feat(apisixupstream): support discovery (#2577)

Author: AlinsRan

api/adc/types.go

@@ -448,18 +448,28 @@ func (n *UpstreamNodes) UnmarshalJSON(p []byte) error {
 	return nil
 }
 
-// MarshalJSON implements the json.Marshaler interface for UpstreamNodes.
-// By default, Go serializes a nil slice as JSON null. However, for compatibility
-// with APISIX semantics, we want a nil UpstreamNodes to be encoded as an empty
-// array ([]) instead of null. Non-nil slices are marshaled as usual.
-//
-// See APISIX upstream nodes schema definition for details:
-// https://github.com/apache/apisix/blob/77dacda31277a31d6014b4970e36bae2a5c30907/apisix/schema_def.lua#L295-L338
-func (n UpstreamNodes) MarshalJSON() ([]byte, error) {
-	if n == nil {
-		return []byte("[]"), nil
+func (n Upstream) MarshalJSON() ([]byte, error) {
+	type Alias Upstream
+	// APISIX does not allow discovery_type and nodes to exist at the same time.
+	// https://github.com/apache/apisix/blob/01b4b49eb2ba642b337f7a1fbe1894a77942910b/apisix/schema_def.lua#L501-L504
+	if n.DiscoveryType != "" {
+		aux := struct {
+			Alias
+			Nodes UpstreamNodes `json:"nodes,omitempty" yaml:"nodes,omitempty"`
+		}{
+			Alias: (Alias)(n),
+		}
+		aux.Nodes = nil
+		return json.Marshal(&aux)
+	}
+
+	// By default Go serializes a nil slice as JSON null.
+	// For APISIX compatibility, nil UpstreamNodes should be encoded as [] instead.
+	// https://github.com/apache/apisix/blob/77dacda31277a31d6014b4970e36bae2a5c30907/apisix/schema_def.lua#L295-L338
+	if n.Nodes == nil {
+		n.Nodes = UpstreamNodes{}
 	}
-	return json.Marshal([]UpstreamNode(n))
+	return json.Marshal((Alias)(n))
 }
 
 // ComposeRouteName uses namespace, name and rule name to compose
@@ -571,8 +581,7 @@ func NewDefaultUpstream() *Upstream {
 				"managed-by": "apisix-ingress-controller",
 			},
 		},
-		Nodes: make(UpstreamNodes, 0),
-		Type:  Roundrobin,
+		Type: Roundrobin,
 	}
 }
 

api/v2/apisixupstream_types.go

@@ -150,7 +150,6 @@ type ApisixUpstreamConfig struct {
 	UpstreamHost string `json:"upstreamHost,omitempty" yaml:"upstreamHost,omitempty"`
 
 	// Discovery configures service discovery for the upstream.
-	// Deprecated: no longer supported in standalone mode.
 	// +kubebuilder:validation:Optional
 	Discovery *Discovery `json:"discovery,omitempty" yaml:"discovery,omitempty"`
 }

config/crd/bases/apisix.apache.org_apisixupstreams.yaml

@@ -42,9 +42,7 @@ spec:
             description: ApisixUpstreamSpec defines the upstream configuration.
             properties:
               discovery:
-                description: |-
-                  Discovery configures service discovery for the upstream.
-                  Deprecated: no longer supported in standalone mode.
+                description: Discovery configures service discovery for the upstream.
                 properties:
                   args:
                     additionalProperties:
@@ -337,9 +335,8 @@ spec:
                     them if they are set on the port level.
                   properties:
                     discovery:
-                      description: |-
-                        Discovery configures service discovery for the upstream.
-                        Deprecated: no longer supported in standalone mode.
+                      description: Discovery configures service discovery for the
+                        upstream.
                       properties:
                         args:
                           additionalProperties:

