Backport JSON InputSource to v1

README.md

@@ -701,9 +701,9 @@ the yaml input source for any flags that are defined on that command.  As a note
 the "load" flag used would also have to be defined on the command flags in order
 for this code snipped to work.
 
-Currently only the aboved specified formats are supported but developers can
-add support for other input sources by implementing the
-altsrc.InputSourceContext for their given sources.
+Currently only YAML and JSON files are supported but developers can add support
+for other input sources by implementing the altsrc.InputSourceContext for their
+given sources.
 
 Here is a more complete sample of a command using YAML support:
 

altsrc/json_command_test.go

@@ -0,0 +1,324 @@
+package altsrc
+
+import (
+	"flag"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"gopkg.in/urfave/cli.v1"
+)
+
+const (
+	fileName   = "current.json"
+	simpleJSON = `{"test": 15}`
+	nestedJSON = `{"top": {"test": 15}}`
+)
+
+func TestCommandJSONFileTest(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, simpleJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("test")
+			expect(t, val, 15)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "test"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestGlobalEnvVarWins(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, simpleJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	os.Setenv("THE_TEST", "10")
+	defer os.Setenv("THE_TEST", "")
+
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("test")
+			expect(t, val, 10)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "test", EnvVar: "THE_TEST"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestGlobalEnvVarWinsNested(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, nestedJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	os.Setenv("THE_TEST", "10")
+	defer os.Setenv("THE_TEST", "")
+
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("top.test")
+			expect(t, val, 10)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "top.test", EnvVar: "THE_TEST"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestSpecifiedFlagWins(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, simpleJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	test := []string{"test-cmd", "--load", fileName, "--test", "7"}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("test")
+			expect(t, val, 7)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "test"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestSpecifiedFlagWinsNested(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, nestedJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	test := []string{"test-cmd", "--load", fileName, "--top.test", "7"}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("top.test")
+			expect(t, val, 7)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "top.test"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestDefaultValueFileWins(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, simpleJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("test")
+			expect(t, val, 15)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "test", Value: 7}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileTestDefaultValueFileWinsNested(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, nestedJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("top.test")
+			expect(t, val, 15)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "top.test", Value: 7}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileFlagHasDefaultGlobalEnvJSONSetGlobalEnvWins(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, simpleJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	os.Setenv("THE_TEST", "11")
+	defer os.Setenv("THE_TEST", "")
+
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("test")
+			expect(t, val, 11)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "test", Value: 7, EnvVar: "THE_TEST"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func TestCommandJSONFileFlagHasDefaultGlobalEnvJSONSetGlobalEnvWinsNested(t *testing.T) {
+	cleanup := writeTempFile(t, fileName, nestedJSON)
+	defer cleanup()
+
+	app := cli.NewApp()
+	set := flag.NewFlagSet("test", 0)
+	os.Setenv("THE_TEST", "11")
+	defer os.Setenv("THE_TEST", "")
+
+	test := []string{"test-cmd", "--load", fileName}
+	set.Parse(test)
+
+	c := cli.NewContext(app, set, nil)
+
+	command := &cli.Command{
+		Name:        "test-cmd",
+		Aliases:     []string{"tc"},
+		Usage:       "this is for testing",
+		Description: "testing",
+		Action: func(c *cli.Context) error {
+			val := c.Int("top.test")
+			expect(t, val, 11)
+			return nil
+		},
+		Flags: []cli.Flag{
+			NewIntFlag(cli.IntFlag{Name: "top.test", Value: 7, EnvVar: "THE_TEST"}),
+			&cli.StringFlag{Name: "load"}},
+	}
+	command.Before = InitInputSourceWithContext(command.Flags, NewJSONSourceFromFlagFunc("load"))
+	err := command.Run(c)
+
+	expect(t, err, nil)
+}
+
+func writeTempFile(t *testing.T, name string, content string) func() {
+	if err := ioutil.WriteFile(name, []byte(content), 0666); err != nil {
+		t.Fatalf("cannot write %q: %v", name, err)
+	}
+	return func() {
+		if err := os.Remove(name); err != nil {
+			t.Errorf("cannot remove %q: %v", name, err)
+		}
+	}
+}