@@ -52,30 +52,3 @@ // SetProof sets the Proof to the BatchInfo data structure
 func (bi *BatchInfo) SetProof(proof *Proof) {
 	bi.proof = proof
 }
-
-// // BatchQueue implements a FIFO queue of BatchInfo
-// type BatchQueue struct {
-// 	queue []*BatchInfo
-// }
-//
-// // NewBatchQueue returns a new *BatchQueue
-// func NewBatchQueue() *BatchQueue {
-// 	return &BatchQueue{
-// 		queue: []*BatchInfo{},
-// 	}
-// }
-//
-// // Push adds the given BatchInfo to the BatchQueue
-// func (bq *BatchQueue) Push(b *BatchInfo) {
-// 	bq.queue = append(bq.queue, b)
-// }
-//
-// // Pop pops the first BatchInfo from the BatchQueue
-// func (bq *BatchQueue) Pop() *BatchInfo {
-// 	if len(bq.queue) == 0 {
-// 		return nil
-// 	}
-// 	b := bq.queue[0]
-// 	bq.queue = bq.queue[1:]
-// 	return b
-// }

@@ -1,27 +0,0 @@
-package coordinator
-
-// import (
-// 	"testing"
-//
-// 	"github.com/hermeznetwork/hermez-node/common"
-// 	"github.com/stretchr/testify/assert"
-// )
-//
-// func TestBatchQueue(t *testing.T) {
-// 	bq := BatchQueue{}
-//
-// 	bq.Push(&BatchInfo{
-// 		batchNum: 0,
-// 	})
-// 	bq.Push(&BatchInfo{
-// 		batchNum: 2,
-// 	})
-// 	bq.Push(&BatchInfo{
-// 		batchNum: 1,
-// 	})
-//
-// 	assert.Equal(t, common.BatchNum(0), bq.Pop().batchNum)
-// 	assert.Equal(t, common.BatchNum(2), bq.Pop().batchNum)
-// 	assert.Equal(t, common.BatchNum(1), bq.Pop().batchNum)
-// 	assert.Nil(t, bq.Pop())
-// }

@@ -2,6 +2,7 @@ package coordinator
 
 import (
 	"fmt"
+	"sync"
 
 	ethCommon "github.com/ethereum/go-ethereum/common"
 	"github.com/hermeznetwork/hermez-node/batchbuilder"
@@ -14,6 +15,8 @@ kvdb "github.com/iden3/go-merkletree/db"
 	"github.com/iden3/go-merkletree/db/memory"
 )
 
+var errTODO = fmt.Errorf("TODO")
+
 // ErrStop is returned when the function is stopped asynchronously via the stop
 // channel.  It doesn't indicate an error.
 var ErrStop = fmt.Errorf("Stopped")
@@ -26,6 +29,7 @@
 // Coordinator implements the Coordinator type
 type Coordinator struct {
 	forging    bool
+	rw         *sync.RWMutex
 	isForgeSeq bool // WIP just for testing while implementing
 
 	config Config
@@ -48,7 +52,7 @@ hdb *historydb.HistoryDB,
 	txsel *txselector.TxSelector,
 	bb *batchbuilder.BatchBuilder,
 	serverProofs []ServerProofInterface,
-	ethClient *eth.Client) *Coordinator { // once synchronizer is ready, synchronizer.Synchronizer will be passed as parameter here
+	ethClient eth.ClientInterface) *Coordinator { // once synchronizer is ready, synchronizer.Synchronizer will be passed as parameter here
 	serverProofPool := NewServerProofPool(len(serverProofs))
 	for _, serverProof := range serverProofs {
 		serverProofPool.Add(serverProof)
@@ -61,6 +65,7 @@ txsel:           txsel,
 		batchBuilder:    bb,
 		ethClient:       ethClient,
 		ethTxStore:      memory.NewMemoryStorage(),
+		rw:              &sync.RWMutex{},
 	}
 	return &c
 }
@@ -68,27 +73,28 @@
 // ForgeLoopFn is the function ran in a loop that checks if it's time to forge
 // and forges a batch if so and sends it to outBatchCh.  Returns true if it's
 // the coordinator turn to forge.
-func (c *Coordinator) ForgeLoopFn(outBatchCh chan *BatchInfo, stopCh chan bool) (bool, error) {
+func (c *Coordinator) ForgeLoopFn(outBatchCh chan *BatchInfo, stopCh chan bool) (forgetime bool, err error) {
 	if !c.isForgeSequence() {
 		if c.forging {
-			log.Info("stop forging")
+			log.Info("ForgeLoopFn: forging state end")
 			c.forging = false
 		}
-		log.Debug("not in forge time")
+		log.Debug("ForgeLoopFn: not in forge time")
 		return false, nil
 	}
-	log.Debug("forge time")
+	log.Debug("ForgeLoopFn: forge time")
 	if !c.forging {
-		log.Info("start forging")
+		// Start pipeline from a batchNum state taken from synchronizer
+		log.Info("ForgeLoopFn: forging state begin")
 		// c.batchNum = c.hdb.GetLastBatchNum() // uncomment when HistoryDB is ready
 		err := c.txsel.Reset(c.batchNum)
 		if err != nil {
-			log.Errorw("TxSelector.Reset", "error", err)
+			log.Errorw("ForgeLoopFn: TxSelector.Reset", "error", err)
 			return true, err
 		}
 		err = c.batchBuilder.Reset(c.batchNum, true)
 		if err != nil {
-			log.Errorw("BatchBuilder.Reset", "error", err)
+			log.Errorw("ForgeLoopFn: BatchBuilder.Reset", "error", err)
 			return true, err
 		}
 		// c.batchQueue = NewBatchQueue()
@@ -100,22 +106,27 @@ // handleReorg() function decides if the reorg must restart the pipeline or not
 	// if c.synchronizer.Reorg():
 	_ = c.handleReorg()
 
