1 // Copyright (c) 2016 Uber Technologies, Inc.
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:
10 // The above copyright notice and this permission notice shall be included in
11 // all copies or substantial portions of the Software.
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
28 "go.uber.org/zap/zapcore"
30 "go.uber.org/multierr"
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
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.
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".
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
51 func Open(paths ...string) (zapcore.WriteSyncer, func(), error) {
52 writers, close, err := open(paths)
57 writer := CombineWriteSyncers(writers...)
58 return writer, close, nil
61 func open(paths []string) ([]zapcore.WriteSyncer, func(), error) {
62 writers := make([]zapcore.WriteSyncer, 0, len(paths))
63 closers := make([]io.Closer, 0, len(paths))
65 for _, c := range closers {
71 for _, path := range paths {
72 sink, err := newSink(path)
74 openErr = multierr.Append(openErr, fmt.Errorf("couldn't open sink %q: %v", path, err))
77 writers = append(writers, sink)
78 closers = append(closers, sink)
82 return writers, nil, openErr
85 return writers, close, nil
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
92 // It's provided purely as a convenience; the result is no different from
93 // using zapcore.NewMultiWriteSyncer and zapcore.Lock individually.
94 func CombineWriteSyncers(writers ...zapcore.WriteSyncer) zapcore.WriteSyncer {
95 if len(writers) == 0 {
96 return zapcore.AddSync(ioutil.Discard)
98 return zapcore.Lock(zapcore.NewMultiWriteSyncer(writers...))