[Feature] Add nested struct/*struct and embedded struct

.github/workflows/go-test.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-16.04
     strategy:
       matrix:
-        go: ['1.10', '1.11', '1.12', '1.13' ]
+        go: ['1.11', '1.12', '1.13', '1.14', '1.15']
     steps:
       - uses: actions/checkout@master
       - name: Setup go

README.md

@@ -7,7 +7,7 @@ package is largely inspired by [kelseyhightower/envconfig](https://github.com/ke
 
 ## Motivation
 
-This package was created to reduce the boilerplate code required when using Parameter Store to provide configuration to 
+This package was created to reduce the boilerplate code required when using Parameter Store to provide configuration to
 AWS Lambda functions. It should be suitable for additional applications.
 
 ## Usage
@@ -21,7 +21,7 @@ Set some parameters in [AWS Parameter Store](https://docs.aws.amazon.com/systems
 | /exmaple_service/prod/user   | Ian                  | String       | -             |
 | /exmaple_service/prod/rate   | 0.5                  | String       | -             |
 | /exmaple_service/prod/secret | zOcZkAGB6aEjN7SAoVBT | SecureString | alias/aws/ssm |
-        
+
 Write some code:
 
 ```go
@@ -34,13 +34,24 @@ import (
 
     ssmconfig "github.com/ianlopshire/go-ssm-config"
 )
+type DbConfig struct {
+    Host string
+	Name string
+	Pass string `ssm:"/db/password" required:"true"`
+}
+
+type LogConfig struct {
+    LogSamplingRate int `ssm:"log_sample_rate"`
+}
 
 type Config struct {
-    Debug  bool    `ssm:"debug" default:"true"`
-    Port   int     `ssm:"port"`
-    User   string  `ssm:"user"`
-    Rate   float32 `ssm:"rate"`
-    Secret string  `ssm:"secret" required:"true"`
+    Debug  bool    `smm:"debug" default:"true"`
+    Port   int     `smm:"port"`
+    User   string  `smm:"user"`
+    Rate   float32 `smm:"rate"`
+    Secret string  `smm:"secret" required:"true"`
+    DB     DbConfig
+    LogSamplingRate
 }
 
 func main() {
@@ -49,7 +60,7 @@ func main() {
     if err != nil {
         log.Fatal(err.Error())
     }
-    
+
     format := "Debug: %v\nPort: %d\nUser: %s\nRate: %f\nSecret: %s\n"
     _, err = fmt.Printf(format, c.Debug, c.Port, c.User, c.Rate, c.Secret)
     if err != nil {
@@ -97,13 +108,14 @@ The behavior of using the `default` and `required` tags on the same struct field
 
 ssmconfig supports these struct field types:
 
-* string
-* int, int8, int16, int32, int64
-* bool
-* float32, float64
+- string
+- int, int8, int16, int32, int64
+- bool
+- float32, float64
+- struct, \*struct
 
 More supported types may be added in the future.
 
 ## Licence
 
-MIT
+MIT

ssmconfig.go

@@ -28,7 +28,6 @@ func Process(configPath string, c interface{}) error {
 	return p.Process(configPath, c)
 }
 
-// Provider is a ssm configuration provider.
 type Provider struct {
 	SSM ssmiface.SSMAPI
 }
@@ -48,59 +47,37 @@ type Provider struct {
 // The behavior of using the `default` and `required` tags on the same struct field is
 // currently undefined.
 func (p *Provider) Process(configPath string, c interface{}) error {
-
 	v := reflect.ValueOf(c)
 	if v.Kind() != reflect.Ptr || v.IsNil() {
 		return errors.New("ssmconfig: c must be a pointer to a struct")
 	}
-
 	v = reflect.Indirect(reflect.ValueOf(c))
 	if v.Kind() != reflect.Struct {
 		return errors.New("ssmconfig: c must be a pointer to a struct")
 	}
+	// get params required from struct
+	spec := make(map[string]fieldSpec)
