fix(telemetry): stop clipping the per-attempt error message at 256 chars

[jarvis9443]

Problem

The error_message an operator reads on the /logs page is truncated before it is ever stored. attempt_error_message caps the string at 256 chars — a bound copied from sanitize_tag, which exists to bound short provider tags (branded_provider, pk_label), not error text.

That cap sits on top of a bound that had already made the string safe to store: an UpstreamStatus message is bounded by the bridge at MAX_UPSTREAM_ERROR_MESSAGE_BYTES (1 KiB) in capture_upstream_error_http. So the 256-char cap was a second, tighter truncation with no budget of its own to defend.

Real upstream errors exceed it. A content-filter refusal — the shape that provoked the issue — runs ~260 chars on its own, so what reached telemetry ended mid-URL:

upstream returned HTTP 400: The response was filtered because the prompt triggered
the provider's content management policy. Please modify your prompt and retry. To
learn more about the content filtering policies that apply here, read the docum

— dropping exactly the part that tells the operator what to do about it.

Implementation

Raise the cap to 2048 chars (MAX_ATTEMPT_ERROR_MESSAGE_CHARS), above the bridge's 1 KiB byte budget, so the bridge's bound is the only limit that fires and the operator sees the whole message the bridge kept. Chars-vs-bytes matters here: a 1 KiB ASCII message is 1024 chars, so a 1024-char cap would still have clipped the prefix upstream returned HTTP 400: worth of tail.

The cap stays as a backstop — BridgeError variants that carry an unbounded string (e.g. Config) still can't write unbounded telemetry.

Baseline. Mainstream gateways bound this field an order of magnitude looser than we did: the closest comparable applies a 2048-char DB-storage cap to the stored error message (env-tunable), and truncates prompts on the same budget. 2048 matches that. None treat a short-tag-sized bound as adequate for error text.

Behavior change

Failed-attempt error_message telemetry can now carry up to ~1 KiB (whatever the bridge kept) instead of 256 chars. Only failed attempts populate the field, and cp-api stores it in a text column with no cap of its own; per-org usage_retention_days pruning is unchanged.

Tests

crates/aisix-proxy/src/attempt.rs — the two regression tests fail on the old cap and pass on the new one; verified by reverting the constant locally:

• long_upstream_message_is_not_clipped — a long refusal survives to its trailing doc URL. The fixture is prose ending in a URL rather than generated filler, because what has to survive is the END of a realistically long message.
• cap_clears_the_bridge_message_bound — a message already at the bridge's byte bound reaches telemetry whole.
• pathological_message_still_hits_the_backstop — an unbounded Config string is still capped.
• control_chars_are_stripped — unchanged sanitisation.

The paired dashboard fix (the detail panel renders this field with a truncate class, clipping it to one line regardless of length) ships separately in api7/AISIX-Cloud#1068.

Fixes api7/AISIX-Cloud#1065

[coderabbitai]

📝 Walkthrough

Walkthrough

Per-attempt error telemetry now permits up to 2048 characters after control-character removal. Tests cover upstream messages, bridge-bounded messages, unbounded errors, and newline or tab sanitization.

Changes

Attempt error telemetry

Layer / File(s)	Summary
Error message backstop and validation crates/aisix-proxy/src/attempt.rs	attempt_error_message uses a 2048-character cap while preserving control-character stripping, with tests covering bounded and unbounded error messages and sanitized output.

Estimated code review effort: 2 (Simple) | ~10 minutes

Suggested reviewers: moonming

🚥 Pre-merge checks | ✅ 5 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
E2e Test Quality Review	⚠️ Warning	Blocking: the PR adds only unit tests for a helper in attempt.rs; it doesn’t exercise the real API→routing→logs path required for E2E coverage.	Add an integration/e2e case that sends a failing request through the real flow and asserts the stored /logs error_message keeps the full tail.

✅ Passed checks (5 passed)

Check name	Status	Explanation
Linked Issues check	✅ Passed	The PR addresses #1065 by making logged error messages more complete and adding regression tests for long and bounded messages.
Out of Scope Changes check	✅ Passed	The changes stay focused on error-message telemetry and related tests, with no obvious unrelated additions.
Security Check	✅ Passed	The change only widens capped attempt telemetry; it still strips controls, and I found no new secret/logging, auth, ownership, TLS, or DB issues.
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: increasing per-attempt telemetry error message clipping from 256 chars.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/telemetry-error-message-cap-1065

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@crates/aisix-proxy/src/attempt.rs`:
- Around line 203-225: Update the long-message regression test and its comment
to use provider-neutral wording and a generated message longer than 256
characters, while preserving the assertions that the full body and tail remain
intact. Rename long_upstream_message_is_not_clipped if needed to remove
provider-specific terminology, and eliminate the Azure/product names and
documentation URL from the fixture.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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Configuration used: Organization UI

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Run ID: b64cbc72-e5e5-439d-a6b3-6482e54231f6

📥 Commits

Reviewing files that changed from the base of the PR and between 3b9253e and fa2e598.

📒 Files selected for processing (1)

• crates/aisix-proxy/src/attempt.rs