P-Chain Support (#123)

* backend structure to support p-chain and c-chain atomic tx (#122) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * lint fixes * /construction/derive support for p-chain and c-chain bech32 addresses (#124) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * /account/balance and /account/coins support for p-chain and c-chain atomic tx (#125) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * /network/options and /network/status support for p-chain (#126) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * /construction/preprocess and /construction/metadata endpoints for p-chain (#127) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Added Postman collection for all endpoints (#129) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * updating account endpoints to exclude multisig utxos (#132) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * trigger checks * /construction/payloads for p-chain (#130) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * /block and /block/transaction endpoints for p-chain (#131) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> Co-authored-by: Raj Ranjan <rranjan01234@gmail.com> * simplify postman collection usage for construction requests (#133) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * /construction/preprocess and /construction/metadata endpoints for c-chain atomic transactions (#134) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * P-chain parse combine hash submit (#136) * /construction/parse and /construction/combine endpoints for p-chain * /construction/hash and /construction/submit endpoints for p-chain Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Account and block endpoint fixes (#137) * adding block identifier to /account calls for c-chain atomic tx * Use transaction ids instead of block ids for C-chain atomic txs * support shared memory balance for p-chain Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * C chain construction rest (#139) * /construction/payloads for c-chain atomic transactions * /construction/parse and /construction/combine for c-chain atomic tx * /construction/hash and /construction/submit endpoints for c-chain atomic tx Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * minor fixes (#140) * skip outputs without any addresses * remove artificial create chain output * add staking parameters to transaction metadata when parsing Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * P-Chain Avalanchego 1.8.x support (#144) * updated platformvm types and added indexer parsing support for Blueberry blocks * fixed indexer parser tests * support parsing of new transaction types * fixed incorrect threshold value set for the staking reward outputs * update CI golang to 1.18 Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Version upgrades (#148) * update avalanchego version to 1.8.5 * change minimum go version to 1.18 Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Merge branch 'master' of https://github.com/ava-labs/avalanche-rosetta into pchain-support * Add cross chain operations to transaction metadata (#149) * added exported outputs and imported inputs to metadata of p-chain transactions * added exported outputs to metadata of c-chain atomic transactions Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * addressed pchain-support merge pr comments (#151) * utilize txs.CodecVersion * fix Blueberry block timestamp handling * handle missing Blueberry transaction types * rename indexer parser initialize method * use blocks.Parse to parse block bytes * code style fixes Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * fix tests * Fixing AdvanceTimeTx lookup and multisig check regression (#152) * added dependency tx handling logic for advance time tx * fix p-chain imported input parsing bug Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * add signer to permissionless validator tx output metadata (#153) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * v1.9.0 support and other fixes requested in #123 (#154) * avalanchego 1.9.0 compatibility changes * added comments to p-chain indexer parser timestamp logic * add multiple transaction support to banff proposal block parsing * added import aliases to p-chain indexer parser code * added comments to isGenesisBlockRequest check * added comments to indexer container lookup logic * better error messages for pre/post height lookup during utxo retrieval Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Multiple fixes (#156) * better error handling for p-chain tx-parser constructor * sort evm input and outputs for c-chain atomic transactions * renamed metadata variables for staking tx builder * added overflow check to staking transaction weight calculations * return error if reward transaction points to an unsupported transaction type * style fixes Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * update codec and version sources and add operation identifier to c-chain export tx (#157) * update codec and version sources * add operation identifier to c-chain export transaction parsing Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Multiple updates (#159) * use tx id generation logic from avalanchego in hash endpoint * added comments to exported types * make genesisTimestamp in p-chain indexer parser more verbose * add operation identifier to p-chain import/export transaction parsing * add support for non-AVAX currencies in account and block endpoints Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * restructured network identifier handling * validate network name in main * fixes * wip: repacking genesis stuff to genesisHandler * dropped code duplication * nit * wip * wip * types cleanup * more types cleanup * cleanup * nit * chainIDs type cleanup * cleanup AvaxTx implementation * fixes following code review * fixed chainID build * fix * DependencyTx cleanup * changed utxosMap indexing * nit * nit * some more cleanup * nit * nit * nit * nits * nits * Fixed Pchain Indexer parser + minor cleanups (#160) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * fixes following code review * reverted blkTime extraction in pchain indexer parser * Backend block cleanup (#162) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * fixes * fixes following code review * fixed chainID build * reverted blkTime extraction in pchain indexer parser * Pchain network id checks (#163) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * restructured network identifier handling * validate network name in main * fixes * fixes following code review * fixed chainID build * fix * reverted blkTime extraction in pchain indexer parser * cleanup * Pchain genesis repack (#164) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * restructured network identifier handling * validate network name in main * fixes * wip: repacking genesis stuff to genesisHandler * dropped code duplication * nit * fixes following code review * fixed chainID build * fix * reverted blkTime extraction in pchain indexer parser * cleanup * fill in asset ids for P-chain allocation transaction outputs * pchain tx parser cleanup (#165) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * restructured network identifier handling * validate network name in main * fixes * wip: repacking genesis stuff to genesisHandler * dropped code duplication * nit * wip * wip * types cleanup * more types cleanup * cleanup * nit * chainIDs type cleanup * cleanup AvaxTx implementation * fixes following code review * fixed chainID build * fix * reverted blkTime extraction in pchain indexer parser * cleanup * fill in asset ids for P-chain allocation transaction outputs * nit * DependencyTx cleanup (#166) * minor cleanups * nits * nit * more cleanup * prepended base to rpc/indexer endpoints, to avoid confusion * appease linter * pchain indexer dropped unused attribute * nit * nit * init pchain parser in constructor * renamed ParseBlockAtIndex to ParseBlockAtHeight * some more cleanup * wip: cleanup timestamp * fixed UTs * nit * comment nit * cleanup * parser cleanup * init chainIDs in backend ctor * nit * restructured network identifier handling * validate network name in main * fixes * wip: repacking genesis stuff to genesisHandler * dropped code duplication * nit * wip * wip * types cleanup * more types cleanup * cleanup * nit * chainIDs type cleanup * cleanup AvaxTx implementation * fixes following code review * fixed chainID build * fix * DependencyTx cleanup * changed utxosMap indexing * nit * nit * some more cleanup * nit * nit * nit * reverted blkTime extraction in pchain indexer parser * cleanup * fill in asset ids for P-chain allocation transaction outputs * nit * merged pchain-support * nit * nit fix * added Initialize to common.AvaxTx * fixed some more uninitilized txs * some more cleanup * nit * TxDependency Bugfix (#172) bugfix + UTs * Accounts nits (#167) nits and cleanup on Accounts * pchain tx parser fix (#168) pchain tx parser - locked inputs fix * fixed network names * cleanup * fix c-chain atomic transaction balance currencies (#173) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * Network name-backward compatible fix (#174) lowercase NetworkIdentifier for backward compatibility * [Codebase cleanup] Network identifier Cleanup (#170) networkIdentifier constants cleanup * rename rpc_endpoint/indexer_endpoint to rpc_base_url/indexer_base_url in Docker entrypoint (#180) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * stopped getting blocks from indexer by ID * notes * Fix Pchain Block ID usage (#182) stopped getting blocks from indexer by ID * Drop proposer type (#183) dropped proposer type * nit * disable p-chain indexer related calls in offline mode (#189) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * no indexer call on genesis (#190) * fixed compilation post merge * fixed network name verification for offline mode * Get network name fix (#194) * reverted faulty change * refactored common methods in cchain and pchain clients * fixed GetNetworkName validation * some more validation fixes * Lazy inits (#195) * Lazily initialized networkID * lazily initialized genesis block * lazily initialized ChainIDs * dropped useless func * nit * appeased linter * Dropped most lazy inits in favour of Avalanchego codebase methods (#196) * drop unused GetNetworkName method from client * dropped GetNetworkID API calls in favour of avalanchego constants package * dropped genesis lazy initialization following GetNetworkID calls removal * appease linter * fix panic in offline mode * tech notes to ease up maintenance * add pending rewards balance support for p-chain (#200) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * add tx fee metadata to cross chain c-chain transaction parsing (#201) Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> * updated avalanchego to v1.9.10 * updated avalanchego version to 1.9.11 --------- Co-authored-by: bilgehansahin <bilgehansahin@gmail.com> Co-authored-by: Bilgehan Sahin <bilgehan.sahin@coinbase.com> Co-authored-by: Alberto Benegiamo <alberto.benegiamo@gmail.com>
ava-labs · Mar 8, 2023 · aa522c5 · aa522c5
1 parent d33c11b
commit aa522c5
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diff --git a/.gitignore b/.gitignore
@@ -21,4 +21,10 @@ rosetta-data
 *.swp
 data
 .vscode*
-__debug_bin*
+__debug_bin*
+
+# *.json is excluded above, make sure we include postman collection
+!postman/*.json
+
+# *.json is excluded above, make sure we include indexer testdata
+!service/backend/pchain/indexer/testdata/**
diff --git a/.golangci.yml b/.golangci.yml
@@ -8,6 +8,13 @@ run:
 issues:
   # Maximum count of issues with the same text. Set to 0 to disable. Default is 3.
   max-same-issues: 0
+  exclude:
+    - "G114: Use of net/http serve function that has no support for setting timeouts"
+  exclude-rules:
+    # ref: https://github.com/dominikh/go-tools/issues/1365
+    - path: client/pchainclient.go
+      linters:
+        - unused
 
