mirror of
https://github.com/oauth2-proxy/oauth2-proxy.git
synced 2026-10-18 13:18:26 +02:00
Add Viper based config loader
This commit is contained in:
Joel Speed
@@ -0,0 +1,132 @@
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package options
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import (
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"fmt"
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"reflect"
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"strings"
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"github.com/mitchellh/mapstructure"
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"github.com/spf13/pflag"
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"github.com/spf13/viper"
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)
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// Load reads in the config file at the path given, then merges in environment
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// variables (prefixed with `OAUTH2_PROXY`) and finally merges in flags from the flagSet.
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// If a config value is unset and the flag has a non-zero value default, this default will be used.
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// Eg. A field defined:
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// FooBar `cfg:"foo_bar" flag:"foo-bar"`
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// Can be set in the config file as `foo_bar="baz"`, in the environment as `OAUTH2_PROXY_FOO_BAR=baz`,
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// or via the command line flag `--foo-bar=baz`.
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func Load(configFileName string, flagSet *pflag.FlagSet, into interface{}) error {
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v := viper.New()
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v.SetConfigFile(configFileName)
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v.SetConfigType("toml") // Config is in toml format
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v.SetEnvPrefix("OAUTH2_PROXY")
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v.AutomaticEnv()
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v.SetTypeByDefaultValue(true)
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if configFileName != "" {
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err := v.ReadInConfig()
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if err != nil {
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return fmt.Errorf("unable to load config file: %w", err)
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}
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}
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err := registerFlags(v, "", flagSet, into)
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if err != nil {
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// This should only happen if there is a programming error
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return fmt.Errorf("unable to register flags: %w", err)
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}
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err = v.Unmarshal(into, decodeFromCfgTag)
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if err != nil {
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return fmt.Errorf("error unmarshalling config: %w", err)
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}
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return nil
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}
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// registerFlags uses `cfg` and `flag` tags to associate flags in the flagSet
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// to the fields in the options interface provided.
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// Each exported field in the options must have a `cfg` tag otherwise an error will occur.
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// - For fields, set `cfg` and `flag` so that `flag` is the name of the flag associated to this config option
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// - For exported fields that are not user facing, set the `cfg` to `,internal`
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// - For structs containing user facing fields, set the `cfg` to `,squash`
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func registerFlags(v *viper.Viper, prefix string, flagSet *pflag.FlagSet, options interface{}) error {
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val := reflect.ValueOf(options)
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var typ reflect.Type
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if val.Kind() == reflect.Ptr {
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typ = val.Elem().Type()
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} else {
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typ = val.Type()
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}
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for i := 0; i < typ.NumField(); i++ {
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// pull out the struct tags:
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// flag - the name of the command line flag
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// cfg - the name of the config file option
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field := typ.Field(i)
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fieldV := reflect.Indirect(val).Field(i)
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fieldName := strings.Join([]string{prefix, field.Name}, ".")
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cfgName := field.Tag.Get("cfg")
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if cfgName == ",internal" {
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// Public but internal types that should not be exposed to users, skip them
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continue
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}
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if isUnexported(field.Name) {
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// Unexported fields cannot be set by a user, so won't have tags or flags, skip them
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continue
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}
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if field.Type.Kind() == reflect.Struct {
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if cfgName != ",squash" {
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return fmt.Errorf("field %q does not have required cfg tag: `,squash`", fieldName)
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}
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err := registerFlags(v, fieldName, flagSet, fieldV.Interface())
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if err != nil {
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return err
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}
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continue
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}
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flagName := field.Tag.Get("flag")
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if flagName == "" || cfgName == "" {
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return fmt.Errorf("field %q does not have required tags (cfg, flag)", fieldName)
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}
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if flagSet == nil {
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return fmt.Errorf("flagset cannot be nil")
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}
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f := flagSet.Lookup(flagName)
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if f == nil {
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return fmt.Errorf("field %q does not have a registered flag", flagName)
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}
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err := v.BindPFlag(cfgName, f)
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if err != nil {
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return fmt.Errorf("error binding flag for field %q: %w", fieldName, err)
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}
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}
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return nil
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}
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// decodeFromCfgTag sets the Viper decoder to read the names from the `cfg` tag
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// on each struct entry.
