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Add usage to readme (#5)
* add usage to `README.md` * add comprehensive usage
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‎README.md

+101-2
Original file line numberDiff line numberDiff line change
@@ -15,9 +15,108 @@ go get github.com/broothie/cli@latest
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## Documentation
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18-
https://pkg.go.dev/github.com/broothie/cli
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Detailed documentation can be found at [pkg.go.dev](https://pkg.go.dev/github.com/broothie/cli).
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## To Do
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## Usage
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Using `cli` is as simple as:
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```go
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// Create and run a command called "fileserver".
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// `Run` automatically passes down a `context.Background()` and parses `os.Args[1:]`.
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// If an error is returned, and it is either a `cli.ExitError` or an `*exec.ExitError`, the error's exit code will be used.
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// For any other errors returned, it exits with code 1.
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cli.Run("fileserver", "An HTTP server.",
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// Add an optional positional argument called "root" which will default to ".".
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cli.AddArg("root", "Directory to serve from", cli.SetArgDefault(".")),
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// Add an optional flag called "port" which will default to 3000.
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cli.AddFlag("port", "Port to run server.", cli.SetFlagDefault(3000)),
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// Register a handler for this command.
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// If no handler is registered, it will simply print help and exit.
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cli.SetHandler(func(ctx context.Context) error {
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// Extract the value of the "root" argument.
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root, _ := cli.ArgValue[string](ctx, "root")
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// Extract the value of the "port" flag.
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port, _ := cli.FlagValue[int](ctx, "port")
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addr := fmt.Sprintf(":%d", port)
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return http.ListenAndServe(addr, http.FileServer(http.Dir(root)))
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}),
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)
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```
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Here's an example using the complete set of options:
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```go
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cmd, err := cli.NewCommand("git", "Modern version control.",
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// Set command version
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cli.SetVersion("2.37.0"),
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// Add a "--version" flag with a short flag "-V" for printing the command version
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cli.AddVersionFlag(cli.AddFlagShort('V')),
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// Add a "--help" flag
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cli.AddHelpFlag(
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// Add a short flag "-h" to help
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cli.AddFlagShort('h'),
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// Make this flag inherited by sub-commands
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cli.SetFlagIsInherited(true),
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),
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// Add a hidden "--debug" flag
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cli.AddFlag("debug", "Enable debugging",
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cli.SetFlagDefault(false), // Default parser for flags is cli.StringParser
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// Make it hidden
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cli.SetFlagIsHidden(true),
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),
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// Add a sub-command "clone"
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cli.AddSubCmd("clone", "Clone a repository.",
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// Add a required argument "<url>"
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cli.AddArg("url", "Repository to clone.",
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// Parse it into a *url.URL
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cli.SetArgParser(cli.URLParser),
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),
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// Add optional argument "<dir?>"
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cli.AddArg("dir", "Directory to clone repo into.",
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// Set its default value to "."
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cli.SetArgDefault("."),
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),
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// Add a flag "--verbose"
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cli.AddFlag("verbose", "Be more verbose.",
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// Add a short "-v"
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cli.AddFlagShort('v'),
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// Make it a boolean that defaults to false
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cli.SetFlagDefault(false),
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),
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),
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)
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if err != nil {
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cli.ExitWithError(err)
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}
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// Pass in your `context.Context` and args
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if err := cmd.Run(context.TODO(), os.Args[1:]); err != nil {
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cli.ExitWithError(err)
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}
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```
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## Roadmap
21120

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- [ ] Audit bare `err` returns
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- [ ] Two types of errors: config and parse

‎command.go

+1-8
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,6 @@ import (
44
"context"
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"fmt"
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"os"
7-
"os/exec"
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"strings"
98

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"github.com/bobg/errors"
@@ -53,13 +52,7 @@ func Run(name, description string, options ...option.Option[*Command]) {
5352
}
5453

