1 files changed, 95 insertions, 0 deletions
diff --git a/logging/logging.go b/logging/logging.go
new file mode 100644
index 0000000..59916b4
--- /dev/null
+++ b/logging/logging.go
@@ -0,0 +1,95 @@
+package logging
+
+import (
+	"context"
+	"sync"
+
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type contextKey = string
+
+const loggerKey = contextKey("logger")
+
+var (
+	defaultLogger     *zap.SugaredLogger
+	defaultLoggerOnce sync.Once
+)
+
+var conf = &Config{
+	Encoding:    "console",
+	Level:       zapcore.InfoLevel,
+	Development: true,
+}
+
+type Config struct {
+	Encoding    string
+	Level       zapcore.Level
+	Development bool
+}
+
+// SetConfig sets given logging configs for DefaultLogger's logger.
+// Must set configs before calling DefaultLogger()
+func SetConfig(c *Config) {
+	conf = &Config{
+		Encoding:    c.Encoding,
+		Level:       c.Level,
+		Development: c.Development,
+	}
+}
+
+func SetLevel(l zapcore.Level) {
+	conf.Level = l
+}
+
+// NewLogger creates a new logger with the given log level
+func NewLogger(conf *Config) *zap.SugaredLogger {
+	ec := zap.NewProductionEncoderConfig()
+	ec.EncodeTime = zapcore.ISO8601TimeEncoder
+	cfg := zap.Config{
+		Encoding:         conf.Encoding,
+		EncoderConfig:    ec,
+		Level:            zap.NewAtomicLevelAt(conf.Level),
+		Development:      conf.Development,
+		OutputPaths:      []string{"stdout"},
+		ErrorOutputPaths: []string{"stderr"},
+	}
+	logger, err := cfg.Build()
+	if err != nil {
+		logger = zap.NewNop()
+	}
+	return logger.Sugar()
+}
+
+// DefaultLogger returns the default logger for the package.
+func DefaultLogger() *zap.SugaredLogger {
+	defaultLoggerOnce.Do(func() {
+		defaultLogger = NewLogger(conf)
+	})
+	return defaultLogger
+}
+
+// WithLogger creates a new context with the provided logger attached.
+func WithLogger(ctx context.Context, logger *zap.SugaredLogger) context.Context {
+	if gCtx, ok := ctx.(*gin.Context); ok {
+		ctx = gCtx.Request.Context()
+	}
+	return context.WithValue(ctx, loggerKey, logger)
+}
+
+// FromContext returns the logger stored in the context. If no such logger
+// exists, a default logger is returned.
+func FromContext(ctx context.Context) *zap.SugaredLogger {
+	if ctx == nil {
+		return DefaultLogger()
+	}
+	if gCtx, ok := ctx.(*gin.Context); ok && gCtx != nil {
+		ctx = gCtx.Request.Context()
+	}
+	if logger, ok := ctx.Value(loggerKey).(*zap.SugaredLogger); ok {
+		return logger
+	}
+	return DefaultLogger()
+}