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| 1 | +// Copyright © 2026 Kube logging authors |
| 2 | +// |
| 3 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | +// you may not use this file except in compliance with the License. |
| 5 | +// You may obtain a copy of the License at |
| 6 | +// |
| 7 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | +// |
| 9 | +// Unless required by applicable law or agreed to in writing, software |
| 10 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | +// See the License for the specific language governing permissions and |
| 13 | +// limitations under the License. |
| 14 | + |
| 15 | +package writers |
| 16 | + |
| 17 | +import ( |
| 18 | + "fmt" |
| 19 | + "os" |
| 20 | + "path/filepath" |
| 21 | + "sync" |
| 22 | + |
| 23 | + logger "github.com/sirupsen/logrus" |
| 24 | + |
| 25 | + "github.com/kube-logging/log-generator/log" |
| 26 | + "github.com/kube-logging/log-generator/metrics" |
| 27 | +) |
| 28 | + |
| 29 | +type FileLogWriterConfig struct { |
| 30 | + Path string |
| 31 | + Create bool |
| 32 | + Append bool |
| 33 | + DirMode os.FileMode |
| 34 | + FileMode os.FileMode |
| 35 | + SyncAfterWrite bool |
| 36 | +} |
| 37 | + |
| 38 | +type FileLogWriter struct { |
| 39 | + config FileLogWriterConfig |
| 40 | + file *os.File |
| 41 | + mu sync.Mutex |
| 42 | + closed bool |
| 43 | +} |
| 44 | + |
| 45 | +func NewFileWriter(config FileLogWriterConfig) LogWriter { |
| 46 | + flw := &FileLogWriter{ |
| 47 | + config: config, |
| 48 | + } |
| 49 | + if err := flw.openLocked(); err != nil { |
| 50 | + logger.Fatalf("failed to open log file: %v", err) |
| 51 | + } |
| 52 | + |
| 53 | + return flw |
| 54 | +} |
| 55 | + |
| 56 | +func (flw *FileLogWriter) Send(l log.Log) { |
| 57 | + msg, size := l.String() |
| 58 | + if l.IsFramed() { |
| 59 | + msg = fmt.Sprintf("%d %s", len(msg), msg) |
| 60 | + } |
| 61 | + msg += "\n" |
| 62 | + |
| 63 | + flw.mu.Lock() |
| 64 | + defer flw.mu.Unlock() |
| 65 | + |
| 66 | + if flw.closed { |
| 67 | + logger.Warn("Attempted to write to closed FileLogWriter") |
| 68 | + return |
| 69 | + } |
| 70 | + |
| 71 | + if flw.wasRotated() { |
| 72 | + logger.Info("Log file was rotated, reopening...") |
| 73 | + if err := flw.openLocked(); err != nil { |
| 74 | + logger.Errorf("failed to reopen rotated log file: %v", err) |
| 75 | + return |
| 76 | + } |
| 77 | + } |
| 78 | + |
| 79 | + _, err := flw.file.WriteString(msg) |
| 80 | + if err != nil { |
| 81 | + logger.Errorf("error writing to file %s: %v", flw.config.Path, err) |
| 82 | + return |
| 83 | + } |
| 84 | + |
| 85 | + if flw.config.SyncAfterWrite { |
| 86 | + if err := flw.file.Sync(); err != nil { |
| 87 | + logger.Errorf("error syncing file %s: %v", flw.config.Path, err) |
| 88 | + } |
| 89 | + } |
| 90 | + |
| 91 | + metrics.EventEmitted.With(l.Labels()).Inc() |
| 92 | + metrics.EventEmittedBytes.With(l.Labels()).Add(size) |
| 93 | +} |
| 94 | + |
| 95 | +func (flw *FileLogWriter) Close() { |
| 96 | + flw.mu.Lock() |
| 97 | + defer flw.mu.Unlock() |
| 98 | + |
| 99 | + if flw.closed { |
| 100 | + return |
| 101 | + } |
| 102 | + flw.closed = true |
| 103 | + |
| 104 | + if flw.file != nil { |
| 105 | + if err := flw.file.Sync(); err != nil { |
| 106 | + logger.Errorf("error syncing file %s on close: %v", flw.config.Path, err) |
| 107 | + } |
| 108 | + if err := flw.file.Close(); err != nil { |
| 109 | + logger.Errorf("error closing file %s: %v", flw.config.Path, err) |
| 110 | + } |
| 111 | + flw.file = nil |
| 112 | + } |
| 113 | +} |
| 114 | + |
| 115 | +func (flw *FileLogWriter) openLocked() error { |
| 116 | + if flw.file != nil { |
| 117 | + _ = flw.file.Sync() |
| 118 | + _ = flw.file.Close() |
| 119 | + flw.file = nil |
| 120 | + } |
| 121 | + |
| 122 | + dir := filepath.Dir(flw.config.Path) |
| 123 | + if dir != "" && dir != "." { |
| 124 | + if _, err := os.Stat(dir); os.IsNotExist(err) { |
| 125 | + if !flw.config.Create { |
| 126 | + return fmt.Errorf("directory %s does not exist and file.create is false", dir) |
| 127 | + } |
| 128 | + if err := os.MkdirAll(dir, flw.config.DirMode); err != nil { |
| 129 | + return fmt.Errorf("failed to create directory %s: %w", dir, err) |
| 130 | + } |
| 131 | + logger.Infof("Created directory: %s", dir) |
| 132 | + } |
| 133 | + } |
| 134 | + |
| 135 | + flags := os.O_WRONLY |
| 136 | + if flw.config.Append { |
| 137 | + flags |= os.O_APPEND |
| 138 | + } else { |
| 139 | + flags |= os.O_TRUNC |
| 140 | + } |
| 141 | + |
| 142 | + if _, err := os.Stat(flw.config.Path); os.IsNotExist(err) { |
| 143 | + if !flw.config.Create { |
| 144 | + return fmt.Errorf("file %s does not exist and file.create is false", flw.config.Path) |
| 145 | + } |
| 146 | + flags |= os.O_CREATE |
| 147 | + } |
| 148 | + |
| 149 | + file, err := os.OpenFile(flw.config.Path, flags, flw.config.FileMode) |
| 150 | + if err != nil { |
| 151 | + return fmt.Errorf("failed to open file %s: %w", flw.config.Path, err) |
| 152 | + } |
| 153 | + flw.file = file |
| 154 | + |
| 155 | + logger.Infof("Opened log file: %s (append=%v, sync=%v)", flw.config.Path, flw.config.Append, flw.config.SyncAfterWrite) |
| 156 | + return nil |
| 157 | +} |
| 158 | + |
| 159 | +func (flw *FileLogWriter) wasRotated() bool { |
| 160 | + if flw.file == nil { |
| 161 | + return true |
| 162 | + } |
| 163 | + |
| 164 | + currentStat, err := flw.file.Stat() |
| 165 | + if err != nil { |
| 166 | + return true |
| 167 | + } |
| 168 | + |
| 169 | + pathStat, err := os.Stat(flw.config.Path) |
| 170 | + if err != nil { |
| 171 | + return true |
| 172 | + } |
| 173 | + |
| 174 | + // compare inodes |
| 175 | + return !os.SameFile(currentStat, pathStat) |
| 176 | +} |
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