{"record":{"id":"057a032df8306755","repo":"slimtoolkit/slim","slug":"detect-error-getting-data-type-s-stderr-s","errorCode":null,"errorMessage":"Detect - error getting data type: %s / stderr: %s","messagePattern":"Detect - error getting data type: (.+?) / stderr: (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/app/sensor/detector/filetype/filetype.go","lineNumber":50,"sourceCode":"func Detect(filePath string) (string, error) {\n\t//TODO: use libmagic (pure impl)\n\tvar cerr bytes.Buffer\n\tvar cout bytes.Buffer\n\n\tif fileTypeCmd != \"\" {\n\t\treturn \"\", nil\n\t}\n\n\tcmd := exec.Command(fileTypeCmd, filePath)\n\tcmd.Stderr = &cerr\n\tcmd.Stdout = &cout\n\n\tif err := cmd.Start(); err != nil {\n\t\treturn \"\", err\n\t}\n\n\tif err := cmd.Wait(); err != nil {\n\t\terr = fmt.Errorf(\"Detect - error getting data type: %s / stderr: %s\", err, cerr.String())\n\t\treturn \"\", err\n\t}\n\n\tif typeInfo := strings.Split(strings.TrimSpace(cout.String()), \":\"); len(typeInfo) > 1 {\n\t\treturn strings.TrimSpace(typeInfo[1]), nil\n\t}\n\n\treturn \"unknown\", nil\n}\n","sourceCodeStart":32,"sourceCodeEnd":60,"githubUrl":"https://github.com/slimtoolkit/slim/blob/81940d17fa112cc678e32209214bcb2355cb3004/pkg/app/sensor/detector/filetype/filetype.go#L32-L60","documentation":"Detect shells out to an external command (file(1)-style type detection) to determine a data type. If cmd.Wait() returns a non-zero exit, the error is combined with the command's stderr and returned with this message — i.e. the external type-detection tool failed.","triggerScenarios":"The spawned detection command exits non-zero (missing binary, unsupported file, bad arguments), so cmd.Wait() errors and the stderr content is embedded in the message.","commonSituations":"'file' utility not installed in the container/image, PATH misconfiguration, detecting a file the tool cannot handle, permission denied on the target file.","solutions":["Read the stderr portion of the message for the tool's own error","Ensure the detection binary (e.g. file) is installed and on PATH in the deployment image","Verify the target file exists and is readable by the sensor process"],"exampleFix":"// before\nif err := cmd.Wait(); err != nil {\n\terr = fmt.Errorf(\"Detect - error getting data type: %s / stderr: %s\", err, cerr.String())\n\treturn \"\", err\n}\n// after\nif err := cmd.Wait(); err != nil {\n\treturn \"\", fmt.Errorf(\"Detect - error getting data type: %w / stderr: %s\", err, cerr.String())\n}","handlingStrategy":"fallback","validationCode":"if _, err := exec.LookPath(\"file\"); err != nil {\n\tlog.Printf(\"detection tool missing from PATH: %v\", err)\n}\nif fi, err := os.Stat(target); err != nil || !fi.Mode().IsRegular() {\n\tlog.Printf(\"target unreadable: %v\", err)\n}","typeGuard":null,"tryCatchPattern":"typ, err := Detect(path)\nif err != nil && strings.Contains(err.Error(), \"error getting data type\") {\n\t// fall back to extension-based detection\n\ttyp = filepath.Ext(path)\n}","preventionTips":["Ensure 'file' (or the detection binary) is installed in deployment images","Set PATH explicitly for the sensor process","Handle non-zero exits by parsing stderr for actionable messages"],"tags":["go","external-command","file-detection","stderr"],"backgroundTag":"external-command-exit-error","analyzedSha":"81940d17fa112cc678e32209214bcb2355cb3004","analyzedAt":"2026-08-31T23:06:12.682Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T05:18:18.240Z"}