MapReduce/shardctrler/common.go

74 lines
1.5 KiB
Go

package shardctrler
//
// Shard controller: assigns shards to replication groups.
//
// RPC interface:
// Join(servers) -- add a set of groups (gid -> server-list mapping).
// Leave(gids) -- delete a set of groups.
// Move(shard, gid) -- hand off one shard from current owner to gid.
// Query(num) -> fetch Config # num, or latest config if num==-1.
//
// A Config (configuration) describes a set of replica groups, and the
// replica group responsible for each shard. Configs are numbered. Config
// #0 is the initial configuration, with no groups and all shards
// assigned to group 0 (the invalid group).
//
// You will need to add fields to the RPC argument structs.
//
// The number of shards.
const NShards = 10
// A configuration -- an assignment of shards to groups.
// Please don't change this.
type Config struct {
Num int // config number
Shards [NShards]int // shard -> gid
Groups map[int][]string // gid -> servers[]
}
const (
OK = "OK"
)
type Err string
type JoinArgs struct {
Servers map[int][]string // new GID -> servers mappings
}
type JoinReply struct {
WrongLeader bool
Err Err
}
type LeaveArgs struct {
GIDs []int
}
type LeaveReply struct {
WrongLeader bool
Err Err
}
type MoveArgs struct {
Shard int
GID int
}
type MoveReply struct {
WrongLeader bool
Err Err
}
type QueryArgs struct {
Num int // desired config number
}
type QueryReply struct {
WrongLeader bool
Err Err
Config Config
}