feat: gRPC mempool service (#275)

* make file nit

* base app set up

* make file update

* makefile nit

* adding service test to e2e

* lint

* type fix

* nit

* unit test + readme

tests/integration/block_sdk_suite.go

@@ -12,6 +12,8 @@ import (
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	stakingtypes "github.com/cosmos/cosmos-sdk/x/staking/types"
+	"github.com/skip-mev/block-sdk/lanes/base"
+	"github.com/skip-mev/block-sdk/lanes/free"
 	interchaintest "github.com/strangelove-ventures/interchaintest/v8"
 	"github.com/strangelove-ventures/interchaintest/v8/chain/cosmos"
 	"github.com/strangelove-ventures/interchaintest/v8/ibc"
@@ -121,6 +123,12 @@ func (s *IntegrationTestSuite) TestQueryParams() {
 	require.NoError(s.T(), params.Validate())
 }
 
+func (s *IntegrationTestSuite) TestMempoolService() {
+	resp, err := QueryMempool(s.T(), s.chain)
+	s.Require().NoError(err)
+	s.Require().Len(resp.Distribution, 3)
+}
+
 // TestValidBids tests the execution of various valid auction bids. There are a few
 // invariants that are tested:
 //
@@ -1298,6 +1306,10 @@ func (s *IntegrationTestSuite) TestNetwork() {
 						s.BroadcastTxs(context.Background(), s.chain.(*cosmos.CosmosChain), []Tx{normalTx})
 					}
 				}
+
+				resp, err := QueryMempool(s.T(), s.chain)
+				s.NoError(err)
+				s.Require().True(resp.Distribution[base.LaneName] > 0)
 			}
 		}
 	})
@@ -1322,6 +1334,10 @@ func (s *IntegrationTestSuite) TestNetwork() {
 						s.BroadcastTxs(context.Background(), s.chain.(*cosmos.CosmosChain), []Tx{freeTx})
 					}
 				}
+
+				resp, err := QueryMempool(s.T(), s.chain)
+				s.NoError(err)
+				s.Require().True(resp.Distribution[free.LaneName] > 0)
 			}
 		}
 	})

tests/integration/chain_setup.go

@@ -37,6 +37,7 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 
+	servicetypes "github.com/skip-mev/block-sdk/block/service/types"
 	auctiontypes "github.com/skip-mev/block-sdk/x/auction/types"
 )
 
@@ -367,6 +368,18 @@ func QueryValidators(t *testing.T, chain *cosmos.CosmosChain) []sdk.ValAddress {
 	return addrs
 }
 
+// QueryMempool queries the mempool of the given chain
+func QueryMempool(t *testing.T, chain ibc.Chain) (*servicetypes.GetTxDistributionResponse, error) {
+	// get grpc client of the node
+	grpcAddr := chain.GetHostGRPCAddress()
+	cc, err := grpc.Dial(grpcAddr, grpc.WithTransportCredentials(insecure.NewCredentials()))
+
+	require.NoError(t, err)
+
+	client := servicetypes.NewServiceClient(cc)
+	return client.GetTxDistribution(context.Background(), &servicetypes.GetTxDistributionRequest{})
+}
+
 // QueryAccountBalance queries a given account's balance on the chain
 func QueryAccountBalance(t *testing.T, chain ibc.Chain, address, denom string) int64 {
 	// cast the chain to a cosmos-chain