WeKnora deployment source with the reviewed wiki identity, summary and recovery fixes

internal/tracing/langfuse/exporter.go

@@ -0,0 +1,41 @@
+package langfuse
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"strings"
+
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+// newExporter builds an OTLP/HTTP trace exporter pointed at the
+// Langfuse v3+ / LiteFuse OTel endpoint (POST /api/public/otel/v1/traces).
+//
+// Auth is HTTP Basic (public_key:secret_key). The x-langfuse-ingestion-version
+// header is the gate opt-in that LiteFuse/Langfuse v3 require for the OTel
+// direct-write path (verified against directWriteHelpers.ts — without it the
+// server returns 400 "requires Python SDK >= 4.0.0"). The x-langfuse-sdk-*
+// markers are sent for parity; WeKnora is a Go client, not the Python SDK.
+func newExporter(ctx context.Context, cfg Config) (sdktrace.SpanExporter, error) {
+	endpoint := strings.TrimRight(cfg.Host, "/") + "/api/public/otel/v1/traces"
+	creds := cfg.PublicKey + ":" + cfg.SecretKey
+	opts := []otlptracehttp.Option{
+		otlptracehttp.WithEndpointURL(endpoint),
+		otlptracehttp.WithHeaders(map[string]string{
+			"Authorization":                "Basic " + base64.StdEncoding.EncodeToString([]byte(creds)),
+			"x-langfuse-ingestion-version": "4",
+			"x-langfuse-sdk-name":          "python",
+			"x-langfuse-sdk-version":       langfuseScopeVersion,
+		}),
+	}
+	if cfg.RequestTimeout > 0 {
+		opts = append(opts, otlptracehttp.WithTimeout(cfg.RequestTimeout))
+	}
+	exp, err := otlptracehttp.New(ctx, opts...)
+	if err != nil {
+		return nil, fmt.Errorf("langfuse: build otlp exporter: %w", err)
+	}
+	return exp, nil
+}