feat(ui): add structured JSON logging for Loki observability

[POWERFULMOVES]

Summary

• Wires logError() to emit structured JSON for Loki/Promtail ingestion
• Production: JSON to stdout (Promtail picks up via docker logs)
• Development: Colorized console output for debugging
• No new infrastructure - uses existing Loki/Promtail stack

Log Format

{
  "timestamp": "2025-12-18T...",
  "level": "error",
  "message": "Failed to send chat message",
  "error": { "name": "Error", "message": "...", "stack": "..." },
  "component": "chat/send",
  "action": "insert"
}

Changes

• UPDATE: pmoves/ui/lib/errorUtils.ts
  • Add StructuredLogEntry interface
  • Add emitStructuredLog() helper
  • Update logError() to use structured logging
  • Remove Sentry TODO (using self-hosted Loki instead)

Test Plan

• Verify JSON output in production mode (NODE_ENV=production)
• Verify logs appear in Loki via Grafana dashboard
• Verify development mode shows readable colored output

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores
  • Enhanced error logging infrastructure with structured JSON formatting for production environments and improved debugging output for development.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

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[coderabbitai]

Walkthrough

The changes enhance error logging in errorUtils.ts by introducing structured logging capabilities. A new StructuredLogEntry type and emitStructuredLog helper are added to emit JSON-formatted logs in production (for Loki/Promtail integration) and pretty-printed colored logs in development. The logError function now routes through this structured logging mechanism, while logForDebugging gains conditional behavior based on development mode or an explicit debug flag. Exported API signatures remain unchanged.

Changes

Cohort / File(s)	Summary
Error Logging Enhancement pmoves/ui/lib/errorUtils.ts	Introduces StructuredLogEntry type and emitStructuredLog helper for dual-mode logging (JSON in production, pretty-printed in development). Routes logError through structured logging; enhances logForDebugging with conditional logging based on development mode or NEXT_PUBLIC_DEBUG_LOGGING flag. Retains existing exported API signatures.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

• Verify emitStructuredLog correctly formats JSON output with timestamp, level, message, error details, and context
• Validate pretty-print formatting logic for development environments
• Confirm conditional logging logic for logForDebugging (development mode vs. explicit debug flag)
• Check that logError properly populates all fields of StructuredLogEntry

Possibly related PRs

• fix(ui/chat): eliminate silent failures and preserve input on error #326: Adds logError calls throughout the codebase that depend on the structured logging infrastructure introduced in this errorUtils update for JWT and UI error handling.

Poem

🐰 Logs now structured, clean and bright,
JSON flows in production's light,
Pretty colors aid the dev's might,
Debugging flags keep errors tight! ✨

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: adding structured JSON logging for Loki observability, which aligns with the changeset's primary objective.
Description check	✅ Passed	The description includes a summary of changes and a test plan, but lacks required sections like 'Required Checks' and 'Reviewer Notes' from the template, though it provides substantive content about the implementation.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat/ui-loki-structured-logging

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

pmoves/ui/lib/errorUtils.ts (1)

83-95: Consider avoiding duplication of component and action in context.

Lines 92-93 extract component and action to top-level fields, while line 94 spreads the entire context object. This means if context contains component or action properties, they'll appear in both the top-level and nested context field.

If this duplication is intentional for Loki query flexibility, consider adding a comment to clarify. Otherwise, consider excluding these fields from the nested context:

🔎 Apply this diff to avoid duplication:

   const entry: StructuredLogEntry = {
     timestamp: new Date().toISOString(),
     level: severity,
     message,
     error: {
       name: errorObj.name,
       message: errorObj.message,
       stack: errorObj.stack,
     },
     component: context?.component,
     action: context?.action,
-    context: context ? { ...context } : undefined,
+    context: context ? Object.fromEntries(
+      Object.entries(context).filter(([key]) => key !== 'component' && key !== 'action')
+    ) : undefined,
   };

📜 Review details

Configuration used: defaults

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 01d032a and b187b2b.

