Add log format flag and default to logfmt formatting for logs

This commit adds a new log format flag which can be used for setting the format
of the logs to either logfmt (default) or json. It also cleans up logger flags
and initalization logic a bit.

cmd/promscale/main.go

@@ -4,7 +4,6 @@
 package main
 
 import (
-	"flag"
 	"fmt"
 	"os"
 
@@ -14,15 +13,14 @@ import (
 )
 
 func main() {
-	logLevel := flag.String("log-level", "debug", "The log level to use [ \"error\", \"warn\", \"info\", \"debug\" ].")
 	cfg := &runner.Config{}
 	cfg, err := runner.ParseFlags(cfg)
 	if err != nil {
 		fmt.Println("Version: ", version.Version, "Commit Hash: ", version.CommitHash)
 		fmt.Println("Fatal error: cannot parse flags ", err)
 		os.Exit(1)
 	}
-	err = log.Init(*logLevel)
+	err = log.Init(cfg.LogCfg)
 	if err != nil {
 		fmt.Println("Version: ", version.Version, "Commit Hash: ", version.CommitHash)
 		fmt.Println("Fatal error: cannot start logger", err)

pkg/api/common_test.go

@@ -12,7 +12,9 @@ import (
 )
 
 func TestCORSWrapper(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 	acceptSpecific, _ := regexp.Compile("^(?:" + "http://some-site.com" + ")$")
 	acceptAny, _ := regexp.Compile("^(?:" + ".*" + ")$")
 

pkg/api/health_test.go

@@ -27,7 +27,9 @@ func (m *mockHealthChecker) HealthCheck() error {
 }
 
 func TestHealth(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 
 	testCases := []struct {
 		name                   string

pkg/api/labels_test.go

@@ -15,7 +15,9 @@ import (
 )
 
 func TestLabels(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 	testCases := []struct {
 		name        string
 		querier     *mockQuerier

pkg/api/query_range_test.go

@@ -18,7 +18,9 @@ import (
 )
 
 func TestRangedQuery(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 	testCases := []struct {
 		name        string
 		timeout     string

pkg/api/query_test.go

@@ -121,7 +121,9 @@ func TestParseDuration(t *testing.T) {
 }
 
 func TestQuery(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 	testCases := []struct {
 		name        string
 		timeout     string

pkg/api/series_test.go

@@ -15,7 +15,9 @@ import (
 )
 
 func TestSeries(t *testing.T) {
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 
 	testCases := []struct {
 		name        string

pkg/api/write_test.go

@@ -24,7 +24,9 @@ import (
 )
 
 func TestWrite(t *testing.T) {
-	testutil.Ok(t, log.Init("debug"))
+	testutil.Ok(t, log.Init(log.Config{
+		Level: "debug",
+	}))
 	testCases := []struct {
 		name             string
 		responseCode     int

pkg/log/log.go

@@ -6,6 +6,7 @@
 package log
 
 import (
+	"flag"
 	"fmt"
 	"os"
 	"time"
@@ -25,16 +26,39 @@ var (
 	)
 )
 
-// Init starts logging given the minimum log level
-func Init(logLevel string) error {
-	l := log.NewJSONLogger(log.NewSyncWriter(os.Stderr))
-	logLevelOption, err := parseLogLevel(logLevel)
+// Config represents a logger configuration used upon initialization.
+type Config struct {
+	Level  string
+	Format string
+}
+
+// ParseFlags parses the configuration flags for logging.
+func ParseFlags(cfg *Config) *Config {
+	flag.StringVar(&cfg.Level, "log-level", "debug", "The log level to use [ \"error\", \"warn\", \"info\", \"debug\" ].")
+	flag.StringVar(&cfg.Format, "log-format", "logfmt", "The log format to use [ \"logfmt\", \"json\" ].")
+	return cfg
+}
+
+// Init starts logging given the configuration. By default, it uses logfmt format
+// and minimum logging level.
+func Init(cfg Config) error {
+	var l log.Logger
+	switch cfg.Format {
+	case "logfmt", "":
+		l = log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
+	case "json":
+		l = log.NewJSONLogger(log.NewSyncWriter(os.Stderr))
+	default:
+		return fmt.Errorf("unrecognized log format %s", cfg.Format)
+	}
+
+	logLevelOption, err := parseLogLevel(cfg.Level)
 	if err != nil {
 		return err
 	}
 
 	l = level.NewFilter(l, logLevelOption)
-	logger = log.With(l, "ts", timestampFormat, "caller", log.Caller(4))
+	logger = log.With(l, "ts", timestampFormat, "caller", log.DefaultCaller)
 	return nil
 }
 

pkg/pgmodel/end_to_end_tests/main_test.go

@@ -41,7 +41,9 @@ func TestMain(m *testing.M) {
 	func() {
 		flag.Parse()
 		ctx := context.Background()
-		_ = log.Init("debug")
+		_ = log.Init(log.Config{
+			Level: "debug",
+		})
 		if !testing.Short() {
 			var err error
 

pkg/pgmodel/upgrade_tests/upgrade_test.go

@@ -51,7 +51,9 @@ func TestMain(m *testing.M) {
 		prevDBImage = "timescaledev/timescale_prometheus_extra:0.1.1-pg12"
 	}
 	flag.Parse()
-	_ = log.Init("debug")
+	_ = log.Init(log.Config{
+		Level: "debug",
+	})
 	code = m.Run()
 	os.Exit(code)
 }

pkg/runner/runner.go

@@ -33,6 +33,7 @@ type Config struct {
 	ListenAddr        string
 	TelemetryPath     string
 	PgmodelCfg        pgclient.Config
+	LogCfg            log.Config
 	HaGroupLockID     int64
 	RestElection      bool
 	PrometheusTimeout time.Duration
@@ -57,6 +58,7 @@ var (
 
 func ParseFlags(cfg *Config) (*Config, error) {
 	pgclient.ParseFlags(&cfg.PgmodelCfg)
+	log.ParseFlags(&cfg.LogCfg)
 
 	flag.StringVar(&cfg.ListenAddr, "web-listen-address", ":9201", "Address to listen on for web endpoints.")
 	flag.StringVar(&cfg.TelemetryPath, "web-telemetry-path", "/metrics", "Address to listen on for web endpoints.")

pkg/runner/runner_test.go

@@ -14,7 +14,9 @@ import (
 
 func TestMain(m *testing.M) {
 	flag.Parse()
-	err := log.Init("debug")
+	err := log.Init(log.Config{
+		Level: "debug",
+	})
 
 	if err != nil {
 		fmt.Println("Error initializing logger", err)

pkg/util/election_test.go

@@ -205,7 +205,9 @@ func TestPrometheusLivenessCheck(t *testing.T) {
 }
 func TestMain(m *testing.M) {
 	flag.Parse()
-	err := log.Init("debug")
+	err := log.Init(log.Config{
+		Level: "debug",
+	})
 	if err != nil {
 		panic(err)
 	}

pkg/util/util_test.go

@@ -17,7 +17,9 @@ const (
 )
 
 func init() {
-	err := log.Init("debug")
+	err := log.Init(log.Config{
+		Level: "debug",
+	})
 	if err != nil {
 		panic(err)
 	}