Initial plugin implementation

* refactor packages, flags, subscriptions
* DRY refactor builder tests
* use mockgen to generate mocks
* update README
* MODE=statediff no longer needed for unit tests
* simplify func names, clean up metrics
* move write params to service field
* sql indexer: confirm quit after ipld cache reset
  prevents negative waitgroup panic
* don't let TotalDifficulty become nil
* use forked plugeth, plugeth-utils for now

indexer/shared/db_kind.go

@@ -28,7 +28,7 @@ const (
 	POSTGRES DBType = "Postgres"
 	DUMP     DBType = "Dump"
 	FILE     DBType = "File"
-	UNKNOWN  DBType = "Unknown"
+	INVALID  DBType = "Invalid"
 )
 
 // ResolveDBType resolves a DBType from a provided string
@@ -41,6 +41,17 @@ func ResolveDBType(str string) (DBType, error) {
 	case "file", "f", "fs":
 		return FILE, nil
 	default:
-		return UNKNOWN, fmt.Errorf("unrecognized db type string: %s", str)
+		return INVALID, fmt.Errorf("unrecognized db type string: %s", str)
 	}
 }
+
+// Set satisfies flag.Value
+func (dbt *DBType) Set(v string) (err error) {
+	*dbt, err = ResolveDBType(v)
+	return
+}
+
+// String satisfies flag.Value
+func (dbt *DBType) String() string {
+	return strings.ToLower(string(*dbt))
+}

indexer/shared/functions.go

@@ -25,13 +25,13 @@ func HandleZeroAddrPointer(to *common.Address) string {
 	if to == nil {
 		return ""
 	}
-	return to.Hex()
+	return to.String()
 }
 
 // HandleZeroAddr will return an empty string for a 0 value address
 func HandleZeroAddr(to common.Address) string {
-	if to.Hex() == "0x0000000000000000000000000000000000000000" {
+	if to == (common.Address{}) {
 		return ""
 	}
-	return to.Hex()
+	return to.String()
 }

indexer/shared/schema/table_test.go

@@ -5,7 +5,7 @@ import (
 
 	"github.com/stretchr/testify/require"
 
-	. "github.com/ethereum/go-ethereum/statediff/indexer/shared/schema"
+	. "github.com/cerc-io/plugeth-statediff/indexer/shared/schema"
 )
 
 var testHeaderTable = Table{