log

gogo/log

A golang package for formatted log messages that works across Linux and Windows supporting ANSI-colors.

gogo/log provides a consistent API for formatting Log Messages (stdout) in Golang Command Line Interface Projects.

Package Dependencies

• github.com/logrusorgru/aurora
• github.com/mattn/go-colorable
• github.com/mattn/go-isatty

Basic Usage

Here is a quick summary of basic usage

import "github.com/knowntraveler/gogo/log"

func main() {
    
    // Standard Log Messages
    log.Print("This is a standard log message")
    log.Printf("This is a standard log message with %s\n", "formatting")

    // Verbose Log Messages -> EnableVerbose()
    log.VPrint("This is a verbose log message")
    log.VPrintf("This is a verbose log message with %s\n", "formatting")

    // Debug Log Messages -> EnableDebug()
    log.Debug("This is a debug log message")
    log.Debug("This is a debug log message with %s\n", "formatting")

    // Trace Log Messages -> EnableTrace()
    log.Trace("This is a trace log message")
    log.Tracef("This is a trace log message with %s\n", "formatting")

    // Success Log Messages
    log.Success("This is a success log message")
    log.Successf("This is a success log message with %s\n", "formatting")

    // Warning Log Messages
    log.Warning("This is a warning log message")
    log.Warningf("This is a warning log message with %s\n", "formatting")

    // Failure Log Messages
    log.Failure("This is a failure log message")
    log.Failuref("This is a failure log message with %s\n", "formatting")

    // Error Log Messages
    log.Error("This is an error log message")
    log.Errorf("This is an errorlog message with %s\n", "formatting")

    // Panic Log Messages
    log.Panic("This is a panic log message")
    log.Panicf("This is a panic log message with %s\n", "formatting")

    // Fatal Log Messages
    log.Fatal("This is a fatal log message")
    log.Fatalf("This is a fatal log message with %s\n", "formatting")     
}

Practical Example

When developing Command Line Utilities (CLI) using Cobra/Viper you can do the following in root.go with package gogo/log

// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
    Use:   "myCommand",
    Short: "A brief description of your application",
    Long: `A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,

    PersistentPreRun: func(cmd *cobra.Command, args []string) {

        // Configure Verbose Logging Option from CLI
        if options.verbose {
            log.EnableVerbose()
        }

        // Configure Logging options from Environment
        logLevel := os.Getenv("MYCOMMAND_LOG_LEVEL")

        if logLevel == "verbose" {
            log.EnableVerbose()
        }

        if logLevel == "debug" {
            log.EnableVerbose()
            log.EnableDebug()
        }

        if logLevel == "trace" {
            log.EnableVerbose()
            log.EnableDebug()
            log.EnableTrace()
        }

    },
}

type rootFlags struct {
	verbose              bool
    nonInteractive       bool
    overrideConfirmation bool
}   

var options rootFlags

func init() {
    // Commands

    // PersistentFlags
    rootCmd.PersistentFlags().BoolVarP(&options.verbose, "verbose", "v", false, "Enable verbose output")
    rootCmd.PersistentFlags().BoolVar(&options.nonInteractive, "non-interactive", false, "Disable interactive prompts")
    rootCmd.PersistentFlags().BoolVarP(&options.overrideConfirmation, "yes", "y", false, "Override confirmations")
}

Running Unit Tests

go test -v
=== RUN   TestPrint
--- PASS: TestPrint (0.00s)
=== RUN   TestPrintf
--- PASS: TestPrintf (0.00s)
=== RUN   TestVPrint
--- PASS: TestVPrint (0.00s)
=== RUN   TestVPrintf
--- PASS: TestVPrintf (0.00s)
=== RUN   TestDebug
--- PASS: TestDebug (0.00s)
=== RUN   TestDebugf
--- PASS: TestDebugf (0.00s)
=== RUN   TestTrace
--- PASS: TestTrace (0.00s)
=== RUN   TestTracef
--- PASS: TestTracef (0.00s)
=== RUN   TestSuccess
--- PASS: TestSuccess (0.00s)
=== RUN   TestSuccessf
--- PASS: TestSuccessf (0.00s)
=== RUN   TestWarning
--- PASS: TestWarning (0.00s)
=== RUN   TestWarningf
--- PASS: TestWarningf (0.00s)
=== RUN   TestFailure
--- PASS: TestFailure (0.00s)
=== RUN   TestFailuref
--- PASS: TestFailuref (0.00s)
=== RUN   TestError
--- PASS: TestError (0.00s)
=== RUN   TestErrorf
--- PASS: TestErrorf (0.00s)
PASS
ok      github.com/knowntraveler/gogo/log       0.002s