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 "fmt" 25 "io" 26 "io/ioutil" 27 28 "go.uber.org/zap/zapcore" 29 30 "go.uber.org/multierr" 31) 32 33// Open is a high-level wrapper that takes a variadic number of URLs, opens or 34// creates each of the specified resources, and combines them into a locked 35// WriteSyncer. It also returns any error encountered and a function to close 36// any opened files. 37// 38// Passing no URLs returns a no-op WriteSyncer. Zap handles URLs without a 39// scheme and URLs with the "file" scheme. Third-party code may register 40// factories for other schemes using RegisterSink. 41// 42// URLs with the "file" scheme must use absolute paths on the local 43// filesystem. No user, password, port, fragments, or query parameters are 44// allowed, and the hostname must be empty or "localhost". 45// 46// Since it's common to write logs to the local filesystem, URLs without a 47// scheme (e.g., "/var/log/foo.log") are treated as local file paths. Without 48// a scheme, the special paths "stdout" and "stderr" are interpreted as 49// os.Stdout and os.Stderr. When specified without a scheme, relative file 50// paths also work. 51func Open(paths ...string) (zapcore.WriteSyncer, func(), error) { 52 writers, close, err := open(paths) 53 if err != nil { 54 return nil, nil, err 55 } 56 57 writer := CombineWriteSyncers(writers...) 58 return writer, close, nil 59} 60 61func open(paths []string) ([]zapcore.WriteSyncer, func(), error) { 62 writers := make([]zapcore.WriteSyncer, 0, len(paths)) 63 closers := make([]io.Closer, 0, len(paths)) 64 close := func() { 65 for _, c := range closers { 66 c.Close() 67 } 68 } 69 70 var openErr error 71 for _, path := range paths { 72 sink, err := newSink(path) 73 if err != nil { 74 openErr = multierr.Append(openErr, fmt.Errorf("couldn't open sink %q: %v", path, err)) 75 continue 76 } 77 writers = append(writers, sink) 78 closers = append(closers, sink) 79 } 80 if openErr != nil { 81 close() 82 return writers, nil, openErr 83 } 84 85 return writers, close, nil 86} 87 88// CombineWriteSyncers is a utility that combines multiple WriteSyncers into a 89// single, locked WriteSyncer. If no inputs are supplied, it returns a no-op 90// WriteSyncer. 91// 92// It's provided purely as a convenience; the result is no different from 93// using zapcore.NewMultiWriteSyncer and zapcore.Lock individually. 94func CombineWriteSyncers(writers ...zapcore.WriteSyncer) zapcore.WriteSyncer { 95 if len(writers) == 0 { 96 return zapcore.AddSync(ioutil.Discard) 97 } 98 return zapcore.Lock(zapcore.NewMultiWriteSyncer(writers...)) 99} 100