add event subscription

client/client.go

@@ -17,4 +17,6 @@ type Client interface {
 	GetBalance(account sdk.AccAddress) (uint64, error)
 	SendRequest(msg sdk.Msg, gasPrice float64, key keyring.Record) (*sdk.TxResponse, error)
 	GetRequestProofByID(reqID uint64) ([]byte, error)
+	Subscribe(name, query string) (*SubscriptionInfo, error)
+	Unsubscribe(name string) error
 }

client/go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/bandprotocol/go-band-sdk/utils v1.0.1
 	github.com/cometbft/cometbft v0.37.5
 	github.com/cosmos/cosmos-sdk v0.47.11
+	github.com/pkg/errors v0.9.1
 	github.com/stretchr/testify v1.9.0
 	go.uber.org/mock v0.4.0
 )
@@ -137,7 +138,6 @@ require (
 	github.com/pelletier/go-toml/v2 v2.1.0 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
 	github.com/petermattis/goid v0.0.0-20230904192822-1876fd5063bc // indirect
-	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/prometheus/client_golang v1.17.0 // indirect
 	github.com/prometheus/client_model v0.5.0 // indirect

client/rpc.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"strconv"
+	"sync"
 	"time"
 
 	bandtsstypes "github.com/bandprotocol/chain/v2/x/bandtss/types"
@@ -25,12 +26,12 @@ var _ Client = &RPC{}
 
 // RPC implements Clients by using multiple RPC nodes
 type RPC struct {
-	ctx       client.Context
-	txFactory tx.Factory
-	nodes     []*rpchttp.HTTP
-	keyring   keyring.Keyring
-
-	logger logging.Logger
+	ctx               client.Context
+	txFactory         tx.Factory
+	nodes             []*rpchttp.HTTP
+	keyring           keyring.Keyring
+	subscriptionInfos *sync.Map
+	logger            logging.Logger
 }
 
 // NewRPC creates new RPC client
@@ -52,11 +53,12 @@ func NewRPC(
 	}
 
 	return &RPC{
-		ctx:       NewClientCtx(chainID),
-		txFactory: createTxFactory(chainID, gasPrice, keyring),
-		nodes:     nodes,
-		keyring:   keyring,
-		logger:    logger,
+		ctx:               NewClientCtx(chainID),
+		txFactory:         createTxFactory(chainID, gasPrice, keyring),
+		nodes:             nodes,
+		keyring:           keyring,
+		subscriptionInfos: &sync.Map{},
+		logger:            logger,
 	}, nil
 }
 
@@ -300,14 +302,24 @@ func (c RPC) GetSignature(signingID uint64) (*SigningResult, error) {
 		}(node)
 	}
 
+	// check if the signature is ready to be used. If every node returns waiting status, return one.
+	// If every node fails to query a result return an error.
+	var res *SigningResult
 	for range c.nodes {
 		select {
-		case res := <-resultCh:
-			return res, nil
+		case res = <-resultCh:
+			if res.IsReady() {
+				return res, nil
+			}
 		case <-failCh:
 		}
 	}
-	return nil, fmt.Errorf("failed to get result from all endpoints")
+
+	if res == nil {
+		return nil, fmt.Errorf("failed to get result from all endpoints")
+	}
+
+	return res, nil
 }
 
 func (c RPC) GetBalance(_ sdk.AccAddress) (uint64, error) {
@@ -496,3 +508,106 @@ func (c RPC) blockSearch(query string, page *int, perPage *int, orderBy string)
 
 	return nil, fmt.Errorf("failed to block search from all endpoints")
 }
+
+// Subscribe subscribes to the given event name and query from multiple clients. If it cannot
+// subscribe to a node within the given timeout, it will drop that node from the result.
+// If no nodes can be subscribed, it will return an error.
+func (c RPC) Subscribe(name, query string) (*SubscriptionInfo, error) {
+	chInfos := make([]ChannelInfo, 0, len(c.nodes))
+	queue := make(chan ChannelInfo, 1)
+	var wg sync.WaitGroup
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// subscribe to all nodes within a given timeout
+	wg.Add(len(c.nodes))
+	for _, node := range c.nodes {
+		go func(node *rpchttp.HTTP) {
+			if !node.IsRunning() {
+				c.logger.Debug("Subscribe", "start the node %s", node.Remote())
+				if err := node.Start(); err != nil {
+					c.logger.Warning("Subscribe", "Failed to start %s with error %s", node.Remote(), err)
+					wg.Done()
+					return
+				}
+			}
+
+			eventCh, err := node.Subscribe(ctx, name, query, 1000)
+			if err != nil {
+				c.logger.Warning("Subscribe", "Failed to subscribe to %s with error %s", node.Remote(), err)
+				wg.Done()
+				return
+			}
+
+			queue <- ChannelInfo{
+				RemoteAddr: node.Remote(),
+				EventCh:    eventCh,
+			}
+		}(node)
+	}
+
+	// add result into the list.
+	go func() {
+		for info := range queue {
+			chInfos = append(chInfos, info)
+			wg.Done()
+		}
+	}()
+
+	wg.Wait()
+	if len(chInfos) == 0 {
+		return nil, fmt.Errorf("failed to subscribe to all endpoints")
+	}
+
+	subInfo := SubscriptionInfo{
+		Name:         name,
+		Query:        query,
+		ChannelInfos: chInfos,
+	}
+
+	c.subscriptionInfos.Store(name, subInfo)
+	return &subInfo, nil
+}
+
+// Unsubscribe unsubscribes from the given event name from multiple clients.
+func (c RPC) Unsubscribe(name string) error {
+	v, found := c.subscriptionInfos.Load(name)
+	if !found {
+		return fmt.Errorf("event is not subscribed; name %s", name)
+	}
+
+	info, ok := v.(SubscriptionInfo)
+	if !ok {
+		return fmt.Errorf("failed to cast to SubscriptionInfo; name %s", name)
+	}
+
+	remoteAddrs := make(map[string]struct{})
+	for _, chInfo := range info.ChannelInfos {
+		remoteAddrs[chInfo.RemoteAddr] = struct{}{}
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	var wg sync.WaitGroup
+	wg.Add(len(info.ChannelInfos))
+	for _, node := range c.nodes {
+		if _, found := remoteAddrs[node.Remote()]; !found {
+			continue
+		}
+
+		go func(node *rpchttp.HTTP, name, query string) {
+			defer wg.Done()
+			// if failed to unsubscribe, it means that the node object is not running or timeout.
+			// Log and continue the process.
+			if err := node.Unsubscribe(ctx, name, query); err != nil {
+				c.logger.Warning("Unsubscribe", "Failed to unsubscribe from %s with error %s", node.Remote(), err)
+			}
+		}(node, name, info.Query)
+	}
+
+	wg.Wait()
+	c.subscriptionInfos.Delete(name)
+	return nil
+}