📒 Files selected for processing (1)

• pmoves/ui/lib/errorUtils.ts (3 hunks)

🧰 Additional context used

📓 Path-based instructions (1)

pmoves/ui/**/*.{js,jsx,ts,tsx}

📄 CodeRabbit inference engine (pmoves/AGENTS.md)

UI updates: run make -C pmoves notebook-workbench-smoke ARGS="--thread=<uuid>" to lint the Next.js bundle and validate Supabase connectivity; reference pmoves/docs/UI_NOTEBOOK_WORKBENCH.md

Files:

• pmoves/ui/lib/errorUtils.ts

🔇 Additional comments (3)

pmoves/ui/lib/errorUtils.ts (3)

15-31: LGTM! Well-structured log entry type.

The StructuredLogEntry interface is well-designed for Loki ingestion with appropriate optional fields and clear typing.

---

57-69: LGTM! Good addition of debug flag.

The updated comment accurately reflects the function's behavior, and the addition of NEXT_PUBLIC_DEBUG_LOGGING flag provides a useful mechanism for enabling debug logs in production when needed.

---

1-138: Verify changes with notebook-workbench-smoke test.

As per coding guidelines, please run the following command to lint the Next.js bundle and validate Supabase connectivity:

#!/bin/bash
# Generate a UUID for the test thread
TEST_UUID=$(uuidgen 2>/dev/null || cat /proc/sys/kernel/random/uuid 2>/dev/null || python3 -c "import uuid; print(uuid.uuid4())")

echo "Running notebook-workbench-smoke test with thread: $TEST_UUID"
make -C pmoves notebook-workbench-smoke ARGS="--thread=$TEST_UUID"

This validates that the logging changes don't break the Next.js bundle or runtime behavior.

[coderabbitai]

⚠️ Potential issue | 🟠 Major

🧩 Analysis chain

🏁 Script executed:

fd errorUtils pmoves/ui -type f

Repository: POWERFULMOVES/PMOVES.AI

Length of output: 237

---

🏁 Script executed:

cat -n pmoves/ui/lib/errorUtils.ts | head -100

Repository: POWERFULMOVES/PMOVES.AI

Length of output: 3443

---

🏁 Script executed:

rg -n "StructuredLogEntry" pmoves/ui/lib/errorUtils.ts

Repository: POWERFULMOVES/PMOVES.AI

Length of output: 206

---

🏁 Script executed:

rg -n "emitStructuredLog" pmoves/ui/ -A 3 -B 3

Repository: POWERFULMOVES/PMOVES.AI

Length of output: 919

---

🏁 Script executed:

# First, let's find and read the errorUtils file
find pmoves/ui -name "errorUtils.ts" -type f 2>/dev/null | head -1 | xargs cat

Repository: POWERFULMOVES/PMOVES.AI

Length of output: 3859

---

Add error handling for JSON serialization failures in production logging.

Line 41 should handle serialization errors. The StructuredLogEntry interface accepts context?: Record<string, unknown>, which allows arbitrary objects to be passed. If the context contains circular references or non-serializable values (functions, symbols, DOM nodes), JSON.stringify(entry) will throw a TypeError, breaking production logging.

Implement a try-catch block to gracefully handle serialization failures:

 function emitStructuredLog(entry: StructuredLogEntry): void {
   if (process.env.NODE_ENV === 'production') {
     // JSON format for Promtail to parse and send to Loki
-    console.log(JSON.stringify(entry));
+    try {
+      console.log(JSON.stringify(entry));
+    } catch (error) {
+      // Fallback serialization on failure
+      console.log(JSON.stringify({
+        timestamp: entry.timestamp,
+        level: entry.level,
+        message: entry.message,
+        error: entry.error,
+        serializationError: 'Failed to serialize full entry context'
+      }));
+    }
   } else {

🤖 Prompt for AI Agents

In pmoves/ui/lib/errorUtils.ts around lines 38 to 55, the production path calls
JSON.stringify(entry) directly which can throw if entry.context contains
circular or non-serializable values; wrap the JSON.stringify call in a
try-catch, and on success keep console.log(JSON.stringify(entry)), but on
failure catch the error, console.error a short message including the
serialization error, and output a safe fallback log (for example a minimal JSON
with entry.level, entry.message and a note that serialization failed, plus a
string describing the context type or entry keys). Ensure the catch does not
rethrow so production logging never crashes.