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func decodeFromCfgTag(c *mapstructure.DecoderConfig) {
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c.TagName = "cfg"
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}
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// isUnexported checks if a field name starts with a lowercase letter and therefore
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// if it is unexported.
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func isUnexported(name string) bool {
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if len(name) == 0 {
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// This should never happen
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panic("field name has len 0")
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}
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first := string(name[0])
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return first == strings.ToLower(first)
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}
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@@ -0,0 +1,288 @@
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package options
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import (
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"fmt"
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"io/ioutil"
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"os"
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"testing"
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. "github.com/onsi/ginkgo"
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. "github.com/onsi/ginkgo/extensions/table"
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. "github.com/onsi/gomega"
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"github.com/spf13/pflag"
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)
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func TestOptionsSuite(t *testing.T) {
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RegisterFailHandler(Fail)
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RunSpecs(t, "Options Suite")
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}
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var _ = Describe("Load", func() {
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Context("with a testOptions structure", func() {
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type TestOptionSubStruct struct {
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StringSliceOption []string `flag:"string-slice-option" cfg:"string_slice_option"`
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}
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type TestOptions struct {
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StringOption string `flag:"string-option" cfg:"string_option"`
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Sub TestOptionSubStruct `cfg:",squash"`
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// Check exported but internal fields do not break loading
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Internal *string `cfg:",internal"`
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// Check unexported fields do not break loading
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unexported string
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}
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type MissingSquashTestOptions struct {
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StringOption string `flag:"string-option" cfg:"string_option"`
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Sub TestOptionSubStruct
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}
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type MissingCfgTestOptions struct {
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StringOption string `flag:"string-option"`
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Sub TestOptionSubStruct `cfg:",squash"`
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}
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type MissingFlagTestOptions struct {
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StringOption string `cfg:"string_option"`
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Sub TestOptionSubStruct `cfg:",squash"`
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}
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var testOptionsConfigBytes = []byte(`
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string_option="foo"
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string_slice_option="a,b,c,d"
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`)
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var testOptionsFlagSet *pflag.FlagSet
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type testOptionsTableInput struct {
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env map[string]string
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args []string
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configFile []byte
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flagSet func() *pflag.FlagSet
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expectedErr error
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input interface{}
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expectedOutput interface{}
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}
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BeforeEach(func() {
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testOptionsFlagSet = pflag.NewFlagSet("testFlagSet", pflag.ExitOnError)
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testOptionsFlagSet.String("string-option", "default", "")
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testOptionsFlagSet.StringSlice("string-slice-option", []string{"a", "b"}, "")
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})
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DescribeTable("Load",
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func(o *testOptionsTableInput) {
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var configFileName string
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if o.configFile != nil {
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By("Creating a config file")
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configFile, err := ioutil.TempFile("", "oauth2-proxy-test-legacy-config-file")
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Expect(err).ToNot(HaveOccurred())
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defer configFile.Close()
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_, err = configFile.Write(o.configFile)
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Expect(err).ToNot(HaveOccurred())
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defer os.Remove(configFile.Name())
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configFileName = configFile.Name()
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}
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if len(o.env) > 0 {
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By("Setting environment variables")
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for k, v := range o.env {
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os.Setenv(k, v)
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defer os.Unsetenv(k)
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}
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}
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Expect(o.flagSet).ToNot(BeNil())
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flagSet := o.flagSet()
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Expect(flagSet).ToNot(BeNil())
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if len(o.args) > 0 {
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By("Parsing flag arguments")
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Expect(flagSet.Parse(o.args)).To(Succeed())
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}
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var input interface{}
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if o.input != nil {
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input = o.input
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} else {
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input = &TestOptions{}
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}
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err := Load(configFileName, flagSet, input)
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if o.expectedErr != nil {
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Expect(err).To(MatchError(o.expectedErr.Error()))
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} else {
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Expect(err).ToNot(HaveOccurred())
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}
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Expect(input).To(Equal(o.expectedOutput))
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},
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Entry("with just a config file", &testOptionsTableInput{
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configFile: testOptionsConfigBytes,
