[HADOOP-9683] Wrap IpcConnectionContext in RPC headers

• Type: Sub-task
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 2.1.0-beta
• Component/s: ipc
• Target Version/s: 2.1.0-beta
• Hadoop Flags: Incompatible change, Reviewed
• Release Note: Connection context is now sent as a rpc header wrapped protobuf.
• Assignee: Daryn Sharp
• Reporter: Luke Lu
• Created: 02/Jul/13 07:39
• Updated: 03/Sep/14 23:02
• Resolved: 16/Jul/13 19:09

Description

After HADOOP-9421, all RPC exchanges (including SASL) are wrapped in RPC headers except IpcConnectionContext, which is still raw protobuf, which makes request pipelining (a desirable feature for things like HDFS-2856) impossible to achieve in a backward compatible way. Let's finish the job and wrap IpcConnectionContext with the RPC request header with the call id of SET_IPC_CONNECTION_CONTEXT. Or simply make it an optional field in the RPC request header that gets set for the first RPC call of a given stream.