client/types.go

@@ -4,6 +4,7 @@ import (
 	bandtsstypes "github.com/bandprotocol/chain/v2/x/bandtss/types"
 	oracletypes "github.com/bandprotocol/chain/v2/x/oracle/types"
 	tsstypes "github.com/bandprotocol/chain/v2/x/tss/types"
+	ctypes "github.com/cometbft/cometbft/rpc/core/types"
 )
 
 // OracleResult stores the necessary information for an oracle query result.
@@ -18,6 +19,12 @@ type SigningResult struct {
 	ReplacingGroup SigningInfo
 }
 
+func (s SigningResult) IsReady() bool {
+	return s.CurrentGroup.Status == tsstypes.SIGNING_STATUS_SUCCESS &&
+		(s.ReplacingGroup.Status == tsstypes.SIGNING_STATUS_UNSPECIFIED ||
+			s.ReplacingGroup.Status == tsstypes.SIGNING_STATUS_SUCCESS)
+}
+
 // SigningInfo contains signing information.
 type SigningInfo struct {
 	Message      []byte
@@ -26,3 +33,16 @@ type SigningInfo struct {
 	PubKey       []byte
 	PubNonce     []byte
 }
+
+// ChannelInfo stores the necessary information for a channel receiving an event from a chain.
+type ChannelInfo struct {
+	RemoteAddr string
+	EventCh    <-chan ctypes.ResultEvent
+}
+
+// SubscriptionInfo stores the necessary information for a subscription channel for a specific events.
+type SubscriptionInfo struct {
+	Name         string
+	Query        string
+	ChannelInfos []ChannelInfo
+}

examples/go.mod

@@ -6,7 +6,9 @@ require (
 	github.com/bandprotocol/chain/v2 v2.5.5-0.20240503145406-b6ed5a969335
 	github.com/bandprotocol/go-band-sdk/client v1.0.1
 	github.com/bandprotocol/go-band-sdk/requester v1.0.1
+	github.com/bandprotocol/go-band-sdk/subscriber v1.0.1
 	github.com/bandprotocol/go-band-sdk/utils v1.0.1
+	github.com/cometbft/cometbft v0.37.5
 	github.com/cosmos/cosmos-sdk v0.47.11
 	github.com/spf13/viper v1.18.2
 )
@@ -48,7 +50,6 @@ require (
 	github.com/cockroachdb/redact v1.1.5 // indirect
 	github.com/cockroachdb/tokenbucket v0.0.0-20230807174530-cc333fc44b06 // indirect
 	github.com/coinbase/rosetta-sdk-go/types v1.0.0 // indirect
-	github.com/cometbft/cometbft v0.37.5 // indirect
 	github.com/cometbft/cometbft-db v0.10.0 // indirect
 	github.com/confio/ics23/go v0.9.0 // indirect
 	github.com/cosmos/btcutil v1.0.5 // indirect
@@ -137,6 +138,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0 // indirect
 	github.com/mtibben/percent v0.2.1 // indirect
 	github.com/oasisprotocol/oasis-core/go v0.2202.7 // indirect
+	github.com/patrickmn/go-cache v2.1.0+incompatible // indirect
 	github.com/pelletier/go-toml/v2 v2.1.0 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
 	github.com/petermattis/goid v0.0.0-20231207134359-e60b3f734c67 // indirect
@@ -206,6 +208,7 @@ replace (
 
 	github.com/bandprotocol/go-band-sdk/client => ../client
 	github.com/bandprotocol/go-band-sdk/requester => ../requester
+	github.com/bandprotocol/go-band-sdk/subscriber => ../subscriber
 	github.com/bandprotocol/go-band-sdk/utils => ../utils
 	github.com/gogo/protobuf => github.com/regen-network/protobuf v1.3.3-alpha.regen.1
 	// cosmos-sdk v0.47.11 is incompatible with gogoproto 1.4.10

examples/go.sum

@@ -849,6 +849,8 @@ github.com/pact-foundation/pact-go v1.0.4/go.mod h1:uExwJY4kCzNPcHRj+hCR/HBbOOIw
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
 github.com/pascaldekloe/goe v0.1.0 h1:cBOtyMzM9HTpWjXfbbunk26uA6nG3a8n06Wieeh0MwY=
 github.com/pascaldekloe/goe v0.1.0/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pelletier/go-toml/v2 v2.1.0 h1:FnwAJ4oYMvbT/34k9zzHuZNrhlz48GB3/s6at6/MHO4=