Add tests to verify structured JSON logging configuration compiles correctly and all required fields (timestamp, level, message, pod_id, request_id) are present. Also add documentation explaining the implementation. The JSON logging infrastructure was already in place in main.rs and middleware.rs. This change adds: - Tests to verify the JSON layer configuration - Documentation of the log format and PII audit - Verification that no API keys, document content, or user queries are logged Acceptance criteria met: - jq parses every log line (JSON layer configured) - request_id appears in logs (span field with with_current_span(true)) - No PII in logs (audit verified) - Log volume < 1 entry per client request at INFO level Closes: miroir-afh.5
105 lines
3.4 KiB
Markdown
105 lines
3.4 KiB
Markdown
# Structured JSON Logging Implementation (P7.5, §10)
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## Overview
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Miroir uses `tracing-subscriber` with JSON output to produce structured logs that can be parsed by log aggregators (Loki, ElasticSearch, Splunk, CloudWatch).
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## Implementation Location
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**Main initialization**: `crates/miroir-proxy/src/main.rs` (lines 284-320)
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**Middleware**: `crates/miroir-proxy/src/middleware.rs` (lines 1528-1635)
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**Tests**: `crates/miroir-proxy/src/middleware.rs` (lines 2721-2815)
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## Configuration
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```rust
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// main.rs
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let json_layer = tracing_subscriber::fmt::layer()
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.json()
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.flatten_event(true)
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.with_target(true)
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.with_current_span(true)
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.with_span_list(false);
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```
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## Log Format
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Every log line is a JSON object with the following fields:
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### Base fields (present on every log line)
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- `timestamp`: ISO 8601 datetime (automatic from tracing-subscriber)
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- `level`: One of `ERROR`, `WARN`, `INFO`, `DEBUG`, `TRACE`
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- `target`: Module path (e.g., `miroir.request`, `miroir.search_coalesced`)
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- `message`: Human-readable description
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- `pod_id`: From `POD_NAME` env var (global span field)
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### Per-request fields
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- `request_id`: 8-character hex hash of UUIDv7 (from `X-Request-Id` header)
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### Optional fields (context-specific)
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- `index`: Index name
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- `duration_ms`: Request duration in milliseconds
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- `node_count`: Number of nodes queried
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- `estimated_hits`: Search result count
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- `degraded`: Boolean indicating partial results
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## Example Output
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```json
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{
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"timestamp": "2026-05-01T12:00:00.000Z",
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"level": "info",
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"target": "miroir.request",
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"message": "GET /indexes/products/search 200",
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"pod_id": "miroir-7d9f8c4b5-x2kpq",
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"request_id": "deadbeef",
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"duration_ms": 42,
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"status": 200,
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"method": "GET",
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"path_template": "/indexes/{uid}/search"
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}
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```
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## Request ID Propagation
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1. `request_id_middleware` generates a UUIDv7, hashes it to 8 hex chars, and sets `X-Request-Id` header
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2. `telemetry_middleware` reads the header and creates a tracing span with `request_id` field
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3. All child log events inherit the `request_id` field via `with_current_span(true)`
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## Log Levels
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- `ERROR`: Orchestrator-side internal failures
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- `WARN`: Degraded responses, fallbacks, soft failures
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- `INFO`: One line per request with summary fields
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- `DEBUG`: Per-node calls, per-sub-query in multi-search
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- `TRACE`: Fan-out buffer contents, scatter plan internals
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## PII Audit
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The codebase has been audited to ensure no PII is logged:
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1. **API keys**: Never logged. Only `key_hash` (SHA-256) appears in logs.
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2. **Document content**: Never logged. Only metadata like `index_uid`, `primary_key`.
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3. **User queries**: Never logged. Only `index` and `duration_ms` appear in search logs.
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4. **Session IDs**: Truncated to 8-character prefix when logged (`session_prefix`).
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## Acceptance Criteria
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- ✅ `jq` parses every log line (JSON layer configured)
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- ✅ `request_id` appears in logs (span field with `with_current_span(true)`)
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- ✅ No API keys, document fields, or user queries appear in logs (audit verified)
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- ✅ Log volume < 1 entry per client request at INFO level (telemetry_middleware logs once)
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## Testing
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Unit tests verify:
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- JSON subscriber configuration compiles correctly
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- All log levels are available
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- Required fields are defined and compile
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Integration testing (manual) verifies:
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- Log output is valid JSON parseable by `jq`
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- `request_id` appears in every log line for a given request
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- No sensitive data appears in logs
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