NET-5824 Exported services api (#20015)

* Exported services api implemented

* Tests added, refactored code

* Adding server tests

* changelog added

* Proto gen added

* Adding codegen changes

* changing url, response object

* Fixing lint error by having namespace and partition directly

* Tests changes

* refactoring tests

* Simplified uniqueness logic for exported services, sorted the response in order of service name

* Fix lint errors, refactored code

.changelog/20015.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+api: add a new api(/v1/exported-services) to list all the exported service and their consumers. 
+```

agent/agent.go

@@ -76,6 +76,7 @@ import (
 	"github.com/hashicorp/consul/lib/routine"
 	"github.com/hashicorp/consul/logging"
 	"github.com/hashicorp/consul/proto-public/pbresource"
+	"github.com/hashicorp/consul/proto/private/pbconfigentry"
 	"github.com/hashicorp/consul/proto/private/pboperator"
 	"github.com/hashicorp/consul/proto/private/pbpeering"
 	"github.com/hashicorp/consul/tlsutil"
@@ -403,8 +404,9 @@ type Agent struct {
 
 	// TODO: pass directly to HTTPHandlers and DNSServer once those are passed
 	// into Agent, which will allow us to remove this field.
-	rpcClientHealth      *health.Client
-	rpcClientConfigEntry *configentry.Client
+	rpcClientHealth       *health.Client
+	rpcClientConfigEntry  *configentry.Client
+	grpcClientConfigEntry pbconfigentry.ConfigEntryServiceClient
 
 	rpcClientPeering pbpeering.PeeringServiceClient
 
@@ -507,6 +509,7 @@ func New(bd BaseDeps) (*Agent, error) {
 
 	a.rpcClientPeering = pbpeering.NewPeeringServiceClient(conn)
 	a.rpcClientOperator = pboperator.NewOperatorServiceClient(conn)
+	a.grpcClientConfigEntry = pbconfigentry.NewConfigEntryServiceClient(conn)
 
 	a.serviceManager = NewServiceManager(&a)
 	a.rpcClientConfigEntry = &configentry.Client{

agent/config_endpoint.go

@@ -10,7 +10,12 @@ import (
 	"strings"
 
 	"github.com/hashicorp/consul/acl"
+	external "github.com/hashicorp/consul/agent/grpc-external"
 	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/proto/private/pbconfigentry"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
 )
 
 const ConfigEntryNotFoundErr string = "Config entry not found"
@@ -176,3 +181,45 @@ func (s *HTTPHandlers) parseEntMetaForConfigEntryKind(kind string, req *http.Req
 	}
 	return s.parseEntMetaNoWildcard(req, entMeta)
 }
+
+// ExportedServices returns all the exported services by resolving wildcards and sameness groups
+// in the exported services configuration entry
+func (s *HTTPHandlers) ExportedServices(resp http.ResponseWriter, req *http.Request) (interface{}, error) {
+	var entMeta acl.EnterpriseMeta
+	if err := s.parseEntMetaPartition(req, &entMeta); err != nil {
+		return nil, err
+	}
+	args := pbconfigentry.GetResolvedExportedServicesRequest{
+		Partition: entMeta.PartitionOrEmpty(),
+	}
+
+	var dc string
+	options := structs.QueryOptions{}
+	s.parse(resp, req, &dc, &options)
+	ctx, err := external.ContextWithQueryOptions(req.Context(), options)
+	if err != nil {
+		return nil, err
+	}
+
+	var header metadata.MD
+	result, err := s.agent.grpcClientConfigEntry.GetResolvedExportedServices(ctx, &args, grpc.Header(&header))
+	if err != nil {
+		return nil, err
+	}
+
+	meta, err := external.QueryMetaFromGRPCMeta(header)
+	if err != nil {
+		return result.Services, fmt.Errorf("could not convert gRPC metadata to query meta: %w", err)
+	}
+	if err := setMeta(resp, &meta); err != nil {
+		return nil, err
+	}
+
+	svcs := make([]api.ResolvedExportedService, len(result.Services))
+
+	for idx, svc := range result.Services {
+		svcs[idx] = *svc.ToAPI()
+	}
+
+	return svcs, nil
+}

agent/config_endpoint_test.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/hashicorp/consul/acl"
 	"github.com/hashicorp/consul/agent/structs"
+	"github.com/hashicorp/consul/api"
 	"github.com/hashicorp/consul/testrpc"
 )
 
