Return an error when parsing environment variables for values fails

Currently cli silently (aside from IntSlice and Int64Slice which oddly
printed directly to the error stream) ignores failures that occur when
parsing environment variables for their value for flags that define
environment variables. Instead, we should propogate up the error to the
user.

This is accomplished in a backwards compatible manner by adding a new,
internal, interface which defines an applyWithError function that all
flags here define. In v2, when we can modify the interface, we can drop
this secondary interface and modify `Apply` to return an error.
This commit is contained in:
Jesse Szwedko
2016-09-17 16:54:29 -07:00
parent a00c3f5872
commit e367fafa3d
7 changed files with 333 additions and 65 deletions

225
flag.go
View File

@@ -62,13 +62,29 @@ type Flag interface {
GetName() string
}
func flagSet(name string, flags []Flag) *flag.FlagSet {
// errorableFlag is an interface that allows us to return errors during apply
// it allows flags defined in this library to return errors in a fashion backwards compatible
// TODO remove in v2 and modify the existing Flag interface to return errors
type errorableFlag interface {
Flag
applyWithError(*flag.FlagSet) error
}
func flagSet(name string, flags []Flag) (*flag.FlagSet, error) {
set := flag.NewFlagSet(name, flag.ContinueOnError)
for _, f := range flags {
f.Apply(set)
//TODO remove in v2 when errorableFlag is removed
if f, ok := f.(errorableFlag); ok {
if err := f.applyWithError(set); err != nil {
return nil, err
}
} else {
f.Apply(set)
}
}
return set
return set, nil
}
func eachName(longName string, fn func(string)) {
@@ -87,13 +103,22 @@ type Generic interface {
// Apply takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
// Ignores parsing errors
func (f GenericFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
func (f GenericFlag) applyWithError(set *flag.FlagSet) error {
val := f.Value
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
val.Set(envVal)
if err := val.Set(envVal); err != nil {
return fmt.Errorf("could not parse %s as value for flag %s: %s", envVal, f.Name, err)
}
break
}
}
@@ -102,9 +127,11 @@ func (f GenericFlag) Apply(set *flag.FlagSet) {
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
return nil
}
// StringSlice is an opaque type for []string to satisfy flag.Value
// StringSlice is an opaque type for []string to satisfy flag.Value and flag.Getter
type StringSlice []string
// Set appends the string value to the list of values
@@ -123,8 +150,19 @@ func (f *StringSlice) Value() []string {
return *f
}
// Get returns the slice of strings set by this flag
func (f *StringSlice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringSliceFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f StringSliceFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
@@ -132,7 +170,9 @@ func (f StringSliceFlag) Apply(set *flag.FlagSet) {
newVal := &StringSlice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
newVal.Set(s)
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as string value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
break
@@ -146,9 +186,11 @@ func (f StringSliceFlag) Apply(set *flag.FlagSet) {
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// IntSlice is an opaque type for []int to satisfy flag.Value
// IntSlice is an opaque type for []int to satisfy flag.Value and flag.Getter
type IntSlice []int
// Set parses the value into an integer and appends it to the list of values
@@ -171,8 +213,19 @@ func (f *IntSlice) Value() []int {
return *f
}
// Get returns the slice of ints set by this flag
func (f *IntSlice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntSliceFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f IntSliceFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
@@ -180,9 +233,8 @@ func (f IntSliceFlag) Apply(set *flag.FlagSet) {
newVal := &IntSlice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
err := newVal.Set(s)
if err != nil {
fmt.Fprintf(ErrWriter, err.Error())
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as int slice value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
@@ -197,9 +249,11 @@ func (f IntSliceFlag) Apply(set *flag.FlagSet) {
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// Int64Slice is an opaque type for []int to satisfy flag.Value
// Int64Slice is an opaque type for []int to satisfy flag.Value and flag.Getter
type Int64Slice []int64
// Set parses the value into an integer and appends it to the list of values
@@ -222,8 +276,19 @@ func (f *Int64Slice) Value() []int64 {
return *f
}
// Get returns the slice of ints set by this flag
