{"record":{"id":"d294188192f30dfc","repo":"hashicorp/packer","slug":"could-not-create-final-plugin-binary-file-w","errorCode":null,"errorMessage":"could not create final plugin binary file: %w","messagePattern":"could not create final plugin binary file: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"packer/plugin-getter/plugins.go","lineNumber":914,"sourceCode":"\t\t\t\t\tif err := checkVersion(tmpBinFileName, pr.Identifier.String(), version); err != nil {\n\t\t\t\t\t\terrs = multierror.Append(errs, err)\n\t\t\t\t\t\tvar continuableError *ContinuableInstallError\n\t\t\t\t\t\tif errors.As(err, &continuableError) {\n\t\t\t\t\t\t\tcontinue\n\t\t\t\t\t\t}\n\t\t\t\t\t\treturn nil, errs\n\t\t\t\t\t}\n\n\t\t\t\t\t// create directories if need be\n\t\t\t\t\tif err := os.MkdirAll(outputFolder, 0755); err != nil {\n\t\t\t\t\t\terr := fmt.Errorf(\"could not create plugin folder %q: %w\", outputFolder, err)\n\t\t\t\t\t\terrs = multierror.Append(errs, err)\n\t\t\t\t\t\tlog.Printf(\"[TRACE] %s\", err.Error())\n\t\t\t\t\t\treturn nil, errs\n\t\t\t\t\t}\n\t\t\t\t\toutputFile, err := os.OpenFile(outputFileName, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0755)\n\t\t\t\t\tif err != nil {\n\t\t\t\t\t\terr = fmt.Errorf(\"could not create final plugin binary file: %w\", err)\n\t\t\t\t\t\terrs = multierror.Append(errs, err)\n\t\t\t\t\t\treturn nil, errs\n\t\t\t\t\t}\n\t\t\t\t\tif _, err := outputFile.Write(outputFileData.Bytes()); err != nil {\n\t\t\t\t\t\terr = fmt.Errorf(\"could not write final plugin binary file: %w\", err)\n\t\t\t\t\t\terrs = multierror.Append(errs, err)\n\t\t\t\t\t\treturn nil, errs\n\t\t\t\t\t}\n\t\t\t\t\toutputFile.Close()\n\n\t\t\t\t\tcs, err = checksum.Checksummer.Sum(&outputFileData)\n\t\t\t\t\tif err != nil {\n\t\t\t\t\t\terr := fmt.Errorf(\"failed to checksum binary file: %s\", err)\n\t\t\t\t\t\terrs = multierror.Append(errs, err)\n\t\t\t\t\t\tlog.Printf(\"[WARNING] %v, ignoring\", err)\n\t\t\t\t\t}\n\t\t\t\t\tif err := os.WriteFile(outputFileName+checksum.Checksummer.FileExt(), []byte(hex.EncodeToString(cs)), 0644); err != nil {\n\t\t\t\t\t\terr := fmt.Errorf(\"failed to write local binary checksum file: %s\", err)","sourceCodeStart":896,"sourceCodeEnd":932,"githubUrl":"https://github.com/hashicorp/packer/blob/eb36e3c3e48a036f3e8cc94087636ee72e1303c9/packer/plugin-getter/plugins.go#L896-L932","documentation":"After creating the destination plugin folder, InstallLatest opens the final plugin binary file (os.OpenFile(outputFileName, O_RDWR|O_CREATE|O_TRUNC, 0755)) to install the verified binary. Failure to open/create this file is wrapped as \"could not create final plugin binary file: %w\" and returned in the multierror, aborting the install of that plugin binary.","triggerScenarios":"InstallLatest when os.OpenFile on the final output path fails — existing binary file not writable by the current user, outputFileName exists as a directory, or the parent folder was removed between MkdirAll and OpenFile.","commonSituations":"An existing plugin binary installed by root (sudo) that the current user cannot truncate; antivirus/EDR locking the executable; a directory unexpectedly named like the binary; read-only mounted plugin volume.","solutions":["Check ownership of the existing binary (ls -l <outputFileName>) and chown/chmod, or remove it, so the current user can overwrite.","Avoid mixing sudo and non-sudo Packer runs; reinstall the plugin as the regular user.","If security software locks plugin executables, add an exclusion for the Packer plugin directory.","Ensure the plugin volume is mounted read-write.","Retry the install after fixing permissions; the wrapped OS error names the exact cause."],"exampleFix":"// before: binary owned by root, cannot overwrite\nsudo rm ~/.packer.d/plugins/github.com/hashicorp/consul/packer-plugin-consul_v1.0.0_x5.0_linux_amd64\n// after: install succeeds\npacker plugins install github.com/hashicorp/consul","handlingStrategy":"validation","validationCode":"// before install: ensure any existing binary at the target can be overwritten\nexisting, err := os.Stat(targetBinaryPath)\nif err == nil && !existing.IsDir() {\n    if err := os.Chmod(targetBinaryPath, 0o755); err != nil {\n        return fmt.Errorf(\"existing plugin binary not overwritable: %w\", err)\n    }\n    // actual write-permission check\n    f, err := os.OpenFile(targetBinaryPath, os.O_WRONLY, 0o755)\n    if err != nil { return fmt.Errorf(\"cannot overwrite existing binary: %w\", err) }\n    f.Close()\n}","typeGuard":null,"tryCatchPattern":"err := getter.InstallLatest(ctx, req)\nif err != nil && strings.Contains(err.Error(), \"could not create final plugin binary file\") {\n    // drop the locked/owned-by-other-user binary and retry\n    os.RemoveAll(existingPluginDir)\n    return getter.InstallLatest(ctx, req)\n}","preventionTips":["Install plugins as one consistent user; avoid sudo runs that create root-owned binaries.","Exclude the Packer plugin directory from antivirus/EDR file locks.","Keep the plugin volume mounted read-write.","Remove old plugin binaries before major version upgrades if permissions differ.","On shared build images, pre-install plugins with correct ownership (755, owned by the runtime user)."],"tags":["go","plugin-install","filesystem","open-file","permissions"],"backgroundTag":"file-permission-denied","analyzedSha":"eb36e3c3e48a036f3e8cc94087636ee72e1303c9","analyzedAt":"2026-09-05T13:20:43.127Z","contentChangedAt":"2026-09-05T13:20:43.127Z","schemaVersion":2},"datasetVersion":"2026-09-12T17:17:11.597Z"}