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go-arg
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Merge pull request #258 from hhromic/implement-204 

Add support for setting a global env var prefix
This commit is contained in:
Alex Flint 2024-11-04 12:58:37 -05:00 committed by GitHub
parent efb1be7122 cb7e5c1905
commit 438bbfff1e
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GPG Key ID: B5690EEEBB952194
3 changed files with 78 additions and 37 deletions
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50
README.md
View File

@ -64,7 +64,7 @@ fmt.Println("Input:", args.Input)
fmt.Println("Output:", args.Output)
```
```
```shell
$ ./example src.txt x.out y.out z.out
Input: src.txt
Output: [x.out y.out z.out]
@ -80,12 +80,12 @@ arg.MustParse(&args)
fmt.Println("Workers:", args.Workers)
```
```
```shell
$ WORKERS=4 ./example
Workers: 4
```
```
```shell
$ WORKERS=4 ./example --workers=6
Workers: 6
```
@ -100,7 +100,7 @@ arg.MustParse(&args)
fmt.Println("Workers:", args.Workers)
```
```
```shell
$ NUM_WORKERS=4 ./example
Workers: 4
```
@ -115,7 +115,7 @@ arg.MustParse(&args)
fmt.Println("Workers:", args.Workers)
```
```
```shell
$ WORKERS='1,99' ./example
Workers: [1 99]
```
@ -130,14 +130,35 @@ arg.MustParse(&args)
fmt.Println("Workers:", args.Workers)
```
```
```shell
$ NUM_WORKERS=6 ./example
Workers: 6
$ NUM_WORKERS=6 ./example --count 4
Workers: 4
```
Configuring a global environment variable name prefix is also possible:
```go
var args struct {
Workers int `arg:"--count,env:NUM_WORKERS"`
}
p, err := arg.NewParser(arg.Config{
EnvPrefix: "MYAPP_",
}, &args)
p.MustParse(os.Args[1:])
fmt.Println("Workers:", args.Workers)
```
```shell
$ MYAPP_NUM_WORKERS=6 ./example
Workers: 6
```
### Usage strings
```go
var args struct {
Input string `arg:"positional"`
@ -185,6 +206,7 @@ arg.MustParse(&args)
```
#### Ignoring environment variables and/or default values
```go
var args struct {
Test string `arg:"-t,env:TEST" default:"something"`
@ -195,10 +217,11 @@ p, err := arg.NewParser(arg.Config{
IgnoreDefault: true,
}, &args)
err = p.Parse(os.Args)
err = p.Parse(os.Args[1:])
```
### Arguments with multiple values
```go
var args struct {
Database string
@ -214,6 +237,7 @@ Fetching the following IDs from foo: [1 2 3]
```
### Arguments that can be specified multiple times, mixed with positionals
```go
var args struct {
Commands []string `arg:"-c,separate"`
@ -231,6 +255,7 @@ Databases [db1 db2 db3]
```
### Arguments with keys and values
```go
var args struct {
UserIDs map[string]int
@ -245,6 +270,7 @@ map[john:123 mary:456]
```
### Version strings
```go
type args struct {
...
@ -269,6 +295,7 @@ someprogram 4.3.0
> If a `--version` flag is defined in `args` or any subcommand, it overrides the built-in versioning.
### Custom validation
```go
var args struct {
Foo string
@ -310,13 +337,11 @@ Options:
--help, -h display this help and exit
```
### Embedded structs
The fields of embedded structs are treated just like regular fields:
```go
type DatabaseOptions struct {
Host string
Username string
@ -384,6 +409,7 @@ func main() {
fmt.Printf("%#v\n", args.Name)
}
```
```shell
$ ./example --name=foo.bar
main.NameDotName{Head:"foo", Tail:"bar"}
@ -420,6 +446,7 @@ func main() {
fmt.Printf("%#v\n", args.Name)
}
```
```shell
$ ./example --help
Usage: test [--name NAME]
@ -445,6 +472,7 @@ var args struct {
}
arg.MustParse(&args)
```
```shell
$ ./example -h
Usage: example [--optimize LEVEL] [--maxjobs N] SRC [DST [DST ...]]
@ -581,7 +609,6 @@ if p.Subcommand() == nil {
}
```
### Custom handling of --help and --version
The following reproduces the internal logic of `MustParse` for the simple case where
@ -722,7 +749,8 @@ func main() {
p.WriteUsageForSubcommand(os.Stdout, p.SubcommandNames()...)
os.Exit(1)
}
}```
}
```
```shell
$ ./example --version

13
parse.go
View File

@ -131,6 +131,9 @@ type Config struct {
// subcommand
StrictSubcommands bool
// EnvPrefix instructs the library to use a name prefix when reading environment variables.
