Add filter option, update Readme

cmd/list.go

@@ -4,6 +4,7 @@ import (
 	"os"
 	"fmt"
 	"log"
+	"errors"
 	"reflect"
 	"strings"
 	"io/ioutil"
@@ -13,6 +14,46 @@ import (
 )
 
 
+// Recurse into structure, returning reflect.Value of wanted field.
+//  Nested fields are named with a dot (ex "MyStruct.MyField")
+func getStructFieldValue(parentStruct interface{}, fieldName string) (reflect.Value, string, error) {
+	v := reflect.ValueOf(parentStruct)
+
+	if v.Kind() == reflect.Ptr {
+		v = v.Elem()
+	}
+
+	if false {
+		for i := 0 ; i < v.NumField(); i++ {
+			f := v.Field(i)
+			if f.Kind() == reflect.String {
+				fmt.Printf("%v=%v\n", v.Type().Field(i).Name, f.Interface())
+			}
+		}
+	}
+
+	if strings.Contains(fieldName, ".") {
+		fs := strings.Split(fieldName, ".")
+		f := v.FieldByName(fs[0])
+		if f.Kind() == reflect.Struct {
+			return getStructFieldValue(f.Interface(), strings.Join(fs[1:], "."))
+		} else {
+			log.Fatalln(fmt.Sprintf("%s is not a struct: %s\n", fs[0], f.Kind().String()))
+		}
+	} else {
+		f := v.FieldByName(fieldName)
+		if f.IsValid() {
+			return f, fieldName, nil
+		} else {
+			return v, fieldName, errors.New(fmt.Sprintf("Field not found: %s", fieldName))
+		}
+	}
+
+	return v, fieldName, nil
+}
+
+
+// TODO : Replace by getStructFieldValue
 // Recurse into structure, returning reflect.Value of wanted field.
 //  Nested fields are named with a dot (ex "MyStruct.MyField")
 func getStructField(parentStruct interface{}, fieldName string) (reflect.Value, string) {
@@ -101,6 +142,11 @@ func displayStructFields(jails []Jail, valsToDisplay []string) {
 		out = append(out, line)
 	}
 
+	if len(out) == 0 {
+		fmt.Printf("Nothing to see here!\n")
+		return
+	}
+
 	// Get real maximum length
 	maxlen := make([]int, len(valsToDisplay))
 	for i := 0; i< len(valsToDisplay); i++ {
@@ -173,6 +219,7 @@ func displayStructFields(jails []Jail, valsToDisplay []string) {
 	// Then display data
 	//  Loop through lines
 	for _, l := range out {
+		
 		// Loop through fields
 		//  In case we need to add a line for a 2nd IP, or whatever object
 		var supplines = make(map[string]string)
@@ -251,29 +298,67 @@ func displayStructFields(jails []Jail, valsToDisplay []string) {
 
 /* Get Jails from datastores. Store config and running metadata into gJails global var */
 func ListJails(args []string, display bool) {
-	//fields := []string{"JID", "Name", "Config.Release", "Config.Ip4_addr", "RootPath", "Running", "Config.Jail_zfs", "Config.Jail_zfs_dataset", "Zpool"}
-	//fields := []string{"JID", "Name", "Config.Release", "Config.Ip4_addr", "Running", "Zpool"}
 	fields := strings.Split(gDisplayColumns, ",")
 
 	for _, d := range viper.GetStringSlice("datastore") {
 		listJailsFromDatastore(d)
 	}
 
-	if display {
-		if len(args) > 0 {
-			var js []Jail
-			for _, a := range args {
-				for _, j := range gJails {
-					if j.Name == a {
-						js = append(js, j)
-						break
+	// This is the structure we will filter, then display
+	var jails []Jail
+
+	/************************************************************************************
+	/   Filter jails with "filter" options
+	/***********************************************************************************/
+	if len(gFilterJails) > 0 && gFilterJails != "none" {
+		flts := make(map[string]string)
+		for _, flt := range strings.Split(gFilterJails, ",") {
+			sa := strings.Split(flt, "=")
+			if len(sa) != 2 {
+				fmt.Printf("Invalid format for filter %s\n", gFilterJails)
+				return
+			}
+			flts[sa[0]] = sa[1]
+		}
+
+		if len(flts) > 0 {
+			// Browse global gJails array to get filtered results
+			for _, j := range gJails {
+				for key, val := range flts {
+					v, _, err := getStructFieldValue(&j, key)
+					if err != nil {
+						fmt.Printf("ERROR: Field %s not found\n", key)
+						return
+					}
+					if strings.EqualFold(fmt.Sprintf("%v", v.Interface()), val) {
+						jails = append(jails, j)
 					}
 				}
 			}
-			displayStructFields(js, fields)
-		} else {
-			displayStructFields(gJails, fields)
 		}
+	} else {
+		jails = gJails
+	}
+
+
+	/************************************************************************************
+	/   Filter jails by names given on command line
+	/***********************************************************************************/
+	if len(args) > 0 {
+		var js []Jail
+		for _, a := range args {
+			for _, j := range jails {
+				if j.Name == a {
+					js = append(js, j)
+					break
+				}
+			}
+		}
+		jails = js
+	}
+
+	if display {
+		displayStructFields(jails, fields)
 	}
 }