imp: redirect go-ethereum's logs to cosmos logger (#948)

* redirect go-ethereum's logs to cosmos logger

Closes: #862

Map go-ethereum's log levels to cosmos ones:
trace -> debug
debug -> debug
info -> info
warn -> info
error -> error
crit -> error

* changelog

* Apply suggestions from code review

* Apply suggestions from code review

CHANGELOG.md

@@ -35,6 +35,12 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
+## Unreleased
+
+### Improvements
+
+- (log) [#948](https://github.com/tharsis/ethermint/pull/948) redirect go-ethereum's logs to cosmos-sdk logger.
+
 ## [v0.10.0-beta1] - 2022-02-15
 
 ### API Breaking

server/json_rpc.go

@@ -10,6 +10,7 @@ import (
 	"github.com/cosmos/cosmos-sdk/client"
 	"github.com/cosmos/cosmos-sdk/server"
 	"github.com/cosmos/cosmos-sdk/server/types"
+	ethlog "github.com/ethereum/go-ethereum/log"
 	ethrpc "github.com/ethereum/go-ethereum/rpc"
 	"github.com/tharsis/ethermint/rpc"
 
@@ -20,6 +21,19 @@ import (
 func StartJSONRPC(ctx *server.Context, clientCtx client.Context, tmRPCAddr, tmEndpoint string, config config.Config) (*http.Server, chan struct{}, error) {
 	tmWsClient := ConnectTmWS(tmRPCAddr, tmEndpoint, ctx.Logger)
 
+	logger := ctx.Logger.With("module", "geth")
+	ethlog.Root().SetHandler(ethlog.FuncHandler(func(r *ethlog.Record) error {
+		switch r.Lvl {
+		case ethlog.LvlTrace, ethlog.LvlDebug:
+			logger.Debug(r.Msg, r.Ctx...)
+		case ethlog.LvlInfo, ethlog.LvlWarn:
+			logger.Info(r.Msg, r.Ctx...)
+		case ethlog.LvlError, ethlog.LvlCrit:
+			logger.Error(r.Msg, r.Ctx...)
+		}
+		return nil
+	}))
+
 	rpcServer := ethrpc.NewServer()
 
 	rpcAPIArr := config.JSONRPC.API