unified output (#14) (#40)

cmd/log.go

@@ -4,12 +4,21 @@
 
 package cmd
 
-import "fmt"
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/olekukonko/tablewriter"
+)
 
 var (
 	showLog bool
 )
 
+const outputUsage = "Specify output format - table (default), csv, simple, tsv or yaml."
+
 // Println println content according the flag
 func Println(a ...interface{}) {
 	if showLog {
@@ -33,3 +42,72 @@ func Error(a ...interface{}) {
 func Errorf(format string, a ...interface{}) {
 	fmt.Printf(format, a...)
 }
+
+// outputtable prints structured data as table
+func outputtable(headers []string, values [][]string) {
+	table := tablewriter.NewWriter(os.Stdout)
+	if len(headers) > 0 {
+		table.SetHeader(headers)
+	}
+	for _, value := range values {
+		table.Append(value)
+	}
+	table.Render()
+}
+
+// outputsimple prints structured data as space delimited value
+func outputsimple(headers []string, values [][]string) {
+	for _, value := range values {
+		fmt.Printf(strings.Join(value, " "))
+		fmt.Printf("\n")
+	}
+}
+
+// outputdsv prints structured data as delimiter separated value format
+func outputdsv(headers []string, values [][]string, delimiterOpt ...string) {
+	delimiter := ","
+	if len(delimiterOpt) > 0 {
+		delimiter = delimiterOpt[0]
+	}
+	fmt.Println("\"" + strings.Join(headers, "\""+delimiter+"\"") + "\"")
+	for _, value := range values {
+		fmt.Printf("\"")
+		fmt.Printf(strings.Join(value, "\""+delimiter+"\""))
+		fmt.Printf("\"")
+		fmt.Printf("\n")
+	}
+}
+
+// outputyaml prints structured data as yaml
+func outputyaml(headers []string, values [][]string) {
+	for _, value := range values {
+		fmt.Println("-")
+		for j, val := range value {
+			intVal, _ := strconv.Atoi(val)
+			if strconv.Itoa(intVal) == val {
+				fmt.Printf("    %s: %s\n", headers[j], val)
+			} else {
+				fmt.Printf("    %s: '%s'\n", headers[j], val)
+			}
+		}
+	}
+}
+
+// Output provides general function to convert given information
+// into several outputs
+func Output(output string, headers []string, values [][]string) {
+	switch {
+	case output == "" || output == "table":
+		outputtable(headers, values)
+	case output == "csv":
+		outputdsv(headers, values, ",")
+	case output == "simple":
+		outputsimple(headers, values)
+	case output == "tsv":
+		outputdsv(headers, values, "\t")
+	case output == "yaml":
+		outputyaml(headers, values)
+	default:
+		Errorf("unknown output type '" + output + "', available types are:\n- csv: comma-separated values\n- simple: space-separated values\n- table: auto-aligned table format (default)\n- tsv: tab-separated values\n- yaml: YAML format\n")
+	}
+}