feat(dot/rpc): Implement childstate_getKeys rpc call

chain/dev/config.toml

@@ -35,5 +35,5 @@ enabled = true
 ws = true
 port = 8545
 host = "localhost"
-modules = ["system", "author", "chain", "state", "rpc", "grandpa"]
+modules = ["system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"]
 ws-port = 8546

chain/dev/defaults.go

@@ -87,7 +87,7 @@ var (
 	// DefaultRPCHTTPPort rpc port
 	DefaultRPCHTTPPort = uint32(8545)
 	// DefaultRPCModules rpc modules
-	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa"}
+	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"}
 	// DefaultRPCWSPort rpc websocket port
 	DefaultRPCWSPort = uint32(8546)
 	// DefaultRPCEnabled enables the RPC server

chain/gssmr/config.toml

@@ -35,5 +35,5 @@ discovery-interval = 10
 enabled = false
 port = 8545
 host = "localhost"
-modules = ["system", "author", "chain", "state", "rpc", "grandpa"]
+modules = ["system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"]
 ws-port = 8546

chain/gssmr/defaults.go

@@ -92,7 +92,7 @@ var (
 	// DefaultRPCHTTPPort rpc port
 	DefaultRPCHTTPPort = uint32(8545)
 	// DefaultRPCModules rpc modules
-	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa"}
+	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"}
 	// DefaultRPCWSPort rpc websocket port
 	DefaultRPCWSPort = uint32(8546)
 )

chain/kusama/config.toml

@@ -35,7 +35,7 @@ enabled = false
 external = false
 port = 8545
 host = "localhost"
-modules = ["system", "author", "chain", "state", "rpc", "grandpa"]
+modules = ["system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"]
 ws-port = 8546
 ws = false
 ws-external = false

chain/kusama/defaults.go

@@ -83,7 +83,7 @@ var (
 	// DefaultRPCHTTPPort rpc port
 	DefaultRPCHTTPPort = uint32(8545)
 	// DefaultRPCModules rpc modules
-	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa"}
+	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"}
 	// DefaultRPCWSPort rpc websocket port
 	DefaultRPCWSPort = uint32(8546)
 )

chain/polkadot/config.toml

@@ -34,5 +34,5 @@ nomdns = false
 enabled = false
 port = 8545
 host = "localhost"
-modules = ["system", "author", "chain", "state", "rpc", "grandpa"]
+modules = ["system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"]
 ws-port = 8546

chain/polkadot/defaults.go

@@ -84,7 +84,7 @@ var (
 	// DefaultRPCHTTPPort rpc port
 	DefaultRPCHTTPPort = uint32(8545)
 	// DefaultRPCModules rpc modules
-	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa"}
+	DefaultRPCModules = []string{"system", "author", "chain", "state", "rpc", "grandpa", "offchain", "childstate"}
 	// DefaultRPCWSPort rpc websocket port
 	DefaultRPCWSPort = uint32(8546)
 )

dot/rpc/http.go

@@ -127,6 +127,8 @@ func (h *HTTPServer) RegisterModules(mods []string) {
 			srvc = modules.NewDevModule(h.serverConfig.BlockProducerAPI, h.serverConfig.NetworkAPI)
 		case "offchain":
 			srvc = modules.NewOffchainModule(h.serverConfig.NodeStorage)
+		case "childstate":
+			srvc = modules.NewChildStateModule(h.serverConfig.StorageAPI, h.serverConfig.BlockAPI)
 		default:
 			h.logger.Warn("Unrecognised module", "module", mod)
 			continue

dot/rpc/modules/api.go

@@ -12,11 +12,13 @@ import (
 	"github.com/ChainSafe/gossamer/lib/grandpa"
 	"github.com/ChainSafe/gossamer/lib/runtime"
 	"github.com/ChainSafe/gossamer/lib/transaction"
+	"github.com/ChainSafe/gossamer/lib/trie"
 )
 
 // StorageAPI is the interface for the storage state
 type StorageAPI interface {
 	GetStorage(root *common.Hash, key []byte) ([]byte, error)
+	GetStorageChild(root *common.Hash, keyToChild []byte) (*trie.Trie, error)
 	GetStorageByBlockHash(bhash common.Hash, key []byte) ([]byte, error)
 	Entries(root *common.Hash) (map[string][]byte, error)
 	GetStateRootFromBlock(bhash *common.Hash) (*common.Hash, error)

