connect: ensure time.Duration fields retain their human readable forms in the API (#6348)

This applies for both config entries and the compiled discovery chain.

Also omit some other config entries fields when empty.

agent/structs/config_entry_discoverychain.go

@@ -1,6 +1,7 @@
 package structs
 
 import (
+	"encoding/json"
 	"fmt"
 	"math"
 	"regexp"
@@ -317,6 +318,42 @@ type ServiceRouteDestination struct {
 	RetryOnStatusCodes []uint32 `json:",omitempty"`
 }
 
+func (e *ServiceRouteDestination) MarshalJSON() ([]byte, error) {
+	type Alias ServiceRouteDestination
+	exported := &struct {
+		RequestTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		RequestTimeout: e.RequestTimeout.String(),
+		Alias:          (*Alias)(e),
+	}
+	if e.RequestTimeout == 0 {
+		exported.RequestTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (e *ServiceRouteDestination) UnmarshalJSON(data []byte) error {
+	type Alias ServiceRouteDestination
+	aux := &struct {
+		RequestTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(e),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.RequestTimeout != "" {
+		if e.RequestTimeout, err = time.ParseDuration(aux.RequestTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (d *ServiceRouteDestination) HasRetryFeatures() bool {
 	return d.NumRetries > 0 || d.RetryOnConnectFailure || len(d.RetryOnStatusCodes) > 0
 }
@@ -563,6 +600,42 @@ type ServiceResolverConfigEntry struct {
 	RaftIndex
 }
 
+func (e *ServiceResolverConfigEntry) MarshalJSON() ([]byte, error) {
+	type Alias ServiceResolverConfigEntry
+	exported := &struct {
+		ConnectTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		ConnectTimeout: e.ConnectTimeout.String(),
+		Alias:          (*Alias)(e),
+	}
+	if e.ConnectTimeout == 0 {
+		exported.ConnectTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (e *ServiceResolverConfigEntry) UnmarshalJSON(data []byte) error {
+	type Alias ServiceResolverConfigEntry
+	aux := &struct {
+		ConnectTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(e),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.ConnectTimeout != "" {
+		if e.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (e *ServiceResolverConfigEntry) SubsetExists(name string) bool {
 	if name == "" {
 		return true

agent/structs/discovery_chain.go

@@ -1,6 +1,7 @@
 package structs
 
 import (
+	"encoding/json"
 	"fmt"
 	"time"
 )
@@ -130,6 +131,42 @@ type DiscoveryResolver struct {
 	Failover       *DiscoveryFailover `json:",omitempty"`
 }
 
+func (r *DiscoveryResolver) MarshalJSON() ([]byte, error) {
+	type Alias DiscoveryResolver
+	exported := &struct {
+		ConnectTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		ConnectTimeout: r.ConnectTimeout.String(),
+		Alias:          (*Alias)(r),
+	}
+	if r.ConnectTimeout == 0 {
+		exported.ConnectTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (r *DiscoveryResolver) UnmarshalJSON(data []byte) error {
+	type Alias DiscoveryResolver
+	aux := &struct {
+		ConnectTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(r),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.ConnectTimeout != "" {
+		if r.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // compiled form of ServiceRoute
 type DiscoveryRoute struct {
 	Definition *ServiceRoute `json:",omitempty"`

api/config_entry.go

@@ -53,15 +53,15 @@ const (
 // services
 type MeshGatewayConfig struct {
 	// Mode is the mode that should be used for the upstream connection.
-	Mode MeshGatewayMode
+	Mode MeshGatewayMode `json:",omitempty"`
 }
 
 type ServiceConfigEntry struct {
 	Kind        string
 	Name        string
-	Protocol    string
-	MeshGateway MeshGatewayConfig
-	ExternalSNI string
+	Protocol    string            `json:",omitempty"`
+	MeshGateway MeshGatewayConfig `json:",omitempty"`
+	ExternalSNI string            `json:",omitempty"`
 	CreateIndex uint64
 	ModifyIndex uint64
 }
@@ -85,8 +85,8 @@ func (s *ServiceConfigEntry) GetModifyIndex() uint64 {
 type ProxyConfigEntry struct {
 	Kind        string
 	Name        string
-	Config      map[string]interface{}
-	MeshGateway MeshGatewayConfig
+	Config      map[string]interface{} `json:",omitempty"`
+	MeshGateway MeshGatewayConfig      `json:",omitempty"`
 	CreateIndex uint64
 	ModifyIndex uint64
 }

