Add RPC support for Beefy & MMR (#249)

* Add client support for Beefy & MMR

* Fix lint errors

* Fix tests

* Add more unit tests

* Add OptionalSignedCommitment type

* Remove obsolete JSON marshalling code

* update things

* fix bugs

* fixlint

rpc/beefy/beefy.go

@@ -0,0 +1,31 @@
+// Go Substrate RPC Client (GSRPC) provides APIs and types around Polkadot and any Substrate-based chain RPC calls
+//
+// Copyright 2021 Snowfork
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package beefy
+
+import (
+	"github.com/centrifuge/go-substrate-rpc-client/v4/client"
+)
+
+// Beefy exposes methods for retrieval of chain data
+type Beefy struct {
+	client client.Client
+}
+
+// NewBeefy creates a new Chain struct
+func NewBeefy(cl client.Client) Beefy {
+	return Beefy{cl}
+}

rpc/beefy/beefy_test.go

@@ -0,0 +1,20 @@
+package beefy
+
+import (
+	"os"
+	"testing"
+
+	"github.com/centrifuge/go-substrate-rpc-client/v4/client"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/config"
+)
+
+var beefy Beefy
+
+func TestMain(m *testing.M) {
+	cl, err := client.Connect(config.Default().RPCURL)
+	if err != nil {
+		panic(err)
+	}
+	beefy = NewBeefy(cl)
+	os.Exit(m.Run())
+}

rpc/beefy/get_finalized_head.go

@@ -0,0 +1,33 @@
+// Go Substrate RPC Client (GSRPC) provides APIs and types around Polkadot and any Substrate-based chain RPC calls
+//
+// Copyright 2021 Snowfork
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package beefy
+
+import (
+	"github.com/centrifuge/go-substrate-rpc-client/v4/types"
+)
+
+// GetFinalizedHead returns the hash of the latest BEEFY block
+func (b *Beefy) GetFinalizedHead() (types.Hash, error) {
+	var res string
+
+	err := b.client.Call(&res, "beefy_getFinalizedHead")
+	if err != nil {
+		return types.Hash{}, err
+	}
+
+	return types.NewHashFromHexString(res)
+}

rpc/beefy/get_finalized_head_test.go

@@ -0,0 +1,29 @@
+// Go Substrate RPC Client (GSRPC) provides APIs and types around Polkadot and any Substrate-based chain RPC calls
+//
+// Copyright 2019 Centrifuge GmbH
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package beefy
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBeefy_GetFinalizedHead(t *testing.T) {
+	t.Skip("API only available in Polkadot")
+	_, err := beefy.GetFinalizedHead()
+	assert.NoError(t, err)
+}

rpc/beefy/subscribe_justifications.go

@@ -0,0 +1,78 @@
+// Go Substrate RPC Client (GSRPC) provides APIs and types around Polkadot and any Substrate-based chain RPC calls
+//
+// Copyright 2021 Snowfork
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package beefy
+
+import (
+	"context"
+	"sync"
+
+	"github.com/centrifuge/go-substrate-rpc-client/v4/config"
+	gethrpc "github.com/centrifuge/go-substrate-rpc-client/v4/gethrpc"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/types"
+)
+
+// JustificationsSubscription is a subscription established through one of the Client's subscribe methods.
+type JustificationsSubscription struct {
+	sub      *gethrpc.ClientSubscription
+	channel  chan types.SignedCommitment
+	quitOnce sync.Once // ensures quit is closed once
+}
+
+// Chan returns the subscription channel.
+//
+// The channel is closed when Unsubscribe is called on the subscription.
+func (s *JustificationsSubscription) Chan() <-chan types.SignedCommitment {
+	return s.channel
+}
+
+// Err returns the subscription error channel. The intended use of Err is to schedule
+// resubscription when the client connection is closed unexpectedly.
+//
+// The error channel receives a value when the subscription has ended due
+// to an error. The received error is nil if Close has been called
+// on the underlying client and no other error has occurred.
+//
+// The error channel is closed when Unsubscribe is called on the subscription.
+func (s *JustificationsSubscription) Err() <-chan error {
+	return s.sub.Err()
+}
+
+// Unsubscribe unsubscribes the notification and closes the error channel.
+// It can safely be called more than once.
+func (s *JustificationsSubscription) Unsubscribe() {
+	s.sub.Unsubscribe()
+	s.quitOnce.Do(func() {
+		close(s.channel)
+	})
+}
+
+// SubscribeJustifications subscribes beefy justifications, returning a subscription that will
+// receive server notifications containing the Header.
+func (b *Beefy) SubscribeJustifications() (*JustificationsSubscription, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), config.Default().SubscribeTimeout)
+	defer cancel()
+
+	ch := make(chan types.SignedCommitment)
+
+	sub, err := b.client.Subscribe(ctx, "beefy", "subscribeJustifications", "unsubscribeJustifications",
+		"justifications", ch)
+	if err != nil {
+		return nil, err
+	}
+
+	return &JustificationsSubscription{sub: sub, channel: ch}, nil
+}

