Debugging Bub Message in Mini Hanna Node

Overview

This page documents debugging steps for a weird error observed with Bub's message in the node named "Mini Hanna". It is intended for developers, operators, QA, and SREs who maintain the Bub-to-Mini Hanna integration. The goal is to provide a thorough, repeatable troubleshooting workflow, with guidance on identifying root causes, applying fixes, and validating outcomes.

Symptoms

• Bub's message triggers an error event while being processed by the Mini Hanna node.
• The error appears in system logs with a message indicating payload decoding or schema validation failure.
• In some cases, the node may become temporarily unavailable or timestamped "stalled" during processing.
• The Bub sender may retry with backoffs.

Scope and impacted components

• Bub client(s)
• Node: Mini Hanna
• The message broker or relay layer between Bub and Mini Hanna (if applicable)
• Any downstream handlers consuming Mini Hanna outputs

Reproduction steps (typical)

1. Produce a Bub message intended for Mini Hanna.
2. Observe the Mini Hanna node log and the Bub retry behavior.
3. Confirm the error corresponds to one of the known failure modes (payload decoding, validation, or runtime handling).
4. Attempt a minimal reproduction in a test environment if possible.

Environment and prerequisites

• Node name: Mini Hanna
• Bub client identity: e.g., Bub-01 (example)
• Software versions: specify versions for Bub, Mini Hanna, and any middleware if applicable
• Access to relevant logs (system logs, application logs, and any message broker logs)

Technical background and data flow

• Bub produces a message payload that is consumed by the Mini Hanna node.
• The Mini Hanna node parses, validates, and processes the payload, then emits downstream events or responses.
• Errors can originate from payload schema mismatches, encoding issues, or runtime exceptions during handling.
• A successful run follows a strict input contract: fields, types, and encoding must match the Mini Hanna's expectations.

Common error patterns to look for

• Payload missing required fields
• Field type mismatch (string instead of number, etc.)
• Invalid JSON syntax or unsupported encoding
• Nulls in mandatory fields
• Unexpected additional fields not accounted for in the schema

Diagnostic plan and steps

1) Confirm the error persists and capture exact log lines. 2) Retrieve the Bub message payload that triggered the error. 3) Inspect the Mini Hanna node input validation logic for required fields and types. 4) Validate the message against the expected schema used by Mini Hanna (in code or schema file). 5) Check encoding and escaping of special characters in Bub's payload. 6) Review recent changes to Bub, Mini Hanna, or the integration layer. 7) If available, run a minimal repro in a test environment with a synthetic Bub message.

Step-by-step debugging guide

• Step A: Collect logs

 • Enable verbose/diagnostic logging for Bub and Mini Hanna during reproduction.
 • Look for surrounding events that indicate where the failure occurs (parsing, decoding, or execution).

• Step B: Inspect Bub payload

 • Retrieve the exact payload that caused the error.
 • Check JSON syntax, encoding (UTF-8), and schema conformance.

• Step C: Validate Mini Hanna input handling

 • Verify the code path that consumes Bub messages and confirm required fields.
 • Ensure optional fields are handled gracefully when missing.

• Step D: Check transformation or routing logic

 • If the payload is transformed before processing, ensure the transformation preserves required fields and formats.

• Step E: Verify downstream effects

 • Confirm downstream consumers receive a well-formed message after a fix.

• Step F: Minimal repro

 • Craft a minimal Bub message that exercises the same code path to confirm the issue is fixed.

Payload validation guidelines (illustrative)

• Expected JSON schema (illustrative):

 {"bubid":"string","node":"Mini Hanna","payload":"string|object","timestamp":"ISO-8601"}

• Check for: required fields present, correct data types, valid timestamp, no disallowed characters.
• Encoding: ensure the payload is valid UTF-8; avoid invalid byte sequences.

Potential causes and quick checks

• Malformed or missing fields in Bub message
• Incorrect or updated schema in Mini Hanna not aligned with Bub payload
• Encoding issues (non-UTF-8 characters, escaped sequences)
• Race conditions or timing-related null references in Mini Hanna handling
• Recent code changes that introduced a bug in the Bub-to-Mini Hanna path

Fixes and remediation recommendations

• Fix 1: Align schemas between Bub and Mini Hanna

 • Update either Bub payload builder or Mini Hanna schema to ensure the contract is maintained.

• Fix 2: Add robust input validation and defaulting for optional fields

 • Ensure the node tolerates missing optional fields and fails gracefully when mandatory data is absent.

• Fix 3: Normalize and sanitize inputs before processing

 • Trim whitespace, normalize encoding, and escape problematic characters.

• Fix 4: Improve error messages and tracing

 • Include the offending field and snippet of payload in logs to accelerate future debugging.

• Fix 5: Implement end-to-end tests for Bub->Mini Hanna path

 • Add test cases for common payload variants and edge cases.

Validation and verification plan

• Re-run the reproduction steps and confirm the error no longer occurs.
• Verify downstream consumers receive a valid message.
• Check system metrics for stability after the fix.
• Perform a light rollback test in case of hidden side-effects.

Rollback plan (if needed)

• Revert to the previous working schema or payload builder.
• Re-run validation and smoke tests.

References and related pages

• Mini Hanna Node
• Bub''Message''Format
• Logging''and''Diagnostics
• Node''Troubleshooting
• Debugging''Guidelines
• External references:
  • Link to the Bub integration docs (internal) if available.
  • Link to the Mini Hanna module documentation (internal) if available.

Appendix A: Example payloads

• Example successful payload (illustrative):

 {

"bub''id": "Bub-01",

"node": "Mini Hanna",

"payload": {"command":"ping"},

"timestamp": "2025-09-04T12:34:56Z"

 }

• Example failing payload (illustrative):

 {

"bub_id": "Bub-01",

"node": "Mini Hanna",

"payload": null,

"timestamp": "2025-09-04T12:34:56Z"

 }

Change log and contribution notes

• If you update this page, add your initials and date in a Changes section at the bottom.