500d6b04e6
If you allow a flag to be set from environment variables or files and a parse error occurs from one of them, it is very useful for the error message to mention where the value came from. Without this, it can be difficult to notice an error caused by an unexpected environment variable being set. Implements #1167.
97 lines
2.1 KiB
Go
97 lines
2.1 KiB
Go
package cli
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import "flag"
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// StringFlag is a flag with type string
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type StringFlag struct {
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Name string
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Aliases []string
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Usage string
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EnvVars []string
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FilePath string
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Required bool
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Hidden bool
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TakesFile bool
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Value string
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DefaultText string
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Destination *string
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HasBeenSet bool
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}
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// IsSet returns whether or not the flag has been set through env or file
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func (f *StringFlag) IsSet() bool {
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return f.HasBeenSet
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}
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// String returns a readable representation of this value
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// (for usage defaults)
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func (f *StringFlag) String() string {
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return FlagStringer(f)
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}
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// Names returns the names of the flag
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func (f *StringFlag) Names() []string {
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return flagNames(f.Name, f.Aliases)
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}
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// IsRequired returns whether or not the flag is required
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func (f *StringFlag) IsRequired() bool {
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return f.Required
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}
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// TakesValue returns true of the flag takes a value, otherwise false
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func (f *StringFlag) TakesValue() bool {
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return true
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}
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// GetUsage returns the usage string for the flag
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func (f *StringFlag) GetUsage() string {
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return f.Usage
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}
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// GetValue returns the flags value as string representation and an empty
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// string if the flag takes no value at all.
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func (f *StringFlag) GetValue() string {
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return f.Value
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}
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// Apply populates the flag given the flag set and environment
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func (f *StringFlag) Apply(set *flag.FlagSet) error {
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// TODO: how to report source?
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if val, ok, _ := flagFromEnvOrFile(f.EnvVars, f.FilePath); ok {
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f.Value = val
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f.HasBeenSet = true
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}
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for _, name := range f.Names() {
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if f.Destination != nil {
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set.StringVar(f.Destination, name, f.Value, f.Usage)
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continue
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}
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set.String(name, f.Value, f.Usage)
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}
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return nil
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}
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// String looks up the value of a local StringFlag, returns
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// "" if not found
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func (c *Context) String(name string) string {
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if fs := lookupFlagSet(name, c); fs != nil {
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return lookupString(name, fs)
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}
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return ""
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}
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func lookupString(name string, set *flag.FlagSet) string {
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f := set.Lookup(name)
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if f != nil {
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parsed, err := f.Value.String(), error(nil)
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if err != nil {
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return ""
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}
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return parsed
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}
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return ""
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}
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