func (f *Int64Slice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f Int64SliceFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
@@ -231,9 +296,8 @@ func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
newVal := &Int64Slice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
err := newVal.Set(s)
if err != nil {
fmt.Fprintf(ErrWriter, err.Error())
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as int64 slice value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
@@ -248,10 +312,17 @@ func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f BoolFlag) applyWithError(set *flag.FlagSet) error {
val := false
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
@@ -263,9 +334,11 @@ func (f BoolFlag) Apply(set *flag.FlagSet) {
}
envValBool, err := strconv.ParseBool(envVal)
if err == nil {
val = envValBool
if err != nil {
return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
}
val = envValBool
break
}
}
@@ -278,10 +351,18 @@ func (f BoolFlag) Apply(set *flag.FlagSet) {
}
set.Bool(name, val, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolTFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f BoolTFlag) applyWithError(set *flag.FlagSet) error {
val := true
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
@@ -293,10 +374,12 @@ func (f BoolTFlag) Apply(set *flag.FlagSet) {
}
envValBool, err := strconv.ParseBool(envVal)
if err == nil {
val = envValBool
break
if err != nil {
return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
}
val = envValBool
break
}
}
}
@@ -308,10 +391,18 @@ func (f BoolTFlag) Apply(set *flag.FlagSet) {
}
set.Bool(name, val, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f StringFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
@@ -329,19 +420,28 @@ func (f StringFlag) Apply(set *flag.FlagSet) {
}
set.String(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f IntFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseInt(envVal, 0, 64)
if err == nil {
f.Value = int(envValInt)
break
if err != nil {
return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
}
f.Value = int(envValInt)
break
}
}
}
@@ -353,19 +453,29 @@ func (f IntFlag) Apply(set *flag.FlagSet) {
}
set.Int(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64Flag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f Int64Flag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseInt(envVal, 0, 64)
if err == nil {
f.Value = envValInt
break
if err != nil {
return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
}
f.Value = envValInt
break
}
}
}
@@ -377,19 +487,29 @@ func (f Int64Flag) Apply(set *flag.FlagSet) {
}
set.Int64(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f UintFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f UintFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseUint(envVal, 0, 64)
if err == nil {
f.Value = uint(envValInt)
break
if err != nil {
return fmt.Errorf("could not parse %s as uint value for flag %s: %s", envVal, f.Name, err)
}
f.Value = uint(envValInt)
break
}
}
}
@@ -401,19 +521,29 @@ func (f UintFlag) Apply(set *flag.FlagSet) {
}
set.Uint(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Uint64Flag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f Uint64Flag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseUint(envVal, 0, 64)
if err == nil {
f.Value = uint64(envValInt)
break
if err != nil {
return fmt.Errorf("could not parse %s as uint64 value for flag %s: %s", envVal, f.Name, err)
}
f.Value = uint64(envValInt)
break
}
}
}
@@ -425,19 +555,29 @@ func (f Uint64Flag) Apply(set *flag.FlagSet) {
}
set.Uint64(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f DurationFlag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f DurationFlag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValDuration, err := time.ParseDuration(envVal)
if err == nil {
f.Value = envValDuration
break
if err != nil {
return fmt.Errorf("could not parse %s as duration for flag %s: %s", envVal, f.Name, err)
}
f.Value = envValDuration
break
}
}
}
@@ -449,18 +589,29 @@ func (f DurationFlag) Apply(set *flag.FlagSet) {
}
set.Duration(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Float64Flag) Apply(set *flag.FlagSet) {
f.applyWithError(set)
}
// applyWithError populates the flag given the flag set and environment
func (f Float64Flag) applyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValFloat, err := strconv.ParseFloat(envVal, 10)
if err == nil {
f.Value = float64(envValFloat)
if err != nil {
return fmt.Errorf("could not parse %s as float64 value for flag %s: %s", envVal, f.Name, err)
}
f.Value = float64(envValFloat)
break
}
}
}
@@ -472,6 +623,8 @@ func (f Float64Flag) Apply(set *flag.FlagSet) {
}
set.Float64(name, f.Value, f.Usage)
})
return nil
}
func visibleFlags(fl []Flag) []Flag {