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "foo",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c", "d"},
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},
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},
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}),
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Entry("when setting env variables", &testOptionsTableInput{
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configFile: testOptionsConfigBytes,
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "bar",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c"},
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},
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},
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}),
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Entry("when setting flags", &testOptionsTableInput{
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configFile: testOptionsConfigBytes,
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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args: []string{
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"--string-option", "baz",
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"--string-slice-option", "a,b,c,d,e",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "baz",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c", "d", "e"},
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},
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},
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}),
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Entry("when setting flags multiple times", &testOptionsTableInput{
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configFile: testOptionsConfigBytes,
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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args: []string{
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"--string-option", "baz",
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"--string-slice-option", "x",
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"--string-slice-option", "y",
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"--string-slice-option", "z",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "baz",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"x", "y", "z"},
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},
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},
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}),
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Entry("when setting env variables without a config file", &testOptionsTableInput{
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "bar",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c"},
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},
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},
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}),
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Entry("when setting flags without a config file", &testOptionsTableInput{
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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args: []string{
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"--string-option", "baz",
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"--string-slice-option", "a,b,c,d,e",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "baz",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c", "d", "e"},
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},
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},
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}),
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Entry("when setting flags without a config file", &testOptionsTableInput{
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env: map[string]string{
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"OAUTH2_PROXY_STRING_OPTION": "bar",
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"OAUTH2_PROXY_STRING_SLICE_OPTION": "a,b,c",
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},
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args: []string{
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"--string-option", "baz",
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"--string-slice-option", "a,b,c,d,e",
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},
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "baz",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b", "c", "d", "e"},
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},
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},
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}),
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Entry("when nothing is set it should use flag defaults", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedOutput: &TestOptions{
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StringOption: "default",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b"},
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},
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},
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}),
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Entry("with an invalid config file", &testOptionsTableInput{
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configFile: []byte(`slice_option = foo`),
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedErr: fmt.Errorf("unable to load config file: While parsing config: (1, 16): never reached"),
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expectedOutput: &TestOptions{},
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}),
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Entry("with an invalid flagset", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet {
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// Missing a flag
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f := pflag.NewFlagSet("testFlagSet", pflag.ExitOnError)
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f.String("string-option", "default", "")
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return f
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},
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expectedErr: fmt.Errorf("unable to register flags: field \"string-slice-option\" does not have a registered flag"),
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expectedOutput: &TestOptions{},
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}),
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Entry("with an struct is missing the squash tag", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedErr: fmt.Errorf("unable to register flags: field \".Sub\" does not have required cfg tag: `,squash`"),
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input: &MissingSquashTestOptions{},
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expectedOutput: &MissingSquashTestOptions{},
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}),
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Entry("with a field is missing the cfg tag", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedErr: fmt.Errorf("unable to register flags: field \".StringOption\" does not have required tags (cfg, flag)"),
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input: &MissingCfgTestOptions{},
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expectedOutput: &MissingCfgTestOptions{},
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}),
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Entry("with a field is missing the flag tag", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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expectedErr: fmt.Errorf("unable to register flags: field \".StringOption\" does not have required tags (cfg, flag)"),
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input: &MissingFlagTestOptions{},
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expectedOutput: &MissingFlagTestOptions{},
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}),
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Entry("with existing unexported fields", &testOptionsTableInput{
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flagSet: func() *pflag.FlagSet { return testOptionsFlagSet },
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input: &TestOptions{
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unexported: "unexported",
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},
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expectedOutput: &TestOptions{
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StringOption: "default",
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Sub: TestOptionSubStruct{
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StringSliceOption: []string{"a", "b"},
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},
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unexported: "unexported",
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},
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}),
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)
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})
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})
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