diff --git a/README.md b/README.md index 761af56..e9075ba 100644 --- a/README.md +++ b/README.md @@ -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 diff --git a/parse.go b/parse.go index 172c7cd..ece7dde 100644 --- a/parse.go +++ b/parse.go @@ -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 diff --git a/parse_test.go b/parse_test.go index 5bc781c..a932c22 100644 --- a/parse_test.go +++ b/parse_test.go @@ -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") } @@ -711,7 +711,7 @@ 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) } @@ -720,7 +720,7 @@ 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) } @@ -729,7 +729,7 @@ 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) } @@ -738,7 +738,7 @@ 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) } @@ -747,7 +747,7 @@ 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) } @@ -755,7 +755,7 @@ 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) } @@ -764,7 +764,7 @@ 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) } @@ -773,7 +773,7 @@ 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) } @@ -782,7 +782,7 @@ 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) } @@ -791,7 +791,7 @@ 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) } @@ -800,7 +800,7 @@ 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) } @@ -809,7 +809,7 @@ 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) } @@ -817,7 +817,7 @@ 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) } @@ -825,7 +825,7 @@ 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]) @@ -836,11 +836,21 @@ 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"` @@ -873,7 +883,7 @@ func TestRequiredEnvironmentOnlyVariableIsMissing(t *testing.T) { Foo string `arg:"required,--,env:FOO"` } - _, err := parseWithEnv("", []string{""}, &args) + _, err := parseWithEnv(Config{}, "", []string{""}, &args) assert.Error(t, err) } @@ -882,7 +892,7 @@ func TestOptionalEnvironmentOnlyVariable(t *testing.T) { Foo string `arg:"env:FOO"` } - _, err := parseWithEnv("", []string{}, &args) + _, err := parseWithEnv(Config{}, "", []string{}, &args) assert.NoError(t, err) }