1 // Copyright (c) 2016-2022 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 21 package zap 22 23 import ( 24 "fmt" 25 "io" 26 27 "go.uber.org/zap/zapcore" 28 29 "go.uber.org/multierr" 30 ) 31 32 // Open is a high-level wrapper that takes a variadic number of URLs, opens or 33 // creates each of the specified resources, and combines them into a locked 34 // WriteSyncer. It also returns any error encountered and a function to close 35 // any opened files. 36 // 37 // Passing no URLs returns a no-op WriteSyncer. Zap handles URLs without a 38 // scheme and URLs with the "file" scheme. Third-party code may register 39 // factories for other schemes using RegisterSink. 40 // 41 // URLs with the "file" scheme must use absolute paths on the local 42 // filesystem. No user, password, port, fragments, or query parameters are 43 // allowed, and the hostname must be empty or "localhost". 44 // 45 // Since it's common to write logs to the local filesystem, URLs without a 46 // scheme (e.g., "/var/log/foo.log") are treated as local file paths. Without 47 // a scheme, the special paths "stdout" and "stderr" are interpreted as 48 // os.Stdout and os.Stderr. When specified without a scheme, relative file 49 // paths also work. 50 func Open(paths ...string) (zapcore.WriteSyncer, func(), error) { 51 writers, closeAll, err := open(paths) 52 if err != nil { 53 return nil, nil, err 54 } 55 56 writer := CombineWriteSyncers(writers...) 57 return writer, closeAll, nil 58 } 59 60 func open(paths []string) ([]zapcore.WriteSyncer, func(), error) { 61 writers := make([]zapcore.WriteSyncer, 0, len(paths)) 62 closers := make([]io.Closer, 0, len(paths)) 63 closeAll := func() { 64 for _, c := range closers { 65 _ = c.Close() 66 } 67 } 68 69 var openErr error 70 for _, path := range paths { 71 sink, err := _sinkRegistry.newSink(path) 72 if err != nil { 73 openErr = multierr.Append(openErr, fmt.Errorf("open sink %q: %w", path, err)) 74 continue 75 } 76 writers = append(writers, sink) 77 closers = append(closers, sink) 78 } 79 if openErr != nil { 80 closeAll() 81 return nil, nil, openErr 82 } 83 84 return writers, closeAll, nil 85 } 86 87 // CombineWriteSyncers is a utility that combines multiple WriteSyncers into a 88 // single, locked WriteSyncer. If no inputs are supplied, it returns a no-op 89 // WriteSyncer. 90 // 91 // It's provided purely as a convenience; the result is no different from 92 // using zapcore.NewMultiWriteSyncer and zapcore.Lock individually. 93 func CombineWriteSyncers(writers ...zapcore.WriteSyncer) zapcore.WriteSyncer { 94 if len(writers) == 0 { 95 return zapcore.AddSync(io.Discard) 96 } 97 return zapcore.Lock(zapcore.NewMultiWriteSyncer(writers...)) 98 } 99