[receiver/awsecscontainermetrics] Aggregate I/O metrics from all devices (open-telemetry#38309)

#### Description

Ensure that the storage.read_bytes and storage.write_bytes metrics
include the i/o counts from all devices listed in
`blkio_stats.io_service_bytes_recursive`.

#### Link to tracking issue
Fixes open-telemetry#38301 

#### Testing

I've extended the existing test condition to cover this general case.

Author: jonnangle

.chloggen/ecs-io-metrics.yaml

@@ -0,0 +1,27 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: awsecscontainermetrics
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Ensure that the storage.read_bytes and storage.write_bytes metrics include i/o counts from all devices
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [38301]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/awsecscontainermetricsreceiver/internal/awsecscontainermetrics/metrics_helper.go

@@ -110,9 +110,10 @@ func extractStorageUsage(stats *DiskStats) (uint64, uint64) {
 	for _, blockStat := range stats.IoServiceBytesRecursives {
 		switch op := blockStat.Op; op {
 		case "Read":
-			readBytes = aws.ToUint64(blockStat.Value)
+			readBytes += aws.ToUint64(blockStat.Value)
 		case "Write":
-			writeBytes = aws.ToUint64(blockStat.Value)
+			writeBytes += aws.ToUint64(blockStat.Value)
+
 		default:
 			// ignoring "Async", "Total", "Sum", etc
 			continue

receiver/awsecscontainermetricsreceiver/internal/awsecscontainermetrics/metrics_helper_test.go

@@ -390,17 +390,22 @@ func TestAggregateTaskMetrics(t *testing.T) {
 
 func TestExtractStorageUsage(t *testing.T) {
 	v := uint64(100)
+	v2 := uint64(200)
 	disk := &DiskStats{
 		IoServiceBytesRecursives: []IoServiceBytesRecursive{
 			{Op: "Read", Value: &v},
 			{Op: "Write", Value: &v},
 			{Op: "Total", Value: &v},
+
+			{Op: "Read", Value: &v2},
+			{Op: "Write", Value: &v2},
+			{Op: "Total", Value: &v2},
 		},
 	}
 	read, write := extractStorageUsage(disk)
 
-	require.EqualValues(t, v, read)
-	require.EqualValues(t, v, write)
+	require.EqualValues(t, v+v2, read)
+	require.EqualValues(t, v+v2, write)
 
 	read, write = extractStorageUsage(nil)
 	v = uint64(0)