Merge pull request #19 from voi-go/add-metrics-to-logger

Add possibility for metrics from the zap logger
voi-oss · May 16, 2020 · 7811f59 · 7811f59
2 parents b2bb0bf + 3e46832
commit 7811f59
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Showing 3 changed files with 114 additions and 84 deletions.
diff --git a/logger.go b/logger.go
@@ -4,22 +4,132 @@ import (
 	"os"
 	"time"
 
+	"github.com/blendle/zapdriver"
+	"github.com/prometheus/client_golang/prometheus"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 )
 
-func newLogger(level zapcore.Level, encoder zapcore.Encoder) (*zap.Logger, zap.AtomicLevel) {
+func (s *SVC) newLogger(level zapcore.Level, encoder zapcore.Encoder) (*zap.Logger, zap.AtomicLevel) {
 	atom := zap.NewAtomicLevel()
 	atom.SetLevel(level)
 
+	zapOpts := append(s.zapOpts, zap.ErrorOutput(zapcore.Lock(os.Stderr)), zap.AddCaller())
+
 	logger := zap.New(zapcore.NewSampler(zapcore.NewCore(
 		encoder,
 		zapcore.Lock(os.Stdout),
 		atom,
 	), time.Second, 100, 10),
-		zap.ErrorOutput(zapcore.Lock(os.Stderr)),
-		zap.AddCaller(),
+		zapOpts...,
 	)
 
 	return logger, atom
 }
+
+// WithZapMetrics will add a hook to the zap logger and emit metrics to prometheus
+// based on log level and log name.
+func WithZapMetrics() Option {
+	return func(s *SVC) error {
+		requestCount := prometheus.NewCounterVec(
+			prometheus.CounterOpts{
+				Name: "logger_emitted_entries",
+				Help: "Number of log messages emitted.",
+			},
+			[]string{"level", "logger_name"},
+		)
+		if err := prometheus.Register(requestCount); err != nil {
+			return err
+		}
+
+		s.zapOpts = append(s.zapOpts,
+			zap.Hooks(func(e zapcore.Entry) error {
+				counter, err := requestCount.GetMetricWithLabelValues(e.Level.String(), e.LoggerName)
+				if err != nil {
+					return err
+				}
+				counter.Inc()
+				return nil
+			}))
+		return nil
+	}
+}
+
+// WithLogger is an option that allows you to provide your own customized logger.
+func WithLogger(logger *zap.Logger, atom zap.AtomicLevel) Option {
+	return func(s *SVC) error {
+		return assignLogger(s, logger, atom)
+	}
+}
+
+// WithDevelopmentLogger is an option that uses a zap Logger with
+// configurations set meant to be used for development.
+func WithDevelopmentLogger() Option {
+	return func(s *SVC) error {
+		logger, atom := s.newLogger(
+			zapcore.DebugLevel,
+			zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
+		)
+		logger = logger.With(zap.String("app", s.Name), zap.String("version", s.Version))
+		return assignLogger(s, logger, atom)
+	}
+}
+
+// WithProductionLogger is an option that uses a zap Logger with configurations
+// set meant to be used for production.
+func WithProductionLogger() Option {
+	return func(s *SVC) error {
+		logger, atom := s.newLogger(
+			zapcore.InfoLevel,
+			zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
+		)
+		logger = logger.With(zap.String("app", s.Name), zap.String("version", s.Version))
+		return assignLogger(s, logger, atom)
+	}
+}
+
+// WithConsoleLogger is an option that uses a zap Logger with configurations
+// set meant to be used for debugging in the console.
+func WithConsoleLogger(level zapcore.Level) Option {
+	return func(s *SVC) error {
+		config := zap.NewProductionEncoderConfig()
+		config.EncodeTime = zapcore.RFC3339TimeEncoder
+
+		logger, atom := s.newLogger(
+			level,
+			zapcore.NewConsoleEncoder(config),
+		)
+		return assignLogger(s, logger, atom)
+	}
+}
+
+// WithStackdriverLogger is an option that uses a zap Logger with configurations
+// set meant to be used for production and is compliant with the GCP/Stackdriver format.
+func WithStackdriverLogger(level zapcore.Level) Option {
+	return func(s *SVC) error {
+		logger, atom := s.newLogger(
+			level,
+			zapcore.NewJSONEncoder(zapdriver.NewProductionEncoderConfig()),
+		)
+		logger = logger.With(zapdriver.ServiceContext(s.Name), zapdriver.Label("version", s.Version))
+		return assignLogger(s, logger, atom)
+	}
+}
+
+func assignLogger(s *SVC, logger *zap.Logger, atom zap.AtomicLevel) error {
+	stdLogger, err := zap.NewStdLogAt(logger, zapcore.ErrorLevel)
+	if err != nil {
+		return err
+	}
+	undo, err := zap.RedirectStdLogAt(logger, zapcore.ErrorLevel)
+	if err != nil {
+		return err
+	}
+
+	s.logger = logger
+	s.stdLogger = stdLogger
+	s.atom = atom
+	s.loggerRedirectUndo = undo
+
+	return nil
+}
diff --git a/options.go b/options.go
@@ -7,11 +7,9 @@ import (
 	"net/http/pprof"
 	"time"
 
