Update logger to facilitate the use of global logger (#150)

* Update logger to facilitate the use of global logger

* Fix demo-cli typo

* Fix linter errors

* Using global log at pkg metrics and runner

* Update CI for deprectaed steps

* Removing already fixed fixme comment

* Updated logger README.md using ia

* Fix logger README.md

.github/workflows/checks.golang.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           submodules: true
       - uses: actions/setup-go@v3

Makefile

@@ -47,6 +47,12 @@ check-modtidy:
 	go mod tidy
 	git diff --exit-code -- go.mod go.sum
 
+fmt:
+	gofmt -l -s -w .
+
+vet:
+	go vet ./...
+
 lint:
 	golangci-lint --version
 	golangci-lint run

cmd/demo-cli/main.go

@@ -13,6 +13,7 @@ func main() {
 		EnvPrefix:   "golem",
 		GitVersion:  version.GitVersion,
 		GitRevision: version.GitRevision,
+		LogLevel:    "debug",
 	}
 
 	// Define application level features

pkg/cli/config.go

@@ -1,7 +1,6 @@
 package cli
 
 import (
-	"context"
 	"fmt"
 	"github.com/zondax/golem/pkg/logger"
 	"strings"
@@ -15,7 +14,7 @@ func SetupConfiguration(c *cobra.Command) {
 	c.PersistentFlags().StringVarP(&configFileFlag, "config", "c", "", "The path to the config file to use.")
 	err := viper.BindPFlag("config", c.PersistentFlags().Lookup("config"))
 	if err != nil {
-		logger.GetLoggerFromContext(context.Background()).Fatalf("unable to bind config flag: %+v", err)
+		logger.Fatalf("unable to bind config flag: %+v", err)
 	}
 
 	viper.SetConfigName("config") // config file name without extension
@@ -50,12 +49,12 @@ func LoadConfig[T Config]() (*T, error) {
 	configFileOverride := viper.GetString("config")
 	if configFileOverride != "" {
 		viper.SetConfigFile(configFileOverride)
-		logger.GetLoggerFromContext(context.Background()).Infof("Using config file: %s", viper.ConfigFileUsed())
+		logger.Infof("Using config file: %s", viper.ConfigFileUsed())
 	}
 
 	err = viper.ReadInConfig()
 	if err != nil {
-		logger.GetLoggerFromContext(context.Background()).Fatalf("%+v", err)
+		logger.Fatalf("%+v", err)
 	}
 
 	// adds all default+configFile values in viper to struct

pkg/cli/handlers.go

@@ -1,11 +1,11 @@
 package cli
 
 import (
-	"context"
-	"github.com/zondax/golem/pkg/logger"
 	"os"
 	"os/signal"
 	"syscall"
+
+	"github.com/zondax/golem/pkg/logger"
 )
 
 var defaultConfigHandler DefaultConfigHandler
@@ -15,7 +15,7 @@ func setupCloseHandler(handler CleanUpHandler) {
 	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
 	go func() {
 		<-c
-		logger.GetLoggerFromContext(context.Background()).Warn("\r- Ctrl+C pressed in Terminal")
+		logger.Warn("\r- Ctrl+C pressed in Terminal")
 
 		if handler != nil {
 			handler()

pkg/cli/root.go

@@ -2,11 +2,11 @@ package cli
 
 import (
 	"fmt"
+	"os"
+
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
-	"github.com/zondax/golem/pkg/constants"
 	"github.com/zondax/golem/pkg/logger"
-	"os"
 )
 
 type AppSettings struct {
@@ -16,6 +16,7 @@ type AppSettings struct {
 	EnvPrefix   string // environment variable MYAPP_.....
 	GitVersion  string
 	GitRevision string
+	LogLevel    string // Global log level for the app
 }
 
 type CLI struct {
@@ -50,9 +51,9 @@ func (c *CLI) init() {
 		Run: func(cmd *cobra.Command, args []string) {
 			err := c.checkConfig()
 			if err != nil {
-				fmt.Printf("%s\n", c.checkConfig().Error())
+				logger.Errorf("%s\n", c.checkConfig().Error())
 			} else {
-				fmt.Printf("Configuration OK\n")
+				logger.Infof("Configuration OK\n")
 			}
 		},
 	}
@@ -61,15 +62,18 @@ func (c *CLI) init() {
 		Use:   "version",
 		Short: "Print version",
 		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Printf("%s\n", c.GetVersionString())
+			logger.Infof("%s\n", c.GetVersionString())
 		},
 	}
 
 	c.GetRoot().AddCommand(checkCmd)
 	c.GetRoot().AddCommand(versionCmd)
 
