blob: 1297c33b32851d00c421f4e48fe5d7504055889f [file] [log] [blame]
divyadesai19009132020-03-04 12:58:08 +00001// Copyright (c) 2016 Uber Technologies, Inc.
2//
3// Permission is hereby granted, free of charge, to any person obtaining a copy
4// of this software and associated documentation files (the "Software"), to deal
5// in the Software without restriction, including without limitation the rights
6// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7// copies of the Software, and to permit persons to whom the Software is
8// furnished to do so, subject to the following conditions:
9//
10// The above copyright notice and this permission notice shall be included in
11// all copies or substantial portions of the Software.
12//
13// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19// THE SOFTWARE.
20
21package zap
22
23import (
24 "encoding/json"
25 "fmt"
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000026 "io"
divyadesai19009132020-03-04 12:58:08 +000027 "net/http"
28
29 "go.uber.org/zap/zapcore"
30)
31
32// ServeHTTP is a simple JSON endpoint that can report on or change the current
33// logging level.
34//
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000035// GET
36//
37// The GET request returns a JSON description of the current logging level like:
divyadesai19009132020-03-04 12:58:08 +000038// {"level":"info"}
39//
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000040// PUT
41//
42// The PUT request changes the logging level. It is perfectly safe to change the
43// logging level while a program is running. Two content types are supported:
44//
45// Content-Type: application/x-www-form-urlencoded
46//
47// With this content type, the level can be provided through the request body or
48// a query parameter. The log level is URL encoded like:
49//
50// level=debug
51//
52// The request body takes precedence over the query parameter, if both are
53// specified.
54//
55// This content type is the default for a curl PUT request. Following are two
56// example curl requests that both set the logging level to debug.
57//
58// curl -X PUT localhost:8080/log/level?level=debug
59// curl -X PUT localhost:8080/log/level -d level=debug
60//
61// For any other content type, the payload is expected to be JSON encoded and
62// look like:
63//
64// {"level":"info"}
65//
66// An example curl request could look like this:
67//
68// curl -X PUT localhost:8080/log/level -H "Content-Type: application/json" -d '{"level":"debug"}'
69//
divyadesai19009132020-03-04 12:58:08 +000070func (lvl AtomicLevel) ServeHTTP(w http.ResponseWriter, r *http.Request) {
71 type errorResponse struct {
72 Error string `json:"error"`
73 }
74 type payload struct {
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000075 Level zapcore.Level `json:"level"`
divyadesai19009132020-03-04 12:58:08 +000076 }
77
78 enc := json.NewEncoder(w)
79
80 switch r.Method {
divyadesai19009132020-03-04 12:58:08 +000081 case http.MethodGet:
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000082 enc.Encode(payload{Level: lvl.Level()})
divyadesai19009132020-03-04 12:58:08 +000083 case http.MethodPut:
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000084 requestedLvl, err := decodePutRequest(r.Header.Get("Content-Type"), r)
85 if err != nil {
divyadesai19009132020-03-04 12:58:08 +000086 w.WriteHeader(http.StatusBadRequest)
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000087 enc.Encode(errorResponse{Error: err.Error()})
divyadesai19009132020-03-04 12:58:08 +000088 return
89 }
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000090 lvl.SetLevel(requestedLvl)
91 enc.Encode(payload{Level: lvl.Level()})
divyadesai19009132020-03-04 12:58:08 +000092 default:
93 w.WriteHeader(http.StatusMethodNotAllowed)
94 enc.Encode(errorResponse{
95 Error: "Only GET and PUT are supported.",
96 })
97 }
98}
David K. Bainbridgebd6b2882021-08-26 13:31:02 +000099
100// Decodes incoming PUT requests and returns the requested logging level.
101func decodePutRequest(contentType string, r *http.Request) (zapcore.Level, error) {
102 if contentType == "application/x-www-form-urlencoded" {
103 return decodePutURL(r)
104 }
105 return decodePutJSON(r.Body)
106}
107
108func decodePutURL(r *http.Request) (zapcore.Level, error) {
109 lvl := r.FormValue("level")
110 if lvl == "" {
111 return 0, fmt.Errorf("must specify logging level")
112 }
113 var l zapcore.Level
114 if err := l.UnmarshalText([]byte(lvl)); err != nil {
115 return 0, err
116 }
117 return l, nil
118}
119
120func decodePutJSON(body io.Reader) (zapcore.Level, error) {
121 var pld struct {
122 Level *zapcore.Level `json:"level"`
123 }
124 if err := json.NewDecoder(body).Decode(&pld); err != nil {
125 return 0, fmt.Errorf("malformed request body: %v", err)
126 }
127 if pld.Level == nil {
128 return 0, fmt.Errorf("must specify logging level")
129 }
130 return *pld.Level, nil
131
132}