prometheus/util/httputil/compression.go
Łukasz Mierzwa 5597020a60 Use github.com/klauspost/compress for gzip and zlib
klauspost/compress is a high quality drop-in replacement for common Go
compression libraries. Since Prometheus sends out a lot of HTTP requests
that often return compressed output having improved compression
libraries helps to save cpu & memory resources.
On a test Prometheus server I was able to see cpu reduction from 31 to
30 cores.

Benchmark results:

name                                old time/op    new time/op    delta
TargetScraperGzip/metrics=1-8         69.4µs ± 4%    69.2µs ± 3%     ~     (p=0.122 n=50+50)
TargetScraperGzip/metrics=100-8       84.3µs ± 2%    80.9µs ± 2%   -4.02%  (p=0.000 n=48+46)
TargetScraperGzip/metrics=1000-8       296µs ± 1%     274µs ±14%   -7.35%  (p=0.000 n=47+45)
TargetScraperGzip/metrics=10000-8     2.06ms ± 1%    1.66ms ± 2%  -19.34%  (p=0.000 n=47+45)
TargetScraperGzip/metrics=100000-8    20.9ms ± 2%    17.5ms ± 3%  -16.50%  (p=0.000 n=49+50)

name                                old alloc/op   new alloc/op   delta
TargetScraperGzip/metrics=1-8         6.06kB ± 0%    6.07kB ± 0%   +0.24%  (p=0.000 n=48+48)
TargetScraperGzip/metrics=100-8       7.04kB ± 0%    6.89kB ± 0%   -2.17%  (p=0.000 n=49+50)
TargetScraperGzip/metrics=1000-8      9.02kB ± 0%    8.35kB ± 1%   -7.49%  (p=0.000 n=50+50)
TargetScraperGzip/metrics=10000-8     18.1kB ± 1%    16.1kB ± 2%  -10.87%  (p=0.000 n=47+47)
TargetScraperGzip/metrics=100000-8    1.21MB ± 0%    1.01MB ± 2%  -16.69%  (p=0.000 n=36+50)

name                                old allocs/op  new allocs/op  delta
TargetScraperGzip/metrics=1-8           71.0 ± 0%      72.0 ± 0%   +1.41%  (p=0.000 n=50+50)
TargetScraperGzip/metrics=100-8         81.0 ± 0%      76.0 ± 0%   -6.17%  (p=0.000 n=50+50)
TargetScraperGzip/metrics=1000-8        92.0 ± 0%      83.0 ± 0%   -9.78%  (p=0.000 n=50+50)
TargetScraperGzip/metrics=10000-8       93.0 ± 0%      91.0 ± 0%   -2.15%  (p=0.000 n=50+50)
TargetScraperGzip/metrics=100000-8       111 ± 0%       135 ± 1%  +21.89%  (p=0.000 n=40+50)

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2024-02-22 17:08:15 +00:00

94 lines
2.8 KiB
Go

// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package httputil
import (
"io"
"net/http"
"strings"
"github.com/klauspost/compress/gzip"
"github.com/klauspost/compress/zlib"
)
const (
acceptEncodingHeader = "Accept-Encoding"
contentEncodingHeader = "Content-Encoding"
gzipEncoding = "gzip"
deflateEncoding = "deflate"
)
// Wrapper around http.Handler which adds suitable response compression based
// on the client's Accept-Encoding headers.
type compressedResponseWriter struct {
http.ResponseWriter
writer io.Writer
}
// Writes HTTP response content data.
func (c *compressedResponseWriter) Write(p []byte) (int, error) {
return c.writer.Write(p)
}
// Closes the compressedResponseWriter and ensures to flush all data before.
func (c *compressedResponseWriter) Close() {
if zlibWriter, ok := c.writer.(*zlib.Writer); ok {
zlibWriter.Flush()
}
if gzipWriter, ok := c.writer.(*gzip.Writer); ok {
gzipWriter.Flush()
}
if closer, ok := c.writer.(io.Closer); ok {
defer closer.Close()
}
}
// Constructs a new compressedResponseWriter based on client request headers.
func newCompressedResponseWriter(writer http.ResponseWriter, req *http.Request) *compressedResponseWriter {
encodings := strings.Split(req.Header.Get(acceptEncodingHeader), ",")
for _, encoding := range encodings {
switch strings.TrimSpace(encoding) {
case gzipEncoding:
writer.Header().Set(contentEncodingHeader, gzipEncoding)
return &compressedResponseWriter{
ResponseWriter: writer,
writer: gzip.NewWriter(writer),
}
case deflateEncoding:
writer.Header().Set(contentEncodingHeader, deflateEncoding)
return &compressedResponseWriter{
ResponseWriter: writer,
writer: zlib.NewWriter(writer),
}
}
}
return &compressedResponseWriter{
ResponseWriter: writer,
writer: writer,
}
}
// CompressionHandler is a wrapper around http.Handler which adds suitable
// response compression based on the client's Accept-Encoding headers.
type CompressionHandler struct {
Handler http.Handler
}
// ServeHTTP adds compression to the original http.Handler's ServeHTTP() method.
func (c CompressionHandler) ServeHTTP(writer http.ResponseWriter, req *http.Request) {
compWriter := newCompressedResponseWriter(writer, req)
c.Handler.ServeHTTP(compWriter, req)
compWriter.Close()
}