/
uds.go
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/
uds.go
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// Copyright Istio Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package log
import (
"bytes"
"context"
"encoding/json"
"fmt"
"net"
"net/http"
"sync"
"time"
"go.uber.org/zap/buffer"
"go.uber.org/zap/zapcore"
)
// An udsCore write entries to an UDS server with HTTP Post. Log messages will be encoded into a JSON array.
type udsCore struct {
client http.Client
minimumLevel zapcore.Level
url string
enc zapcore.Encoder
buffers []*buffer.Buffer
mu sync.Mutex
}
// teeToUDSServer returns a zapcore.Core that writes entries to both the provided core and to an uds server.
func teeToUDSServer(baseCore zapcore.Core, address, path string) zapcore.Core {
c := http.Client{
Transport: &http.Transport{
DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
return net.Dial("unix", address)
},
},
Timeout: time.Second,
}
uc := &udsCore{
client: c,
url: "http://unix" + path,
enc: zapcore.NewJSONEncoder(defaultEncoderConfig),
buffers: make([]*buffer.Buffer, 0),
}
for l := zapcore.DebugLevel; l <= zapcore.FatalLevel; l++ {
if baseCore.Enabled(l) {
uc.minimumLevel = l
break
}
}
return zapcore.NewTee(baseCore, uc)
}
// Enabled implements zapcore.Core.
func (u *udsCore) Enabled(l zapcore.Level) bool {
return l >= u.minimumLevel
}
// With implements zapcore.Core.
func (u *udsCore) With(fields []zapcore.Field) zapcore.Core {
return &udsCore{
client: u.client,
minimumLevel: u.minimumLevel,
}
}
// Check implements zapcore.Core.
func (u *udsCore) Check(e zapcore.Entry, ce *zapcore.CheckedEntry) *zapcore.CheckedEntry {
if u.Enabled(e.Level) {
return ce.AddCore(e, u)
}
return ce
}
// Sync implements zapcore.Core. It sends log messages with HTTP POST.
func (u *udsCore) Sync() error {
logs := u.logsFromBuffer()
msg, err := json.Marshal(logs)
if err != nil {
return fmt.Errorf("failed to sync uds log: %v", err)
}
resp, err := u.client.Post(u.url, "application/json", bytes.NewReader(msg))
if err != nil {
return fmt.Errorf("failed to send logs to uds server %v: %v", u.url, err)
}
if resp.StatusCode != http.StatusOK {
return fmt.Errorf("uds server returns non-ok status %v: %v", u.url, resp.Status)
}
return nil
}
// Write implements zapcore.Core. Log messages will be temporarily buffered and sent to
// UDS server asyncrhonously.
func (u *udsCore) Write(entry zapcore.Entry, fields []zapcore.Field) error {
buffer, err := u.enc.EncodeEntry(entry, fields)
if err != nil {
return fmt.Errorf("failed to write log to uds logger: %v", err)
}
u.mu.Lock()
u.buffers = append(u.buffers, buffer)
u.mu.Unlock()
return nil
}
func (u *udsCore) logsFromBuffer() []string {
u.mu.Lock()
defer u.mu.Unlock()
logs := make([]string, 0, len(u.buffers))
for _, b := range u.buffers {
logs = append(logs, b.String())
b.Free()
}
u.buffers = make([]*buffer.Buffer, 0)
return logs
}