diff --git a/vendor/go.uber.org/zap/logger.go b/vendor/go.uber.org/zap/logger.go
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+// 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 (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"strings"
+
+	"go.uber.org/zap/zapcore"
+)
+
+// A Logger provides fast, leveled, structured logging. All methods are safe
+// for concurrent use.
+//
+// The Logger is designed for contexts in which every microsecond and every
+// allocation matters, so its API intentionally favors performance and type
+// safety over brevity. For most applications, the SugaredLogger strikes a
+// better balance between performance and ergonomics.
+type Logger struct {
+	core zapcore.Core
+
+	development bool
+	addCaller   bool
+	onFatal     zapcore.CheckWriteAction // default is WriteThenFatal
+
+	name        string
+	errorOutput zapcore.WriteSyncer
+
+	addStack zapcore.LevelEnabler
+
+	callerSkip int
+
+	clock zapcore.Clock
+}
+
+// New constructs a new Logger from the provided zapcore.Core and Options. If
+// the passed zapcore.Core is nil, it falls back to using a no-op
+// implementation.
+//
+// This is the most flexible way to construct a Logger, but also the most
+// verbose. For typical use cases, the highly-opinionated presets
+// (NewProduction, NewDevelopment, and NewExample) or the Config struct are
+// more convenient.
+//
+// For sample code, see the package-level AdvancedConfiguration example.
+func New(core zapcore.Core, options ...Option) *Logger {
+	if core == nil {
+		return NewNop()
+	}
+	log := &Logger{
+		core:        core,
+		errorOutput: zapcore.Lock(os.Stderr),
+		addStack:    zapcore.FatalLevel + 1,
+		clock:       zapcore.DefaultClock,
+	}
+	return log.WithOptions(options...)
+}
+
+// NewNop returns a no-op Logger. It never writes out logs or internal errors,
+// and it never runs user-defined hooks.
+//
+// Using WithOptions to replace the Core or error output of a no-op Logger can
+// re-enable logging.
+func NewNop() *Logger {
+	return &Logger{
+		core:        zapcore.NewNopCore(),
+		errorOutput: zapcore.AddSync(ioutil.Discard),
+		addStack:    zapcore.FatalLevel + 1,
+		clock:       zapcore.DefaultClock,
+	}
+}
+
+// NewProduction builds a sensible production Logger that writes InfoLevel and
+// above logs to standard error as JSON.
+//
+// It's a shortcut for NewProductionConfig().Build(...Option).
+func NewProduction(options ...Option) (*Logger, error) {
+	return NewProductionConfig().Build(options...)
+}
+
+// NewDevelopment builds a development Logger that writes DebugLevel and above
+// logs to standard error in a human-friendly format.
+//
+// It's a shortcut for NewDevelopmentConfig().Build(...Option).
+func NewDevelopment(options ...Option) (*Logger, error) {
+	return NewDevelopmentConfig().Build(options...)
+}
+
+// NewExample builds a Logger that's designed for use in zap's testable
+// examples. It writes DebugLevel and above logs to standard out as JSON, but
+// omits the timestamp and calling function to keep example output
+// short and deterministic.
+func NewExample(options ...Option) *Logger {
+	encoderCfg := zapcore.EncoderConfig{
+		MessageKey:     "msg",
+		LevelKey:       "level",
+		NameKey:        "logger",
+		EncodeLevel:    zapcore.LowercaseLevelEncoder,
+		EncodeTime:     zapcore.ISO8601TimeEncoder,
+		EncodeDuration: zapcore.StringDurationEncoder,
+	}
+	core := zapcore.NewCore(zapcore.NewJSONEncoder(encoderCfg), os.Stdout, DebugLevel)
+	return New(core).WithOptions(options...)
+}
+
+// Sugar wraps the Logger to provide a more ergonomic, but slightly slower,
+// API. Sugaring a Logger is quite inexpensive, so it's reasonable for a
+// single application to use both Loggers and SugaredLoggers, converting
+// between them on the boundaries of performance-sensitive code.
+func (log *Logger) Sugar() *SugaredLogger {
+	core := log.clone()
+	core.callerSkip += 2
+	return &SugaredLogger{core}
+}
+
+// Named adds a new path segment to the logger's name. Segments are joined by
+// periods. By default, Loggers are unnamed.
+func (log *Logger) Named(s string) *Logger {
+	if s == "" {
+		return log
+	}
+	l := log.clone()
+	if log.name == "" {
+		l.name = s
+	} else {
+		l.name = strings.Join([]string{l.name, s}, ".")
+	}
+	return l
+}
+
+// WithOptions clones the current Logger, applies the supplied Options, and
+// returns the resulting Logger. It's safe to use concurrently.
+func (log *Logger) WithOptions(opts ...Option) *Logger {
+	c := log.clone()
+	for _, opt := range opts {
+		opt.apply(c)
+	}
+	return c
+}
+
+// With creates a child logger and adds structured context to it. Fields added
+// to the child don't affect the parent, and vice versa.
+func (log *Logger) With(fields ...Field) *Logger {
+	if len(fields) == 0 {
+		return log
+	}
+	l := log.clone()
+	l.core = l.core.With(fields)
+	return l
+}
+
+// Check returns a CheckedEntry if logging a message at the specified level
+// is enabled. It's a completely optional optimization; in high-performance
+// applications, Check can help avoid allocating a slice to hold fields.
