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