@@ -739,3 +740,84 @@ func TestConfig_Apply_ProxyDefaultsExpose(t *testing.T) {
 		require.Equal(t, expose, entry.Expose)
 	}
 }
+
+func TestConfig_Exported_Services(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	t.Parallel()
+	a := NewTestAgent(t, "")
+	testrpc.WaitForTestAgent(t, a.RPC, "dc1")
+	defer a.Shutdown()
+
+	{
+		// Register exported services
+		args := &structs.ExportedServicesConfigEntry{
+			Name: "default",
+			Services: []structs.ExportedService{
+				{
+					Name: "api",
+					Consumers: []structs.ServiceConsumer{
+						{
+							Peer: "east",
+						},
+						{
+							Peer: "west",
+						},
+					},
+				},
+				{
+					Name: "db",
+					Consumers: []structs.ServiceConsumer{
+						{
+							Peer: "east",
+						},
+					},
+				},
+			},
+		}
+		req := structs.ConfigEntryRequest{
+			Datacenter: "dc1",
+			Entry:      args,
+		}
+		var configOutput bool
+		require.NoError(t, a.RPC(context.Background(), "ConfigEntry.Apply", &req, &configOutput))
+		require.True(t, configOutput)
+	}
+
+	t.Run("exported services", func(t *testing.T) {
+		req, _ := http.NewRequest("GET", "/v1/exported-services", nil)
+		resp := httptest.NewRecorder()
+		raw, err := a.srv.ExportedServices(resp, req)
+		require.NoError(t, err)
+		require.Equal(t, http.StatusOK, resp.Code)
+
+		services, ok := raw.([]api.ResolvedExportedService)
+		require.True(t, ok)
+		require.Len(t, services, 2)
+		assertIndex(t, resp)
+
+		entMeta := acl.DefaultEnterpriseMeta()
+
+		expected := []api.ResolvedExportedService{
+			{
+				Service:   "api",
+				Partition: entMeta.PartitionOrEmpty(),
+				Namespace: entMeta.NamespaceOrEmpty(),
+				Consumers: api.ResolvedConsumers{
+					Peers: []string{"east", "west"},
+				},
+			},
+			{
+				Service:   "db",
+				Partition: entMeta.PartitionOrEmpty(),
+				Namespace: entMeta.NamespaceOrEmpty(),
+				Consumers: api.ResolvedConsumers{
+					Peers: []string{"east"},
+				},
+			},
+		}
+		require.Equal(t, expected, services)
+	})
+}

agent/consul/configentry_backend.go

@@ -0,0 +1,31 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package consul
+
+import (
+	"github.com/hashicorp/consul/acl"
+	"github.com/hashicorp/consul/acl/resolver"
+	"github.com/hashicorp/consul/agent/grpc-external/services/configentry"
+)
+
+type ConfigEntryBackend struct {
+	srv *Server
+}
+
+var _ configentry.Backend = (*ConfigEntryBackend)(nil)
+
+// NewConfigEntryBackend returns a configentry.Backend implementation that is bound to the given server.
+func NewConfigEntryBackend(srv *Server) *ConfigEntryBackend {
+	return &ConfigEntryBackend{
+		srv: srv,
+	}
+}
+
+func (b *ConfigEntryBackend) EnterpriseCheckPartitions(partition string) error {
+	return b.enterpriseCheckPartitions(partition)
+}
+
+func (b *ConfigEntryBackend) ResolveTokenAndDefaultMeta(token string, entMeta *acl.EnterpriseMeta, authzCtx *acl.AuthorizerContext) (resolver.Result, error) {
+	return b.srv.ResolveTokenAndDefaultMeta(token, entMeta, authzCtx)
+}

agent/consul/configentry_backend_ce.go

@@ -0,0 +1,18 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+//go:build !consulent
+
+package consul
+
+import (
+	"fmt"
+	"strings"
+)
+
+func (b *ConfigEntryBackend) enterpriseCheckPartitions(partition string) error {
+	if partition == "" || strings.EqualFold(partition, "default") {
+		return nil
+	}
+	return fmt.Errorf("Partitions are a Consul Enterprise feature")
+}

