Do not override if parent sizer is not set. Adds tests for case that was not handled before

Author: mx-psi

exporter/exporterhelper/README.md

@@ -32,7 +32,7 @@ The following configuration options can be modified:
     - `flush_timeout` (default (if section is defined) = 200 ms): time after which a batch will be sent regardless of its size. Must be a non-zero value
     - `min_size` (default (if section is defined) = 8192): the minimum size of a batch.
     - `max_size` (default (if section is defined) = 0): the maximum size of a batch, enables batch splitting. The maximum size of a batch should be greater than or equal to the minimum size of a batch. If set to zero, there is no maximum size.
-    - `sizer` (default (if section is defined) = items): Overrides the sizer set at the `sending_queue` level for batching. Available options:
+    - `sizer` (default (if section is defined and `sending_queue::sizer` is not set) = items): Overrides the sizer set at the `sending_queue` level for batching. If `sending_queue::sizer` is not set, it defaults to `items`. Available options:
       - `items`: number of the smallest parts of each signal (spans, metric data points, log records);
       - `bytes`: the size of serialized data in bytes (the least performant option).
 

exporter/exporterhelper/internal/queuebatch/config.go

@@ -53,8 +53,12 @@ func (cfg *Config) Unmarshal(conf *confmap.Conf) error {
 		return err
 	}
 
-	// If the batch sizer is not set and the batch section is nonempty, use the same value as the queue sizer.
-	if !conf.IsSet("batch::sizer") && conf.IsSet("batch") && conf.Get("batch") != nil {
+	// If all of the following hold:
+	// 1. the sizer is set,
+	// 2. the batch sizer is not set and
+	// 3. the batch section is nonempty,
+	// then use the same value as the queue sizer.
+	if conf.IsSet("sizer") && !conf.IsSet("batch::sizer") && conf.IsSet("batch") && conf.Get("batch") != nil {
 		cfg.Batch.Get().Sizer = cfg.Sizer
 	}
 	return nil

exporter/exporterhelper/internal/queuebatch/config_test.go

@@ -147,6 +147,20 @@ func TestUnmarshal(t *testing.T) {
 				return cfg
 			},
 		},
+		{
+			path: "batch_set_nonempty_no_explicit_sizer.yaml",
+			expectedCfg: func() Config {
+				cfg := newBaseCfg()
+				cfg.QueueSize = 2000
+				cfg.Batch = configoptional.Some(BatchConfig{
+					FlushTimeout: 200 * time.Millisecond,
+					// Sizer has NOT been overridden by parent sizer
+					Sizer:   request.SizerTypeItems,
+					MinSize: 100,
+				})
+				return cfg
+			},
+		},
 		{
 			path: "batch_unset.yaml",
 			// Batch remains unset, sizer override does not apply.

exporter/exporterhelper/internal/queuebatch/testdata/batch_set_nonempty_no_explicit_sizer.yaml

@@ -0,0 +1,5 @@
+enabled: true
+queue_size: 2000 
+batch:
+  # sizer is NOT overridden here by parent sizer, since parent sizer is not set
+  min_size: 100