config: fix setting of non top level flags from environment variables

Before this fix, attempting to set a non top level environment
variable would fail with "Couldn't find flag".

This fixes it by passing in the flags that the env var is being set
from.

Fixes #3615

fs/config/flags/flags.go

@@ -13,11 +13,11 @@ import (
 
 // setDefaultFromEnv constructs a name from the flag passed in and
 // sets the default from the environment if possible.
-func setDefaultFromEnv(name string) {
+func setDefaultFromEnv(flags *pflag.FlagSet, name string) {
 	key := fs.OptionToEnv(name)
 	newValue, found := os.LookupEnv(key)
 	if found {
-		flag := pflag.Lookup(name)
+		flag := flags.Lookup(name)
 		if flag == nil {
 			log.Fatalf("Couldn't find flag %q", name)
 		}
@@ -35,7 +35,7 @@ func setDefaultFromEnv(name string) {
 // It is a thin wrapper around pflag.StringP
 func StringP(name, shorthand string, value string, usage string) (out *string) {
 	out = pflag.StringP(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -44,7 +44,7 @@ func StringP(name, shorthand string, value string, usage string) (out *string) {
 // It is a thin wrapper around pflag.StringVarP
 func StringVarP(flags *pflag.FlagSet, p *string, name, shorthand string, value string, usage string) {
 	flags.StringVarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // BoolP defines a flag which can be overridden by an environment variable
@@ -52,7 +52,7 @@ func StringVarP(flags *pflag.FlagSet, p *string, name, shorthand string, value s
 // It is a thin wrapper around pflag.BoolP
 func BoolP(name, shorthand string, value bool, usage string) (out *bool) {
 	out = pflag.BoolP(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -61,7 +61,7 @@ func BoolP(name, shorthand string, value bool, usage string) (out *bool) {
 // It is a thin wrapper around pflag.BoolVarP
 func BoolVarP(flags *pflag.FlagSet, p *bool, name, shorthand string, value bool, usage string) {
 	flags.BoolVarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // IntP defines a flag which can be overridden by an environment variable
@@ -69,7 +69,7 @@ func BoolVarP(flags *pflag.FlagSet, p *bool, name, shorthand string, value bool,
 // It is a thin wrapper around pflag.IntP
 func IntP(name, shorthand string, value int, usage string) (out *int) {
 	out = pflag.IntP(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -78,7 +78,7 @@ func IntP(name, shorthand string, value int, usage string) (out *int) {
 // It is a thin wrapper around pflag.IntP
 func Int64P(name, shorthand string, value int64, usage string) (out *int64) {
 	out = pflag.Int64P(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -87,7 +87,7 @@ func Int64P(name, shorthand string, value int64, usage string) (out *int64) {
 // It is a thin wrapper around pflag.Int64VarP
 func IntVar64P(flags *pflag.FlagSet, p *int64, name, shorthand string, value int64, usage string) {
 	flags.Int64VarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // IntVarP defines a flag which can be overridden by an environment variable
@@ -95,7 +95,7 @@ func IntVar64P(flags *pflag.FlagSet, p *int64, name, shorthand string, value int
 // It is a thin wrapper around pflag.IntVarP
 func IntVarP(flags *pflag.FlagSet, p *int, name, shorthand string, value int, usage string) {
 	flags.IntVarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // Uint32VarP defines a flag which can be overridden by an environment variable
@@ -103,7 +103,7 @@ func IntVarP(flags *pflag.FlagSet, p *int, name, shorthand string, value int, us
 // It is a thin wrapper around pflag.Uint32VarP
 func Uint32VarP(flags *pflag.FlagSet, p *uint32, name, shorthand string, value uint32, usage string) {
 	flags.Uint32VarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // Float64P defines a flag which can be overridden by an environment variable
@@ -111,7 +111,7 @@ func Uint32VarP(flags *pflag.FlagSet, p *uint32, name, shorthand string, value u
 // It is a thin wrapper around pflag.Float64P
 func Float64P(name, shorthand string, value float64, usage string) (out *float64) {
 	out = pflag.Float64P(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -120,7 +120,7 @@ func Float64P(name, shorthand string, value float64, usage string) (out *float64
 // It is a thin wrapper around pflag.Float64VarP
 func Float64VarP(flags *pflag.FlagSet, p *float64, name, shorthand string, value float64, usage string) {
 	flags.Float64VarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // DurationP defines a flag which can be overridden by an environment variable
@@ -128,7 +128,7 @@ func Float64VarP(flags *pflag.FlagSet, p *float64, name, shorthand string, value
 // It is a thin wrapper around pflag.DurationP
 func DurationP(name, shorthand string, value time.Duration, usage string) (out *time.Duration) {
 	out = pflag.DurationP(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -137,7 +137,7 @@ func DurationP(name, shorthand string, value time.Duration, usage string) (out *
 // It is a thin wrapper around pflag.DurationVarP
 func DurationVarP(flags *pflag.FlagSet, p *time.Duration, name, shorthand string, value time.Duration, usage string) {
 	flags.DurationVarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // VarP defines a flag which can be overridden by an environment variable
@@ -145,7 +145,7 @@ func DurationVarP(flags *pflag.FlagSet, p *time.Duration, name, shorthand string
 // It is a thin wrapper around pflag.VarP
 func VarP(value pflag.Value, name, shorthand, usage string) {
 	pflag.VarP(value, name, shorthand, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 }
 
 // FVarP defines a flag which can be overridden by an environment variable
@@ -153,7 +153,7 @@ func VarP(value pflag.Value, name, shorthand, usage string) {
 // It is a thin wrapper around pflag.VarP
 func FVarP(flags *pflag.FlagSet, value pflag.Value, name, shorthand, usage string) {
 	flags.VarP(value, name, shorthand, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // StringArrayP defines a flag which can be overridden by an environment variable
@@ -163,7 +163,7 @@ func FVarP(flags *pflag.FlagSet, value pflag.Value, name, shorthand, usage strin
 // It is a thin wrapper around pflag.StringArrayP
 func StringArrayP(name, shorthand string, value []string, usage string) (out *[]string) {
 	out = pflag.StringArrayP(name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -174,7 +174,7 @@ func StringArrayP(name, shorthand string, value []string, usage string) (out *[]
 // It is a thin wrapper around pflag.StringArrayVarP
 func StringArrayVarP(flags *pflag.FlagSet, p *[]string, name, shorthand string, value []string, usage string) {
 	flags.StringArrayVarP(p, name, shorthand, value, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }
 
 // CountP defines a flag which can be overridden by an environment variable
@@ -182,7 +182,7 @@ func StringArrayVarP(flags *pflag.FlagSet, p *[]string, name, shorthand string,
 // It is a thin wrapper around pflag.CountP
 func CountP(name, shorthand string, usage string) (out *int) {
 	out = pflag.CountP(name, shorthand, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(pflag.CommandLine, name)
 	return out
 }
 
@@ -191,5 +191,5 @@ func CountP(name, shorthand string, usage string) (out *int) {
 // It is a thin wrapper around pflag.CountVarP
 func CountVarP(flags *pflag.FlagSet, p *int, name, shorthand string, usage string) {
 	flags.CountVarP(p, name, shorthand, usage)
-	setDefaultFromEnv(name)
+	setDefaultFromEnv(flags, name)
 }