rpc/main.go

@@ -19,7 +19,9 @@ package rpc
 import (
 	"github.com/centrifuge/go-substrate-rpc-client/v4/client"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/author"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/beefy"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/chain"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/mmr"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/offchain"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/state"
 	"github.com/centrifuge/go-substrate-rpc-client/v4/rpc/system"
@@ -28,7 +30,9 @@ import (
 
 type RPC struct {
 	Author   author.Author
+	Beefy    beefy.Beefy
 	Chain    chain.Chain
+	MMR      mmr.MMR
 	Offchain offchain.Offchain
 	State    state.State
 	System   system.System
@@ -47,7 +51,9 @@ func NewRPC(cl client.Client) (*RPC, error) {
 
 	return &RPC{
 		Author:   author.NewAuthor(cl),
+		Beefy:    beefy.NewBeefy(cl),
 		Chain:    chain.NewChain(cl),
+		MMR:      mmr.NewMMR(cl),
 		Offchain: offchain.NewOffchain(cl),
 		State:    st,
 		System:   system.NewSystem(cl),

rpc/mmr/generate_proof.go

@@ -0,0 +1,27 @@
+package mmr
+
+import (
+	"github.com/centrifuge/go-substrate-rpc-client/v4/client"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/types"
+)
+
+// GenerateProof retrieves a MMR proof and leaf for the specified leave index, at the given blockHash (useful to query a
+// proof at an earlier block, likely with antoher MMR root)
+func (c *MMR) GenerateProof(leafIndex uint64, blockHash types.Hash) (types.GenerateMMRProofResponse, error) {
+	return c.generateProof(leafIndex, &blockHash)
+}
+
+// GenerateProofLatest retrieves the latest MMR proof and leaf for the specified leave index
+func (c *MMR) GenerateProofLatest(leafIndex uint64) (types.GenerateMMRProofResponse, error) {
+	return c.generateProof(leafIndex, nil)
+}
+
+func (c *MMR) generateProof(leafIndex uint64, blockHash *types.Hash) (types.GenerateMMRProofResponse, error) {
+	var res types.GenerateMMRProofResponse
+	err := client.CallWithBlockHash(c.client, &res, "mmr_generateProof", blockHash, leafIndex)
+	if err != nil {
+		return types.GenerateMMRProofResponse{}, err
+	}
+
+	return res, nil
+}

rpc/mmr/mmr.go

@@ -0,0 +1,13 @@
+package mmr
+
+import "github.com/centrifuge/go-substrate-rpc-client/v4/client"
+
+// MMR exposes methods for retrieval of MMR data
+type MMR struct {
+	client client.Client
+}
+
+// NewMMR creates a new MMR struct
+func NewMMR(c client.Client) MMR {
+	return MMR{client: c}
+}

teste2e/beefy_subscribe_justifications_test.go

@@ -0,0 +1,59 @@
+// Go Substrate RPC Client (GSRPC) provides APIs and types around Polkadot and any Substrate-based chain RPC calls
+//
+// Copyright 2019 Centrifuge GmbH
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package teste2e
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	gsrpc "github.com/centrifuge/go-substrate-rpc-client/v4"
+	"github.com/centrifuge/go-substrate-rpc-client/v4/config"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBeefy_SubscribeJustifications(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping end-to-end test in short mode.")
+	}
+
+	api, err := gsrpc.NewSubstrateAPI(config.Default().RPCURL)
+	assert.NoError(t, err)
+
+	sub, err := api.RPC.Beefy.SubscribeJustifications()
+	assert.NoError(t, err)
+	defer sub.Unsubscribe()
+
+	timeout := time.After(300 * time.Second)
+	received := 0
+
+	for {
+		select {
+		case commitment := <-sub.Chan():
+			fmt.Printf("%#v\n", commitment)
+
+			received++
+
+			if received >= 2 {
+				return
+			}
+		case <-timeout:
+			assert.FailNow(t, "timeout reached without getting 2 notifications from subscription")
+			return
+		}
+	}
+}