EnvPrefix string
// Exit is called to terminate the process with an error code (defaults to os.Exit)
Exit func(int)
@ -235,7 +238,7 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) {
panic(fmt.Sprintf("%s is not a pointer (did you forget an ampersand?)", t))
}
cmd, err := cmdFromStruct(name, path{root: i}, t)
cmd, err := cmdFromStruct(name, path{root: i}, t, config.EnvPrefix)
if err != nil {
return nil, err
}
@ -285,7 +288,7 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) {
return &p, nil
}
func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) {
func cmdFromStruct(name string, dest path, t reflect.Type, envPrefix string) (*command, error) {
// commands can only be created from pointers to structs
if t.Kind() != reflect.Ptr {
return nil, fmt.Errorf("subcommands must be pointers to structs but %s is a %s",
@ -372,9 +375,9 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) {
case key == "env":
// Use override name if provided
if value != "" {
spec.env = value
spec.env = envPrefix + value
} else {
spec.env = strings.ToUpper(field.Name)
spec.env = envPrefix + strings.ToUpper(field.Name)
}
case key == "subcommand":
// decide on a name for the subcommand
@ -389,7 +392,7 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) {
}
// parse the subcommand recursively
subcmd, err := cmdFromStruct(cmdnames[0], subdest, field.Type)
subcmd, err := cmdFromStruct(cmdnames[0], subdest, field.Type, envPrefix)
if err != nil {
errs = append(errs, err.Error())
return false

52
parse_test.go
View File

@ -28,11 +28,11 @@ func parse(cmdline string, dest interface{}) error {
}
func pparse(cmdline string, dest interface{}) (*Parser, error) {
return parseWithEnv(cmdline, nil, dest)
return parseWithEnv(Config{}, cmdline, nil, dest)
}
func parseWithEnv(cmdline string, env []string, dest interface{}) (*Parser, error) {
p, err := NewParser(Config{}, dest)
func parseWithEnv(config Config, cmdline string, env []string, dest interface{}) (*Parser, error) {
p, err := NewParser(config, dest)
if err != nil {
return nil, err
}
@ -231,7 +231,7 @@ func TestRequiredWithEnvOnly(t *testing.T) {
var args struct {
Foo string `arg:"required,--,-,env:FOO"`
}
_, err := parseWithEnv("", []string{}, &args)
_, err := parseWithEnv(Config{}, "", []string{}, &args)
require.Error(t, err, "environment variable FOO is required")
}
@ -720,7 +720,7 @@ func TestEnvironmentVariable(t *testing.T) {
var args struct {
Foo string `arg:"env"`
}
_, err := parseWithEnv("", []string{"FOO=bar"}, &args)
_, err := parseWithEnv(Config{}, "", []string{"FOO=bar"}, &args)
require.NoError(t, err)
assert.Equal(t, "bar", args.Foo)
}
@ -729,7 +729,7 @@ func TestEnvironmentVariableNotPresent(t *testing.T) {
var args struct {
NotPresent string `arg:"env"`
}
_, err := parseWithEnv("", nil, &args)
_, err := parseWithEnv(Config{}, "", nil, &args)
require.NoError(t, err)
assert.Equal(t, "", args.NotPresent)
}
@ -738,7 +738,7 @@ func TestEnvironmentVariableOverrideName(t *testing.T) {
var args struct {
Foo string `arg:"env:BAZ"`
}
_, err := parseWithEnv("", []string{"BAZ=bar"}, &args)
_, err := parseWithEnv(Config{}, "", []string{"BAZ=bar"}, &args)
require.NoError(t, err)
assert.Equal(t, "bar", args.Foo)
}
@ -747,7 +747,7 @@ func TestEnvironmentVariableOverrideArgument(t *testing.T) {
var args struct {
Foo string `arg:"env"`
}
_, err := parseWithEnv("--foo zzz", []string{"FOO=bar"}, &args)
_, err := parseWithEnv(Config{}, "--foo zzz", []string{"FOO=bar"}, &args)
require.NoError(t, err)
assert.Equal(t, "zzz", args.Foo)
}
@ -756,7 +756,7 @@ func TestEnvironmentVariableError(t *testing.T) {
var args struct {
Foo int `arg:"env"`
}
_, err := parseWithEnv("", []string{"FOO=bar"}, &args)
_, err := parseWithEnv(Config{}, "", []string{"FOO=bar"}, &args)
assert.Error(t, err)
}
@ -764,7 +764,7 @@ func TestEnvironmentVariableRequired(t *testing.T) {
