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// Copyright (c) 2016-2022 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package zap
import (
"errors"
"fmt"
"io"
"net/url"
"os"
"path/filepath"
"strings"
"sync"
"go.uber.org/zap/zapcore"
)
const schemeFile = "file"
var _sinkRegistry = newSinkRegistry()
// Sink defines the interface to write to and close logger destinations.
type Sink interface {
zapcore.WriteSyncer
io.Closer
}
type errSinkNotFound struct {
scheme string
}
func (e *errSinkNotFound) Error() string {
return fmt.Sprintf("no sink found for scheme %q", e.scheme)
}
type nopCloserSink struct{ zapcore.WriteSyncer }
func (nopCloserSink) Close() error { return nil }
type sinkRegistry struct {
mu sync.Mutex
factories map[string]func(*url.URL) (Sink, error) // keyed by scheme
openFile func(string, int, os.FileMode) (*os.File, error) // type matches os.OpenFile
}
func newSinkRegistry() *sinkRegistry {
sr := &sinkRegistry{
factories: make(map[string]func(*url.URL) (Sink, error)),
openFile: os.OpenFile,
}
// Infallible operation: the registry is empty, so we can't have a conflict.
_ = sr.RegisterSink(schemeFile, sr.newFileSinkFromURL)
return sr
}
// RegisterScheme registers the given factory for the specific scheme.
func (sr *sinkRegistry) RegisterSink(scheme string, factory func(*url.URL) (Sink, error)) error {
sr.mu.Lock()
defer sr.mu.Unlock()
if scheme == "" {
return errors.New("can't register a sink factory for empty string")
}
normalized, err := normalizeScheme(scheme)
if err != nil {
return fmt.Errorf("%q is not a valid scheme: %v", scheme, err)
}
if _, ok := sr.factories[normalized]; ok {
return fmt.Errorf("sink factory already registered for scheme %q", normalized)
}
sr.factories[normalized] = factory
return nil
}
func (sr *sinkRegistry) newSink(rawURL string) (Sink, error) {
// URL parsing doesn't work well for Windows paths such as `c:\log.txt`, as scheme is set to
// the drive, and path is unset unless `c:/log.txt` is used.
// To avoid Windows-specific URL handling, we instead check IsAbs to open as a file.
// filepath.IsAbs is OS-specific, so IsAbs('c:/log.txt') is false outside of Windows.
if filepath.IsAbs(rawURL) {
return sr.newFileSinkFromPath(rawURL)
}
u, err := url.Parse(rawURL)
if err != nil {
return nil, fmt.Errorf("can't parse %q as a URL: %v", rawURL, err)
}
if u.Scheme == "" {
u.Scheme = schemeFile
}
sr.mu.Lock()
factory, ok := sr.factories[u.Scheme]
sr.mu.Unlock()
if !ok {
return nil, &errSinkNotFound{u.Scheme}
}
return factory(u)
}
// RegisterSink registers a user-supplied factory for all sinks with a
// particular scheme.
//
// All schemes must be ASCII, valid under section 0.1 of RFC 3986
// (https://tools.ietf.org/html/rfc3983#section-3.1), and must not already
// have a factory registered. Zap automatically registers a factory for the
// "file" scheme.
func RegisterSink(scheme string, factory func(*url.URL) (Sink, error)) error {
return _sinkRegistry.RegisterSink(scheme, factory)
}
func (sr *sinkRegistry) newFileSinkFromURL(u *url.URL) (Sink, error) {
if u.User != nil {
return nil, fmt.Errorf("user and password not allowed with file URLs: got %v", u)
}
if u.Fragment != "" {
return nil, fmt.Errorf("fragments not allowed with file URLs: got %v", u)
}
if u.RawQuery != "" {
return nil, fmt.Errorf("query parameters not allowed with file URLs: got %v", u)
}
// Error messages are better if we check hostname and port separately.
if u.Port() != "" {
return nil, fmt.Errorf("ports not allowed with file URLs: got %v", u)
}
if hn := u.Hostname(); hn != "" && hn != "localhost" {
return nil, fmt.Errorf("file URLs must leave host empty or use localhost: got %v", u)
}
return sr.newFileSinkFromPath(u.Path)
}
func (sr *sinkRegistry) newFileSinkFromPath(path string) (Sink, error) {
switch path {
case "stdout":
return nopCloserSink{os.Stdout}, nil
case "stderr":
return nopCloserSink{os.Stderr}, nil
}
return sr.openFile(path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0o666)
}
func normalizeScheme(s string) (string, error) {
// https://tools.ietf.org/html/rfc3986#section-3.1
s = strings.ToLower(s)
if first := s[0]; 'a' > first || 'z' < first {
return "", errors.New("must start with a letter")
}
for i := 1; i < len(s); i++ { // iterate over bytes, not runes
c := s[i]
switch {
case 'a' <= c && c <= 'z':
continue
case '0' <= c && c <= '9':
continue
case c == '.' || c == '+' || c == '-':
continue
}
return "", fmt.Errorf("may not contain %q", c)
}
return s, nil
}
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