+func (log *Logger) Check(lvl zapcore.Level, msg string) *zapcore.CheckedEntry {
+	return log.check(lvl, msg)
+}
+
+// Debug logs a message at DebugLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+func (log *Logger) Debug(msg string, fields ...Field) {
+	if ce := log.check(DebugLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Info logs a message at InfoLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+func (log *Logger) Info(msg string, fields ...Field) {
+	if ce := log.check(InfoLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Warn logs a message at WarnLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+func (log *Logger) Warn(msg string, fields ...Field) {
+	if ce := log.check(WarnLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Error logs a message at ErrorLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+func (log *Logger) Error(msg string, fields ...Field) {
+	if ce := log.check(ErrorLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// DPanic logs a message at DPanicLevel. The message includes any fields
+// passed at the log site, as well as any fields accumulated on the logger.
+//
+// If the logger is in development mode, it then panics (DPanic means
+// "development panic"). This is useful for catching errors that are
+// recoverable, but shouldn't ever happen.
+func (log *Logger) DPanic(msg string, fields ...Field) {
+	if ce := log.check(DPanicLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Panic logs a message at PanicLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+//
+// The logger then panics, even if logging at PanicLevel is disabled.
+func (log *Logger) Panic(msg string, fields ...Field) {
+	if ce := log.check(PanicLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Fatal logs a message at FatalLevel. The message includes any fields passed
+// at the log site, as well as any fields accumulated on the logger.
+//
+// The logger then calls os.Exit(1), even if logging at FatalLevel is
+// disabled.
+func (log *Logger) Fatal(msg string, fields ...Field) {
+	if ce := log.check(FatalLevel, msg); ce != nil {
+		ce.Write(fields...)
+	}
+}
+
+// Sync calls the underlying Core's Sync method, flushing any buffered log
+// entries. Applications should take care to call Sync before exiting.
+func (log *Logger) Sync() error {
+	return log.core.Sync()
+}
+
+// Core returns the Logger's underlying zapcore.Core.
+func (log *Logger) Core() zapcore.Core {
+	return log.core
+}
+
+func (log *Logger) clone() *Logger {
+	copy := *log
+	return &copy
+}
+
+func (log *Logger) check(lvl zapcore.Level, msg string) *zapcore.CheckedEntry {
+	// check must always be called directly by a method in the Logger interface
+	// (e.g., Check, Info, Fatal).
+	const callerSkipOffset = 2
+
+	// Check the level first to reduce the cost of disabled log calls.
+	// Since Panic and higher may exit, we skip the optimization for those levels.
+	if lvl < zapcore.DPanicLevel && !log.core.Enabled(lvl) {
+		return nil
+	}
+
+	// Create basic checked entry thru the core; this will be non-nil if the
+	// log message will actually be written somewhere.
+	ent := zapcore.Entry{
+		LoggerName: log.name,
+		Time:       log.clock.Now(),
+		Level:      lvl,
+		Message:    msg,
+	}
+	ce := log.core.Check(ent, nil)
+	willWrite := ce != nil
+
+	// Set up any required terminal behavior.
+	switch ent.Level {
+	case zapcore.PanicLevel:
+		ce = ce.Should(ent, zapcore.WriteThenPanic)
+	case zapcore.FatalLevel:
+		onFatal := log.onFatal
+		// Noop is the default value for CheckWriteAction, and it leads to
+		// continued execution after a Fatal which is unexpected.
+		if onFatal == zapcore.WriteThenNoop {
+			onFatal = zapcore.WriteThenFatal
+		}
+		ce = ce.Should(ent, onFatal)
+	case zapcore.DPanicLevel:
+		if log.development {
+			ce = ce.Should(ent, zapcore.WriteThenPanic)
+		}
+	}
+
+	// Only do further annotation if we're going to write this message; checked
+	// entries that exist only for terminal behavior don't benefit from
+	// annotation.
+	if !willWrite {
+		return ce
+	}
+
+	// Thread the error output through to the CheckedEntry.
+	ce.ErrorOutput = log.errorOutput
+	if log.addCaller {
+		frame, defined := getCallerFrame(log.callerSkip + callerSkipOffset)
+		if !defined {
+			fmt.Fprintf(log.errorOutput, "%v Logger.check error: failed to get caller\n", ent.Time.UTC())
+			log.errorOutput.Sync()
+		}
+
+		ce.Entry.Caller = zapcore.EntryCaller{
+			Defined:  defined,
+			PC:       frame.PC,
+			File:     frame.File,
+			Line:     frame.Line,
+			Function: frame.Function,
+		}
+	}
+	if log.addStack.Enabled(ce.Entry.Level) {
+		ce.Entry.Stack = StackSkip("", log.callerSkip+callerSkipOffset).String
+	}
+
+	return ce
+}
+
+// getCallerFrame gets caller frame. The argument skip is the number of stack
+// frames to ascend, with 0 identifying the caller of getCallerFrame. The
+// boolean ok is false if it was not possible to recover the information.
+//
+// Note: This implementation is similar to runtime.Caller, but it returns the whole frame.
+func getCallerFrame(skip int) (frame runtime.Frame, ok bool) {
+	const skipOffset = 2 // skip getCallerFrame and Callers
+
+	pc := make([]uintptr, 1)
+	numFrames := runtime.Callers(skip+skipOffset, pc)
+	if numFrames < 1 {
+		return
+	}
+
+	frame, _ = runtime.CallersFrames(pc).Next()
+	return frame, frame.PC != 0
+}