github.com/cloudwego/kitex@v0.9.0/pkg/logid/logid.go (about)

     1  /*
     2   * Copyright 2023 CloudWeGo Authors
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package logid
    18  
    19  import (
    20  	"context"
    21  	"strconv"
    22  	"strings"
    23  	"sync/atomic"
    24  	"time"
    25  
    26  	"github.com/bytedance/gopkg/lang/fastrand"
    27  )
    28  
    29  const (
    30  	logIDVersion   = "02"
    31  	logIDMaxLength = 21
    32  	maxRandNum     = 1<<24 - 1<<20
    33  )
    34  
    35  var (
    36  	logIDGenerator func(ctx context.Context) string
    37  	logIDExtra     atomic.Value
    38  )
    39  
    40  func init() {
    41  	SetLogIDGenerator(DefaultLogIDGenerator)
    42  	SetLogIDExtra("")
    43  }
    44  
    45  // SetLogIDGenerator allows custom log id generator
    46  func SetLogIDGenerator(g func(ctx context.Context) string) {
    47  	logIDGenerator = g
    48  }
    49  
    50  // SetLogIDExtra allows custom log id extra
    51  // For example, local ip address can be used to improve the uniqueness
    52  func SetLogIDExtra(extra string) {
    53  	logIDExtra.Store(extra)
    54  }
    55  
    56  // loadLogIDExtra returns the log ID extra as a string.
    57  //
    58  // It does not take any parameters.
    59  // It returns a string.
    60  func loadLogIDExtra() string {
    61  	return logIDExtra.Load().(string)
    62  }
    63  
    64  // DefaultLogIDGenerator generates a default log ID using a combination of random numbers and timestamps.
    65  // `SetLogIDExtra` can be used to add extra information to each log ID.
    66  // The format is `<version><timestamp><extra><random>`, where
    67  // - `<version>` is the version string, "02" by default
    68  // - `<timestamp>` is the timestamp in milliseconds, consuming 13 digits
    69  // - `<extra>` is the extra information string, empty by default
    70  // - `<random>` is the random number, consuming 6 hex digits
    71  // It returns a string that represents the generated log ID.
    72  func DefaultLogIDGenerator(ctx context.Context) string {
    73  	r := fastrand.Uint32n(maxRandNum) + 1<<20
    74  	sb := strings.Builder{}
    75  	extra := loadLogIDExtra()
    76  	sb.Grow(logIDMaxLength + len(extra))
    77  	sb.WriteString(logIDVersion)
    78  	ts := time.Now().UnixNano() / int64(time.Millisecond)
    79  	sb.WriteString(strconv.FormatUint(uint64(ts), 10))
    80  	sb.WriteString(extra)
    81  	sb.WriteString(strconv.FormatUint(uint64(r), 16))
    82  	return sb.String()
    83  }