Allow tuning the logging level (#55)

Author: vegarsti

README.md

@@ -27,7 +27,7 @@ Build the binary for your OS:
 ```bash
 $ make build
 
-$ BLOCKCHAIN_NAME='foo' RPC_NODE_URL='http://localhost:8545' DUNE_API_KEY='your-key-here' ./indexer
+$ BLOCKCHAIN_NAME='foo' RPC_NODE_URL='http://localhost:8545' DUNE_API_KEY='your-key-here' LOG=debug ./indexer
 ```
 
 Or run it directly with `go run`:
@@ -43,6 +43,9 @@ docker run duneanalytics/node-indexer --help
 
 Also, we mention some of the options here:
 
+### Log level
+Use `LOG=debug` (`--log`) to emit more logs than the default `info` level. To emit less logs, use `warn`, or `error` (least).
+
 ### Tuning RPC concurrency
 The flag `--rpc-concurrency` (environment variable `RPC_CONCURRENCY`) specifies the number of threads (goroutines)
 to run concurrently to perform RPC node requests. Default is 25.

cmd/main.go

@@ -31,7 +31,20 @@ func main() {
 	if err != nil {
 		stdlog.Fatal(err)
 	}
-	logger := slog.New(slog.NewTextHandler(os.Stderr, nil))
+	logOptions := &slog.HandlerOptions{}
+	switch cfg.LogLevel {
+	case "debug":
+		logOptions.Level = slog.LevelDebug
+	case "info":
+		logOptions.Level = slog.LevelInfo
+	case "warn":
+		logOptions.Level = slog.LevelWarn
+	case "error":
+		logOptions.Level = slog.LevelError
+	default:
+		stdlog.Fatalf("unsupported log level: '%s'", cfg.LogLevel)
+	}
+	logger := slog.New(slog.NewTextHandler(os.Stderr, logOptions))
 	slog.SetDefault(logger)
 
 	duneClient, err := duneapi.New(logger, duneapi.Config{

config/config.go

@@ -52,6 +52,7 @@ type Config struct {
 	RPCStack               models.EVMStack `long:"rpc-stack" env:"RPC_STACK" description:"Stack for the RPC client" default:"opstack"`                                                 // nolint:lll
 	RPCConcurrency         int             `long:"rpc-concurrency" env:"RPC_CONCURRENCY" description:"Number of concurrent requests to the RPC node" default:"25"`                     // nolint:lll
 	BlockSubmitInterval    time.Duration   `long:"block-submit-interval" env:"BLOCK_SUBMIT_INTERVAL" description:"Interval at which to submit batched blocks to Dune" default:"500ms"` // nolint:lll
+	LogLevel               string          `long:"log" env:"LOG" description:"Log level" choice:"info" choice:"debug" choice:"warn" choice:"error" default:"info"`                     // nolint:lll
 }
 
 func (c Config) HasError() error {