zzstoatzz.io
logfire client for zig
fix: implement context propagation for parent-child span relationships
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>
+36
-6
src/otel_wrapper.zig
+36
-6
src/otel_wrapper.zig
···
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var global_allocator: ?std.mem.Allocator = null;
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// ============================================================================
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+
// thread-local span context tracking for parent-child relationships
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// ============================================================================
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+
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/// thread-local current span context - enables parent-child span linking
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threadlocal var tl_current_span_context: ?otel_api.trace.Span.Context = null;
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+
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+
// ============================================================================
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// Logfire - main SDK type
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// ============================================================================
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···
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pub fn createSpan(self: *Self, name: []const u8, attrs: anytype) Span {
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if (self.tracer) |*tracer| {
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const otel_attrs = attrsToOtel(attrs);
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-
const ctx = &[_]otel_api.ContextKeyValue{};
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+
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// capture parent context before creating new span
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const parent_context = tl_current_span_context;
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+
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// build context with parent span if one exists
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var ctx_storage: [1]otel_api.ContextKeyValue = undefined;
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const ctx: []const otel_api.ContextKeyValue = if (parent_context) |parent| blk: {
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ctx_storage[0] = .{
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.key = otel_api.trace.context_keys.active_span_context_key.key_id,
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.value = otel_api.trace.context_keys.active_span_context_key.wrapValue(parent),
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};
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break :blk &ctx_storage;
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} else &[_]otel_api.ContextKeyValue{};
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+
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const span_result = tracer.startSpan(name, .{
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.kind = .internal,
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.attributes = otel_attrs,
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}, ctx) catch {
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-
return .{ .inner = null };
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return .{ .inner = null, .parent_context = parent_context };
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};
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return .{ .inner = span_result };
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+
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// update thread-local context with new span
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tl_current_span_context = span_result.getSpanContext();
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return .{ .inner = span_result, .parent_context = parent_context };
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}
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-
return .{ .inner = null };
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return .{ .inner = null, .parent_context = null };
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}
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// ========================================================================
···
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pub const Span = struct {
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inner: ?otel_api.trace.Span,
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parent_context: ?otel_api.trace.Span.Context,
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/// end the span - takes *const for API compatibility with legacy logfire
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pub fn end(self: *const Span) void {
···
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s.end(null);
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s.deinit();
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mutable.inner = null;
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// restore parent context (enables proper nesting)
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tl_current_span_context = mutable.parent_context;
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}
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}
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}
···
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if (self.inner != null) {
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const mutable = @constCast(self);
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if (mutable.inner) |*s| {
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-
s.setAttribute(.{ .key = key, .value = toOtelValue(value) });
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if (toOtelValue(value)) |val| {
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s.setAttribute(.{ .key = key, .value = val });
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}
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}
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}
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}
···
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if (global_instance) |lf| {
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return lf.createSpan(name, attrs);
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}
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-
return .{ .inner = null };
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return .{ .inner = null, .parent_context = null };
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}
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/// log at trace level