RFQ API: add GET /ack endpoint

services/rfq/api/config/config.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 
 	"github.com/jftuga/ellipsis"
 	"gopkg.in/yaml.v2"
@@ -21,8 +22,19 @@ type Config struct {
 	Database   DatabaseConfig `yaml:"database"`
 	OmniRPCURL string         `yaml:"omnirpc_url"`
 	// bridges is a map of chainid->address
-	Bridges map[uint32]string `yaml:"bridges"`
-	Port    string            `yaml:"port"`
+	Bridges         map[uint32]string `yaml:"bridges"`
+	Port            string            `yaml:"port"`
+	RelayAckTimeout time.Duration     `yaml:"relay_ack_timeout"`
+}
+
+const defaultRelayAckTimeout = 5 * time.Second
+
+// GetRelayAckTimeout returns the relay ack timeout.
+func (c Config) GetRelayAckTimeout() time.Duration {
+	if c.RelayAckTimeout == 0 {
+		return defaultRelayAckTimeout
+	}
+	return c.RelayAckTimeout
 }
 
 // LoadConfig loads the config from the given path.

services/rfq/api/rest/server.go

@@ -5,6 +5,7 @@
 	"context"
 	"fmt"
 	"net/http"
+	"sync"
 	"time"
 
 	"github.com/ipfs/go-log"
@@ -25,6 +26,7 @@
 	"github.com/synapsecns/sanguine/services/rfq/api/docs"
 	"github.com/synapsecns/sanguine/services/rfq/api/model"
 	"github.com/synapsecns/sanguine/services/rfq/contracts/fastbridge"
+	"github.com/synapsecns/sanguine/services/rfq/relayer/relapi"
 )
 
 // QuoterAPIServer is a struct that holds the configuration, database connection, gin engine, RPC client, metrics handler, and fast bridge contracts.
@@ -37,6 +39,11 @@
 	handler             metrics.Handler
 	fastBridgeContracts map[uint32]*fastbridge.FastBridge
 	roleCache           map[uint32]*ttlcache.Cache[string, bool]
+	// relayAckCache contains a set of transactionID values that reflect
+	// transactions that have been acked for relay
+	relayAckCache *ttlcache.Cache[string, bool]
+	// ackMux is a mutex used to ensure that only one transaction id can be acked at a time.
+	ackMux sync.Mutex
 }
 
 // NewAPI holds the configuration, database connection, gin engine, RPC client, metrics handler, and fast bridge contracts.
@@ -80,27 +87,40 @@
 			ttlcache.WithTTL[string, bool](cacheInterval),
 		)
 		roleCache := roles[chainID]
-
 		go roleCache.Start()
 		go func() {
 			<-ctx.Done()
 			roleCache.Stop()
 		}()
 	}
 
+	// create the relay ack cache
+	relayAckCache := ttlcache.New[string, bool](
+		ttlcache.WithTTL[string, bool](cfg.GetRelayAckTimeout()),
+		ttlcache.WithDisableTouchOnHit[string, bool](),
+	)
+	go relayAckCache.Start()
+	go func() {
+		<-ctx.Done()
+		relayAckCache.Stop()
+	}()
+
 	return &QuoterAPIServer{
 		cfg:                 cfg,
 		db:                  store,
 		omnirpcClient:       omniRPCClient,
 		handler:             handler,
 		fastBridgeContracts: bridges,
 		roleCache:           roles,
+		relayAckCache:       relayAckCache,
+		ackMux:              sync.Mutex{},
 	}, nil
 }
 
 // QuoteRoute is the API endpoint for handling quote related requests.
 const (
 	QuoteRoute    = "/quotes"
+	AckRoute      = "/ack"
 	cacheInterval = time.Minute
 )
 
