{"record":{"id":"7900b311d7afa174","repo":"vxcontrol/pentagi","slug":"tar-archive-content-serialization-failed-w","errorCode":null,"errorMessage":"tar archive content serialization failed: %w","messagePattern":"tar archive content serialization failed: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"backend/pkg/tools/terminal.go","lineNumber":479,"sourceCode":"\t// Docker SDK requires TAR format for file transfer\n\ttarBuffer := &bytes.Buffer{}\n\tarchiveWriter := tar.NewWriter(tarBuffer)\n\tdefer archiveWriter.Close()\n\n\tfilename := filepath.Base(path)\n\tfileDescriptor := &tar.Header{\n\t\tName: filename,\n\t\tMode: 0600,\n\t\tSize: int64(len(content)),\n\t}\n\terr = archiveWriter.WriteHeader(fileDescriptor)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"tar archive header generation failed: %w\", err)\n\t}\n\n\t_, err = archiveWriter.Write([]byte(content))\n\tif err != nil {\n\t\treturn fmt.Errorf(\"tar archive content serialization failed: %w\", err)\n\t}\n\n\terr = archiveWriter.Close()\n\tif err != nil {\n\t\treturn fmt.Errorf(\"failed to close tar writer: %w\", err)\n\t}\n\n\tdir := filepath.Dir(path)\n\terr = t.dockerClient.CopyToContainer(ctx, containerName, dir, tarBuffer, client.CopyToContainerOptions{\n\t\tAllowOverwriteDirWithFile: true,\n\t})\n\tif err != nil {\n\t\treturn fmt.Errorf(\"container file transfer failed: %w\", err)\n\t}\n\n\treturn nil\n}\n","sourceCodeStart":461,"sourceCodeEnd":497,"githubUrl":"https://github.com/vxcontrol/pentagi/blob/ea665308baaff015b226f308438a68d929d0f29b/backend/pkg/tools/terminal.go#L461-L497","documentation":"After writing the tar header, writeFileToContainer writes the file bytes into the in-memory tar archive via archiveWriter.Write. This error wraps that Write failing. Because the underlying writer is a bytes.Buffer, the only realistic cause is memory exhaustion while buffering the content — the error is effectively an out-of-memory signal, not a disk or network problem.","triggerScenarios":"WriteFile or EditFile invoked with content so large that appending []byte(content) to the tar buffer exceeds available memory (allocation failure inside bytes.Buffer grow).","commonSituations":"Agents attempting to write very large files (huge logs, binary blobs, base64 payloads) into the sandbox container on memory-limited hosts; OOM-killer pressure inside the backend process.","solutions":["Reduce the size of the content being written; split into multiple smaller WriteFile calls","Increase memory available to the backend container/host","Check the wrapped error for an out-of-memory/alloc message and confirm with runtime metrics","Pre-check content size before calling writeFileToContainer and reject implausibly large writes early"],"exampleFix":"// before\n_, err = archiveWriter.Write([]byte(content))\nif err != nil {\n    return fmt.Errorf(\"tar archive content serialization failed: %w\", err)\n}\n// after\nconst maxWriteSize = 64 << 20 // 64MB\nif int64(len(content)) > maxWriteSize {\n    return fmt.Errorf(\"content of %d bytes exceeds max write size %d\", len(content), maxWriteSize)\n}\n_, err = archiveWriter.Write([]byte(content))\nif err != nil {\n    return fmt.Errorf(\"tar archive content serialization failed: %w\", err)\n}","handlingStrategy":"validation","validationCode":"if int64(len(content)) >= 1<<30 {\n    return fmt.Errorf(\"content too large for in-memory tar: %d bytes\", len(content))\n}","typeGuard":null,"tryCatchPattern":"if _, err := term.WriteFile(ctx, flowID, content, path); err != nil {\n    var wrapped error = err\n    for errors.Unwrap(wrapped) != nil { wrapped = errors.Unwrap(wrapped) }\n    if strings.Contains(wrapped.Error(), \"cannot allocate\") { /* OOM: reduce size and retry */ }\n}","preventionTips":["Cap file-write sizes in the agent tooling layer","Provision adequate memory for the backend container","Watch for OOM killer events (dmesg) when agents write large files"],"tags":["docker","tar","memory","file-write"],"backgroundTag":"tar-archive-write-failed","analyzedSha":"ea665308baaff015b226f308438a68d929d0f29b","analyzedAt":"2026-09-01T14:16:31.421Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}