 linters:
   # please, do not use `enable-all`: it's deprecated and will be removed soon.

diff --git a/Makefile b/Makefile
@@ -11,7 +11,7 @@ DOCKER_ORG          ?= avaplatform
 DOCKER_IMAGE        ?= ${DOCKER_ORG}/${PROJECT}
 DOCKER_LABEL        ?= latest
 DOCKER_TAG          ?= ${DOCKER_IMAGE}:${DOCKER_LABEL}
-AVALANCHE_VERSION   ?= v1.9.9
+AVALANCHE_VERSION   ?= v1.9.11
 
 build:
 	export CGO_CFLAGS="-O -D__BLST_PORTABLE__" && go build -o ./rosetta-server ./cmd/server
@@ -118,3 +118,6 @@ check-mainnet-construction:
 mocks:
 	rm -rf mocks;
 	mockery --dir client --all --case underscore --outpkg client --output mocks/client;
+	mockery --dir service --name '.*Backend' --case underscore --outpkg chain --output mocks/service;
+	mockery --dir service/backend --all --case underscore --outpkg chain --output mocks/service/backend;
+	mockery --dir service/backend/pchain/indexer --all --case underscore --outpkg chain --output mocks/service/backend/pchain/indexer;
diff --git a/README.md b/README.md
@@ -33,7 +33,7 @@ Before you start running the server you need to create a configuration file:
 
 ```json
 {
-  "rpc_endpoint": "https://api.avax-test.network",
+  "rpc_base_url": "https://api.avax-test.network",
   "mode": "online",
   "listen_addr": "0.0.0.0:8080",
   "genesis_block_hash" :"0x31ced5b9beb7f8782b014660da0cb18cc409f121f408186886e1ca3e8eeca96b",
@@ -45,14 +45,15 @@ Start the server by running the following command:
 ```bash
 ./rosetta-server -config=./config.json
 ```
+
 ## Configuration
 
 Full configuration example:
 
 ```json
 {
   "mode": "online",
-  "rpc_endpoint": "http://localhost:9650",
+  "rpc_base_url": "http://localhost:9650",
   "listen_addr": "0.0.0.0:8080",
   "network_name": "Fuji",
   "chain_id": 43113,
@@ -71,7 +72,7 @@ Where:
 | Name          | Type    | Default | Description
 |---------------|---------|---------|-------------------------------------------
 | mode          | string  | `online` | Mode of operations. One of: `online`, `offline`
-| rpc_endpoint  | string  | `http://localhost:9650` | Avalanche RPC endpoint
+| rpc_base_url  | string  | `http://localhost:9650` | Avalanche RPC base url
 | listen_addr   | string  | `http://localhost:8080` | Rosetta server listen address (host/port)
 | network_name  | string  | -       | Avalanche network name
 | chain_id      | integer | -       | Avalanche C-Chain ID
@@ -156,7 +157,7 @@ Run the construction check for ERC-20s:
 make check-testnet-construction-erc20
 ```
 
-## Rebuild the ContractInfoToken.go autogen file.
+## Rebuild the ContractInfoToken.go autogen file
 
