{"record":{"id":"258f317468601e38","repo":"valyala/fasthttp","slug":"cannot-obtain-info-for-file-q-w","errorCode":null,"errorMessage":"cannot obtain info for file %q: %w","messagePattern":"cannot obtain info for file %q: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"fs.go","lineNumber":1682,"sourceCode":"\t}\n\treturn ff, nil\n}\n\nconst (\n\tfsMinCompressRatio        = 0.8\n\tfsMaxCompressibleFileSize = 8 * 1024 * 1024\n)\n\nfunc (h *fsHandler) compressAndOpenFSFile(filePath, fileEncoding string) (*fsFile, error) {\n\tf, err := h.filesystem.Open(filePath)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\n\tfileInfo, err := f.Stat()\n\tif err != nil {\n\t\t_ = f.Close()\n\t\treturn nil, fmt.Errorf(\"cannot obtain info for file %q: %w\", filePath, err)\n\t}\n\n\tif fileInfo.IsDir() {\n\t\t_ = f.Close()\n\t\treturn nil, errDirIndexRequired\n\t}\n\n\tif strings.HasSuffix(filePath, h.compressedFileSuffixes[fileEncoding]) ||\n\t\tfileInfo.Size() > fsMaxCompressibleFileSize ||\n\t\t!isFileCompressible(f, fsMinCompressRatio) {\n\t\treturn h.newFSFile(f, fileInfo, false, filePath, \"\")\n\t}\n\n\tcompressedFilePath := h.filePathToCompressed(filePath)\n\n\tif _, ok := h.filesystem.(*osFS); !ok {\n\t\treturn h.newCompressedFSFileCache(f, fileInfo, compressedFilePath, fileEncoding)\n\t}","sourceCodeStart":1664,"sourceCodeEnd":1700,"githubUrl":"https://github.com/valyala/fasthttp/blob/c96f600972c6f4a7a30d664257b340ebe9d60124/fs.go#L1664-L1700","documentation":"This error is returned by the fasthttp filesystem handler (fsHandler) when os.Stat (via fs.File.Stat) fails on an original file it just opened, before compression/caching. The library needs file metadata (size, modtime, IsDir) to decide whether to serve, compress, or cache the file; without it the file cannot be handled. The original file handle is closed before returning, and the underlying OS error is wrapped in %w.","triggerScenarios":"Calling fasthttp's FS handler / RequestCtx.SendFile / ServeFile with a path that resolves to a file that exists at open time but whose Stat fails: file deleted between Open and Stat, permission revoked on parent directory, or a filesystem (e.g. FUSE/NFS) whose Stat errors.","commonSituations":"Race where a file is removed while the static file server is serving it; running the server as a user lacking execute permission on a parent directory; network mounts (NFS) returning ESTALE; serving from an overlay/FUSE filesystem with flaky Stat.","solutions":["Check the wrapped cause (errors.Is/As on the %w error) — if it is fs.ErrNotExist, the file was removed concurrently; re-check your file lifecycle or disable aggressive deletion.","Verify the process user has read+execute (r+x) permission on every directory component of the path.","If serving from a network/FUSE mount, ensure the mount is healthy and Stat is supported.","Retry the request: this is often transient if caused by a concurrent rename/delete."],"exampleFix":"// before (handler side, file disappearing under load)\nfs := &fasthttp.FS{Root: \"./static\"}\n// after (guard the file exists and is readable before serving)\nif _, err := os.Stat(\"./static/\" + name); err != nil {\n    ctx.Error(\"file unavailable\", fasthttp.StatusNotFound)\n    return\n}\nfsHandler.NewRequestHandler()(ctx)","handlingStrategy":"retry","validationCode":"if fi, err := os.Stat(path); err != nil || fi.IsDir() {\n    // skip serving / return 404 before calling the handler\n}","typeGuard":"func isStatErr(err error) bool { return strings.Contains(err.Error(), \"cannot obtain info for file\") }","tryCatchPattern":"if err := handler(ctx); err != nil && strings.Contains(err.Error(), \"cannot obtain info for file\") {\n    ctx.Error(\"file unavailable\", fasthttp.StatusNotFound) // or retry once\n}","preventionTips":["Avoid deleting files while the server serves them; use atomic rename-on-replace.","Ensure the service user has r+x on all path components.","Prefer local disks over flaky network mounts for static roots."],"tags":["filesystem","fasthttp","file-metadata","stat"],"backgroundTag":"file-stat-failed","analyzedSha":"c96f600972c6f4a7a30d664257b340ebe9d60124","analyzedAt":"2026-08-31T22:48:28.265Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T05:18:18.240Z"}