{"record":{"id":"e3a275325b2bbe20","repo":"hashicorp/nomad","slug":"error-creating-file-header-w","errorCode":null,"errorMessage":"error creating file header: %w","messagePattern":"error creating file header: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"client/allocdir/alloc_dir.go","lineNumber":231,"sourceCode":"\t\t}\n\n\t\t// Include the path of the file name relative to the alloc dir\n\t\t// so that we can put the files in the right directories\n\t\trelPath, err := filepath.Rel(a.AllocDir, path)\n\t\tif err != nil {\n\t\t\treturn err\n\t\t}\n\t\tlink := \"\"\n\t\tif fileInfo.Mode()&os.ModeSymlink != 0 {\n\t\t\ttarget, err := os.Readlink(path)\n\t\t\tif err != nil {\n\t\t\t\treturn fmt.Errorf(\"error reading symlink: %v\", err)\n\t\t\t}\n\t\t\tlink = target\n\t\t}\n\t\thdr, err := tar.FileInfoHeader(fileInfo, link)\n\t\tif err != nil {\n\t\t\treturn fmt.Errorf(\"error creating file header: %w\", err)\n\t\t}\n\t\thdr.Name = relPath\n\t\tif err := tw.WriteHeader(hdr); err != nil {\n\t\t\treturn err\n\t\t}\n\n\t\t// If it's a directory or symlink we just write the header into the tar\n\t\tif fileInfo.IsDir() || (fileInfo.Mode()&os.ModeSymlink != 0) {\n\t\t\treturn nil\n\t\t}\n\n\t\t// Write the file into the archive\n\t\tfile, err := os.Open(path)\n\t\tif err != nil {\n\t\t\treturn err\n\t\t}\n\t\tdefer file.Close()\n","sourceCodeStart":213,"sourceCodeEnd":249,"githubUrl":"https://github.com/hashicorp/nomad/blob/482b49bf1aec006f089bcfc7e632d8f6ac303e5e/client/allocdir/alloc_dir.go#L213-L249","documentation":"During tar snapshot construction, tar.FileInfoHeader converts the walked file's os.FileInfo into a tar header. If the OS rejects the header construction (unsupported file type, stat inconsistency, or a corrupt/unusual mode), the snapshot returns this wrapped error. It is rare and indicates an OS/filesystem-level incompatibility.","triggerScenarios":"os.FileInfo inconsistent with the on-disk entry (file replaced between lstat and header creation); exotic file types unsupported by tar; platform-specific header limitations.","commonSituations":"Snapshotting while tasks churn the directory; unusual filesystems (FUSE, 9p) reporting odd modes; Go/tar version edge cases with special files.","solutions":["Retry the snapshot after transient races clear","Exclude problematic paths (sockets, devices) from snapshot scope","Update Go/runtime to pick up tar fixes","Check filesystem health (fsck) if persistent"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"err := allocDir.Snapshot(w)\nif err != nil && strings.Contains(err.Error(), \"error creating file header\") {\n  // inspect the file type at the reported path; skip or handle special files\n}","preventionTips":["Keep runtimes/Go version current for tar fixes","Avoid exotic filesystems (FUSE/9p) for alloc dirs","Clean up sockets/special files from shared dirs"],"tags":["filesystem","tar","archive"],"backgroundTag":"tar-fileinfo-header-failed","analyzedSha":"482b49bf1aec006f089bcfc7e632d8f6ac303e5e","analyzedAt":"2026-09-04T07:54:14.808Z","contentChangedAt":"2026-09-04T07:54:14.808Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}