fleshed out some shard operations, working on reshard...

forwarding/forwarding.go

@@ -10,7 +10,7 @@ import (
 	"io/ioutil"
 
 	"github.com/gorilla/mux"
-	"github.com/mrhea/CMPS128_Assignment3/structs"
+	"github.com/mrhea/CMPS128_Assignment4/structs"
 
 	"log"
 	"net/http"

gossip/gossip.go

@@ -7,8 +7,8 @@ import (
 	"net/http"
 	"time"
 
-	"github.com/mrhea/CMPS128_Assignment3/structs"
-	"github.com/mrhea/CMPS128_Assignment3/view"
+	"github.com/mrhea/CMPS128_Assignment4/structs"
+	"github.com/mrhea/CMPS128_Assignment4/view"
 )
 
 // Query health check message to nodes.

main.go

@@ -5,7 +5,7 @@ import (
 	"log"
 	"os"
 
-	"github.com/mrhea/CMPS128_Assignment3/rest"
+	"github.com/mrhea/CMPS128_Assignment4/rest"
 )
 
 // func main() {
@@ -46,8 +46,11 @@ func main() {
 
 	viewString := os.Getenv("VIEW")
 
+	shardCount := os.Getenv("SHARD_COUNT")
+
 	log.Printf("Starting replica instance at IP: %s", owner)
 
 	// Initialize endpoints, database, and view
-	rest.InitServer(owner, viewString)
-}
+
+	rest.InitServer(owner, viewString, shardCount)
+	}

rest/rest.go

@@ -3,24 +3,26 @@ package rest
 import (
 	"bytes"
 	"encoding/json"
+	"github.com/mrhea/CMPS128_Assignment4/shard"
 	"io/ioutil"
 	"log"
 	"net/http"
 	"strings"
 	"time"
 
 	"github.com/gorilla/mux"
-	gsp "github.com/mrhea/CMPS128_Assignment3/gossip"
-	"github.com/mrhea/CMPS128_Assignment3/kvs"
-	"github.com/mrhea/CMPS128_Assignment3/structs"
-	"github.com/mrhea/CMPS128_Assignment3/view"
+	gsp "github.com/mrhea/CMPS128_Assignment4/gossip"
+	"github.com/mrhea/CMPS128_Assignment4/kvs"
+	"github.com/mrhea/CMPS128_Assignment4/structs"
+	"github.com/mrhea/CMPS128_Assignment4/view"
 )
 
 //const NULL int = -999
 
 type server struct {
 	db      *kvs.Database
 	V       *view.View
+	S 		*shard.ShardView
 	stalled []*kvs.Entry
 }
 
@@ -598,7 +600,7 @@ func fetchEntries(w http.ResponseWriter, r *http.Request) {
 }
 
 // InitServer setups a RESTful-accessible API.
-func InitServer(socket, viewString string) {
+func InitServer(socket, viewString, shardCount string) {
 	log.Println("REST: Initializing a new server node")
 	// Init router
 	log.Println("REST: Initializing a new router")
@@ -608,6 +610,10 @@ func InitServer(socket, viewString string) {
 	log.Println("REST: Initializing VIEW for router")
 	node.V = view.InitView(socket, viewString)
 
+	// Init shards
+	log.Println("REST: Initializing SHARDS for router")
+	node.S = shard.InitShards(socket, shardCount, viewString)
+
 	// Init database
 	log.Println("REST: Initializing DATABASE for router")
 	node.db = kvs.InitDB()

shard/shard.go

@@ -1,10 +1,98 @@
 package shard
 
 import (
-
+	"log"
+	"os"
+	"strconv"
+	"strings"
 )
 