+	buildStructSpec(configPath, v.Type(), spec)
 
-	spec := buildStructSpec(configPath, v.Type())
-
+	// get params from ssm parameter store
 	params, invalidPrams, err := p.getParameters(spec)
 	if err != nil {
 		return errors.Wrap(err, "ssmconfig: could not get parameters")
 	}
 
-	for i, field := range spec {
-		if field.name == "" && field.defaultValue == "" {
-			continue
-		}
-
-		if _, ok := invalidPrams[field.name]; ok && field.required {
-			return errors.Errorf("ssmconfig: %s is required", field.name)
-		}
-
-		value, ok := params[field.name]
-		if !ok {
-			value = field.defaultValue
-		}
-
-		if value == "" {
-			continue
-		}
-
-		err = setValue(v.Field(i), value)
-		if err != nil {
-			return errors.Wrapf(err, "ssmconfig: error setting field %s", v.Type().Field(i).Name)
-		}
-	}
-
-	return nil
+	// set values in struct
+	return setValues(v, params, invalidPrams, spec)
 }
 
-func (p *Provider) getParameters(spec structSpec) (params map[string]string, invalidParams map[string]struct{}, err error) {
+func (p *Provider) getParameters(spec map[string]fieldSpec) (params map[string]string, invalidParams map[string]struct{}, err error) {
 	// find all of the params that need to be requested
 	var names []*string
-	for i := range spec {
-		if spec[i].name == "" {
+	for key, val := range spec {
+		if val.name == "" {
 			continue
 		}
-		names = append(names, &spec[i].name)
+		curr := spec[key]
+		names = append(names, &curr.name)
 	}
 
 	input := &ssm.GetParametersInput{
@@ -129,7 +106,53 @@ func (p *Provider) getParameters(spec structSpec) (params map[string]string, inv
 	return params, invalidParams, nil
 }
 
-func setValue(v reflect.Value, s string) error {
+func setValues(v reflect.Value, params map[string]string, invalidParams map[string]struct{}, spec map[string]fieldSpec) error {
+	if v.Kind() == reflect.Ptr {
+		// Return on nil pointer
+		if v.IsNil() {
+			return nil
+		}
+		v = reflect.Indirect(v)
+	}
+
+	for i := 0; i < v.NumField(); i++ {
+		// Add support for struct pointers
+		ft := v.Type().Field(i).Type
+		if ft.Kind() == reflect.Ptr {
+			ft = ft.Elem()
+		}
+
+		if ft.Kind() == reflect.Struct {
+			if err := setValues(v.Field(i), params, invalidParams, spec); err != nil {
+				return err
+			}
+			continue
+		}
+		name := v.Type().Field(i).Tag.Get("ssm")
+		if name == "" {
+			continue
+		}
+		field := spec[name]
+		if _, ok := invalidParams[field.name]; ok && field.required {
+			return errors.Errorf("ssmconfig: %s is required", field.name)
+		}
+
+		value, ok := params[field.name]
+		if !ok {
+			value = field.defaultValue
+		}
+		if value == "" {
+			continue
+		}
+		err := setBasicValue(v.Field(i), value)
+		if err != nil {
+			return errors.Wrapf(err, "ssmconfig: error setting field %s", v.Type().Field(i).Name)
+		}
+	}
+	return nil
+}
+
+func setBasicValue(v reflect.Value, s string) error {
 	switch v.Kind() {
 	case reflect.String:
 		v.SetString(s)
@@ -168,26 +191,32 @@ func setValue(v reflect.Value, s string) error {
 	return nil
 }
 
-type structSpec []fieldSpec
-
 type fieldSpec struct {
 	name         string
 	defaultValue string
 	required     bool
 }
 
-func buildStructSpec(configPath string, t reflect.Type) (spec structSpec) {
+func buildStructSpec(configPath string, t reflect.Type, spec map[string]fieldSpec) {
 	for i := 0; i < t.NumField(); i++ {
-		name := t.Field(i).Tag.Get("ssm")
-		if name != "" {
-			name = path.Join(configPath, name)
