- Authors: Jun Liu
Dubbo2 遗留系统运行的 RPC 协议规范
-
Magic - Magic High & Magic Low (16 bits)
Identifies dubbo protocol with value: 0xdabb
-
Req/Res (1 bit)
Identifies this is a request or response. Request - 1; Response - 0.
-
2 Way (1 bit)
Only useful when Req/Res is 1 (Request), expect for a return value from server or not. Set to 1 if need a return value from server.
-
Event (1 bit)
Identifies an event message or not, for example, heartbeat event. Set to 1 if this is an event.
-
Serialization ID (5 bit)
Identifies serialization type: the value for fastjson is 6.
-
Status (8 bits)
Only useful when Req/Res is 0 (Response), identifies the status of response
- 20 - OK
- 30 - CLIENT_TIMEOUT
- 31 - SERVER_TIMEOUT
- 40 - BAD_REQUEST
- 50 - BAD_RESPONSE
- 60 - SERVICE_NOT_FOUND
- 70 - SERVICE_ERROR
- 80 - SERVER_ERROR
- 90 - CLIENT_ERROR
- 100 - SERVER_THREADPOOL_EXHAUSTED_ERROR
-
Request ID (64 bits)
Identifies an unique request. Numeric (long).
-
Data Length (32)
Length of the content (the variable part) after serialization, counted by bytes. Numeric (integer).
-
Variable Part
Each part is a byte[] after serialization with specific serialization type, identifies by Serialization ID.
Every part is a byte[] after serialization with specific serialization type, identifies by Serialization ID
-
If the content is a Request (Req/Res = 1), each part consists of the content, in turn is:
- Dubbo version
- Service name
- Service version
- Method name
- Method parameter types
- Method arguments
- Attachments
-
If the content is a Response (Req/Res = 0), each part consists of the content, in turn is:
- Return value type, identifies what kind of value returns from server side: RESPONSE_NULL_VALUE - 2, RESPONSE_VALUE - 1, RESPONSE_WITH_EXCEPTION - 0.
- Return value, the real value returns from server.
注意： 对于(Variable Part)变长部分，当前版本的dubbo框架使用json序列化时，在每部分内容间额外增加了换行符作为分隔，请选手在Variable Part的每个part后额外增加换行符， 如：
Dubbo version bytes (换行符)
Service name bytes (换行符)
...