feat(zap): silent zap logging (#308)

* feat(silent_zap): allow logging only if there is an error

* feat(silent_zap): lint fixes

* feat(silent_zap): rename silentlogger to silenzap, add custom logger functionality

---------

Co-authored-by: Ivan Maidurov <ivan.maidurov@omnevo.net>

app.go

@@ -13,6 +13,9 @@ import (
 	"time"
 
 	"flamingo.me/dingo"
+	"github.com/spf13/cobra"
+	"go.opencensus.io/plugin/ochttp"
+
 	"flamingo.me/flamingo/v3/core/runtime"
 	"flamingo.me/flamingo/v3/core/zap"
 	"flamingo.me/flamingo/v3/framework"
@@ -21,8 +24,6 @@ import (
 	"flamingo.me/flamingo/v3/framework/flamingo"
 	"flamingo.me/flamingo/v3/framework/opencensus"
 	"flamingo.me/flamingo/v3/framework/web"
-	"github.com/spf13/cobra"
-	"go.opencensus.io/plugin/ochttp"
 )
 
 type (
@@ -33,6 +34,7 @@ type (
 		area            *config.Area
 		args            []string
 		routesModules   []web.RoutesModule
+		loggerModule    dingo.Module
 		defaultContext  string
 		eagerSingletons bool
 		flagset         *flag.FlagSet
@@ -84,6 +86,13 @@ func WithRoutes(routesModule web.RoutesModule) ApplicationOption {
 	}
 }
 
+// WithCustomLogger allows to use custom logger modules for flamingo app, if nothing available default will be used
+func WithCustomLogger(logger dingo.Module) ApplicationOption {
+	return func(config *Application) {
+		config.loggerModule = logger
+	}
+}
+
 type eventRouterProvider func() flamingo.EventRouter
 
 type arrayFlags []string
@@ -103,6 +112,7 @@ func NewApplication(modules []dingo.Module, options ...ApplicationOption) (*Appl
 		configDir:      "config",
 		args:           os.Args[1:],
 		defaultContext: "root",
+		loggerModule:   new(zap.Module),
 	}
 
 	for _, option := range options {
@@ -128,7 +138,7 @@ func NewApplication(modules []dingo.Module, options ...ApplicationOption) (*Appl
 
 	modules = append([]dingo.Module{
 		new(framework.InitModule),
-		new(zap.Module),
+		app.loggerModule,
 		new(runtime.Module),
 		new(cmd.Module),
 	}, modules...)

core/silentzap/context.go

@@ -0,0 +1,66 @@
+package silentzap
+
+import (
+	"sync"
+
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+)
+
+type (
+	SilentContext struct {
+		mu            sync.RWMutex
+		storedEntries []storedEntry
+		willWrite     bool
+	}
+
+	storedEntry struct {
+		CheckedLogEntry *zapcore.CheckedEntry
+		Fields          []zap.Field
+	}
+)
+
+//nolint:unparam // taking zap into account we should have possibilities to store fields
+func (c *SilentContext) store(entry *zapcore.CheckedEntry, fields ...zap.Field) {
+	if c == nil {
+		return
+	}
+
+	go func() {
+		c.mu.Lock()
+		defer c.mu.Unlock()
+
+		c.storedEntries = append(
+			c.storedEntries,
+			storedEntry{
+				CheckedLogEntry: entry,
+				Fields:          fields,
+			},
+		)
+	}()
+}
+
+// get returns stored entries and allows direct writing
+func (c *SilentContext) get() []storedEntry {
+	if c == nil {
+		return nil
+	}
+
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	c.willWrite = true
+
+	return c.storedEntries
+}
+
+func (c *SilentContext) isWritingAllowed() bool {
+	if c == nil {
+		return true
+	}
+
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.willWrite
+}