Config and logging

go.mod

@@ -4,11 +4,14 @@ go 1.23.4
 
 require (
 	github.com/caarlos0/env/v9 v9.0.0
+	github.com/rs/zerolog v1.33.0
 	golang.org/x/sys v0.28.0
 	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
 	github.com/kr/pretty v0.3.1 // indirect
+	github.com/mattn/go-colorable v0.1.13 // indirect
+	github.com/mattn/go-isatty v0.0.19 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )

go.sum

@@ -1,13 +1,27 @@
 github.com/caarlos0/env/v9 v9.0.0 h1:SI6JNsOA+y5gj9njpgybykATIylrRMklbs5ch6wO6pc=
 github.com/caarlos0/env/v9 v9.0.0/go.mod h1:ye5mlCVMYh6tZ+vCgrs/B95sj88cg5Tlnc0XIzgZ020=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
+github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
+github.com/mattn/go-isatty v0.0.16/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
+github.com/mattn/go-isatty v0.0.19 h1:JITubQf0MOLdlGRuRq+jtsDlekdYPia9ZFsB8h/APPA=
+github.com/mattn/go-isatty v0.0.19/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
 github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
+github.com/rs/xid v1.5.0/go.mod h1:trrq9SKmegXys3aeAKXMUTdJsYXVwGY3RLcfgqegfbg=
+github.com/rs/zerolog v1.33.0 h1:1cU2KZkvPxNyfgEmhHAz/1A9Bz+llsdYzklWFzgp0r8=
+github.com/rs/zerolog v1.33.0/go.mod h1:/7mN4D5sKwJLZQ2b/znpjC3/GQWY/xaDXUM0kKWRHss=
+golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
 golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

main.go

@@ -4,35 +4,44 @@
 // spans and metrics to an OTEL collector if configured
 // to do so. Will also stand up a prometheus metrics
 // endpoint.
+//
+// Configuration and logger stored in context
 package main
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"os/signal"
 
+	"github.com/rs/zerolog"
 	"golang.org/x/sys/unix"
 
 	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/config"
+	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/logging"
 )
 
 func main() {
 	ctx, cncl := signal.NotifyContext(context.Background(), os.Interrupt, unix.SIGTERM)
 	defer cncl()
 
-	conf, err := config.LoadConfig()
+	// Set up app config and logging
-	if err != nil {
+	ctx, err := config.LoadConfig(ctx)
-		panic(err)
-	}
-	ctx = conf.AddToCtx(ctx)
-
-	conf, err = config.FromCtx(ctx)
 	if err != nil {
 		panic(err)
 	}
 
-	fmt.Printf("%#v\n", conf)
+	cfg := config.MustFromCtx(ctx)
+	ctx = logging.MustInitLogging(ctx)
+
+	l := zerolog.Ctx(ctx)
+	l.Trace().Any("config", *cfg).Send()
+	l.Info().
+		Str("name", cfg.Name).
+		Str("version", cfg.Version).
+		Str("logLevel", cfg.Logging.Level).
+		Msg("app initialized")
+
+	<-ctx.Done()
 }
 
 func init() {}

pkg/config/config.go

@@ -1,52 +1,45 @@
 package config
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"os"
+	"runtime/debug"
 
 	"github.com/caarlos0/env/v9"
 	"gopkg.in/yaml.v3"
 )
 
-type AppConfig struct {
+// To be set by ldflags in go build command or
-	Name        string     `yaml:"name" env:"APP_NAME" envDefault:"go-http-server-with-otel"`
+// retrieved from build meta below
-	Environment string     `yaml:"environment" env:"APP_ENVIRONMENT" envDefault:"development"`
+var Version = "(devel)"
-	Version     string     `yaml:"version" env:"APP_VERSION"`
-	Logging     LogConfig  `yaml:"logging"`
-	HTTP        HTTPConfig `yaml:"http"`
-	OTEL        OTELConfig `yaml:"otel"`
-}
-
-type LogConfig struct {
-	Enabled bool   `yaml:"enabled" env:"APP_LOGGING_ENABLED" envDefault:"true"`
-	Level   string `yaml:"level" env:"APP_LOGGING_LEVEL" envDefault:"info"`
-	Format  string `yaml:"format" env:"APP_LOGGING_FORMAT" envDefault:"json"`
-}
-
-type HTTPConfig struct {
-	Listen         string `yaml:"listen" env:"APP_HTTP_LISTEN" envDefault:"127.0.0.1:8080"`
-	RequestTimeout int    `yaml:"request_timeout" env:"APP_HTTP_REQUEST_TIMEOUT" envDefault:"30"`
-}
-
-type OTELConfig struct {
-	Enabled           bool   `yaml:"enabled" env:"APP_OTEL_ENABLED" envDefault:"true"`
-	PrometheusEnabled bool   `yaml:"prometheus_enabled" env:"APP_OTEL_PROMETHEUS_ENABLED" envDefault:"true"`
-	PrometheusPath    string `yaml:"prometheus_path" env:"APP_OTEL_PROMETHEUS_PATH" envDefault:"/metrics"`
-}
 