 ```bash
 abigen --abi contractInfo.abi --pkg main --type ContractInfoToken --out client/contractInfoToken.go

diff --git a/client/client.go b/client/client.go
@@ -5,18 +5,23 @@ import (
 	"math/big"
 	"strings"
 
+	"github.com/ava-labs/avalanche-rosetta/constants"
+	"github.com/ava-labs/avalanchego/api"
 	"github.com/ava-labs/avalanchego/api/info"
-	"github.com/ava-labs/avalanchego/utils/rpc"
+	"github.com/ava-labs/avalanchego/ids"
 	ethtypes "github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/interfaces"
+	"github.com/ava-labs/coreth/plugin/evm"
 	ethcommon "github.com/ethereum/go-ethereum/common"
 )
 
 // Interface compliance
 var _ Client = &client{}
 
 type Client interface {
-	IsBootstrapped(context.Context, string, ...rpc.Option) (bool, error)
+	// info.Client methods
+	InfoClient
+
 	ChainID(context.Context) (*big.Int, error)
 	BlockByHash(context.Context, ethcommon.Hash) (*ethtypes.Block, error)
 	BlockByNumber(context.Context, *big.Int) (*ethtypes.Block, error)
@@ -32,14 +37,18 @@ type Client interface {
 	SuggestGasPrice(context.Context) (*big.Int, error)
 	EstimateGas(context.Context, interfaces.CallMsg) (uint64, error)
 	TxPoolContent(context.Context) (*TxPoolContent, error)
-	GetNetworkName(context.Context, ...rpc.Option) (string, error)
-	Peers(context.Context, ...rpc.Option) ([]info.Peer, error)
 	GetContractInfo(ethcommon.Address, bool) (string, uint8, error)
 	CallContract(context.Context, interfaces.CallMsg, *big.Int) ([]byte, error)
+	IssueTx(ctx context.Context, txBytes []byte) (ids.ID, error)
+	GetAtomicUTXOs(ctx context.Context, addrs []string, sourceChain string, limit uint32, startAddress, startUTXOID string) ([][]byte, api.Index, error)
+	EstimateBaseFee(ctx context.Context) (*big.Int, error)
 }
 
+type EvmClient evm.Client
+
 type client struct {
 	info.Client
+	EvmClient
 	*EthClient
 	*ContractClient
 }
@@ -53,8 +62,9 @@ func NewClient(ctx context.Context, endpoint string) (Client, error) {
 		return nil, err
 	}
 
-	return client{
+	return &client{
 		Client:         info.NewClient(endpoint),
+		EvmClient:      evm.NewClient(endpoint, constants.CChain.String()),
 		EthClient:      eth,
 		ContractClient: NewContractClient(eth.Client),
 	}, nil

diff --git a/client/contract.go b/client/contract.go
@@ -10,17 +10,17 @@ const (
 	contractCacheSize = 1024
 )
 
-type ContractInfo struct {
-	Symbol   string
-	Decimals uint8
-}
-
 // ContractClient is a client for the calling contract information
 type ContractClient struct {
 	ethClient ethclient.Client
 	cache     *cache.LRU[common.Address, *ContractInfo]
 }
 
+type ContractInfo struct {
+	Symbol   string
+	Decimals uint8
+}
+
 // NewContractClient returns a new ContractInfo client
 func NewContractClient(c ethclient.Client) *ContractClient {
 	return &ContractClient{
@@ -31,6 +31,8 @@ func NewContractClient(c ethclient.Client) *ContractClient {
 