docs/en/latest/reference/api-reference.md

@@ -1325,7 +1325,7 @@ ApisixUpstreamConfig defines configuration for upstream services.
 | `subsets` _[ApisixUpstreamSubset](#apisixupstreamsubset) array_ | Subsets defines labeled subsets of service endpoints, typically used for service versioning or canary deployments. |
 | `passHost` _string_ | PassHost configures how the host header should be determined when a request is forwarded to the upstream. Default is `pass`. Can be `pass`, `node` or `rewrite`:<br /> • `pass`: preserve the original Host header<br /> • `node`: use the upstream node’s host<br /> • `rewrite`: set to a custom host via upstreamHost |
 | `upstreamHost` _string_ | UpstreamHost sets a custom Host header when passHost is set to `rewrite`. |
-| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. Deprecated: no longer supported in standalone mode. |
+| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. |
 
 
 _Appears in:_
@@ -1385,7 +1385,7 @@ definitions and custom configuration.
 | `subsets` _[ApisixUpstreamSubset](#apisixupstreamsubset) array_ | Subsets defines labeled subsets of service endpoints, typically used for service versioning or canary deployments. |
 | `passHost` _string_ | PassHost configures how the host header should be determined when a request is forwarded to the upstream. Default is `pass`. Can be `pass`, `node` or `rewrite`:<br /> • `pass`: preserve the original Host header<br /> • `node`: use the upstream node’s host<br /> • `rewrite`: set to a custom host via upstreamHost |
 | `upstreamHost` _string_ | UpstreamHost sets a custom Host header when passHost is set to `rewrite`. |
-| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. Deprecated: no longer supported in standalone mode. |
+| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. |
 | `portLevelSettings` _[PortLevelSettings](#portlevelsettings) array_ | PortLevelSettings allows fine-grained upstream configuration for specific ports, useful when a backend service exposes multiple ports with different behaviors or protocols. |
 
 
@@ -1555,7 +1555,7 @@ them if they are set on the port level.
 | `subsets` _[ApisixUpstreamSubset](#apisixupstreamsubset) array_ | Subsets defines labeled subsets of service endpoints, typically used for service versioning or canary deployments. |
 | `passHost` _string_ | PassHost configures how the host header should be determined when a request is forwarded to the upstream. Default is `pass`. Can be `pass`, `node` or `rewrite`:<br /> • `pass`: preserve the original Host header<br /> • `node`: use the upstream node’s host<br /> • `rewrite`: set to a custom host via upstreamHost |
 | `upstreamHost` _string_ | UpstreamHost sets a custom Host header when passHost is set to `rewrite`. |
-| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. Deprecated: no longer supported in standalone mode. |
+| `discovery` _[Discovery](#discovery)_ | Discovery configures service discovery for the upstream. |
 | `port` _integer_ | Port is a Kubernetes Service port. |
 
 

docs/en/latest/upgrade-guide.md

@@ -138,14 +138,6 @@ spec:
 
 ### API Changes
 
-#### `ApisixUpstream`
-
-Due to current limitations in the [ADC](https://github.com/api7/adc) component, the following fields are not yet supported:
-
-* `spec.discovery`: Service Discovery
-
-More details: [ADC Backend Differences](https://github.com/api7/adc/blob/2449ca81e3c61169f8c1e59efb4c1173a766bce2/libs/backend-apisix-standalone/README.md#differences-in-upstream)
-
 #### `ApisixClusterConfig`
 
 The `ApisixClusterConfig` CRD has been removed in 2.0.0. global rules and configurations should now be managed through the `ApisixGlobalRule` CRDs.

internal/adc/translator/apisixroute.go

@@ -271,7 +271,7 @@ func (t *Translator) buildUpstream(tctx *provider.TranslateContext, service *adc
 	}
 
 	// no valid upstream
-	if len(upstreams) == 0 || len(upstreams[0].Nodes) == 0 {
+	if len(upstreams) == 0 {
 		return
 	}
 

internal/adc/translator/apisixupstream.go

@@ -21,7 +21,9 @@ import (
 	"cmp"
 	"fmt"
 
+	"github.com/api7/gopkg/pkg/log"
 	"github.com/pkg/errors"
+	"go.uber.org/zap"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/types"
 