 // Calling this will try to load from config if -config is
-// provided, otherwise will return *AppConfig with defaults,
+// provided as a file, and will apply any environment overrides
-// performing any environment substitutions
+// on-top of configuration defaults.
-func LoadConfig() (*AppConfig, error) {
+// Config is stored in returned context, and can be retrieved
+// using config.FromCtx(ctx)
+func LoadConfig(ctx context.Context) (context.Context, error) {
 	configPath := flag.String("config", "", "Path to the configuration file")
 	flag.Parse()
 
-	return loadConfig(*configPath)
+	// Start with defaults
+	// Load from config if provided
+	// Layer on environment
+	cfg, err := loadConfig(*configPath)
+	if err != nil {
+		return ctx, err
+	}
+
+	// Add config to context, and return
+	// an updated context
+	ctx = cfg.AddToCtx(ctx)
+	return ctx, nil
 }
 
 func loadConfig(configPath string) (*AppConfig, error) {
-	cfg := AppConfig{}
+	cfg := newAppConfig()
 
 	if configPath != "" {
 		file, err := os.Open(configPath)
@@ -56,14 +49,21 @@ func loadConfig(configPath string) (*AppConfig, error) {
 		defer file.Close()
 
 		decoder := yaml.NewDecoder(file)
-		if err := decoder.Decode(&cfg); err != nil {
+		if err := decoder.Decode(cfg); err != nil {
 			return nil, fmt.Errorf("could not decode config file: %w", err)
 		}
 	}
 
-	if err := env.Parse(&cfg); err != nil {
+	if err := env.Parse(cfg); err != nil {
 		return nil, fmt.Errorf("could not parse environment variables: %w", err)
 	}
 
-	return &cfg, nil
+	return cfg, nil
+}
+
+func getVersion() string {
+	if info, ok := debug.ReadBuildInfo(); ok && info.Main.Version != "(devel)" {
+		return info.Main.Version
+	}
+	return Version
 }

pkg/config/ctx.go

@@ -13,6 +13,14 @@ func (a *AppConfig) AddToCtx(ctx context.Context) context.Context {
 	return context.WithValue(ctx, appConfigCtxKey, a)
 }
 
+func MustFromCtx(ctx context.Context) *AppConfig {
+	cfg, err := FromCtx(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return cfg
+}
+
 func FromCtx(ctx context.Context) (*AppConfig, error) {
 	ctxData := ctx.Value(appConfigCtxKey)
 	if ctxData == nil {