agent/consul/configentry_backend_ce_test.go

@@ -0,0 +1,87 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+//go:build !consulent
+
+package consul
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	gogrpc "google.golang.org/grpc"
+
+	"github.com/hashicorp/consul/proto/private/pbconfigentry"
+	"github.com/hashicorp/consul/sdk/freeport"
+	"github.com/hashicorp/consul/testrpc"
+)
+
+func TestConfigEntryBackend_RejectsPartition(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	t.Parallel()
+
+	_, s1 := testServerWithConfig(t, func(c *Config) {
+		c.GRPCTLSPort = freeport.GetOne(t)
+	})
+	testrpc.WaitForLeader(t, s1.RPC, "dc1")
+
+	// make a grpc client to dial s1 directly
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	t.Cleanup(cancel)
+
+	conn, err := gogrpc.DialContext(ctx, s1.config.RPCAddr.String(),
+		gogrpc.WithContextDialer(newServerDialer(s1.config.RPCAddr.String())),
+		//nolint:staticcheck
+		gogrpc.WithInsecure(),
+		gogrpc.WithBlock())
+	require.NoError(t, err)
+	t.Cleanup(func() { conn.Close() })
+
+	configEntryClient := pbconfigentry.NewConfigEntryServiceClient(conn)
+
+	req := pbconfigentry.GetResolvedExportedServicesRequest{
+		Partition: "test",
+	}
+	_, err = configEntryClient.GetResolvedExportedServices(ctx, &req)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "Partitions are a Consul Enterprise feature")
+}
+
+func TestConfigEntryBackend_IgnoresDefaultPartition(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	t.Parallel()
+
+	_, s1 := testServerWithConfig(t, func(c *Config) {
+		c.GRPCTLSPort = freeport.GetOne(t)
+	})
+
+	testrpc.WaitForLeader(t, s1.RPC, "dc1")
+
+	// make a grpc client to dial s1 directly
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	t.Cleanup(cancel)
+
+	conn, err := gogrpc.DialContext(ctx, s1.config.RPCAddr.String(),
+		gogrpc.WithContextDialer(newServerDialer(s1.config.RPCAddr.String())),
+		//nolint:staticcheck
+		gogrpc.WithInsecure(),
+		gogrpc.WithBlock())
+	require.NoError(t, err)
+	t.Cleanup(func() { conn.Close() })
+
+	configEntryClient := pbconfigentry.NewConfigEntryServiceClient(conn)
+
+	req := pbconfigentry.GetResolvedExportedServicesRequest{
+		Partition: "DeFaUlT",
+	}
+	_, err = configEntryClient.GetResolvedExportedServices(ctx, &req)
+	require.NoError(t, err)
+}

agent/consul/configentry_backend_test.go

@@ -0,0 +1,49 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: BUSL-1.1
+
+package consul
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/hashicorp/consul/proto/private/pbconfigentry"
+	"github.com/hashicorp/consul/sdk/freeport"
+	"github.com/hashicorp/consul/testrpc"
+	"github.com/stretchr/testify/require"
+	gogrpc "google.golang.org/grpc"
+)
+
+func TestConfigEntryBackend_EmptyPartition(t *testing.T) {
+	if testing.Short() {
+		t.Skip("too slow for testing.Short")
+	}
+
+	t.Parallel()
+
+	_, s1 := testServerWithConfig(t, func(c *Config) {
+		c.GRPCTLSPort = freeport.GetOne(t)
+	})
+	testrpc.WaitForLeader(t, s1.RPC, "dc1")
+
+	// make a grpc client to dial s1 directly
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
+	t.Cleanup(cancel)
+
+	conn, err := gogrpc.DialContext(ctx, s1.config.RPCAddr.String(),
+		gogrpc.WithContextDialer(newServerDialer(s1.config.RPCAddr.String())),
+		//nolint:staticcheck
+		gogrpc.WithInsecure(),
+		gogrpc.WithBlock())
+	require.NoError(t, err)
+	t.Cleanup(func() { conn.Close() })
+
+	configEntryClient := pbconfigentry.NewConfigEntryServiceClient(conn)
+
+	req := pbconfigentry.GetResolvedExportedServicesRequest{
+		Partition: "",
+	}
+	_, err = configEntryClient.GetResolvedExportedServices(ctx, &req)
+	require.NoError(t, err)
+}