dot/rpc/modules/childstate.go

@@ -0,0 +1,55 @@
+package modules
+
+import (
+	"net/http"
+
+	"github.com/ChainSafe/gossamer/lib/common"
+)
+
+// GetKeysRequest represents the request to retrieve the keys of a child storage
+type GetKeysRequest struct {
+	Key    []byte
+	Prefix []byte
+	Hash   common.Hash
+}
+
+// ChildStateModule is the module responsible to implement all the childstate RPC calls
+type ChildStateModule struct {
+	storageAPI StorageAPI
+	blockAPI   BlockAPI
+}
+
+// NewChildStateModule returns a new ChildStateModule
+func NewChildStateModule(s StorageAPI, b BlockAPI) *ChildStateModule {
+	return &ChildStateModule{
+		storageAPI: s,
+		blockAPI:   b,
+	}
+}
+
+// GetKeys returns the keys from the specified child storage. The keys can also be filtered based on a prefix.
+func (cs *ChildStateModule) GetKeys(_ *http.Request, req *GetKeysRequest, res *[]string) error {
+	if req.Hash == common.EmptyHash {
+		req.Hash = cs.blockAPI.BestBlockHash()
+	}
+
+	stateRoot, err := cs.storageAPI.GetStateRootFromBlock(&req.Hash)
+	if err != nil {
+		return err
+	}
+
+	trie, err := cs.storageAPI.GetStorageChild(stateRoot, req.Key)
+	if err != nil {
+		return err
+	}
+
+	keys := trie.GetKeysWithPrefix(req.Prefix)
+	hexKeys := make([]string, len(keys))
+	for idx, k := range keys {
+		hex := common.BytesToHex(k)
+		hexKeys[idx] = hex
+	}
+
+	*res = hexKeys
+	return nil
+}

dot/rpc/modules/childstate_test.go

@@ -0,0 +1,96 @@
+package modules
+
+import (
+	"math/big"
+	"testing"
+
+	"github.com/ChainSafe/gossamer/dot/types"
+	"github.com/ChainSafe/gossamer/lib/common"
+	"github.com/ChainSafe/gossamer/lib/trie"
+	"github.com/stretchr/testify/require"
+)
+
+func TestChildStateGetKeys(t *testing.T) {
+	childStateModule, currBlockHash := setupChildStateStorage(t)
+
+	req := &GetKeysRequest{
+		Key:    []byte(":child_storage_key"),
+		Prefix: []byte{},
+		Hash:   common.EmptyHash,
+	}
+
+	res := make([]string, 0)
+	err := childStateModule.GetKeys(nil, req, &res)
+	require.NoError(t, err)
+	require.Len(t, res, 3)
+
+	for _, r := range res {
+		b, dErr := common.HexToBytes(r)
+		require.NoError(t, dErr)
+		require.Contains(t, []string{
+			":child_first", ":child_second", ":another_child",
+		}, string(b))
+	}
+
+	req = &GetKeysRequest{
+		Key:    []byte(":child_storage_key"),
+		Prefix: []byte(":child_"),
+		Hash:   currBlockHash,
+	}
+
+	err = childStateModule.GetKeys(nil, req, &res)
+	require.NoError(t, err)
+	require.Len(t, res, 2)
+
+	for _, r := range res {
+		b, err := common.HexToBytes(r)
+		require.NoError(t, err)
+		require.Contains(t, []string{
+			":child_first", ":child_second",
+		}, string(b))
+	}
+}
+
+func setupChildStateStorage(t *testing.T) (*ChildStateModule, common.Hash) {
+	t.Helper()
+
+	st := newTestStateService(t)
+
+	tr, err := st.Storage.TrieState(nil)
+	require.NoError(t, err)
+
+	tr.Set([]byte(":first_key"), []byte(":value1"))
+	tr.Set([]byte(":second_key"), []byte(":second_value"))
+
+	childTr := trie.NewEmptyTrie()
+	childTr.Put([]byte(":child_first"), []byte(":child_first_value"))
+	childTr.Put([]byte(":child_second"), []byte(":child_second_value"))
+	childTr.Put([]byte(":another_child"), []byte("value"))
+
+	err = tr.SetChild([]byte(":child_storage_key"), childTr)
+	require.NoError(t, err)
+
+	stateRoot, err := tr.Root()
+	require.NoError(t, err)
+
+	bb, err := st.Block.BestBlock()
+	require.NoError(t, err)
+
+	err = st.Storage.StoreTrie(tr, nil)
+	require.NoError(t, err)
+
+	b := &types.Block{
+		Header: types.Header{
+			ParentHash: bb.Header.Hash(),
+			Number:     big.NewInt(0).Add(big.NewInt(1), bb.Header.Number),
+			StateRoot:  stateRoot,
+		},
+		Body: []byte{},
+	}
+
+	err = st.Block.AddBlock(b)
+	require.NoError(t, err)
+
+	hash, _ := st.Block.GetBlockHash(b.Header.Number)
+	return NewChildStateModule(st.Storage, st.Block), hash
+}