adding in logging

vendor/go.uber.org/zap/zaptest/observer/observer.go

@@ -0,0 +1,174 @@
+// 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 observer provides a zapcore.Core that keeps an in-memory,
+// encoding-agnostic repesentation of log entries. It's useful for
+// applications that want to unit test their log output without tying their
+// tests to a particular output encoding.
+package observer // import "go.uber.org/zap/zaptest/observer"
+
+import (
+	"strings"
+	"sync"
+	"time"
+
+	"go.uber.org/zap/zapcore"
+)
+
+// An LoggedEntry is an encoding-agnostic representation of a log message.
+// Field availability is context dependant.
+type LoggedEntry struct {
+	zapcore.Entry
+	Context []zapcore.Field
+}
+
+// ObservedLogs is a concurrency-safe, ordered collection of observed logs.
+type ObservedLogs struct {
+	mu   sync.RWMutex
+	logs []LoggedEntry
+}
+
+// Len returns the number of items in the collection.
+func (o *ObservedLogs) Len() int {
+	o.mu.RLock()
+	n := len(o.logs)
+	o.mu.RUnlock()
+	return n
+}
+
+// All returns a copy of all the observed logs.
+func (o *ObservedLogs) All() []LoggedEntry {
+	o.mu.RLock()
+	ret := make([]LoggedEntry, len(o.logs))
+	for i := range o.logs {
+		ret[i] = o.logs[i]
+	}
+	o.mu.RUnlock()
+	return ret
+}
+
+// TakeAll returns a copy of all the observed logs, and truncates the observed
+// slice.
+func (o *ObservedLogs) TakeAll() []LoggedEntry {
+	o.mu.Lock()
+	ret := o.logs
+	o.logs = nil
+	o.mu.Unlock()
+	return ret
+}
+
+// AllUntimed returns a copy of all the observed logs, but overwrites the
+// observed timestamps with time.Time's zero value. This is useful when making
+// assertions in tests.
+func (o *ObservedLogs) AllUntimed() []LoggedEntry {
+	ret := o.All()
+	for i := range ret {
+		ret[i].Time = time.Time{}
+	}
+	return ret
+}
+
+// FilterMessage filters entries to those that have the specified message.
+func (o *ObservedLogs) FilterMessage(msg string) *ObservedLogs {
+	return o.filter(func(e LoggedEntry) bool {
+		return e.Message == msg
+	})
+}
+
+// FilterMessageSnippet filters entries to those that have a message containing the specified snippet.
+func (o *ObservedLogs) FilterMessageSnippet(snippet string) *ObservedLogs {
+	return o.filter(func(e LoggedEntry) bool {
+		return strings.Contains(e.Message, snippet)
+	})
+}
+
+// FilterField filters entries to those that have the specified field.
+func (o *ObservedLogs) FilterField(field zapcore.Field) *ObservedLogs {
+	return o.filter(func(e LoggedEntry) bool {
+		for _, ctxField := range e.Context {
+			if ctxField.Equals(field) {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+func (o *ObservedLogs) filter(match func(LoggedEntry) bool) *ObservedLogs {
+	o.mu.RLock()
+	defer o.mu.RUnlock()
+
+	var filtered []LoggedEntry
+	for _, entry := range o.logs {
+		if match(entry) {
+			filtered = append(filtered, entry)
+		}
+	}
+	return &ObservedLogs{logs: filtered}
+}
+
+func (o *ObservedLogs) add(log LoggedEntry) {
+	o.mu.Lock()
+	o.logs = append(o.logs, log)
+	o.mu.Unlock()
+}
+
+// New creates a new Core that buffers logs in memory (without any encoding).
+// It's particularly useful in tests.
+func New(enab zapcore.LevelEnabler) (zapcore.Core, *ObservedLogs) {
+	ol := &ObservedLogs{}
+	return &contextObserver{
+		LevelEnabler: enab,
+		logs:         ol,
+	}, ol
+}
+
+type contextObserver struct {
+	zapcore.LevelEnabler
+	logs    *ObservedLogs
+	context []zapcore.Field
+}
+
+func (co *contextObserver) Check(ent zapcore.Entry, ce *zapcore.CheckedEntry) *zapcore.CheckedEntry {
+	if co.Enabled(ent.Level) {
+		return ce.AddCore(ent, co)
+	}
+	return ce
+}
+
+func (co *contextObserver) With(fields []zapcore.Field) zapcore.Core {
+	return &contextObserver{
+		LevelEnabler: co.LevelEnabler,
+		logs:         co.logs,
+		context:      append(co.context[:len(co.context):len(co.context)], fields...),
+	}
+}
+
+func (co *contextObserver) Write(ent zapcore.Entry, fields []zapcore.Field) error {
+	all := make([]zapcore.Field, 0, len(fields)+len(co.context))
+	all = append(all, co.context...)
+	all = append(all, fields...)
+	co.logs.add(LoggedEntry{ent, all})
+	return nil
+}
+
+func (co *contextObserver) Sync() error {
+	return nil
+}