Protocol Buffers Client API

This is an overview of the operations you can perform using the Protocol Buffers Client (PBC) interface to Riak, and can be used as a guide for developing a PBC-compliant Riak client.

Protocol

Riak listens on a TCP port (8087 by default) for incoming connections. Once connected, the client can send a stream of requests on the same connection.

Each operation consists of a request message and one or more response messages. Messages are all encoded the same way, consisting of:

• 32-bit length of message code + Protocol Buffers message in network order
• 8-bit message code to identify the Protocol Buffers message
• N bytes of Protocol Buffers-encoded message

Example

00 00 00 07 09 0A 01 62 12 01 6B
|----Len---|MC|----Message-----|

Len = 0x07
Message Code (MC) = 0x09 = RpbGetReq
RpbGetReq Message = 0x0A 0x01 0x62 0x12 0x01 0x6B

Decoded Message:
bucket: "b"
key: "k"

Message Codes

Error Response

If the request does not result in an error, Riak will return one of a variety of response messages, e.g. RpbGetResp or RpbPutResp, depending on which request message is sent.

If the server experiences an error processing a request, however, it will return an RpbErrorResp message instead of the response expected for the given request (e.g. RbpGetResp is the expected response to RbpGetReq). Error messages contain an error string and an error code, like this:

message RpbErrorResp {
    required bytes errmsg = 1;
    required uint32 errcode = 2;
}

Values

• errmsg - A string representation of what went wrong
• errcode - A numeric code. Currently, only RIAKC_ERR_GENERAL=1 is defined.

Bucket Operations

• PBC List Buckets
• PBC List Keys
• PBC Get Bucket Properties
• PBC Set Bucket Properties
• PBC Reset Bucket Properties

Object/Key Operations

• PBC Fetch Object
• PBC Store Object
• PBC Delete Object

Query Operations

• PBC MapReduce
• PBC Secondary Indexes

Server Operations

• PBC Ping
• PBC Server Info

Bucket Type Operations

• PBC Get Bucket Type
• PBC Set Bucket Type

Data Type Operations

• PBC Data Type Fetch
• PBC Data Type Union
• PBC Data Type Store
• PBC Data Type Counter Store
• PBC Data Type Set Store
• PBC Data Type Map Store