pkg/config/types.go

@@ -0,0 +1,68 @@
+package config
+
+func newAppConfig() *AppConfig {
+	return &AppConfig{
+		Version: getVersion(),
+		Logging: &LogConfig{},
+		HTTP:    &HTTPConfig{},
+		OTEL:    &OTELConfig{},
+	}
+}
+
+type AppConfig struct {
+	Name        string `yaml:"name" env:"APP_NAME" envDefault:"go-http-server-with-otel"`
+	Environment string `yaml:"environment" env:"APP_ENVIRONMENT" envDefault:"development"`
+	// This should either be set by ldflags, such as with
+	// go build -ldflags "-X gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/config.Version=$(VERSION)"
+	// or allow this to use build meta. Will default to (devel)
+	Version string      `yaml:"version" env:"APP_VERSION"`
+	Logging *LogConfig  `yaml:"logging"`
+	HTTP    *HTTPConfig `yaml:"http"`
+	OTEL    *OTELConfig `yaml:"otel"`
+}
+
+// Logging Configuration
+type LogConfig struct {
+	Enabled    bool       `yaml:"enabled" env:"APP_LOG_ENABLED" envDefault:"true"`
+	Level      string     `yaml:"level" env:"APP_LOG_LEVEL" envDefault:"info"`
+	Format     LogFormat  `yaml:"format" env:"APP_LOG_FORMAT" envDefault:"json"`
+	Output     LogOutput  `yaml:"output" env:"APP_LOG_OUTPUT" envDefault:"stderr"`
+	TimeFormat TimeFormat `yaml:"timeFormat" env:"APP_LOG_TIME_FORMAT" envDefault:"short"`
+}
+
+type LogFormat string
+
+const (
+	LogFormatConsole LogFormat = "console"
+	LogFormatJSON    LogFormat = "json"
+)
+
+type TimeFormat string
+
+const (
+	TimeFormatShort   TimeFormat = "short"
+	TimeFormatLong    TimeFormat = "long"
+	TimeFormatUnix    TimeFormat = "unix"
+	TimeFormatRFC3339 TimeFormat = "rfc3339"
+	TimeFormatOff     TimeFormat = "off"
+)
+
+type LogOutput string
+
+const (
+	LogOutputStdout LogOutput = "stdout"
+	LogOutputStderr LogOutput = "stderr"
+)
+
+// HTTP Configuration
+type HTTPConfig struct {
+	Listen         string `yaml:"listen" env:"APP_HTTP_LISTEN" envDefault:"127.0.0.1:8080"`
+	RequestTimeout int    `yaml:"request_timeout" env:"APP_HTTP_REQUEST_TIMEOUT" envDefault:"30"`
+}
+
+// OTEL Configuration
+type OTELConfig struct {
+	Enabled           bool   `yaml:"enabled" env:"APP_OTEL_ENABLED" envDefault:"true"`
+	PrometheusEnabled bool   `yaml:"prometheus_enabled" env:"APP_OTEL_PROMETHEUS_ENABLED" envDefault:"true"`
+	PrometheusPath    string `yaml:"prometheus_path" env:"APP_OTEL_PROMETHEUS_PATH" envDefault:"/metrics"`
+}

pkg/logging/logging.go

@@ -1 +1,72 @@
 package logging
+
+import (
+	"context"
+	"os"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+
+	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/config"
+)
+
+func MustInitLogging(ctx context.Context) context.Context {
+	cfg := config.MustFromCtx(ctx)
+
+	logger, err := configureLogger(cfg.Logging)
+	if err != nil {
+		panic(err)
+	}
+
+	return logger.WithContext(ctx)
+}
+
+func configureLogger(cfg *config.LogConfig) (*zerolog.Logger, error) {
+	setTimeFormat(cfg.TimeFormat)
+
+	// Default JSON logger
+	logger := zerolog.New(os.Stderr)
+	if cfg.TimeFormat != config.TimeFormatOff {
+		logger = logger.With().Timestamp().Logger()
+	}
+
+	// Pretty console logger
+	if cfg.Format == config.LogFormatConsole {
+		consoleWriter := zerolog.ConsoleWriter{
+			Out:        os.Stderr,
+			TimeFormat: zerolog.TimeFieldFormat,
+		}
+		if cfg.TimeFormat == config.TimeFormatOff {
+			consoleWriter.FormatTimestamp = func(_ interface{}) string {
+				return ""
+			}
+		}
+		logger = log.Output(consoleWriter)
+	}
+
+	level, err := zerolog.ParseLevel(cfg.Level)
+	if err != nil {
+		level = zerolog.InfoLevel
+	}
+
+	logger = logger.Level(level)
+	zerolog.SetGlobalLevel(level)
+
+	return &logger, err
+}
+
+func setTimeFormat(format config.TimeFormat) {
+	switch format {
+	case config.TimeFormatShort:
+		zerolog.TimeFieldFormat = time.Kitchen
+	case config.TimeFormatUnix:
+		zerolog.TimeFieldFormat = zerolog.TimeFormatUnix
+	case config.TimeFormatLong:
+		zerolog.TimeFieldFormat = time.DateTime
+	case config.TimeFormatRFC3339:
+		zerolog.TimeFieldFormat = time.RFC3339
+	case config.TimeFormatOff:
+		zerolog.TimeFieldFormat = ""
+	}
+}