Improved logging and metrics. (#227)

1. Improve logging to include API method, user ID, etc in the output. We do this by intercepting the request details in the "middleware" and adding them to the request context, as well as adding a wrapper to logrus that simplifies including the fields in the output.

2. Breakdown API metrics by method. This will allow us to differentiate call counts and durations by API method (eg, eth_call vs eth_getStorageAt).

pkg/shared/functions.go

@@ -17,12 +17,12 @@
 package shared
 
 import (
+	"github.com/cerc-io/ipld-eth-server/v4/pkg/log"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ipfs/go-cid"
 	blockstore "github.com/ipfs/go-ipfs-blockstore"
 	dshelp "github.com/ipfs/go-ipfs-ds-help"
 	"github.com/jmoiron/sqlx"
-	"github.com/sirupsen/logrus"
 )
 
 // HandleZeroAddrPointer will return an emtpy string for a nil address pointer
@@ -44,7 +44,7 @@ func HandleZeroAddr(to common.Address) string {
 // Rollback sql transaction and log any error
 func Rollback(tx *sqlx.Tx) {
 	if err := tx.Rollback(); err != nil {
-		logrus.Error(err)
+		log.Error(err)
 	}
 }