api/config_entry_discoverychain.go

@@ -1,12 +1,15 @@
 package api
 
-import "time"
+import (
+	"encoding/json"
+	"time"
+)
 
 type ServiceRouterConfigEntry struct {
 	Kind string
 	Name string
 
-	Routes []ServiceRoute
+	Routes []ServiceRoute `json:",omitempty"`
 
 	CreateIndex uint64
 	ModifyIndex uint64
@@ -64,11 +67,47 @@ type ServiceRouteDestination struct {
 	RetryOnStatusCodes    []uint32      `json:",omitempty"`
 }
 
+func (e *ServiceRouteDestination) MarshalJSON() ([]byte, error) {
+	type Alias ServiceRouteDestination
+	exported := &struct {
+		RequestTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		RequestTimeout: e.RequestTimeout.String(),
+		Alias:          (*Alias)(e),
+	}
+	if e.RequestTimeout == 0 {
+		exported.RequestTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (e *ServiceRouteDestination) UnmarshalJSON(data []byte) error {
+	type Alias ServiceRouteDestination
+	aux := &struct {
+		RequestTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(e),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.RequestTimeout != "" {
+		if e.RequestTimeout, err = time.ParseDuration(aux.RequestTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 type ServiceSplitterConfigEntry struct {
 	Kind string
 	Name string
 
-	Splits []ServiceSplit
+	Splits []ServiceSplit `json:",omitempty"`
 
 	CreateIndex uint64
 	ModifyIndex uint64
@@ -100,6 +139,42 @@ type ServiceResolverConfigEntry struct {
 	ModifyIndex uint64
 }
 
+func (e *ServiceResolverConfigEntry) MarshalJSON() ([]byte, error) {
+	type Alias ServiceResolverConfigEntry
+	exported := &struct {
+		ConnectTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		ConnectTimeout: e.ConnectTimeout.String(),
+		Alias:          (*Alias)(e),
+	}
+	if e.ConnectTimeout == 0 {
+		exported.ConnectTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (e *ServiceResolverConfigEntry) UnmarshalJSON(data []byte) error {
+	type Alias ServiceResolverConfigEntry
+	aux := &struct {
+		ConnectTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(e),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.ConnectTimeout != "" {
+		if e.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (e *ServiceResolverConfigEntry) GetKind() string        { return e.Kind }
 func (e *ServiceResolverConfigEntry) GetName() string        { return e.Name }
 func (e *ServiceResolverConfigEntry) GetCreateIndex() uint64 { return e.CreateIndex }

api/discovery_chain.go

@@ -1,6 +1,7 @@
 package api
 
 import (
+	"encoding/json"
 	"fmt"
 	"time"
 )
@@ -169,6 +170,42 @@ type DiscoveryResolver struct {
 	Failover       *DiscoveryFailover
 }
 
+func (r *DiscoveryResolver) MarshalJSON() ([]byte, error) {
+	type Alias DiscoveryResolver
+	exported := &struct {
+		ConnectTimeout string `json:",omitempty"`
+		*Alias
+	}{
+		ConnectTimeout: r.ConnectTimeout.String(),
+		Alias:          (*Alias)(r),
+	}
+	if r.ConnectTimeout == 0 {
+		exported.ConnectTimeout = ""
+	}
+
+	return json.Marshal(exported)
+}
+
+func (r *DiscoveryResolver) UnmarshalJSON(data []byte) error {
+	type Alias DiscoveryResolver
+	aux := &struct {
+		ConnectTimeout string
+		*Alias
+	}{
+		Alias: (*Alias)(r),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	var err error
+	if aux.ConnectTimeout != "" {
+		if r.ConnectTimeout, err = time.ParseDuration(aux.ConnectTimeout); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // compiled form of ServiceResolverFailover
 type DiscoveryFailover struct {
 	Targets []string