make etcd param MaxCallSendMsgSize configurable

changelog/12666.txt

@@ -0,0 +1,4 @@
+
+```release-note:improvement
+storage/etcd: Make etcd parameter MaxCallSendMsgSize configurable
+```

physical/etcd/etcd3.go

@@ -119,6 +119,15 @@ func newEtcd3Backend(conf map[string]string, logger log.Logger) (physical.Backen
 		cfg.MaxCallRecvMsgSize = int(val)
 	}
 
+	if maxCall, ok := conf["max_call_size"]; ok {
+		// grpc converts this to uint32 internally, so parse as that to avoid passing invalid values
+		val, err := strconv.ParseUint(maxCall, 10, 32)
+		if err != nil {
+			return nil, fmt.Errorf("value of 'max_call_size' (%v) could not be understood: %w", maxCall, err)
+		}
+		cfg.MaxCallSendMsgSize = int(val)
+	}
+
 	etcd, err := clientv3.New(cfg)
 	if err != nil {
 		return nil, err

website/content/docs/configuration/storage/etcd.mdx

@@ -84,6 +84,14 @@ storage "etcd" {
 - `lock_timeout` `(string: "15s")` – Specifies lock timeout for master
   Vault instance. Set bigger value if you don't need faster recovery.
 
+- `max_receive_size` `(int32: math.MaxInt32)` – Specifies the client-side response receive limit.
+Make sure that "MaxCallRecvMsgSize" >= server-side default send/recv limit.
+("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
+
+- `max_call_size` `(int32: 2 * 1024 * 1024)` – Specifies the client-side request send limit in bytes.
+Make sure that "MaxCallSendMsgSize" < server-side default send/recv limit.
+("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").
+
 ## `etcd` Examples
 
 ### DNS Discovery of cluster members