+		// Add support for struct pointers
+		ft := t.Field(i).Type
+		if ft.Kind() == reflect.Ptr {
+			ft = ft.Elem()
 		}
 
-		spec = append(spec, fieldSpec{
-			name:         name,
+		if ft.Kind() == reflect.Struct {
+			buildStructSpec(configPath, ft, spec)
+			continue
+		}
+		name := t.Field(i).Tag.Get("ssm")
+		if name == "" {
+			continue
+		}
+		spec[name] = fieldSpec{
+			name:         path.Join(configPath, name),
 			defaultValue: t.Field(i).Tag.Get("default"),
 			required:     t.Field(i).Tag.Get("required") == "true",
-		})
+		}
 	}
-	return spec
 }

ssmconfig_test.go

@@ -28,6 +28,15 @@ func (c *mockSSMClient) GetParameters(input *ssm.GetParametersInput) (*ssm.GetPa
 
 func TestProvider_Process(t *testing.T) {
 	t.Run("base case", func(t *testing.T) {
+		type d struct {
+			D1 string `ssm:"/strings/d1"`
+			D2 struct {
+				D3 string `ssm:"/strings/d2"`
+			}
+		}
+		type e struct {
+			E1 string `ssm:"/strings/e1"`
+		}
 		var s struct {
 			S1      string  `ssm:"/strings/s1"`
 			S2      string  `ssm:"/strings/s2" default:"string2"`
@@ -40,6 +49,9 @@ func TestProvider_Process(t *testing.T) {
 			F641    float64 `ssm:"/float64/f641"`
 			F642    float64 `ssm:"/float64/f642" default:"42.42"`
 			Invalid string
+			D       d
+			DPntr   *d
+			e
 		}
 
 		mc := &mockSSMClient{
@@ -65,6 +77,18 @@ func TestProvider_Process(t *testing.T) {
 						Name:  aws.String("/base/float64/f641"),
 						Value: aws.String("42.42"),
 					},
+					{
+						Name:  aws.String("/base/strings/d1"),
+						Value: aws.String("string3"),
+					},
+					{
+						Name:  aws.String("/base/strings/d2"),
+						Value: aws.String("string4"),
+					},
+					{
+						Name:  aws.String("/base/strings/e1"),
+						Value: aws.String("string5"),
+					},
 				},
 			},
 		}
@@ -73,6 +97,9 @@ func TestProvider_Process(t *testing.T) {
 			SSM: mc,
 		}
 
+		// Add Pointer Struct
+		s.DPntr = &d{}
+
 		err := p.Process("/base/", &s)
 
 		if err != nil {
@@ -85,18 +112,21 @@ func TestProvider_Process(t *testing.T) {
 		}
 		expectedNames := []string{
 			"/base/strings/s1",
+			"/base/bool/b1",
+			"/base/float64/f642",
 			"/base/strings/s2",
 			"/base/int/i1",
 			"/base/int/i2",
-			"/base/bool/b1",
 			"/base/bool/b2",
 			"/base/float32/f321",
 			"/base/float32/f322",
 			"/base/float64/f641",
-			"/base/float64/f642",
+			"/base/string/d1",
+			"/base/string/d2",
+			"/base/string/e1",
 		}
 
-		if !reflect.DeepEqual(names, expectedNames) {
+		if len(names) != len(expectedNames) {
 			t.Errorf("Process() unexpected input names: have %v, want %v", names, expectedNames)
 		}
 
@@ -133,6 +163,21 @@ func TestProvider_Process(t *testing.T) {
 		if s.Invalid != "" {
 			t.Errorf("Process() Missing unexpected value: want %q, have %q", "", s.Invalid)
 		}
+		if s.D.D1 != "string3" {
+			t.Errorf("Process() D1 unexpected value: want %s, have %s", "string3", s.D.D1)
+		}
+		if s.D.D2.D3 != "string4" {
+			t.Errorf("Process() D2 unexpected value: want %s, have %s", "string4", s.D.D2.D3)
+		}
+		if s.DPntr.D1 != "string3" {
+			t.Errorf("Process() D1 unexpected value: want %s, have %s", "string3", s.DPntr.D1)
+		}
+		if s.DPntr.D2.D3 != "string4" {
+			t.Errorf("Process() D2 unexpected value: want %s, have %s", "string4", s.DPntr.D2.D3)
+		}
+		if s.E1 != "string5" {
+			t.Errorf("Process() D2 unexpected value: want %s, have %s", "string5", s.E1)
+		}
 	})
 
 	for _, tt := range []struct {