cmd/geth: dump config for metrics (#22083)

* cmd/geth: dump config

* cmd/geth: dump config

* cmd/geth: properly read config again

* cmd/geth: override metrics if flags are set

* cmd/geth: write metrics regardless if enabled

* cmd/geth: renamed to metricsfromcliargs

* metrics: add default configuration

metrics/config.go

@@ -0,0 +1,45 @@
+// Copyright 2021 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package metrics
+
+// Config contains the configuration for the metric collection.
+type Config struct {
+	Enabled          bool   `toml:",omitempty"`
+	EnabledExpensive bool   `toml:",omitempty"`
+	HTTP             string `toml:",omitempty"`
+	Port             int    `toml:",omitempty"`
+	EnableInfluxDB   bool   `toml:",omitempty"`
+	InfluxDBEndpoint string `toml:",omitempty"`
+	InfluxDBDatabase string `toml:",omitempty"`
+	InfluxDBUsername string `toml:",omitempty"`
+	InfluxDBPassword string `toml:",omitempty"`
+	InfluxDBTags     string `toml:",omitempty"`
+}
+
+// DefaultConfig is the default config for metrics used in go-ethereum.
+var DefaultConfig = Config{
+	Enabled:          false,
+	EnabledExpensive: false,
+	HTTP:             "127.0.0.1",
+	Port:             6060,
+	EnableInfluxDB:   false,
+	InfluxDBEndpoint: "http://localhost:8086",
+	InfluxDBDatabase: "geth",
+	InfluxDBUsername: "test",
+	InfluxDBPassword: "test",
+	InfluxDBTags:     "host=localhost",
+}