Add support for logger and yml config

cmd/server/main.go

@@ -2,9 +2,12 @@ package main
 
 import (
 	"context"
+	"flag"
 	"fmt"
 	"net/http"
+	"os"
 
+	"git.faercol.me/monitoring/sys-exporter/config"
 	"git.faercol.me/monitoring/sys-exporter/registry"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 
@@ -15,6 +18,8 @@ import (
 	_ "git.faercol.me/monitoring/sys-exporter/collector/uptime"
 )
 
+var confFileLocation string
+
 // type gatherer struct {
 // 	reg *prometheus.Registry
 // }
@@ -24,10 +29,27 @@ import (
 // }
 
 func main() {
-	fmt.Println("starting server")
+	flag.Parse()
 
+	conf, err := config.New(confFileLocation)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to open configuration: %s\n", err)
+		os.Exit(1)
+	}
+
+	logger, err := conf.ZapConfig().Build()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to init logger: %s\n", err)
+		os.Exit(1)
+	}
+
+	logger.Info("Starting server")
 	registry.R.Run(context.Background())
 
 	http.Handle("/metrics", promhttp.HandlerFor(registry.R.PromRegistry(), promhttp.HandlerOpts{}))
 	http.ListenAndServe(":2112", nil)
 }
+
+func init() {
+	flag.StringVar(&confFileLocation, "config", config.DefaultConfigFileLocation, "Location of the config file")
+}

config/config.go

@@ -0,0 +1,82 @@
+package config
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/goccy/go-yaml"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+const DefaultConfigFileLocation = "/etc/sys-exporter/config.yml"
+
+type logConfigJson struct {
+	Level string `yaml:"level"`
+}
+
+func (c logConfigJson) logConfig() (LogConfig, error) {
+	lvl, err := zap.ParseAtomicLevel(c.Level)
+	if err != nil {
+		return LogConfig{}, err
+	}
+	return LogConfig{
+		Level: lvl,
+	}, nil
+}
+
+type appConfigJson struct {
+	LogConfig logConfigJson `yaml:"logging"`
+}
+
+func (c appConfigJson) appConfig() (AppConfig, error) {
+	lc, err := c.LogConfig.logConfig()
+	if err != nil {
+		return AppConfig{}, err
+	}
+
+	return AppConfig{
+		LogConfig: lc,
+	}, nil
+}
+
+type LogConfig struct {
+	Level zap.AtomicLevel `yaml:"level"`
+}
+
+func (c *LogConfig) ZapConfig() zap.Config {
+	fmt.Println(c.Level)
+	zapC := zap.Config{
+		Level:            c.Level,
+		Development:      true, // TODO: remove later
+		Encoding:         "console",
+		EncoderConfig:    zap.NewDevelopmentEncoderConfig(),
+		OutputPaths:      []string{"stdout"},
+		ErrorOutputPaths: []string{"stderr"},
+	}
+
+	zapC.EncoderConfig.EncodeLevel = zapcore.CapitalColorLevelEncoder
+
+	return zapC
+}
+
+type AppConfig struct {
+	LogConfig `yaml:"logging"`
+}
+
+func New(filepath string) (*AppConfig, error) {
+	fileContent, err := os.ReadFile(filepath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to open config file: %w", err)
+	}
+
+	var v appConfigJson
+	if err := yaml.Unmarshal(fileContent, &v); err != nil {
+		return nil, fmt.Errorf("failed to parse config file: %w", err)
+	}
+	trueConf, err := v.appConfig()
+	if err != nil {
+		return nil, fmt.Errorf("failed to validate config: %w", err)
+	}
+	return &trueConf, nil
+}

go.mod

@@ -2,7 +2,11 @@ module git.faercol.me/monitoring/sys-exporter
 
 go 1.23.3
 
-require github.com/prometheus/client_golang v1.20.5
+require (
+	github.com/goccy/go-yaml v1.15.6
+	github.com/prometheus/client_golang v1.20.5
+	go.uber.org/zap v1.27.0
+)
 
 require (
 	github.com/beorn7/perks v1.0.1 // indirect
@@ -12,6 +16,7 @@ require (
 	github.com/prometheus/client_model v0.6.1 // indirect
 	github.com/prometheus/common v0.55.0 // indirect
 	github.com/prometheus/procfs v0.15.1 // indirect
+	go.uber.org/multierr v1.10.0 // indirect
 	golang.org/x/sys v0.22.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 )

go.sum

@@ -2,6 +2,10 @@ github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
 github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
 github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/goccy/go-yaml v1.15.6 h1:gy5kf1yjMia3/c3wWD+u1z3lU5XlhpT8FZGaLJU9cOA=
+github.com/goccy/go-yaml v1.15.6/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/klauspost/compress v1.17.9 h1:6KIumPrER1LHsvBVuDa0r5xaG0Es51mhhB9BQB2qeMA=
@@ -10,6 +14,8 @@ github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq1c1nUAm88MOHcQC9l5mIlSMApZMrHA=
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v1.20.5 h1:cxppBPuYhUnsO6yo/aoRol4L7q7UFfdm+bR9r+8l63Y=
 github.com/prometheus/client_golang v1.20.5/go.mod h1:PIEt8X02hGcP8JWbeHyeZ53Y/jReSnHgO035n//V5WE=
 github.com/prometheus/client_model v0.6.1 h1:ZKSh/rekM+n3CeS952MLRAdFwIKqeY8b62p8ais2e9E=
@@ -18,7 +24,17 @@ github.com/prometheus/common v0.55.0 h1:KEi6DK7lXW/m7Ig5i47x0vRzuBsHuvJdi5ee6Y3G
 github.com/prometheus/common v0.55.0/go.mod h1:2SECS4xJG1kd8XF9IcM1gMX6510RAEL65zxzNImwdc8=
 github.com/prometheus/procfs v0.15.1 h1:YagwOFzUgYfKKHX6Dr+sHT7km/hxC76UB0learggepc=
 github.com/prometheus/procfs v0.15.1/go.mod h1:fB45yRUv8NstnjriLhBQLuOUt+WW4BsoGhij/e3PBqk=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
+go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
+go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
+go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
+go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
 golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=
 google.golang.org/protobuf v1.34.2/go.mod h1:qYOHts0dSfpeUzUFpOMr/WGzszTmLH+DiWniOlNbLDw=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=