73558d1412
This middleware adds support for grepping objects in-place using the GREP
method and the "e" query parameter. "e" was chosen go match grep(1). Other
grep parameters may be implemented later if needed.
It detects gzip and bzip2 files and decompresses them inline.
This is intended to allow backend tools to search log files.
Example:
GREP /sda/123/account/container/object?e=SEARCH HTTP/1.1
Change-Id: I569a72f4fc0f8ab85b90e8677f6daff0e28e8a79
102 lines
2.6 KiB
Go
102 lines
2.6 KiB
Go
// Copyright (c) 2015 Rackspace
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
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// implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package middleware
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import (
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"bufio"
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"compress/bzip2"
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"compress/gzip"
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"io"
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"net/http"
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"regexp"
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)
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type grepWriter struct {
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w io.Writer
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h http.Header
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status int
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}
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func (g *grepWriter) Header() http.Header {
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return g.h
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}
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func (g *grepWriter) Write(buf []byte) (int, error) {
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return g.w.Write(buf)
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}
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func (g *grepWriter) WriteHeader(status int) {
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g.status = status
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}
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// GrepObject is an http middleware that searches objects line-by-line on the object server, similar to grep(1).
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func GrepObject(next http.Handler) http.Handler {
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return http.HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
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if request.Method != "GREP" {
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next.ServeHTTP(writer, request)
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return
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}
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pr, pw := io.Pipe()
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defer pr.Close()
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defer pw.Close()
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newWriter := &grepWriter{w: pw, h: make(http.Header), status: 200}
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newRequest, _ := http.NewRequest("GET", request.URL.String(), nil)
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newRequest.Header = request.Header
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go func() {
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defer pw.Close()
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next.ServeHTTP(newWriter, newRequest)
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}()
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q := request.URL.Query().Get("e")
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if q == "" {
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writer.WriteHeader(400)
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return
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}
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re, err := regexp.Compile(q)
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if err != nil {
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writer.WriteHeader(400)
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return
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}
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// peek at response data first to make sure the downstream handler has set a status code
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br := bufio.NewReader(pr)
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magic, err := br.Peek(4)
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if newWriter.status == 200 {
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var scanner *bufio.Scanner
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if err == nil && magic[0] == 0x1f && magic[1] == 0x8b {
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if gzr, err := gzip.NewReader(br); err != nil {
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writer.WriteHeader(500)
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return
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} else {
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scanner = bufio.NewScanner(gzr)
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}
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} else if err == nil && magic[0] == 'B' && magic[1] == 'Z' && magic[2] == 'h' && magic[3] >= '1' && magic[3] <= '9' {
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scanner = bufio.NewScanner(bzip2.NewReader(br))
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} else {
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scanner = bufio.NewScanner(br)
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}
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writer.WriteHeader(200)
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for scanner.Scan() {
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if line := scanner.Bytes(); re.Match(line) {
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writer.Write(line)
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writer.Write([]byte{'\n'})
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}
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}
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} else {
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writer.WriteHeader(newWriter.status)
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io.Copy(writer, br)
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}
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})
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}
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