-	// 0. If there's an available server proof: Start pipeline for batchNum = batchNum + 1.
-	// non-blocking call, returns nil if a server proof is
-	// not available, or non-nil otherwise.
+	// 0. Wait for an available server proof
+	// blocking call
 	serverProof, err := c.serverProofPool.Get(stopCh)
 	if err != nil {
 		return true, err
 	}
-	log.Debugw("got serverProof", "server", serverProof)
+	defer func() {
+		if !forgetime || err != nil {
+			c.serverProofPool.Add(serverProof)
+		}
+	}()
 
-	log.Debugw("start forge")
+	log.Debugw("ForgeLoopFn: using serverProof", "server", serverProof)
+	log.Debugw("ForgeLoopFn: forge start")
+	// forge for batchNum = batchNum + 1.
 	batchInfo, err := c.forge(serverProof)
 	if err != nil {
 		log.Errorw("forge", "error", err)
 		return true, err
 	}
-	log.Debugw("end forge", "batchNum", batchInfo.batchNum)
+	log.Debugw("ForgeLoopFn: forge end", "batchNum", batchInfo.batchNum)
 	outBatchCh <- batchInfo
 	return true, nil
 }
@@ -126,14 +137,14 @@ // function in the Rollup Smart Contract, and sends the batch to outBatchCh.
 func (c *Coordinator) GetProofCallForgeLoopFn(inBatchCh, outBatchCh chan *BatchInfo, stopCh chan bool) error {
 	select {
 	case <-stopCh:
-		log.Info("forgeLoopFn stopped")
+		log.Info("GetProofCallForgeLoopFn: forgeLoopFn stopped")
 		return ErrStop
 	case batchInfo := <-inBatchCh:
-		log.Debugw("start getProofCallForge", "batchNum", batchInfo.batchNum)
+		log.Debugw("GetProofCallForgeLoopFn: getProofCallForge start", "batchNum", batchInfo.batchNum)
 		if err := c.getProofCallForge(batchInfo, stopCh); err != nil {
 			return err
 		}
-		log.Debugw("end getProofCallForge", "batchNum", batchInfo.batchNum)
+		log.Debugw("GetProofCallForgeLoopFn: getProofCallForge end", "batchNum", batchInfo.batchNum)
 		outBatchCh <- batchInfo
 	}
 	return nil
@@ -145,14 +156,14 @@ // ethereum transaction confirmation.
 func (c *Coordinator) ForgeCallConfirmLoopFn(inBatchCh chan *BatchInfo, stopCh chan bool) error {
 	select {
 	case <-stopCh:
-		log.Info("forgeConfirmLoopFn stopped")
+		log.Info("ForgeCallConfirmLoopFn: forgeConfirmLoopFn stopped")
 		return ErrStop
 	case batchInfo := <-inBatchCh:
-		log.Debugw("start forgeCallConfirm", "batchNum", batchInfo.batchNum)
+		log.Debugw("ForgeCallConfirmLoopFn: forgeCallConfirm start", "batchNum", batchInfo.batchNum)
 		if err := c.forgeCallConfirm(batchInfo); err != nil {
 			return err
 		}
-		log.Debugw("end forgeCallConfirm", "batchNum", batchInfo.batchNum)
+		log.Debugw("ForgeCallConfirmLoopFn: forgeCallConfirm  end", "batchNum", batchInfo.batchNum)
 	}
 	return nil
 }
@@ -226,6 +237,8 @@ // getProofCallForge gets the generated zkProof & sends it to the SmartContract
 func (c *Coordinator) getProofCallForge(batchInfo *BatchInfo, stopCh chan bool) error {
 	serverProof := batchInfo.serverProof
 	proof, err := serverProof.GetProof(stopCh) // blocking call, until not resolved don't continue. Returns when the proof server has calculated the proof
+	c.serverProofPool.Add(serverProof)
+	batchInfo.serverProof = nil
 	if err != nil {
 		return err
 	}
@@ -266,6 +279,8 @@ }
 
