string
+}
+
+func (c *config) validate() error {
+ if c.level != gzip.DefaultCompression && (c.level < gzip.BestSpeed || c.level > gzip.BestCompression) {
+ return fmt.Errorf("invalid compression level requested: %d", c.level)
+ }
+
+ if c.minSize < 0 {
+ return fmt.Errorf("minimum size must be more than zero")
+ }
+
+ return nil
+}
+
+type option func(c *config)
+
+func MinSize(size int) option {
+ return func(c *config) {
+ c.minSize = size
+ }
+}
+
+func CompressionLevel(level int) option {
+ return func(c *config) {
+ c.level = level
+ }
+}
+
+func ContentTypes(types []string) option {
+ return func(c *config) {
+ c.contentTypes = []string{}
+ for _, v := range types {
+ c.contentTypes = append(c.contentTypes, strings.ToLower(v))
+ }
+ }
+}
+
+// GzipHandler wraps an HTTP handler, to transparently gzip the response body if
+// the client supports it (via the Accept-Encoding header). This will compress at
+// the default compression level.
+func GzipHandler(h http.Handler) http.Handler {
+ wrapper, _ := NewGzipLevelHandler(gzip.DefaultCompression)
+ return wrapper(h)
+}
+
+// acceptsGzip returns true if the given HTTP request indicates that it will
+// accept a gzipped response.
+func acceptsGzip(r *http.Request) bool {
+ acceptedEncodings, _ := parseEncodings(r.Header.Get(acceptEncoding))
+ return acceptedEncodings["gzip"] > 0.0
+}
+
+// returns true if we've been configured to compress the specific content type.
+func handleContentType(contentTypes []string, w http.ResponseWriter) bool {
+ // If contentTypes is empty we handle all content types.
+ if len(contentTypes) == 0 {
+ return true
+ }
+
+ ct := strings.ToLower(w.Header().Get(contentType))
+ for _, c := range contentTypes {
+ if c == ct {
+ return true
+ }
+ }
+
+ return false
+}
+
+// parseEncodings attempts to parse a list of codings, per RFC 2616, as might
+// appear in an Accept-Encoding header. It returns a map of content-codings to
+// quality values, and an error containing the errors encountered. It's probably
+// safe to ignore those, because silently ignoring errors is how the internet
+// works.
+//
+// See: http://tools.ietf.org/html/rfc2616#section-14.3.
+func parseEncodings(s string) (codings, error) {
+ c := make(codings)
+ var e []string
+
+ for _, ss := range strings.Split(s, ",") {
+ coding, qvalue, err := parseCoding(ss)
+
+ if err != nil {
+ e = append(e, err.Error())
+ } else {
+ c[coding] = qvalue
+ }
+ }
+
+ // TODO (adammck): Use a proper multi-error struct, so the individual errors
+ // can be extracted if anyone cares.
+ if len(e) > 0 {
+ return c, fmt.Errorf("errors while parsing encodings: %s", strings.Join(e, ", "))
+ }
+
+ return c, nil
+}
+
+// parseCoding parses a single conding (content-coding with an optional qvalue),
+// as might appear in an Accept-Encoding header. It attempts to forgive minor
+// formatting errors.
+func parseCoding(s string) (coding string, qvalue float64, err error) {
+ for n, part := range strings.Split(s, ";") {
+ part = strings.TrimSpace(part)
+ qvalue = DefaultQValue
+
+ if n == 0 {
+ coding = strings.ToLower(part)
+ } else if strings.HasPrefix(part, "q=") {
+ qvalue, err = strconv.ParseFloat(strings.TrimPrefix(part, "q="), 64)
+
+ if qvalue < 0.0 {
+ qvalue = 0.0
+ } else if qvalue > 1.0 {
+ qvalue = 1.0
+ }
+ }
+ }
+
+ if coding == "" {
+ err = fmt.Errorf("empty content-coding")
+ }
+
+ return
+}