5554
if err := command.Run(context.Background(), os.Args[1:]); err != nil {
56-
fmt.Println(err)
57-
58-
if exitErr := new(exec.ExitError); errors.As(err, &exitErr) {
59-
os.Exit(exitErr.ExitCode())
60-
} else {
61-
os.Exit(1)
62-
}
55+
ExitWithError(err)
6356
}
6457
}
6558

‎command_test.go

+3-5
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,12 @@
11
package cli
22

3-
import (
4-
"os"
5-
)
3+
import "os"
64

75
func ExampleNewCommand() {
86
command, _ := NewCommand("server", "An http server.",
9-
AddHelpFlag(AddFlagShort('h')),
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SetVersion("v0.1.0"),
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AddVersionFlag(AddFlagShort('V')),
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AddHelpFlag(AddFlagShort('h')),
1210
AddFlag("port", "Port to run server on.",
1311
SetFlagDefault(3000),
1412
AddFlagShort('p'),
@@ -34,8 +32,8 @@ func ExampleNewCommand() {
3432
// proxy: Proxy requests to another server.
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//
3634
// Flags:
37-
// --help -h Print help. (type: bool, default: "false")
3835
// --version -V Print version. (type: bool, default: "false")
36+
// --help -h Print help. (type: bool, default: "false")
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// --port -p Port to run server on. (type: int, default: "3000")
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// --auth-required Whether to require authentication. (type: bool, default: "true")
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}

‎error.go

+33
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,33 @@
1+
package cli
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3+
import (
4+
"fmt"
5+
"os"
6+
"os/exec"
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8+
"github.com/bobg/errors"
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)
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type ExitError struct {
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Code int
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}
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func (e ExitError) Error() string {
16+
return fmt.Sprintf("exit status %d", e.Code)
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}
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func ExitCode(code int) ExitError {
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return ExitError{Code: code}
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}
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func ExitWithError(err error) {
24+
fmt.Println(err)
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26+
if exitErr := new(ExitError); errors.As(err, &exitErr) {
27+
os.Exit(exitErr.Code)
28+
} else if exitErr := new(exec.ExitError); errors.As(err, &exitErr) {
29+
os.Exit(exitErr.ExitCode())
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} else {
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os.Exit(1)
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}
33+
}