 // isForgeSequence returns true if the node is the Forger in the current ethereum block
 func (c *Coordinator) isForgeSequence() bool {
+	c.rw.RLock()
+	defer c.rw.RUnlock()
 	return c.isForgeSeq // TODO
 }
 
@@ -282,5 +297,6 @@ return false // TODO
 }
 
 func (c *Coordinator) prepareForgeBatchArgs(batchInfo *BatchInfo) *eth.RollupForgeBatchArgs {
-	return nil // TODO
+	// TODO
+	return &eth.RollupForgeBatchArgs{}
 }

@@ -10,8 +10,8 @@ "github.com/hermeznetwork/hermez-node/batchbuilder"
 	"github.com/hermeznetwork/hermez-node/db/historydb"
 	"github.com/hermeznetwork/hermez-node/db/l2db"
 	"github.com/hermeznetwork/hermez-node/db/statedb"
-	"github.com/hermeznetwork/hermez-node/eth"
 	"github.com/hermeznetwork/hermez-node/log"
+	"github.com/hermeznetwork/hermez-node/test"
 	"github.com/hermeznetwork/hermez-node/txselector"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -77,7 +77,7 @@ return
 				} else if err != nil {
 					log.Errorw("CoordNode ForgeLoopFn", "error", err)
 				} else if !forge {
-					time.Sleep(500 * time.Millisecond)
+					time.Sleep(200 * time.Millisecond)
 				}
 			}
 		}
@@ -121,13 +121,28 @@ cn.stopGetProofCallForge <- true
 	cn.stopForgeCallConfirm <- true
 }
 
+type timer struct {
+	time int64
+}
+
+func (t *timer) Time() int64 {
+	currentTime := t.time
+	t.time++
+	return currentTime
+}
+
 func TestCoordinator(t *testing.T) {
 	txsel, bb := newTestModules(t)
 
 	conf := Config{}
 	hdb := &historydb.HistoryDB{}
 	serverProofs := []ServerProofInterface{&ServerProof{}, &ServerProof{}}
-	ethClient := &eth.Client{}
+
+	var timer timer
+	ethClientSetup := test.NewClientSetupExample()
+	addr := ethClientSetup.AuctionVariables.BootCoordinator
+	ethClient := test.NewClient(true, &timer, addr, ethClientSetup)
+
 	c := NewCoordinator(conf, hdb, txsel, bb, serverProofs, ethClient)
 	cn := NewCoordNode(c)
 	cn.Start()
@@ -135,18 +150,24 @@ time.Sleep(1 * time.Second)
 
 	// simulate forgeSequence time
 	log.Info("simulate entering in forge time")
+	c.rw.Lock()
 	c.isForgeSeq = true
+	c.rw.Unlock()
 	time.Sleep(1 * time.Second)
 
 	// simulate going out from forgeSequence
 	log.Info("simulate going out from forge time")
+	c.rw.Lock()
 	c.isForgeSeq = false
+	c.rw.Unlock()
 	time.Sleep(1 * time.Second)
 
 	// simulate entering forgeSequence time again
 	log.Info("simulate entering in forge time again")
+	c.rw.Lock()
 	c.isForgeSeq = true
-	time.Sleep(1 * time.Second)
+	c.rw.Unlock()
+	time.Sleep(2 * time.Second)
 
 	// simulate stopping forgerLoop by channel
 	log.Info("simulate stopping forgerLoop by closing coordinator stopch")

@@ -1,10 +1,13 @@
 package coordinator
 
 import (
+	"time"
+
 	"github.com/hermeznetwork/hermez-node/common"
 	"github.com/hermeznetwork/hermez-node/log"
 )
 
+// ServerProofInterface is the interface to a ServerProof that calculates zk proofs
 type ServerProofInterface interface {
 	CalculateProof(zkInputs *common.ZKInputs) error
 	GetProof(stopCh chan bool) (*Proof, error)
@@ -17,6 +20,7 @@ URL       string
 	Available bool
 }
 
