Add fetch/conversion metrics and improve logging

FetchResult now includes:
- StatusCode: HTTP status from upstream
- FetchDurationMs: time to fetch from upstream
- RemoteAddr: upstream server address

SourceMetadata now stores:
- ContentLength: size from upstream
- FetchDurationMs: fetch timing
- RemoteAddr: for debugging

Image conversion log now includes:
- host: source hostname (was missing)
- path: source path (renamed from file)
- convert_ms: image processing time
- quality: requested quality setting
- fit: requested fit mode

internal/imgcache/cache.go

@@ -238,10 +238,13 @@ func (c *Cache) StoreSource(
 		Path:            req.SourcePath,
 		Query:           req.SourceQuery,
 		ContentHash:     contentHash,
-		StatusCode:      httpStatusOK,
+		StatusCode:      result.StatusCode,
 		ContentType:     result.ContentType,
+		ContentLength:   result.ContentLength,
 		ResponseHeaders: result.Headers,
 		FetchedAt:       time.Now().Unix(),
+		FetchDurationMs: result.FetchDurationMs,
+		RemoteAddr:      result.RemoteAddr,
 	}
 
 	if err := c.srcMetadata.Store(req.SourceHost, pathHash, meta); err != nil {

internal/imgcache/fetcher.go

@@ -164,7 +164,12 @@ func (f *HTTPFetcher) Fetch(ctx context.Context, url string) (*FetchResult, erro
 	req.Header.Set("User-Agent", f.config.UserAgent)
 	req.Header.Set("Accept", strings.Join(f.config.AllowedContentTypes, ", "))
 
+	startTime := time.Now()
+
 	resp, err := f.client.Do(req)
+
+	fetchDuration := time.Since(startTime)
+
 	if err != nil {
 		if errors.Is(err, context.DeadlineExceeded) {
 			return nil, ErrUpstreamTimeout
@@ -173,6 +178,12 @@ func (f *HTTPFetcher) Fetch(ctx context.Context, url string) (*FetchResult, erro
 		return nil, fmt.Errorf("upstream request failed: %w", err)
 	}
 
+	// Get remote address if available
+	var remoteAddr string
+	if resp.Request != nil && resp.Request.URL != nil {
+		remoteAddr = resp.Request.Host
+	}
+
 	// Check status code
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
 		_ = resp.Body.Close()
@@ -198,10 +209,13 @@ func (f *HTTPFetcher) Fetch(ctx context.Context, url string) (*FetchResult, erro
 	success = true
 
 	return &FetchResult{
-		Content:       &semaphoreReleasingReadCloser{limitedBody, resp.Body, sem},
-		ContentLength: resp.ContentLength,
-		ContentType:   contentType,
-		Headers:       resp.Header,
+		Content:         &semaphoreReleasingReadCloser{limitedBody, resp.Body, sem},
+		ContentLength:   resp.ContentLength,
+		ContentType:     contentType,
+		Headers:         resp.Header,
+		StatusCode:      resp.StatusCode,
+		FetchDurationMs: fetchDuration.Milliseconds(),
+		RemoteAddr:      remoteAddr,
 	}, nil
 }
 

internal/imgcache/imgcache.go

@@ -178,6 +178,12 @@ type FetchResult struct {
 	ContentType string
 	// Headers contains all response headers from upstream
 	Headers map[string][]string
+	// StatusCode is the HTTP status code from upstream
+	StatusCode int
+	// FetchDurationMs is how long the fetch took in milliseconds
+	FetchDurationMs int64
+	// RemoteAddr is the IP:port of the upstream server
+	RemoteAddr string
 }
 
 // Processor handles image transformation (resize, format conversion)

internal/imgcache/service.go

@@ -157,18 +157,23 @@ func (s *Service) fetchAndProcess(ctx context.Context, req *ImageRequest) (*Imag
 	}
 
 	// Process the image
+	processStart := time.Now()
+
 	processResult, err := s.processor.Process(ctx, bytes.NewReader(sourceData), req)
 	if err != nil {
 		return nil, fmt.Errorf("image processing failed: %w", err)
 	}
 
+	processDuration := time.Since(processStart)
+
 	// Log conversion details
 	inputSize := int64(len(sourceData))
 	outputSize := processResult.ContentLength
 	sizePercent := float64(outputSize) / float64(inputSize) * 100.0 //nolint:mnd // percentage calculation
 
 	s.log.Info("image converted",
-		"file", req.SourcePath,
+		"host", req.SourceHost,
+		"path", req.SourcePath,
 		"input_format", processResult.InputFormat,
 		"output_format", req.Format,
 		"input_bytes", inputSize,
@@ -176,6 +181,9 @@ func (s *Service) fetchAndProcess(ctx context.Context, req *ImageRequest) (*Imag
 		"input_dimensions", fmt.Sprintf("%dx%d", processResult.InputWidth, processResult.InputHeight),
 		"output_dimensions", fmt.Sprintf("%dx%d", processResult.Width, processResult.Height),
 		"size_ratio", fmt.Sprintf("%.1f%%", sizePercent),
+		"convert_ms", processDuration.Milliseconds(),
+		"quality", req.Quality,
+		"fit", req.FitMode,
 	)
 
 	// Store output content to cache

internal/imgcache/storage.go

@@ -194,11 +194,14 @@ type SourceMetadata struct {
 	ContentHash     string              `json:"content_hash,omitempty"`
 	StatusCode      int                 `json:"status_code"`
 	ContentType     string              `json:"content_type,omitempty"`
+	ContentLength   int64               `json:"content_length,omitempty"`
 	ResponseHeaders map[string][]string `json:"response_headers,omitempty"`
 	FetchedAt       int64               `json:"fetched_at"`
+	FetchDurationMs int64               `json:"fetch_duration_ms,omitempty"`
 	ExpiresAt       int64               `json:"expires_at,omitempty"`
 	ETag            string              `json:"etag,omitempty"`
 	LastModified    string              `json:"last_modified,omitempty"`
+	RemoteAddr      string              `json:"remote_addr,omitempty"`
 }
 
 // Store writes metadata to storage.