1// 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" 26 "net/http" 27 28 "go.uber.org/zap/zapcore" 29) 30 31// ServeHTTP is a simple JSON endpoint that can report on or change the current 32// logging level. 33// 34// GET requests return a JSON description of the current logging level. PUT 35// requests change the logging level and expect a payload like: 36// {"level":"info"} 37// 38// It's perfectly safe to change the logging level while a program is running. 39func (lvl AtomicLevel) ServeHTTP(w http.ResponseWriter, r *http.Request) { 40 type errorResponse struct { 41 Error string `json:"error"` 42 } 43 type payload struct { 44 Level *zapcore.Level `json:"level"` 45 } 46 47 enc := json.NewEncoder(w) 48 49 switch r.Method { 50 51 case http.MethodGet: 52 current := lvl.Level() 53 enc.Encode(payload{Level: ¤t}) 54 55 case http.MethodPut: 56 var req payload 57 58 if errmess := func() string { 59 if err := json.NewDecoder(r.Body).Decode(&req); err != nil { 60 return fmt.Sprintf("Request body must be well-formed JSON: %v", err) 61 } 62 if req.Level == nil { 63 return "Must specify a logging level." 64 } 65 return "" 66 }(); errmess != "" { 67 w.WriteHeader(http.StatusBadRequest) 68 enc.Encode(errorResponse{Error: errmess}) 69 return 70 } 71 72 lvl.SetLevel(*req.Level) 73 enc.Encode(req) 74 75 default: 76 w.WriteHeader(http.StatusMethodNotAllowed) 77 enc.Encode(errorResponse{ 78 Error: "Only GET and PUT are supported.", 79 }) 80 } 81} 82