-type Shard struct {
-	ID int //data type subject to change
-	Members []string
+type shard struct {
+	members []string
+	numKeys int //probably don't need this?
+}
+
+type ShardView struct {
+	id int //shard ID of current node...
+	shardDB []*shard
+}
+ //Each Node has a shardView, where it can see all the shards, and the members of all the shards/
+ //It can also see it's own shardID, so we can access that data without a lookup.
+func InitShards(owner, shardString, viewOfReplicas string) *ShardView {
+	shardCount, err := strconv.Atoi(shardString)
+	if err != nil{
+		panic(err)
+	}
+	var S ShardView
+	//S.shardDB = make(map[int]*shard)
+
+	replicas := strings.Split(viewOfReplicas, ",")
+	if 2*shardCount > len(replicas) { //check minimum length(each shard must have @ least 2)
+		log.Println("Shard count too small, ERROR") //throw an error here?
+		os.Exit(126)
+	}
+	//correct length, continue...
+	for i := 1; i <= shardCount; i++ {
+		if len(replicas) >= 2 {
+			var ip1 string
+			var ip2 string
+			ip1, ip2, replicas = replicas[0], replicas[1], replicas[2:]
+			temp := &shard{members:[], numKeys:0}
+			temp.members = append(temp.members, ip1)
+			temp.members = append(temp.members, ip2)
+			S.shardDB = append(S.shardDB, temp) //is this the right way of doing this?
+			if owner == ip1 || owner == ip2 {
+				S.id = i
+			}
+		} else if len(replicas) == 1{
+			ip3 := replicas[0]
+			temp := &S.shardDB[i-1].members
+			*temp = append(*temp, ip3)
+			if owner == ip3 {
+				S.id = i-1
+			}
+		}
+	}
+	//we are now correctly sharded in either groups of 2,
+	//with one group of 3 for odd lengths
+	//this can change, if we want larger default groups...
+	return &S
+}
+
+func Reshard(shardCount int, s *ShardView){
+	/*
+	How do we implement this? We'd have to decide which kvs values go where...
+	It'd probably be easiest to figure out which IPs aren't in any shards, and
+	append them one by one to the smallest shard. So:
+	1. Locate smallest shard
+	2. Append new IP
+	3. Copy all KVS
+	4. Repeat until all IP's are in a shard
+	(Don't delete this ^, add to mechanisms.txt)
+	 */
+}
+
+//gets all active shards in the form of an int list.
+//easy to marshall into json data.
+func GetAllShards(s *ShardView) []int {
+	shardIDs := make([]int, 0) //apparently if you make a slice like this, it outputs correctly to json?
+	//var shardIDs []int
+	for i := 1; i <= len(s.shardDB); i++{
+		if s.shardDB[i] != nil {
+			shardIDs = append(shardIDs, i)
+		}
+	}
+	return shardIDs
+}
+
+func GetCurrentShard(s *ShardView) int {
+	return s.id
+}
+
+func GetMembersOfShard(ID int, s *ShardView) []string {
+	return s.shardDB[ID].members
+}
+
+func GetNumKeys(s *ShardView) int {
+	//I'm not sure if I want to keep track of this data in the shard...
 }

structs/structs.go

@@ -105,26 +105,7 @@ type ViewDeleteError struct {
 	Message string `json:"message"`
 }
 
-// CausalPut response
-// May be used for either forwarding metadata between
-// replicas, or responding to a forward
-type CausalPut struct {
+type NodeShard struct {
 	Message string `json:"message"`
-	Version string `json:"version"`
-}
-
-// CausalGet response
-type CausalGet struct {
-	Message  string `json:"message"`
-	Version  string `json:"version"`
-	Metadata string `json:"causal-metadata"`
-	Value    string `json:"value"`
-}
-
-// CausalGetError response
-// Used in case of GET request for key-value pair with a
-// version number that does not yet exist.
-type CausalGetError struct {
-	Error   string `json:"message"`
-	Version string `json:"version"`
-}
+	ID      string `json:"shard-id"`
+}

view/view.go

@@ -18,7 +18,7 @@ type View struct {
 }
 
 // Replica holds the address of a replica.
-// Used in: rest.go/PutView
+// Used in: rest.go/PutViewv
 type Replica struct {
 	Address string `json:"socket-address"` // the address of a replica
 }