-	// TODO: We can make this optional? and more configurable if we see the need
-	logger.InitLogger(logger.Config{Level: constants.DebugLevel})
+	// If app log level is defined it is configued, logger.defaultConfig by default
+	if len(c.app.LogLevel) > 0 {
+		logger.InitLogger(logger.Config{Level: c.app.LogLevel})
+	}
+
 	setupCloseHandler(nil)
 	// Set Configuration Defaults
 	setupDefaultConfiguration(func() {
@@ -91,10 +95,7 @@ func (c *CLI) GetVersionString() string {
 
 func (c *CLI) Run() {
 	if err := c.rootCmd.Execute(); err != nil {
-		_, err := fmt.Fprintln(os.Stderr, err)
-		if err != nil {
-			return
-		}
+		logger.Error(err.Error())
 		_ = logger.Sync()
 		os.Exit(1)
 	}

pkg/logger/README.md

@@ -0,0 +1,162 @@
+# Logger Package
+
+A structured logging package built on top of [uber-go/zap](https://github.com/uber-go/zap), providing both global and context-aware logging capabilities with sensible defaults.
+
+## Features
+
+- Built on top of the high-performance zap logger
+- Supports both structured and printf-style logging
+- Context-aware logging
+- Global and instance-based logging
+- Configurable log levels and encoding formats
+- Request ID tracking support
+- Easy integration with existing applications
+
+## Installation
+
+```go
+go get -u github.com/zondax/golem/pkg/logger
+```
+
+## Quick Start
+
+```go
+// Initialize with default configuration
+logger.InitLogger(logger.Config{
+    Level:    "info",
+    Encoding: "json",
+})
+
+// Basic logging
+logger.Info("Server started")
+logger.Error("Connection failed")
+
+// Structured logging with fields
+log := logger.NewLogger(
+    logger.Field{Key: "service", Value: "api"},
+    logger.Field{Key: "version", Value: "1.0.0"},
+)
+log.Info("Service initialized")
+```
+
+## Configuration
+
+### Logger Config
+
+```go
+type Config struct {
+    Level    string `json:"level"`    // Logging level
+    Encoding string `json:"encoding"` // Output format
+}
+```
+
+### Log Levels
+
+Available log levels (in order of increasing severity):
+- `debug`: Detailed information for debugging
+- `info`: General operational information
+- `warn`: Warning messages for potentially harmful situations
+- `error`: Error conditions that should be addressed
+- `dpanic`: Critical errors in development that cause panic
+- `panic`: Critical errors that cause panic in production
+- `fatal`: Fatal errors that terminate the program
+
+### Encoding Formats
+
+1. **JSON Format** (Default)
+   - Recommended for production
+   - Machine-readable structured output
+   ```json
+   {"level":"INFO","ts":"2024-03-20T10:00:00.000Z","msg":"Server started","service":"api"}
+   ```
+
+2. **Console Format**
+   - Recommended for development
+   - Human-readable output
+   ```
+   2024-03-20T10:00:00.000Z INFO Server started service=api
+   ```
+
+## Advanced Usage
+
+### Context-Aware Logging
+
+```go
+// Create a context with logger
+ctx := context.Background()
+log := logger.NewLogger(logger.Field{
+    Key: logger.RequestIDKey,
+    Value: "req-123",
+})
+ctx = logger.ContextWithLogger(ctx, log)
+
+// Get logger from context
+contextLogger := logger.GetLoggerFromContext(ctx)
+contextLogger.Info("Processing request")
+```
+
+### Structured Logging with Fields
+
+```go
+log := logger.NewLogger()
+log.WithFields(
+    zap.String("user_id", "12345"),
+    zap.String("action", "login"),
+    zap.Int("attempt", 1),
+).Info("User login attempt")
+```
+
+### Printf-Style Logging
+
+```go
+logger.Infof("Processing item %d of %d", current, total)
+logger.Errorf("Failed to connect to %s: %v", host, err)
+```
+
+## Best Practices
+
+1. **Use Structured Logging**
+   ```go
+   // Good
+   log.WithFields(
+       zap.String("user_id", "12345"),
+       zap.String("action", "purchase"),
+       zap.Float64("amount", 99.99),
+   ).Info("Purchase completed")
+
+   // Avoid
+   log.Infof("User %s completed purchase of $%.2f", userID, amount)
+   ```
+
+2. **Include Request IDs**
+   ```go
+   log.WithFields(
+       zap.String(logger.RequestIDKey, requestID),
+   ).Info("Handling request")
+   ```
+
+3. **Proper Error Logging**
+   ```go
+   if err != nil {
+       log.WithFields(
+           zap.Error(err),
+           zap.String("operation", "database_query"),
+       ).Error("Query failed")
+   }
+   ```
+
+4. **Resource Cleanup**
+   ```go
+   defer logger.Sync()
+   ```
+
+## Performance Considerations
+
+- The logger is designed to be zero-allocation in most cases
+- JSON encoding is more CPU-intensive but provides structured data
+- Log level checks are performed atomically
+- Field allocation is optimized for minimal overhead
+
+## Thread Safety
+
+The logger is completely thread-safe and can be used concurrently from multiple goroutines.