 // GetContractInfo returns the symbol and decimals for [addr].
 func (c *ContractClient) GetContractInfo(addr common.Address, erc20 bool) (string, uint8, error) {
+	// We don't define another struct because this is never used outside of this
+	// function.
 	if currency, cached := c.cache.Get(addr); cached {
 		return currency.Symbol, currency.Decimals, nil
 	}

diff --git a/client/info_client.go b/client/info_client.go
@@ -0,0 +1,17 @@
+package client
+
+import (
+	"context"
+
+	"github.com/ava-labs/avalanchego/api/info"
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/utils/rpc"
+)
+
+// InfoClient collects all Avalanchego info.Client methods common
+// to Rosetta Clients
+type InfoClient interface {
+	GetBlockchainID(context.Context, string, ...rpc.Option) (ids.ID, error)
+	IsBootstrapped(context.Context, string, ...rpc.Option) (bool, error)
+	Peers(context.Context, ...rpc.Option) ([]info.Peer, error)
+}
diff --git a/client/pchainclient.go b/client/pchainclient.go
@@ -0,0 +1,96 @@
+package client
+
+import (
+	"context"
+	"strings"
+
+	"github.com/ava-labs/avalanchego/api"
+	"github.com/ava-labs/avalanchego/api/info"
+	"github.com/ava-labs/avalanchego/ids"
+	"github.com/ava-labs/avalanchego/indexer"
+	"github.com/ava-labs/avalanchego/utils/rpc"
+	"github.com/ava-labs/avalanchego/vms/avm"
+	"github.com/ava-labs/avalanchego/vms/platformvm"
+	"github.com/ava-labs/avalanchego/vms/platformvm/signer"
+
+	"github.com/ava-labs/avalanche-rosetta/constants"
+)
+
+// Interface compliance
+var _ PChainClient = &pchainClient{}
+
+// PChainClient contains all client methods used to interact with avalanchego in order to support P-chain operations in Rosetta.
+//
+// These methods are cloned from the underlying avalanchego client interfaces, following the example of Client interface used to support C-chain operations.
+type PChainClient interface {
+	// info.Client methods
+	InfoClient
+	GetNodeID(context.Context, ...rpc.Option) (ids.NodeID, *signer.ProofOfPossession, error)
+	GetTxFee(context.Context, ...rpc.Option) (*info.GetTxFeeResponse, error)
+
+	// indexer.Client methods
+	// Note: we use indexer only to be able to retrieve blocks by height.
+	// Blocks by ID are retrieved via platformVM.GetBlock, thus ignoring the proposerVM part
+	// and using Pchain Block ID rather than encompassing Snowman++ block ID
+	GetContainerByIndex(ctx context.Context, index uint64, options ...rpc.Option) (indexer.Container, error)
+	GetLastAccepted(context.Context, ...rpc.Option) (indexer.Container, uint64, error)
+
+	// platformvm.Client methods
+	GetUTXOs(
+		ctx context.Context,
+		addrs []ids.ShortID,
+		limit uint32,
+		startAddress ids.ShortID,
+		startUTXOID ids.ID,
+		options ...rpc.Option,
+	) ([][]byte, ids.ShortID, ids.ID, error)
+	GetAtomicUTXOs(
+		ctx context.Context,
+		addrs []ids.ShortID,
+		sourceChain string,
+		limit uint32,
+		startAddress ids.ShortID,
+		startUTXOID ids.ID,
+		options ...rpc.Option,
+	) ([][]byte, ids.ShortID, ids.ID, error)
+	GetRewardUTXOs(context.Context, *api.GetTxArgs, ...rpc.Option) ([][]byte, error)
+	GetHeight(ctx context.Context, options ...rpc.Option) (uint64, error)
+	GetBalance(ctx context.Context, addrs []ids.ShortID, options ...rpc.Option) (*platformvm.GetBalanceResponse, error)
+	GetTx(ctx context.Context, txID ids.ID, options ...rpc.Option) ([]byte, error)
+	GetBlock(ctx context.Context, blockID ids.ID, options ...rpc.Option) ([]byte, error)
+	IssueTx(ctx context.Context, tx []byte, options ...rpc.Option) (ids.ID, error)
+	GetStake(ctx context.Context, addrs []ids.ShortID, options ...rpc.Option) (map[ids.ID]uint64, [][]byte, error)