@@ -40,6 +42,7 @@ func (t *Translator) translateApisixUpstream(tctx *provider.TranslateContext, au
 		translateApisixUpstreamRetriesAndTimeout,
 		translateApisixUpstreamPassHost,
 		translateUpstreamHealthCheck,
+		translateUpstreamDiscovery,
 	} {
 		if err = f(au, ups); err != nil {
 			return
@@ -54,6 +57,8 @@ func (t *Translator) translateApisixUpstream(tctx *provider.TranslateContext, au
 		}
 	}
 
+	log.Debugw("translated ApisixUpstream", zap.Any("upstream", ups),
+		zap.String("namespace", au.Namespace), zap.String("name", au.Name))
 	return
 }
 
@@ -340,3 +345,14 @@ func translateUpstreamPassiveHealthCheck(config *apiv2.PassiveHealthCheck) *adc.
 	}
 	return &passive
 }
+
+func translateUpstreamDiscovery(au *apiv2.ApisixUpstream, ups *adc.Upstream) error {
+	discovery := au.Spec.Discovery
+	if discovery == nil {
+		return nil
+	}
+	ups.ServiceName = discovery.ServiceName
+	ups.DiscoveryType = discovery.Type
+	ups.DiscoveryArgs = discovery.Args
+	return nil
+}

test/e2e/crds/v2/upstream.go

@@ -135,4 +135,51 @@ spec:
 			}
 		})
 	})
+
+	Context("external service discovery", func() {
+		ar := `
+apiVersion: apisix.apache.org/v2
+kind: ApisixRoute
+metadata:
+  name: httpbin-route
+spec:
+  ingressClassName: %s
+  http:
+  - name: rule1
+    match:
+      hosts:
+      - httpbin.org
+      paths:
+        - /*
+    upstreams:
+    - name: httpbin-dns
+`
+
+		au := `
+apiVersion: apisix.apache.org/v2
+kind: ApisixUpstream
+metadata:
+  name: httpbin-dns
+spec:
+  ingressClassName: %s
+  discovery:
+    type: dns
+    serviceName: %s
+`
+
+		It("should be able to access through service discovery", func() {
+			svcName := fmt.Sprintf("httpbin-service-e2e-test.%s.svc.cluster.local", s.Namespace())
+			applier.MustApplyAPIv2(types.NamespacedName{Namespace: s.Namespace(), Name: "httpbin-dns"},
+				&apiv2.ApisixUpstream{}, fmt.Sprintf(au, s.Namespace(), svcName))
+			applier.MustApplyAPIv2(types.NamespacedName{Namespace: s.Namespace(), Name: "httpbin-route"},
+				&apiv2.ApisixRoute{}, fmt.Sprintf(ar, s.Namespace()))
+
+			s.RequestAssert(&scaffold.RequestAssert{
+				Method: "GET",
+				Path:   "/ip",
+				Host:   "httpbin.org",
+				Check:  scaffold.WithExpectedStatus(200),
+			})
+		})
+	})
 })

test/e2e/framework/manifests/apisix-standalone.yaml

@@ -42,6 +42,11 @@ data:
           - 9100
         udp:                        # UDP proxy port list
           - 9200
+    discovery:
+      dns:
+        servers:
+        - "10.96.0.10:53"        # use the real address of your dns server.
+                                 # currently we use KIND as the standard test environment, so here we can hard-code the default DNS address first.
 ---
 apiVersion: apps/v1
 kind: Deployment

test/e2e/framework/manifests/apisix.yaml

@@ -49,6 +49,11 @@ data:
           - 9100
         udp:                        # UDP proxy port list
           - 9200
+    discovery:
+      dns:
+        servers:
+        - "10.96.0.10:53"        # use the real address of your dns server.
+                                 # currently we use KIND as the standard test environment, so here we can hard-code the default DNS address first.
 ---
 apiVersion: apps/v1
 kind: Deployment