diff --git a/vendor/go.uber.org/zap/sink.go b/vendor/go.uber.org/zap/sink.go
new file mode 100644
index 0000000..ff0becf
--- /dev/null
+++ b/vendor/go.uber.org/zap/sink.go
@@ -0,0 +1,161 @@
+// Copyright (c) 2016 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"
+	"strings"
+	"sync"
+
+	"go.uber.org/zap/zapcore"
+)
+
+const schemeFile = "file"
+
+var (
+	_sinkMutex     sync.RWMutex
+	_sinkFactories map[string]func(*url.URL) (Sink, error) // keyed by scheme
+)
+
+func init() {
+	resetSinkRegistry()
+}
+
+func resetSinkRegistry() {
+	_sinkMutex.Lock()
+	defer _sinkMutex.Unlock()
+
+	_sinkFactories = map[string]func(*url.URL) (Sink, error){
+		schemeFile: newFileSink,
+	}
+}
+
+// Sink defines the interface to write to and close logger destinations.
+type Sink interface {
+	zapcore.WriteSyncer
+	io.Closer
+}
+
+type nopCloserSink struct{ zapcore.WriteSyncer }
+
+func (nopCloserSink) Close() error { return nil }
+
+type errSinkNotFound struct {
+	scheme string
+}
+
+func (e *errSinkNotFound) Error() string {
+	return fmt.Sprintf("no sink found for scheme %q", e.scheme)
+}
+
+// RegisterSink registers a user-supplied factory for all sinks with a
+// particular scheme.
+//
+// All schemes must be ASCII, valid under section 3.1 of RFC 3986
+// (https://tools.ietf.org/html/rfc3986#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 {
+	_sinkMutex.Lock()
+	defer _sinkMutex.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 := _sinkFactories[normalized]; ok {
+		return fmt.Errorf("sink factory already registered for scheme %q", normalized)
+	}
+	_sinkFactories[normalized] = factory
+	return nil
+}
+
+func newSink(rawURL string) (Sink, error) {
+	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
+	}
+
+	_sinkMutex.RLock()
+	factory, ok := _sinkFactories[u.Scheme]
+	_sinkMutex.RUnlock()
+	if !ok {
+		return nil, &errSinkNotFound{u.Scheme}
+	}
+	return factory(u)
+}
+
+func newFileSink(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)
+	}
+	switch u.Path {
+	case "stdout":
+		return nopCloserSink{os.Stdout}, nil
+	case "stderr":
+		return nopCloserSink{os.Stderr}, nil
+	}
+	return os.OpenFile(u.Path, os.O_WRONLY|os.O_APPEND|os.O_CREATE, 0644)
+}
+
+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
+}