‎examples_test.go

+103
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,103 @@
1+
package cli_test
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3+
import (
4+
"context"
5+
"fmt"
6+
"net/http"
7+
"os"
8+
9+
"github.com/broothie/cli"
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)
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func Example_basic_usage() {
13+
// Create and run a command called "fileserver".
14+
// `Run` automatically passes down a `context.Background()` and parses `os.Args[1:]`.
15+
// If an error is returned, and it is either a `cli.ExitError` or an `*exec.ExitError`, the error's exit code will be used.
16+
// For any other errors returned, it exits with code 1.
17+
cli.Run("fileserver", "An HTTP server.",
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19+
// Add an optional positional argument called "root" which will default to ".".
20+
cli.AddArg("root", "Directory to serve from", cli.SetArgDefault(".")),
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22+
// Add an optional flag called "port" (usage: --port) which will default to 3000.
23+
cli.AddFlag("port", "Port to run server.", cli.SetFlagDefault(3000)),
24+
25+
// Register a handler for this command.
26+
// If no handler is registered, it will simply print help and exit.
27+
cli.SetHandler(func(ctx context.Context) error {
28+
// Extract the value of the "root" argument.
29+
root, _ := cli.ArgValue[string](ctx, "root")
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// Extract the value of the "port" flag.
32+
port, _ := cli.FlagValue[int](ctx, "port")
33+
34+
addr := fmt.Sprintf(":%d", port)
35+
return http.ListenAndServe(addr, http.FileServer(http.Dir(root)))
36+
}),
37+
)
38+
}
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func Example_kitchen_sink() {
41+
// Create a new command
42+
cmd, err := cli.NewCommand("git", "Modern version control.",
43+
// Set command version
44+
cli.SetVersion("2.37.0"),
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// Add a "--version" flag with a short flag "-V" for printing the command version
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cli.AddVersionFlag(cli.AddFlagShort('V')),
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// Add a "--help" flag
50+
cli.AddHelpFlag(
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52+
// Add a short flag "-h" to help
53+
cli.AddFlagShort('h'),
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// Make this flag inherited by sub-commands
56+
cli.SetFlagIsInherited(true),
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),
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// Add a hidden "--debug" flag
60+
cli.AddFlag("debug", "Enable debugging",
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cli.SetFlagDefault(false), // Default parser for flags is cli.StringParser
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// Make it hidden
64+
cli.SetFlagIsHidden(true),
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),
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// Add a sub-command "clone"
68+
cli.AddSubCmd("clone", "Clone a repository.",
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70+
// Add a required argument "<url>"
71+
cli.AddArg("url", "Repository to clone.",
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73+
// Parse it into a *url.URL
74+
cli.SetArgParser(cli.URLParser),
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),
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// Add optional argument "<dir?>"
78+
cli.AddArg("dir", "Directory to clone repo into.",
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80+
// Set its default value to "."
81+
cli.SetArgDefault("."),
82+
),
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84+
// Add a flag "--verbose"
85+
cli.AddFlag("verbose", "Be more verbose.",
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87+
// Add a short "-v"
88+
cli.AddFlagShort('v'),
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90+
// Make it a boolean that defaults to false
91+
cli.SetFlagDefault(false),
92+
),
93+
),
94+
)
95+
if err != nil {
96+
cli.ExitWithError(err)
97+
}
98+
99+
// Pass in your `context.Context` and args
100+
if err := cmd.Run(context.TODO(), os.Args[1:]); err != nil {
101+
cli.ExitWithError(err)
102+
}
103+
}

‎help.go

+6-1
Original file line numberDiff line numberDiff line change
@@ -77,11 +77,16 @@ func (h helpContext) ArgumentList() string {
7777

7878
func (h helpContext) ArgumentTable() (string, error) {
7979
return tableToString(lo.Map(h.Arguments(), func(argument *Argument, _ int) []string {
80+
valueInfo := fmt.Sprintf("(type: %T)", argument.parser.Type())
81+
if argument.isOptional() {
82+
valueInfo = fmt.Sprintf("(type: %T, default: %q)", argument.parser.Type(), fmt.Sprint(argument.defaultValue))
83+
}
84+
8085
return []string{
8186
"",
8287
argument.inBrackets(),
8388
argument.description,
84-
fmt.Sprintf("(type: %T)", argument.parser.Type()),
89+
valueInfo,
8590
}
8691
}))
8792
}

‎help_test.go

+6-2
Original file line numberDiff line numberDiff line change
@@ -29,6 +29,9 @@ func TestCommand_renderHelp(t *testing.T) {
2929
SetFlagDefaultAndParser(CustomType{Field: "field default"}, func(s string) (CustomType, error) { return CustomType{Field: s}, nil }),
3030
),
3131
AddFlag("hidden-flag", "some hidden flag", SetFlagIsHidden(true)),
32+
AddArg("another-arg", "another arg",
33+
SetArgDefault(123),
34+
),
3235
AddArg("some-arg", "some arg",
3336
SetArgParser(TimeLayoutParser(time.RubyDate)),
3437
),
@@ -44,10 +47,11 @@ func TestCommand_renderHelp(t *testing.T) {
4447
test v1.2.3-rc10: test command
4548
4649
Usage:
47-
test [flags] <some-arg>
50+
test [flags] <some-arg> <another-arg?>
4851
4952
Arguments:
50-
<some-arg> some arg (type: time.Time)
53+
<some-arg> some arg (type: time.Time)
54+
<another-arg?> another arg (type: int, default: "123")
5155
5256
Flags:
5357
--help Print help. (type: bool, default: "false")

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