@@ -120,6 +140,7 @@
 	// GET routes without the AuthMiddleware
 	// engine.PUT("/quotes", h.ModifyQuote)
 	engine.GET(QuoteRoute, h.GetQuotes)
+	engine.GET(AckRoute, r.GetRelayAck)
 
 	r.engine = engine
 
@@ -188,3 +209,28 @@
 		c.Next()
 	}
 }
+
+// GetRelayAck checks if a relay is pending or not.
+func (r *QuoterAPIServer) GetRelayAck(c *gin.Context) {
+	transactionID := c.Query("id")
+	if transactionID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Must specify 'id'"})
+		return
+	}
+
+	// If the tx id is already in the cache, it should not be relayed.
+	// Otherwise, insert into the cache.
+	r.ackMux.Lock()
+	ack := r.relayAckCache.Get(transactionID)
+	shouldRelay := ack == nil
+	if shouldRelay {
+		r.relayAckCache.Set(transactionID, true, ttlcache.DefaultTTL)
+	}
+	r.ackMux.Unlock()
+
+	resp := relapi.GetRelayAckResponse{
+		TxID:        transactionID,
+		ShouldRelay: shouldRelay,
+	}
+	c.JSON(http.StatusOK, resp)
+}

services/rfq/api/rest/server_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/synapsecns/sanguine/ethergo/signer/wallet"
 	"github.com/synapsecns/sanguine/services/rfq/api/model"
+	"github.com/synapsecns/sanguine/services/rfq/relayer/relapi"
 )
 
 func (c *ServerSuite) TestNewQuoterAPIServer() {
@@ -203,6 +204,50 @@ func (c *ServerSuite) TestPutAndGetQuoteByRelayer() {
 	c.Assert().True(found, "Newly added quote not found")
 }
 
+func (c *ServerSuite) TestGetAck() {
+	c.startQuoterAPIServer()
+
+	// Send GET request
+	client := &http.Client{}
+	testTxID := "0x123"
+	req, err := http.NewRequestWithContext(c.GetTestContext(), http.MethodGet, fmt.Sprintf("http://localhost:%d/ack?id=%s", c.port, testTxID), nil)
+	c.Require().NoError(err)
+	resp, err := client.Do(req)
+	c.Require().NoError(err)
+	c.Equal(http.StatusOK, resp.StatusCode)
+
+	// Expect ack with shouldRelay=true
+	var result relapi.GetRelayAckResponse
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	c.Require().NoError(err)
+	expectedResult := relapi.GetRelayAckResponse{
+		TxID:        testTxID,
+		ShouldRelay: true,
+	}
+	c.Equal(expectedResult, result)
+	err = resp.Body.Close()
+	c.Require().NoError(err)
+
+	// Send another request with same txID
+	req, err = http.NewRequestWithContext(c.GetTestContext(), http.MethodGet, fmt.Sprintf("http://localhost:%d/ack?id=%s", c.port, testTxID), nil)
+	c.Require().NoError(err)
+	resp, err = client.Do(req)
+	c.Require().NoError(err)
+	c.Equal(http.StatusOK, resp.StatusCode)
+
+	// Expect ack with shouldRelay=false
+	err = json.NewDecoder(resp.Body).Decode(&result)
+	c.Require().NoError(err)
+	expectedResult = relapi.GetRelayAckResponse{
+		TxID:        testTxID,
+		ShouldRelay: false,
+	}
+	c.Equal(expectedResult, result)
+	err = resp.Body.Close()
+	c.Require().NoError(err)
+	c.GetTestContext().Done()
+}
+
 // startQuoterAPIServer starts the API server and waits for it to initialize.
 func (c *ServerSuite) startQuoterAPIServer() {
 	go func() {

services/rfq/relayer/relapi/handler.go

@@ -60,7 +60,7 @@
 func (h *Handler) GetQuoteRequestStatusByTxID(c *gin.Context) {
 	txIDStr := c.Query("id")
 	if txIDStr == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": "Must specify 'txID'"})
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Must specify 'id'"})
 		return
 	}
 

services/rfq/relayer/relapi/model.go

@@ -15,3 +15,9 @@ type GetTxRetryResponse struct {
 	Nonce     uint64 `json:"nonce"`
 	GasAmount string `json:"gas_amount"`
 }
+
+// GetRelayAckResponse contains the schema for a POST /relay/ack response.
+type GetRelayAckResponse struct {
+	TxID        string `json:"tx_id"`
+	ShouldRelay bool   `json:"should_relay"`
+}