-	"github.com/blendle/zapdriver"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/zap"
-	"go.uber.org/zap/zapcore"
 )
 
 // Option defines SVC's option type.
@@ -44,85 +42,6 @@ func WithRouter(router *http.ServeMux) Option {
 	}
 }
 
-// WithLogger is an option that allows you to provide your own customized logger.
-func WithLogger(logger *zap.Logger, atom zap.AtomicLevel) Option {
-	return func(s *SVC) error {
-		return assignLogger(s, logger, atom)
-	}
-}
-
-// WithDevelopmentLogger is an option that uses a zap Logger with
-// configurations set meant to be used for development.
-func WithDevelopmentLogger() Option {
-	return func(s *SVC) error {
-		logger, atom := newLogger(
-			zapcore.DebugLevel,
-			zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
-		)
-		logger = logger.With(zap.String("app", s.Name), zap.String("version", s.Version))
-		return assignLogger(s, logger, atom)
-	}
-}
-
-// WithProductionLogger is an option that uses a zap Logger with configurations
-// set meant to be used for production.
-func WithProductionLogger() Option {
-	return func(s *SVC) error {
-		logger, atom := newLogger(
-			zapcore.InfoLevel,
-			zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig()),
-		)
-		logger = logger.With(zap.String("app", s.Name), zap.String("version", s.Version))
-		return assignLogger(s, logger, atom)
-	}
-}
-
-// WithConsoleLogger is an option that uses a zap Logger with configurations
-// set meant to be used for debugging in the console.
-func WithConsoleLogger(level zapcore.Level) Option {
-	return func(s *SVC) error {
-		config := zap.NewProductionEncoderConfig()
-		config.EncodeTime = zapcore.RFC3339TimeEncoder
-
-		logger, atom := newLogger(
-			level,
-			zapcore.NewConsoleEncoder(config),
-		)
-		return assignLogger(s, logger, atom)
-	}
-}
-
-// WithStackdriverLogger is an option that uses a zap Logger with configurations
-// set meant to be used for production and is compliant with the GCP/Stackdriver format.
-func WithStackdriverLogger(level zapcore.Level) Option {
-	return func(s *SVC) error {
-		logger, atom := newLogger(
-			level,
-			zapcore.NewJSONEncoder(zapdriver.NewProductionEncoderConfig()),
-		)
-		logger = logger.With(zapdriver.ServiceContext(s.Name), zapdriver.Label("version", s.Version))
-		return assignLogger(s, logger, atom)
-	}
-}
-
-func assignLogger(s *SVC, logger *zap.Logger, atom zap.AtomicLevel) error {
-	stdLogger, err := zap.NewStdLogAt(logger, zapcore.ErrorLevel)
-	if err != nil {
-		return err
-	}
-	undo, err := zap.RedirectStdLogAt(logger, zapcore.ErrorLevel)
-	if err != nil {
-		return err
-	}
-
-	s.logger = logger
-	s.stdLogger = stdLogger
-	s.atom = atom
-	s.loggerRedirectUndo = undo
-
-	return nil
-}
-
 // WithLogLevelHandlers is an option that sets up HTTP routes to read write the
 // log level.
 func WithLogLevelHandlers() Option {

diff --git a/svc.go b/svc.go
@@ -31,6 +31,7 @@ type SVC struct {
 	signals                chan os.Signal
 
 	logger             *zap.Logger
+	zapOpts            []zap.Option
 	stdLogger          *log.Logger
 	atom               zap.AtomicLevel
 	loggerRedirectUndo func()