+// NewServerProof creates a new ServerProof
 func NewServerProof(URL string) *ServerProof {
 	return &ServerProof{URL: URL}
 }
@@ -24,12 +28,33 @@
 // CalculateProof sends the *common.ZKInputs to the ServerProof to compute the
 // Proof
 func (p *ServerProof) CalculateProof(zkInputs *common.ZKInputs) error {
+	return errTODO
+}
+
+// GetProof retreives the Proof from the ServerProof
+func (p *ServerProof) GetProof(stopCh chan bool) (*Proof, error) {
+	return nil, errTODO
+}
+
+// ServerProofMock is a mock ServerProof to be used in tests.  It doesn't calculate anything
+type ServerProofMock struct {
+}
+
+// CalculateProof sends the *common.ZKInputs to the ServerProof to compute the
+// Proof
+func (p *ServerProofMock) CalculateProof(zkInputs *common.ZKInputs) error {
 	return nil
 }
 
 // GetProof retreives the Proof from the ServerProof
-func (p *ServerProof) GetProof(stopCh chan bool) (*Proof, error) {
-	return nil, nil
+func (p *ServerProofMock) GetProof(stopCh chan bool) (*Proof, error) {
+	// Simulate a delay
+	select {
+	case <-time.After(200 * time.Millisecond): //nolint:gomnd
+		return &Proof{}, nil
+	case <-stopCh:
+		return nil, ErrStop
+	}
 }
 
 // ServerProofPool contains the multiple ServerProof
@@ -37,17 +62,19 @@ type ServerProofPool struct {
 	pool chan ServerProofInterface
 }
 
+// NewServerProofPool creates a new pool of ServerProofs.
 func NewServerProofPool(maxServerProofs int) *ServerProofPool {
 	return &ServerProofPool{
 		pool: make(chan ServerProofInterface, maxServerProofs),
 	}
 }
 
+// Add a ServerProof to the pool
 func (p *ServerProofPool) Add(serverProof ServerProofInterface) {
 	p.pool <- serverProof
 }
 
-// Get returns the available ServerProof
+// Get returns the next available ServerProof
 func (p *ServerProofPool) Get(stopCh chan bool) (ServerProofInterface, error) {
 	select {
 	case <-stopCh:

@@ -20,6 +20,7 @@ github.com/russross/meddler v1.0.0
 	github.com/stretchr/testify v1.6.1
 	github.com/urfave/cli v1.22.1
 	github.com/urfave/cli/v2 v2.2.0
-	go.uber.org/zap v1.13.0
+	go.uber.org/multierr v1.6.0 // indirect
+	go.uber.org/zap v1.16.0
 	gopkg.in/go-playground/validator.v9 v9.29.1
 )

@@ -601,13 +601,23 @@ go.uber.org/atomic v1.3.2/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.5.0 h1:OI5t8sDa1Or+q8AeE+yKeB/SDYioSHAgcVljj9JIETY=
 go.uber.org/atomic v1.5.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/atomic v1.6.0 h1:Ezj3JGmsOnG1MoRWQkPBsKLe9DwWD9QeXzTRzzldNVk=
+go.uber.org/atomic v1.6.0/go.mod h1:sABNBOSYdrvTF6hTgEIbc7YasKWGhgEQZyfxyTvoXHQ=
+go.uber.org/atomic v1.7.0 h1:ADUqmZGgLDDfbSL9ZmPxKTybcoEYHgpYfELNoN+7hsw=
+go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.3.0 h1:sFPn2GLc3poCkfrpIXGhBD2X0CMIo4Q/zSULXrj/+uc=
 go.uber.org/multierr v1.3.0/go.mod h1:VgVr7evmIr6uPjLBxg28wmKNXyqE9akIJ5XnfpiKl+4=
+go.uber.org/multierr v1.5.0 h1:KCa4XfM8CWFCpxXRGok+Q0SS/0XBhMDbHHGABQLvD2A=
+go.uber.org/multierr v1.5.0/go.mod h1:FeouvMocqHpRaaGuG9EjoKcStLC43Zu/fmqdUMPcKYU=
+go.uber.org/multierr v1.6.0 h1:y6IPFStTAIT5Ytl7/XYmHvzXQ7S3g/IeZW9hyZ5thw4=
+go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
 go.uber.org/tools v0.0.0-20190618225709-2cfd321de3ee/go.mod h1:vJERXedbb3MVM5f9Ejo0C68/HhF8uaILCdgjnY+goOA=
 go.uber.org/zap v1.10.0/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=
 go.uber.org/zap v1.13.0 h1:nR6NoDBgAf67s68NhaXbsojM+2gxp3S1hWkHDl27pVU=
 go.uber.org/zap v1.13.0/go.mod h1:zwrFLgMcdUuIBviXEYEH1YKNaOBnKXsx2IPda5bBwHM=
+go.uber.org/zap v1.16.0 h1:uFRZXykJGK9lLY4HtgSw44DnIcAM+kRBP7x5m+NpAOM=
+go.uber.org/zap v1.16.0/go.mod h1:MA8QOfq0BHJwdXa996Y4dYkAqRKB8/1K1QMMZVaNZjQ=
 golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20181029021203-45a5f77698d3/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=