feat: enforce max chains during new session

x/nodes/keeper/validator.go

@@ -188,7 +188,8 @@ func (k Keeper) ClearSessionCache() {
 
 // IterateAndExecuteOverVals - Goes through the validator set and executes handler
 func (k Keeper) IterateAndExecuteOverVals(
-	ctx sdk.Ctx, fn func(index int64, validator exported.ValidatorI) (stop bool)) {
+	ctx sdk.Ctx, fn func(index int64, validator exported.ValidatorI) (stop bool),
+) {
 	store := ctx.KVStore(k.storeKey)
 	iterator, _ := sdk.KVStorePrefixIterator(store, types.AllValidatorsKey)
 	defer iterator.Close()
@@ -233,6 +234,11 @@ func (k Keeper) AllValidators(ctx sdk.Ctx) (validators []exported.ValidatorI) {
 	return validators
 }
 
+// ValidatorHasLessOrEqualMaxChains - Check if the validator has less or equal than the maximum chains param
+func (k Keeper) ValidatorHasLessOrEqualMaxChains(ctx sdk.Ctx, val exported.ValidatorI) bool {
+	return int64(len(val.GetChains())) <= k.GetParams(ctx).MaximumChains
+}
+
 // map of validator addresses to serialized power
 type valPowerMap map[[sdk.AddrLen]byte][]byte
 

x/nodes/types/validator.go

@@ -4,10 +4,11 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"github.com/pokt-network/pocket-core/codec"
 	"strings"
 	"time"
 
+	"github.com/pokt-network/pocket-core/codec"
+
 	"github.com/pokt-network/pocket-core/crypto"
 
 	sdk "github.com/pokt-network/pocket-core/types"

x/pocketcore/types/expectedKeepers.go

@@ -20,6 +20,7 @@ type PosKeeper interface {
 	BlocksPerSession(ctx sdk.Ctx) (res int64)
 	StakeDenom(ctx sdk.Ctx) (res string)
 	GetValidatorsByChain(ctx sdk.Ctx, networkID string) (validators []sdk.Address, total int)
+	ValidatorHasLessOrEqualMaxChains(ctx sdk.Ctx, val nodesexported.ValidatorI) bool
 }
 
 type AppsKeeper interface {

x/pocketcore/types/session.go

@@ -4,10 +4,11 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
+	"log"
+
 	sdk "github.com/pokt-network/pocket-core/types"
 	appexported "github.com/pokt-network/pocket-core/x/apps/exported"
 	"github.com/pokt-network/pocket-core/x/nodes/exported"
-	"log"
 )
 
 // "Session" - The relationship between an application and the pocket network
@@ -110,11 +111,11 @@ func NewSessionNodes(sessionCtx, ctx sdk.Ctx, keeper PosKeeper, chain string, se
 	}
 	sessionNodes = make(SessionNodes, sessionNodesCount)
 	var node exported.ValidatorI
-	//unique address map to avoid re-checking a pseudorandomly selected servicer
+	// unique address map to avoid re-checking a pseudorandomly selected servicer
 	m := make(map[string]struct{})
 	// only select the nodesAddrs if not jailed
 	for i, numOfNodes := 0, 0; ; i++ {
-		//if this is true we already checked all nodes we got on getValidatorsBychain
+		// if this is true we already checked all nodes we got on getValidatorsBychain
 		if len(m) >= totalNodes {
 			return nil, NewInsufficientNodesError(ModuleName)
 		}
@@ -124,17 +125,21 @@ func NewSessionNodes(sessionCtx, ctx sdk.Ctx, keeper PosKeeper, chain string, se
 		sessionKey = Hash(sessionKey)
 		// get the node from the array
 		n := nodesAddrs[index.Int64()]
-		//if we already have seen this address we continue as it's either on the list or discarded
+		// if we already have seen this address we continue as it's either on the list or discarded
 		if _, ok := m[n.String()]; ok {
 			continue
 		}
-		//add the node address to the map
+		// add the node address to the map
 		m[n.String()] = struct{}{}
 
 		// cross check the node from the `new` or `end` world state
 		node = keeper.Validator(ctx, n)
-		// if not found or jailed, don't add to session and continue
-		if node == nil || node.IsJailed() || !NodeHasChain(chain, node) || sessionNodes.Contains(node.GetAddress()) {
+		// if not found or jailed or staked chains is too large, don't add to session and continue
+		if node == nil ||
+			node.IsJailed() ||
+			!NodeHasChain(chain, node) ||
+			sessionNodes.Contains(node.GetAddress()) ||
+			!keeper.ValidatorHasLessOrEqualMaxChains(ctx, node) {
 			continue
 		}
 		// else add the node to the session
@@ -267,8 +272,8 @@ func BlockHash(ctx sdk.Context) string {
 
 // "MaxPossibleRelays" - Returns the maximum possible amount of relays for an App on a sessions
 func MaxPossibleRelays(app appexported.ApplicationI, sessionNodeCount int64) sdk.BigInt {
-	//GetMaxRelays Max value is bound to math.MaxUint64,
-	//current worse case is 1 chain and 5 nodes per session with a result of 3689348814741910323 which can be used safely as int64
+	// GetMaxRelays Max value is bound to math.MaxUint64,
+	// current worse case is 1 chain and 5 nodes per session with a result of 3689348814741910323 which can be used safely as int64
 	return app.GetMaxRelays().ToDec().Quo(sdk.NewDec(int64(len(app.GetChains())))).Quo(sdk.NewDec(sessionNodeCount)).RoundInt()
 }