mats
6be6aa891a
Error/Info helpers emit a structured log record AND touch the active span (status + stack trace), so failures show up as red markers in Jaeger/Tempo with correlated log lines. No-op safe when no span is active. First consumer: go-cart-actor cmd/order.
63 lines
2.5 KiB
Go
63 lines
2.5 KiB
Go
// Package otellog provides logging helpers that bridge slog with OpenTelemetry
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// spans. Every Error/Info call both emits a structured log record AND touches
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// the active span — so errors appear as red markers in Jaeger/Tempo AND as
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// correlated log lines in your log backend (Loki, Elasticsearch, etc.).
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//
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// Usage:
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//
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// otellog.Error(ctx, logger, "checkout failed", err, "orderId", id.String())
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//
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// The helpers are safe when no span is active (the span is a no-op in that
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// case) — callers don't need to guard the call.
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package otellog
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import (
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"context"
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"log/slog"
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"go.opentelemetry.io/otel"
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"go.opentelemetry.io/otel/codes"
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"go.opentelemetry.io/otel/trace"
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)
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// Error records an error on the active span (with stack trace) and emits a
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// structured slog.ErrorContext log. The span status is set to Error.
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// Any extra key/value pairs are appended to the log record.
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func Error(ctx context.Context, logger *slog.Logger, msg string, err error, args ...any) {
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if span := trace.SpanFromContext(ctx); span != nil {
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span.RecordError(err, trace.WithStackTrace(true))
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span.SetStatus(codes.Error, msg)
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}
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all := make([]any, 0, len(args)+2)
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all = append(all, "error", err)
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all = append(all, args...)
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logger.ErrorContext(ctx, msg, all...)
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}
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// Info emits a structured slog.InfoContext log. When a span is active the
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// trace/span IDs are automatically injected by the OTel slog handler (if
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// configured), correlating the log line with the trace.
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func Info(ctx context.Context, logger *slog.Logger, msg string, args ...any) {
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logger.InfoContext(ctx, msg, args...)
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}
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// Warn emits a structured slog.WarnContext log. Like Info, span correlation
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// is handled by the OTel slog handler when configured.
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func Warn(ctx context.Context, logger *slog.Logger, msg string, args ...any) {
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logger.WarnContext(ctx, msg, args...)
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}
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// SpanFromContext returns the current span — useful when callers need to add
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// attributes or events directly. Returns a valid (no-op) span when no span is
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// active, so the caller never needs a nil check.
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func SpanFromContext(ctx context.Context) trace.Span {
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return trace.SpanFromContext(ctx)
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}
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// StartSpan is a convenience wrapper around otel.Tracer(name).Start(ctx, name)
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// that returns the ctx and span. Panics if the tracer provider is not
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// configured — but in practice the global no-op provider handles that.
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func StartSpan(ctx context.Context, tracerName, spanName string, opts ...trace.SpanStartOption) (context.Context, trace.Span) {
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return otel.Tracer(tracerName).Start(ctx, spanName, opts...)
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}
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