improved logging for debug

internal/open_figi.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"log/slog"
 	"net/http"
 	"sync"
 	"time"
@@ -33,7 +34,10 @@ func NewOpenFIGI(c *http.Client, apiKey string) *OpenFIGI {
 	// Rate limits as per https://www.openfigi.com/api/documentation#rate-limits
 	limiter := rate.NewLimiter(rate.Every(time.Minute), 25)
 	if len(apiKey) > 0 {
+		slog.Debug("OpenFIGI client: created with API Key rate limits")
 		limiter = rate.NewLimiter(rate.Every(time.Second*6), 25)
+	} else {
+		slog.Debug("OpenFIGI client: created with puplic rate limits")
 	}
 
 	return &OpenFIGI{
@@ -48,10 +52,16 @@ func (of *OpenFIGI) SecurityTypeByISIN(ctx context.Context, isin string) (string
 	of.mu.RLock()
 	if secType, ok := of.securityTypeCache[isin]; ok {
 		of.mu.RUnlock()
+		slog.Debug("OpenFIGI client: SecurityTypeByISIN cache hit",
+			slog.String("isin", isin),
+			slog.String("security_type", secType))
 		return secType, nil
 	}
 	of.mu.RUnlock()
 
+	slog.Debug("OpenFIGI client: SecurityTypeByISIN cache miss",
+		slog.String("isin", isin))
+
 	of.mu.Lock()
 	defer of.mu.Unlock()
 
@@ -85,6 +95,10 @@ func (of *OpenFIGI) SecurityTypeByISIN(ctx context.Context, isin string) (string
 		req.Header.Add(OpenFIGIAPIKeyHeader, of.apiKey)
 	}
 
+	if !of.mappingLimiter.Allow() {
+		slog.Debug("OpenFIGI client: mapping limiter waiting for rate limiter capacity")
+	}
+
 	err = of.mappingLimiter.Wait(ctx)
 	if err != nil {
 		return "", fmt.Errorf("wait for mapping request capacity: %w", err)
@@ -123,6 +137,10 @@ func (of *OpenFIGI) SecurityTypeByISIN(ctx context.Context, isin string) (string
 
 	of.securityTypeCache[isin] = secType
 
+	slog.Debug("OpenFIGI client: SecurityTypeByISIN cached mapping",
+		slog.String("isin", isin),
+		slog.String("security_type", secType))
+
 	return secType, nil
 }