var args struct {
Foo string `arg:"env,required"`
}
_, err := parseWithEnv("", []string{"FOO=bar"}, &args)
_, err := parseWithEnv(Config{}, "", []string{"FOO=bar"}, &args)
require.NoError(t, err)
assert.Equal(t, "bar", args.Foo)
}
@ -773,7 +773,7 @@ func TestEnvironmentVariableSliceArgumentString(t *testing.T) {
var args struct {
Foo []string `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=bar,"baz, qux"`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=bar,"baz, qux"`}, &args)
require.NoError(t, err)
assert.Equal(t, []string{"bar", "baz, qux"}, args.Foo)
}
@ -782,7 +782,7 @@ func TestEnvironmentVariableSliceEmpty(t *testing.T) {
var args struct {
Foo []string `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=`}, &args)
require.NoError(t, err)
assert.Len(t, args.Foo, 0)
}
@ -791,7 +791,7 @@ func TestEnvironmentVariableSliceArgumentInteger(t *testing.T) {
var args struct {
Foo []int `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=1,99`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=1,99`}, &args)
require.NoError(t, err)
assert.Equal(t, []int{1, 99}, args.Foo)
}
@ -800,7 +800,7 @@ func TestEnvironmentVariableSliceArgumentFloat(t *testing.T) {
var args struct {
Foo []float32 `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=1.1,99.9`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=1.1,99.9`}, &args)
require.NoError(t, err)
assert.Equal(t, []float32{1.1, 99.9}, args.Foo)
}
@ -809,7 +809,7 @@ func TestEnvironmentVariableSliceArgumentBool(t *testing.T) {
var args struct {
Foo []bool `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=true,false,0,1`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=true,false,0,1`}, &args)
require.NoError(t, err)
assert.Equal(t, []bool{true, false, false, true}, args.Foo)
}
@ -818,7 +818,7 @@ func TestEnvironmentVariableSliceArgumentWrongCsv(t *testing.T) {
var args struct {
Foo []int `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=1,99\"`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=1,99\"`}, &args)
assert.Error(t, err)
}
@ -826,7 +826,7 @@ func TestEnvironmentVariableSliceArgumentWrongType(t *testing.T) {
var args struct {
Foo []bool `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=one,two`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=one,two`}, &args)
assert.Error(t, err)
}
@ -834,7 +834,7 @@ func TestEnvironmentVariableMap(t *testing.T) {
var args struct {
Foo map[int]string `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=1=one,99=ninetynine`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=1=one,99=ninetynine`}, &args)
require.NoError(t, err)
assert.Len(t, args.Foo, 2)
assert.Equal(t, "one", args.Foo[1])
@ -845,11 +845,21 @@ func TestEnvironmentVariableEmptyMap(t *testing.T) {
var args struct {
Foo map[int]string `arg:"env"`
}
_, err := parseWithEnv("", []string{`FOO=`}, &args)
_, err := parseWithEnv(Config{}, "", []string{`FOO=`}, &args)
require.NoError(t, err)
assert.Len(t, args.Foo, 0)
}
func TestEnvironmentVariableWithPrefix(t *testing.T) {
var args struct {
Foo string `arg:"env"`
}
_, err := parseWithEnv(Config{EnvPrefix: "MYAPP_"}, "", []string{"MYAPP_FOO=bar"}, &args)
require.NoError(t, err)
assert.Equal(t, "bar", args.Foo)
}
func TestEnvironmentVariableIgnored(t *testing.T) {
var args struct {
Foo string `arg:"env"`
@ -882,7 +892,7 @@ func TestRequiredEnvironmentOnlyVariableIsMissing(t *testing.T) {
Foo string `arg:"required,--,env:FOO"`
}
_, err := parseWithEnv("", []string{""}, &args)
_, err := parseWithEnv(Config{}, "", []string{""}, &args)
assert.Error(t, err)
}
@ -891,7 +901,7 @@ func TestOptionalEnvironmentOnlyVariable(t *testing.T) {
Foo string `arg:"env:FOO"`
}
_, err := parseWithEnv("", []string{}, &args)
_, err := parseWithEnv(Config{}, "", []string{}, &args)
assert.NoError(t, err)
}