{"record":{"id":"22e90b11b0e4c9ec","repo":"cloudflare/cloudflared","slug":"error-opening-file-s-w","errorCode":null,"errorMessage":"error opening file %s: %w","messagePattern":"error opening file (.+?): %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"diagnostic/log_collector_utils.go","lineNumber":91,"sourceCode":"\t// when iterating the path files they are already in\n\t// chronological order\n\tfiles, err := os.ReadDir(path)\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"error reading directory %s: %w\", path, err)\n\t}\n\n\t// nolint: gosec\n\toutputHandle, err := os.Create(filepath.Join(os.TempDir(), logFilename))\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"creating temporary log file %s: %w\", logFilename, err)\n\t}\n\tdefer func() { _ = outputHandle.Close() }()\n\n\tfor _, file := range files {\n\t\t// nolint: gosec\n\t\tlogHandle, err := os.Open(filepath.Join(path, file.Name()))\n\t\tif err != nil {\n\t\t\treturn \"\", fmt.Errorf(\"error opening file %s: %w\", file.Name(), err)\n\t\t}\n\t\t_, err = io.Copy(outputHandle, logHandle)\n\t\t_ = logHandle.Close()\n\t\tif err != nil {\n\t\t\treturn \"\", fmt.Errorf(\"error copying file %s: %w\", file.Name(), err)\n\t\t}\n\t}\n\n\t// nolint: gosec\n\tlogHandle, err := os.Open(filepath.Join(path, defaultLogFilename))\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"error opening file %s:%w\", defaultLogFilename, err)\n\t}\n\tdefer func() { _ = logHandle.Close() }()\n\n\t_, err = io.Copy(outputHandle, logHandle)\n\tif err != nil {\n\t\treturn \"\", fmt.Errorf(\"error copying file %s:%w\", logHandle.Name(), err)","sourceCodeStart":73,"sourceCodeEnd":109,"githubUrl":"https://github.com/cloudflare/cloudflared/blob/2253eeeb25a44a713a4b60b8ba1e1b3f377d1a0f/diagnostic/log_collector_utils.go#L73-L109","documentation":"Wrapped os.Open failure inside the per-file loop of diagnostic CopyFilesFromDirectory: one of the rolling log files in the directory could not be opened (deleted mid-iteration or permission denied), aborting the copy of the log bundle.","triggerScenarios":"os.Open(filepath.Join(path, file.Name())) fails for one of the files listed by ReadDir — typically permission changes, or the file was deleted between ReadDir and Open (rotation race).","commonSituations":"Log rotation removing files mid-collection; mixed-permission files in the log directory; dangling entries.","solutions":["Ensure the collector user can read all files in the log directory","Disable/retry around log rotation while collecting (re-run after rotation completes)","Re-run the diagnostic; transient races usually resolve on retry"],"exampleFix":"// before\ncloudflared diagnostic collect   # fails on file deleted mid-run\n// after\n# stop/retry after rotation window, or chown log dir to collector user\nchown -R cloudflared:cloudflared /var/log/cloudflared","handlingStrategy":"retry","validationCode":"// best-effort pre-check that entries are readable\nentries, _ := os.ReadDir(logDir)\nfor _, e := range entries {\n\tif f, err := os.Open(filepath.Join(logDir, e.Name())); err == nil { f.Close() } else { /* warn */ }\n}","typeGuard":null,"tryCatchPattern":"out, err := diagnostic.CopyFilesFromDirectory(ctx, fs, logDir, logFilename)\nif err != nil && strings.Contains(err.Error(), \"error opening file\") {\n\ttime.Sleep(time.Second) // let rotation settle\n\tout, err = diagnostic.CopyFilesFromDirectory(ctx, fs, logDir, logFilename)\n}","preventionTips":["Retry collection outside log-rotation windows","Grant the collector read permission on all log files","Ignore/log-and-skip unreadable individual files where the tool allows"],"tags":["filesystem","file-open","diagnostics"],"backgroundTag":"file-open-failed","analyzedSha":"2253eeeb25a44a713a4b60b8ba1e1b3f377d1a0f","analyzedAt":"2026-09-06T04:14:33.757Z","contentChangedAt":"2026-09-06T04:14:33.757Z","schemaVersion":2},"datasetVersion":"2026-09-14T00:17:10.932Z"}