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

100