feat: Add indexer.toml file

use os.ReadFile instead

refactor: Keep err in scope of Run()

refactor: Make test same scope as config package

refactor: Better names and better comments

Update indexer/cmd/indexer-refresh/main.go

indexer/cmd/indexer-refresh/main.go

@@ -9,6 +9,7 @@ import (
 	"github.com/urfave/cli"
 
 	"github.com/ethereum-optimism/optimism/indexer"
+	"github.com/ethereum-optimism/optimism/indexer/config"
 	"github.com/ethereum-optimism/optimism/indexer/flags"
 )
 
@@ -28,6 +29,16 @@ func main() {
 		),
 	)
 
+	// TODO https://linear.app/optimism/issue/DX-55/api-implement-rest-api-with-mocked-data
+	// don't hardcode this
+	conf, err := config.LoadConfig("../../indexer.toml")
+
+	if err != nil {
+		log.Crit("Failed to load config", "message", err)
+	}
+
+	log.Debug("Loaded config", "config", conf)
+
 	app := cli.NewApp()
 	app.Flags = flags.Flags
 	app.Version = fmt.Sprintf("%s-%s", GitVersion, params.VersionWithCommit(GitCommit, GitDate))
@@ -37,8 +48,7 @@ func main() {
 		"by account on L1 and L2"
 
 	app.Action = indexer.Main(GitVersion)
-	err := app.Run(os.Args)
-	if err != nil {
+	if err := app.Run(os.Args); err != nil {
 		log.Crit("Application failed", "message", err)
 	}
 }

indexer/config/config.go

+package config
+
+import (
+	"os"
+
+	"github.com/BurntSushi/toml"
+)
+
+// Config represents the `indexer.toml` file used to configure the indexer
+type Config struct {
+	Chain   ChainConfig
+	RPCs    RPCsConfig `toml:"rpcs"`
+	DB      DBConfig
+	API     APIConfig
+	Metrics MetricsConfig
+}
+
+// ChainConfig configures of the chain being indexed
+type ChainConfig struct {
+	// Configure known chains with the l2 chain id
+	Preset int
+}
+
+// RPCsConfig configures the RPC urls
+type RPCsConfig struct {
+	L1RPC string `toml:"l1-rpc"`
+	L2RPC string `toml:"l2-rpc"`
+}
+
+// DBConfig configures the postgres database
+type DBConfig struct {
+	Host     string
+	Port     int
+	User     string
+	Password string
+}
+
+// APIConfig configures the API server
+type APIConfig struct {
+	Host string
+	Port int
+}
+
+// MetricsConfig configures the metrics server
+type MetricsConfig struct {
+	Host string
+	Port int
+}
+
+// LoadConfig loads the `indexer.toml` config file from a given path
+func LoadConfig(path string) (Config, error) {
+	var conf Config
+
+	// Read the config file.
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return conf, err
+	}
+
+	// Replace environment variables.
+	data = []byte(os.ExpandEnv(string(data)))
+
+	// Decode the TOML data.
+	if _, err := toml.Decode(string(data), &conf); err != nil {
+		return conf, err
+	}
+
+	return conf, nil
+}

indexer/config/config_test.go

+package config
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestLoadConfig(t *testing.T) {
+	tmpfile, err := os.CreateTemp("", "test.toml")
+	require.NoError(t, err)
+	defer os.Remove(tmpfile.Name())
+	defer tmpfile.Close()
+
+	testData := `
+		[chain]
+		preset = 1234
+
+		[rpcs]
+		l1-rpc = "https://l1.example.com"
+		l2-rpc = "https://l2.example.com"
+
+		[db]
+		host = "127.0.0.1"
+		port = 5432
+		user = "postgres"
+		password = "postgres"
+
+		[api]
+		host = "127.0.0.1"
+		port = 8080
+
+		[metrics]
+		host = "127.0.0.1"
+		port = 7300
+	`
+
+	data := []byte(testData)
+	err = os.WriteFile(tmpfile.Name(), data, 0644)
+	require.NoError(t, err)
+	defer os.Remove(tmpfile.Name())
+
+	err = tmpfile.Close()
+	require.NoError(t, err)
+
+	conf, err := LoadConfig(tmpfile.Name())
+	require.NoError(t, err)
+
+	require.Equal(t, conf.Chain.Preset, 1234)
+	require.Equal(t, conf.RPCs.L1RPC, "https://l1.example.com")
+	require.Equal(t, conf.RPCs.L2RPC, "https://l2.example.com")
+	require.Equal(t, conf.DB.Host, "127.0.0.1")
+	require.Equal(t, conf.DB.Port, 5432)
+	require.Equal(t, conf.DB.User, "postgres")
+	require.Equal(t, conf.DB.Password, "postgres")
+	require.Equal(t, conf.API.Host, "127.0.0.1")
+	require.Equal(t, conf.API.Port, 8080)
+	require.Equal(t, conf.Metrics.Host, "127.0.0.1")
+	require.Equal(t, conf.Metrics.Port, 7300)
+}

indexer/go.mod

@@ -17,6 +17,7 @@ require (
 )
 
 require (
+	github.com/BurntSushi/toml v1.3.0 // indirect
 	github.com/DataDog/zstd v1.5.2 // indirect
 	github.com/VictoriaMetrics/fastcache v1.10.0 // indirect
 	github.com/benbjohnson/clock v1.3.0 // indirect

indexer/go.sum

@@ -28,6 +28,8 @@ git.apache.org/thrift.git v0.0.0-20180902110319-2566ecd5d999/go.mod h1:fPE2ZNJGy
 github.com/AndreasBriese/bbloom v0.0.0-20190306092124-e2d15f34fcf9/go.mod h1:bOvUY6CB00SOBii9/FifXqc0awNKxLFCL/+pkDPuyl8=
 github.com/AndreasBriese/bbloom v0.0.0-20190825152654-46b345b51c96 h1:cTp8I5+VIoKjsnZuH8vjyaysT/ses3EvZeaV/1UkF2M=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/BurntSushi/toml v1.3.0 h1:Ws8e5YmnrGEHzZEzg0YvK/7COGYtTC5PbaH9oSSbgfA=
+github.com/BurntSushi/toml v1.3.0/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/CloudyKit/fastprinter v0.0.0-20200109182630-33d98a066a53/go.mod h1:+3IMCy2vIlbG1XG/0ggNQv0SvxCAIpPM5b1nCz56Xno=
 github.com/CloudyKit/jet/v3 v3.0.0/go.mod h1:HKQPgSJmdK8hdoAbKUUWajkHyHo4RaU5rMdUywE7VMo=

indexer/indexer.toml

+[chain]
+preset = 420
+
+[rpcs]
+l1-rpc = "${INDEXER_RPC_URL_L1}"
+l2-rpc = "${INDEXER_RPC_URL_L2}"
+
+[db]
+host = "127.0.0.1"
+port = 5432
+user = "postgres"
+password = "postgres"
+
+[api]
+host = "127.0.0.1"
+port = 8080
+
+[metrics]
+host = "127.0.0.1"
+port = 7300
+