Protocol
requests and responses of rpcx use the same message format.
One message contains:
- Header: 4 bytes
- Message ID: 8 bytes
- total size: 4 bytes, doesn't contain size of header and itself, uint32
- size of servicePath: 4 bytes, uint32
- servicePath: UTF-8 string
- size of serviceMethod: 4 bytes, uint32
- serviceMethod: UTF-8 string
- size of metadata: 4 bytes, uint32
- metadata: format:
size
key1 string
size
value1 string
, can contains multipl e=key, value - size of playload: 4 bytes, uint32
- playload: slice of byte
#4
+#6
+#8
+#10 + (4 + 4 + 4 + 4)
must be equal to#3
.
servicePath
、serviceMethod
、key
and value
in metadata must be UTF-8 string.
rpcx uses size of an element
+ element
format to define one element. It is like TLVbut rpcx doesn't use Type
because Type
of those elements are UTF-8 string.
Use BigEndian
for size (integer type, int64, uint32, etc.)
1、The first byte must be 0x08
. It is a magic number.
2、The second byte is version
. Current version is 0.
3、MessageType can be: 0: Request 1: Response
4、Heartbeat: bool. This message is heartbeat message or not
5、Oneway: bool. Need return response or not.
6、CompressType: 0: don't compress 1: Gzip
7、MessageStatusType: indicates response is an error or a normal response 0: Normal 1: Error
8、SerializeType 0: use raw bytes 1: JSON 2: Protobuf 3: MessagePack
If one service fails to handle requests, it can return an error. It sets MessageStatusType of response is 1
(ERROR) and sets the error message in metadata of the response. The key for the error is rpcx_error, and the value is error message.
By smallnest updated 2018-12-04 11:47:26