config/source/cli: fix default flag value loading (micro#1178)

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/source/cli/cli.go

@@ -21,7 +21,9 @@ type cliSource struct {
 func (c *cliSource) Read() (*source.ChangeSet, error) {
 	var changes map[string]interface{}
 
-	for _, name := range c.ctx.FlagNames() {
+	// directly using app cli flags, to access default values of not specified options
+	for _, f := range c.ctx.App.Flags {
+		name := f.Names()[0]
 		tmp := toEntry(name, c.ctx.Generic(name))
 		mergo.Map(&changes, tmp) // need to sort error handling
 	}
@@ -100,13 +102,10 @@ func NewSource(opts ...source.Option) source.Source {
 
 	var ctx *cli.Context
 
-	c, ok := options.Context.Value(contextKey{}).(*cli.Context)
-	if ok {
+	if c, ok := options.Context.Value(contextKey{}).(*cli.Context); ok {
 		ctx = c
-	}
-
-	// no context
-	if ctx == nil {
+	} else {
+		// no context
 		// get the default app/flags
 		app := cmd.App()
 		flags := app.Flags

config/source/cli/cli_test.go

@@ -6,18 +6,64 @@ import (
 	"testing"
 
 	"github.com/micro/cli/v2"
+	"github.com/micro/go-micro/v2"
+	"github.com/micro/go-micro/v2/config"
 	"github.com/micro/go-micro/v2/config/cmd"
 	"github.com/micro/go-micro/v2/config/source"
 )
 
+func TestCliSourceDefault(t *testing.T) {
+	const expVal string = "flagvalue"
+
+	service := micro.NewService(
+		micro.Flags(
+			// to be able to run insude go test
+			&cli.StringFlag{
+				Name: "test.timeout",
+			},
+			&cli.BoolFlag{
+				Name: "test.v",
+			},
+			&cli.StringFlag{
+				Name: "test.run",
+			},
+			&cli.StringFlag{
+				Name:    "flag",
+				Usage:   "It changes something",
+				EnvVars: []string{"flag"},
+				Value:   expVal,
+			},
+		),
+	)
+	var cliSrc source.Source
+	service.Init(
+		// Loads CLI configuration
+		micro.Action(func(c *cli.Context) error {
+			cliSrc = NewSource(
+				Context(c),
+			)
+			return nil
+		}),
+	)
+
+	config.Load(cliSrc)
+	if fval := config.Get("flag").String("default"); fval != expVal {
+		t.Fatalf("default flag value not loaded %v != %v", fval, expVal)
+	}
+}
+
 func test(t *testing.T, withContext bool) {
 	var src source.Source
 
 	// setup app
 	app := cmd.App()
 	app.Name = "testapp"
 	app.Flags = []cli.Flag{
-		&cli.StringFlag{Name: "db-host"},
+		&cli.StringFlag{
+			Name:    "db-host",
+			EnvVars: []string{"db-host"},
+			Value:   "myval",
+		},
 	}
 
 	// with context