blob: 86a709ab0be28795471298513dc3ac369e5c11d9 [file] [log] [blame]
Girish Gowdra64503432020-01-07 10:59:10 +05301// 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}