+	GetCurrentValidators(ctx context.Context, subnetID ids.ID, nodeIDs []ids.NodeID, options ...rpc.Option) ([]platformvm.ClientPermissionlessValidator, error)
+
+	// avm.Client methods
+	GetAssetDescription(ctx context.Context, assetID string, options ...rpc.Option) (*avm.GetAssetDescriptionReply, error)
+}
+
+type (
+	indexerClient    = indexer.Client
+	platformvmClient = platformvm.Client
+	infoClient       = info.Client
+)
+
+type pchainClient struct {
+	platformvmClient
+	indexerClient
+	infoClient
+	xChainClient avm.Client
+}
+
+// NewPChainClient returns a new client for Avalanche APIs related to P-chain
+func NewPChainClient(ctx context.Context, rpcBaseURL, indexerBaseURL string) PChainClient {
+	rpcBaseURL = strings.TrimSuffix(rpcBaseURL, "/")
+
+	return pchainClient{
+		platformvmClient: platformvm.NewClient(rpcBaseURL),
+		xChainClient:     avm.NewClient(rpcBaseURL, constants.XChain.String()),
+		infoClient:       info.NewClient(rpcBaseURL),
+		indexerClient:    indexer.NewClient(indexerBaseURL + "/ext/index/P/block"),
+	}
+}
+
+func (p pchainClient) GetAssetDescription(ctx context.Context, assetID string, options ...rpc.Option) (*avm.GetAssetDescriptionReply, error) {
+	return p.xChainClient.GetAssetDescription(ctx, assetID, options...)
+}
diff --git a/cmd/server/README.md b/cmd/server/README.md
@@ -0,0 +1,34 @@
+# Avalanche Rosetta: some technical notes
+
+Some notes to ease up maintenance handover
+
+## Emerging architecture
+
+Avalanche-Rosetta used to be centered around the C-chain. Support for P-Chain and X-chain (the latter to allow import/export tracking) has been added later on. To host these chains a structure is emerging:
+
+- Clients: client package collects all the calls to AvalancheGo node backing Rosetta server. Note that to support P-chain, the indexer must be supported by the AvalancheGo node backing Rosetta. The indexer is required to poll P-chain block by height (C-chain supports that natively, P-chain does not).  
+- Backends: backends of P-chain and X-chain pull information from client and implements the logic for the various services that Rosetta provides. C-chain has not (yet) a backend since its logic is still implemented at the service level. Creation of C-chain backend is left for a future refactoring.  
+- Services: the entry points for the API that Rosetta provides. Services route the  request to the right backend (P-chain,  X-chain or fallback to C-chain logic not yet repackaged into its backend). Moreover it returns the backend response to client.  
+
+## P-chain Block querying and Genesis special case
+
+P-chain blocks are queried as follows:  
+
+- by hash. In such case GetBlock API of platformVM is hit  
+- by height. In such case the indexer is used. Note that the indexer returns the whole proposerVM blocks. So block retrieved by proposerVM is further processed to extract the P-chain inner block and only the latter is returned.
+
+**P-chain Genesis Data must not be polled from APIs**.  The reasons are that:
+
+- `NetworkStatus` endpoint must return Genesis ID and Timestamp if AvalancheGo P-chain client has not complete bootstrapping yet  
+- If AvalancheGo P-chain node has not done bootstrapping, GetBlock endpoint cannot serve P-chain Genesis block.  
+
+Genesis Block information is parsed directly from AvalancheGo codebase rather than be called from GetBlock endpoint.  
+
+## Snowman++ handling
+
+Snowman++ headers (aka proposerVM header) are not returned to client. P-chain blocks are referenced by:
+
+- Their height  
+- Their BlockID (not the full proposerVM block ID)  
+
+ProposerVM headers are used only to retrieved timestamp for pre-Banff blocks. Note that indexer timestamp is never used as it cannot guarantee a deployment-independent information.