Godoc for indexer constructor

indexer/constructor.go

@@ -33,16 +33,19 @@ import (
 )
 
 // NewStateDiffIndexer creates and returns an implementation of the StateDiffIndexer interface.
+// The returned indexer is used to process state diffs and write them to a database.
+// The returned SQL database, if non-nil, is the indexer's backing database.
+// `ctx` is used to cancel an underlying DB connection.
 // `chainConfig` is used when processing chain state.
 // `nodeInfo` contains metadata on the Ethereum node, which is inserted with the indexed state.
 // `config` contains configuration specific to the indexer.
-// `diff` tells us to mark state nodes as belonging to an incremental diff, as opposed to a full snapshot.
+// `isDiff` means to mark state nodes as belonging to an incremental diff, as opposed to a full snapshot.
 func NewStateDiffIndexer(
 	ctx context.Context,
 	chainConfig *params.ChainConfig,
 	nodeInfo node.Info,
 	config interfaces.Config,
-	diff bool,
+	isDiff bool,
 ) (
 	sql.Database,
 	interfaces.StateDiffIndexer,
@@ -55,7 +58,7 @@ func NewStateDiffIndexer(
 		if !ok {
 			return nil, nil, fmt.Errorf("file config is not the correct type: got %T, expected %T", config, file.Config{})
 		}
-		ind, err := file.NewStateDiffIndexer(chainConfig, fc, nodeInfo, diff)
+		ind, err := file.NewStateDiffIndexer(chainConfig, fc, nodeInfo, isDiff)
 		return nil, ind, err
 	case shared.POSTGRES:
 		log.Info("Starting statediff service in Postgres writing mode")
@@ -80,7 +83,7 @@ func NewStateDiffIndexer(
 			return nil, nil, fmt.Errorf("unrecognized Postgres driver type: %s", pgc.Driver)
 		}
 		db := postgres.NewPostgresDB(driver, pgc.Upsert)
-		ind, err := sql.NewStateDiffIndexer(ctx, chainConfig, db, diff)
+		ind, err := sql.NewStateDiffIndexer(ctx, chainConfig, db, isDiff)
 		return db, ind, err
 	case shared.DUMP:
 		log.Info("Starting statediff service in data dump mode")

indexer/database/file/indexer.go

@@ -63,7 +63,11 @@ type StateDiffIndexer struct {
 }
 
 // NewStateDiffIndexer creates a void implementation of interfaces.StateDiffIndexer
-func NewStateDiffIndexer(chainConfig *params.ChainConfig, config Config, nodeInfo node.Info, diff bool) (*StateDiffIndexer, error) {
+// `chainConfig` is used when processing chain state.
+// `config` contains configuration specific to the indexer.
+// `nodeInfo` contains metadata on the Ethereum node, which is inserted with the indexed state.
+// `isDiff` means to mark state nodes as belonging to an incremental diff, as opposed to a full snapshot.
+func NewStateDiffIndexer(chainConfig *params.ChainConfig, config Config, nodeInfo node.Info, isDiff bool) (*StateDiffIndexer, error) {
 	var err error
 	var writer FileWriter
 
@@ -86,7 +90,7 @@ func NewStateDiffIndexer(chainConfig *params.ChainConfig, config Config, nodeInf
 		}
 		log.Info("Writing watched addresses to file", "file", watchedAddressesFilePath)
 
-		writer, err = NewCSVWriter(outputDir, watchedAddressesFilePath, diff)
+		writer, err = NewCSVWriter(outputDir, watchedAddressesFilePath, isDiff)
 		if err != nil {
 			return nil, err
 		}
@@ -109,7 +113,7 @@ func NewStateDiffIndexer(chainConfig *params.ChainConfig, config Config, nodeInf
 		}
 		log.Info("Writing watched addresses to file", "file", watchedAddressesFilePath)
 
-		writer = NewSQLWriter(file, watchedAddressesFilePath, diff)
+		writer = NewSQLWriter(file, watchedAddressesFilePath, isDiff)
 	default:
 		return nil, fmt.Errorf("unrecognized file mode: %s", config.Mode)
 	}

indexer/database/file/sql_writer.go

@@ -56,12 +56,15 @@ type SQLWriter struct {
 	watchedAddressesFilePath string
 }
 
-// NewSQLWriter creates a new pointer to a Writer
-func NewSQLWriter(wc io.WriteCloser, watchedAddressesFilePath string, diff bool) *SQLWriter {
+// NewSQLWriter creates a new Writer.
+// `wc` is the underlying io.WriteCloser to write to.
+// `watchedAddressesFilePath` is the path to the file containing watched addresses.
+// `isDiff` means to mark state nodes as belonging to an incremental diff, as opposed to a full snapshot.
+func NewSQLWriter(wc io.WriteCloser, watchedAddressesFilePath string, isDiff bool) *SQLWriter {
 	return &SQLWriter{
 		wc:                       wc,
 		stmts:                    make(chan []byte),
-		isDiff:                   diff,
+		isDiff:                   isDiff,
 		collatedStmt:             make([]byte, writeBufferSize),
 		flushChan:                make(chan struct{}),
 		flushFinished:            make(chan struct{}),

indexer/database/sql/indexer.go

@@ -51,13 +51,17 @@ type StateDiffIndexer struct {
 }
 
 // NewStateDiffIndexer creates a sql implementation of interfaces.StateDiffIndexer
+// `ctx` is used to cancel the underlying DB connection.
+// `chainConfig` is used when processing chain state.
+// `db` is the backing database to use.
+// `isDiff` means to mark state nodes as belonging to an incremental diff, as opposed to a full snapshot.
 func NewStateDiffIndexer(
-	ctx context.Context, chainConfig *params.ChainConfig, db Database, diff bool,
+	ctx context.Context, chainConfig *params.ChainConfig, db Database, isDiff bool,
 ) (*StateDiffIndexer, error) {
 	return &StateDiffIndexer{
 		ctx:         ctx,
 		chainConfig: chainConfig,
-		dbWriter:    NewWriter(db, diff),
+		dbWriter:    NewWriter(db, isDiff),
 	}, nil
 }