log, metric, trace clients: close body uniformly

There were inconsistencies in closing the response body. For traces, the
Close happened in a defer statement and any error was logged. Logs and
metrics were less rigorous. It appeared Close() wasn't always called,
and when it was, errors were returned sometimes and ignored at other
times.

This applies the defer logic from traces to the other two and removes
other Close() calls.

exporters/otlp/otlplog/otlploghttp/client.go

@@ -149,6 +149,13 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 		if err != nil {
 			return err
 		}
+		if resp != nil && resp.Body != nil {
+			defer func() {
+				if err := resp.Body.Close(); err != nil {
+					otel.Handle(err)
+				}
+			}()
+		}
 
 		var rErr error
 		switch sc := resp.StatusCode; {
@@ -193,7 +200,6 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 			// debugging the actual issue.
 			var respData bytes.Buffer
 			if _, err := io.Copy(&respData, resp.Body); err != nil {
-				_ = resp.Body.Close()
 				return err
 			}
 
@@ -208,9 +214,6 @@ func (c *httpClient) uploadLogs(ctx context.Context, data []*logpb.ResourceLogs)
 			rErr = fmt.Errorf("failed to send logs to %s: %s", request.URL, resp.Status)
 		}
 
-		if err := resp.Body.Close(); err != nil {
-			return err
-		}
 		return rErr
 	})
 }

exporters/otlp/otlpmetric/otlpmetrichttp/client.go

@@ -152,6 +152,13 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 		if err != nil {
 			return err
 		}
+		if resp != nil && resp.Body != nil {
+			defer func() {
+				if err := resp.Body.Close(); err != nil {
+					otel.Handle(err)
+				}
+			}()
+		}
 
 		var rErr error
 		switch sc := resp.StatusCode; {
@@ -196,7 +203,6 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 			// debugging the actual issue.
 			var respData bytes.Buffer
 			if _, err := io.Copy(&respData, resp.Body); err != nil {
-				_ = resp.Body.Close()
 				return err
 			}
 
@@ -211,9 +217,6 @@ func (c *client) UploadMetrics(ctx context.Context, protoMetrics *metricpb.Resou
 			rErr = fmt.Errorf("failed to send metrics to %s: %s", request.URL, resp.Status)
 		}
 
-		if err := resp.Body.Close(); err != nil {
-			return err
-		}
 		return rErr
 	})
 }

exporters/otlp/otlptrace/otlptracehttp/client.go

@@ -208,7 +208,6 @@ func (d *client) UploadTraces(ctx context.Context, protoSpans []*tracepb.Resourc
 			// debugging the actual issue.
 			var respData bytes.Buffer
 			if _, err := io.Copy(&respData, resp.Body); err != nil {
-				_ = resp.Body.Close()
 				return err
 			}