CLI: Use colorized console output

This extracts some of the colored logging functionality into some
convenience functions to log directly to the console (stdout) w/o
the usual logging prefixes and flags.  It's intended for console
messages when using grafana commands.

pkg/log/console.go

@@ -6,6 +6,7 @@ package log
 
 import (
 	"encoding/json"
+	"fmt"
 	"log"
 	"os"
 	"runtime"
@@ -21,15 +22,26 @@ func NewBrush(color string) Brush {
 	}
 }
 
-var colors = []Brush{
-	NewBrush("1;36"), // Trace      cyan
-	NewBrush("1;34"), // Debug      blue
-	NewBrush("1;32"), // Info       green
-	NewBrush("1;33"), // Warn       yellow
-	NewBrush("1;31"), // Error      red
-	NewBrush("1;35"), // Critical   purple
-	NewBrush("1;31"), // Fatal      red
-}
+var (
+	Red    = NewBrush("1;31")
+	Purple = NewBrush("1;35")
+	Yellow = NewBrush("1;33")
+	Green  = NewBrush("1;32")
+	Blue   = NewBrush("1;34")
+	Cyan   = NewBrush("1;36")
+
+	colors = []Brush{
+		Cyan,   // Trace      cyan
+		Blue,   // Debug      blue
+		Green,  // Info       green
+		Yellow, // Warn       yellow
+		Red,    // Error      red
+		Purple, // Critical   purple
+		Red,    // Fatal      red
+	}
+	consoleWriter = &ConsoleWriter{lg: log.New(os.Stdout, "", 0),
+		Level: TRACE}
+)
 
 // ConsoleWriter implements LoggerInterface and writes messages to terminal.
 type ConsoleWriter struct {
@@ -68,6 +80,76 @@ func (_ *ConsoleWriter) Flush() {
 func (_ *ConsoleWriter) Destroy() {
 }
 
+func printConsole(level int, msg string) {
+	consoleWriter.WriteMsg(msg, 0, level)
+}
+
+func printfConsole(level int, format string, v ...interface{}) {
+	consoleWriter.WriteMsg(fmt.Sprintf(format, v...), 0, level)
+}
+
+// ConsoleTrace prints to stdout using TRACE colors
+func ConsoleTrace(s string) {
+	printConsole(TRACE, s)
+}
+
+// ConsoleTracef prints a formatted string to stdout using TRACE colors
+func ConsoleTracef(format string, v ...interface{}) {
+	printfConsole(TRACE, format, v...)
+}
+
+// ConsoleDebug prints to stdout using DEBUG colors
+func ConsoleDebug(s string) {
+	printConsole(DEBUG, s)
+}
+
+// ConsoleDebugf prints a formatted string to stdout using DEBUG colors
+func ConsoleDebugf(format string, v ...interface{}) {
+	printfConsole(DEBUG, format, v...)
+}
+
+// ConsoleInfo prints to stdout using INFO colors
+func ConsoleInfo(s string) {
+	printConsole(INFO, s)
+}
+
+// ConsoleInfof prints a formatted string to stdout using INFO colors
+func ConsoleInfof(format string, v ...interface{}) {
+	printfConsole(INFO, format, v...)
+}
+
+// ConsoleWarn prints to stdout using WARN colors
+func ConsoleWarn(s string) {
+	printConsole(WARN, s)
+}
+
+// ConsoleWarnf prints a formatted string to stdout using WARN colors
+func ConsoleWarnf(format string, v ...interface{}) {
+	printfConsole(WARN, format, v...)
+}
+
+// ConsoleError prints to stdout using ERROR colors
+func ConsoleError(s string) {
+	printConsole(ERROR, s)
+}
+
+// ConsoleErrorf prints a formatted string to stdout using ERROR colors
+func ConsoleErrorf(format string, v ...interface{}) {
+	printfConsole(ERROR, format, v...)
+}
+
+// ConsoleFatal prints to stdout using FATAL colors
+func ConsoleFatal(s string) {
+	printConsole(FATAL, s)
+	os.Exit(1)
+}
+
+// ConsoleFatalf prints a formatted string to stdout using FATAL colors
+func ConsoleFatalf(format string, v ...interface{}) {
+	printfConsole(FATAL, format, v...)
+	os.Exit(1)
+}
+
 func init() {
 	Register("console", NewConsole)
 }