otel-zig's BatchSpanProcessor held the mutex during HTTP export,
blocking all span.end() callers for seconds. Updated to version
that releases the lock before exporting.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

original repo (ibd1279/otel-zig) has single maintainer and 3.5 months
of inactivity. forking to zzstoatzz/otel-zig ensures we can apply
0.16 updates when needed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

the logfire-legacy module (direct OTLP/JSON implementation) was never
used by any downstream projects - both prefect-server and leaflet-search
use the otel-backed logfire module.

deleted:
- src/exporter.zig, root.zig, attribute.zig, span.zig, log.zig, metrics.zig
- examples/basic.zig
- docs/otel-adoption-plan.md

~75KB of dead code removed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

BasicSpanProcessor exports synchronously on every span.end(), causing
major latency overhead (~100-200ms per span for OTLP HTTP requests).

BatchSpanProcessor queues spans and exports them in batches every 1s
via a background thread, eliminating export latency from the request path.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

framework integrations for common span patterns:
- httpSpan(method, path) -> "HTTP GET /api/..." with standard attrs
- sqlSpan(sql, db_system) -> truncated SQL with db.system attr

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

enables HTTP and DB instrumentation with proper error tracking:
- StatusCode enum (unset, ok, error) per otel semantic conventions
- setStatus(code, description) for explicit status setting
- recordError(e) - zig-idiomatic naming (not recordException)
zig has errors, not exceptions; maps to otel's recordException internally

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- clarify we now use otel-zig with OTLP/protobuf (not JSON)
- update status: metrics are stubs, logging is console-only
- add example showing nested span parent-child linking
- note cross-platform support (macOS + Linux)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

adds thread-local tracking of current span context so nested spans
properly share trace_id and have parent_span_id set correctly.

- adds threadlocal tl_current_span_context for tracking active span
- createSpan now passes parent context to otel-zig's startSpan
- Span.end restores parent context for proper nesting
- also fixes setAttribute to check for null from toOtelValue

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

setGlobalTracerProvider expects the interface type, not the concrete
provider pointer.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

TracerProvider doesn't have addProcessor method - need to use
pipelineBuilder().with(link).done() pattern instead.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

otel-zig's setupGlobalProvider calls detectResource which only supports
macOS (uses _NSGetExecutablePath). bypass this by:

- manually creating TracerProvider instead of setupGlobalProvider
- implementing createMinimalResource with platform-specific detection:
- linux: /proc/self/exe symlink
- macos: _NSGetExecutablePath
- others: skip executable info (pid still works)

tested in docker (debian bookworm + zig 0.15.2) - passes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- toOtelValue now returns ?AttributeValue
- attrsToOtel skips null values from optionals
- enables leaflet-search patterns like .{ .uri = optional_uri }

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- `logfire` module now points to otel_wrapper.zig (recommended)
- `logfire-legacy` module available for transition period
- example renamed to use main module
- both modules tested in `zig build test`

leaflet-search can now adopt without import changes.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- global instance pattern (like Python's DEFAULT_LOGFIRE_INSTANCE)
- convenience functions: configure(), span(), info/warn/err/debug/trace()
- const span support via @constCast for `const span = ...` pattern
- metrics stubs: counter(), gaugeInt(), gaugeDouble()
- fixed Zig 0.15 stderr API (use std.debug.print)
- fixed comptime/runtime attrs via static storage per type

API now matches leaflet-search usage patterns.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

adds otel-zig dependency and creates wrapper module that:
- configures OTLP exporter with Logfire endpoint/auth
- provides OtelLogfire struct with span() API
- handles token-based region detection (us/eu)

new files:
- src/otel_wrapper.zig: logfire-otel module wrapping otel-zig
- examples/otel_basic.zig: demonstrates new otel-backed API
- tests/validate_otel_export.zig: validates OTLP export to Logfire
- docs/otel-adoption-plan.md: migration plan and findings

build targets:
- zig build otel-example: run otel-backed example
- zig build validate-otel: test OTLP export (requires LOGFIRE_TOKEN)

legacy API unchanged - both APIs available during transition.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- fix CLAUDE.md: zig build example (not run-example)
- update README status: mark batched async export and parent-child spans as done
- clarify remaining work: histograms need convenience API, protobuf not started

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

zig's struct copy semantics caused dangling pointers when Span.Data
was copied (in span.end()). the Value.string slice pointed to the
original struct's _string_storage, not the copy's.

fix: don't store a slice in Value.string at all. store string data in
_string_storage and reconstruct the slice via getString() on access.
this ensures the slice always points to the current struct's storage.

- Value.string is now just a tag (no payload)
- added getString() method to reconstruct slice from internal storage
- copyString() no longer returns a slice
- all consumers now use getString() instead of .string
- for loops capture |*attr| to get pointers

added test verifying copy safety: the getString() pointer comes from
the copy's _string_storage, not the original's.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- escape bytes 0x80-0xFF as \u00XX to ensure valid JSON
- escape DEL (0x7f) with other control characters
- add tests for string attributes with special chars and raw bytes
- update example to demonstrate string attribute handling

fixes "invalid unicode code point" errors when attribute values
contain invalid UTF-8 or non-ASCII bytes from URL-decoded data.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

jw.write() wasn't reliably serializing strings from internal storage.
bypass it with manual JSON string writing using beginWriteRaw/endWriteRaw
to maintain Stringify state while writing escaped strings directly.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

slices pointing to internal _string_storage need explicit cast to
[]const u8 for std.json.Stringify to serialize them as strings
rather than byte arrays.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

attributes now copy string data into internal storage instead of
storing pointers. this fixes segfaults when arena-allocated strings
are passed as span attributes - the data outlives the arena.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

track current span ID on thread so child spans can reference their
parent. when creating a span while another is active:
- capture current span as parent_span_id
- update tl_current_span_id to new span
- on span end, restore parent as current

adds parentSpanId to OTLP JSON output when present.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

concurrent requests on different thread pool workers were sharing
the same trace_id because current_trace_id was process-global.

now each thread has its own trace context via threadlocal:
- tl_trace_id: current trace ID for this thread
- tl_active_span_count: span nesting depth for this thread

this ensures each HTTP request gets its own trace_id even when
handled by different workers concurrently.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

the OTLP JSON format expects asInt/asDouble and histogram counts
to be numbers, not strings. only timestamps are strings.

compared against official examples in opentelemetry-proto repo.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1. trace ID: generate new ID for each root span (when no active spans)
- add active_span_count tracking
- add newTrace() for explicit trace boundaries

2. metrics: change from cumulative to delta temporality
- each counter() call is an increment, not aggregated total

3. memory: track allocated NumberDataPoints and free on flush
- allocated_data_points list tracks allocations
- freed in flush() and deinit()

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

flushes pending data every batch_timeout_ms (default 500ms).
stops cleanly on shutdown().

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

- metrics: Counter, Gauge, UpDownCounter, Histogram, ExponentialHistogram
- attributes: typed key-value pairs for spans/logs/metrics
- exporter: rewrite with std.json.Stringify (no manual string building)
- root: add counter(), gaugeInt(), gaugeDouble() convenience functions
- CLAUDE.md: project patterns and zig 0.15 notes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>