implement reference grpc server

Makefile

@@ -3,8 +3,7 @@ CMD_NAME := demo-app # TODO: Update app name
 .PHONY: all test build docker install clean proto check_protoc
 
 VERSION ?= development # Default to "development" if VERSION is not set
-APIVERSION := v1alpha1
+API_DIR := api/
-API_DIR := api/$(APIVERSION)
 PROTO_DIRS := $(wildcard proto/demo/app/*) # TODO: Update path (probably not demo)
 PLATFORMS := linux/amd64 linux/arm64 darwin/amd64 darwin/arm64
 OUTPUT_DIR := bin

config.yaml

@@ -1,21 +1,29 @@
 # yaml-language-server: $schema=contrib/schema.json
 
 # Custom demo-app config
-demoType:
+timezone: EST5EDT
-  optName: demo opt
+opts:
-  optField: 99
+  factLang: en
-demoField: 99
+  factType: random
 
 # go-app config
-name: Demo go-app HTTP App
+name: Demo go-app
 logging:
   format: console
   level: trace
   enabled: true
 otel:
-  enabled: false
+  enabled: true
-grpc:
+  stdoutEnabled: true
-  enabled: false
 http:
   enabled: true
   listen: :8080
+  logRequests: true
+grpc:
+  enabled: true
+  enableReflection: true
+  listen: :8081
+  grpcGatewayPath: /api
+  enableGRPCGateway: true
+  enableInstrumentation: true
+  logRequests: true

contrib/schema.json

@@ -2,10 +2,16 @@
   "definitions": {
     "ConfigDemoOpts": {
       "properties": {
-        "optField": {
+        "factLang": {
-          "type": "integer"
+          "default": "en",
+          "type": "string"
         },
-        "optName": {
+        "factType": {
+          "default": "random",
+          "enum": [
+            "today",
+            "random"
+          ],
           "type": "string"
         }
       },
@@ -104,12 +110,6 @@
     }
   },
   "properties": {
-    "demoField": {
-      "type": "integer"
-    },
-    "demoType": {
-      "$ref": "#/definitions/ConfigDemoOpts"
-    },
     "environment": {
       "type": "string"
     },
@@ -125,9 +125,16 @@
     "name": {
       "type": "string"
     },
+    "opts": {
+      "$ref": "#/definitions/ConfigDemoOpts"
+    },
     "otel": {
       "$ref": "#/definitions/ConfigOTELConfig"
     },
+    "timezone": {
+      "default": "UTC",
+      "type": "string"
+    },
     "version": {
       "type": "string"
     }

go.mod

@@ -4,8 +4,14 @@ go 1.24.1
 
 require (
 	gitea.libretechconsulting.com/rmcguire/go-app v0.9.2
+	github.com/go-resty/resty/v2 v2.16.5
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.3
 	github.com/rs/zerolog v1.34.0
 	golang.org/x/sys v0.31.0
+	google.golang.org/genproto/googleapis/api v0.0.0-20250324211829-b45e905df463
+	google.golang.org/grpc v1.71.0
+	google.golang.org/protobuf v1.36.6
+	k8s.io/utils v0.0.0-20250321185631-1f6e0b77f77e
 )
 
 require (
@@ -35,7 +41,6 @@ require (
 	github.com/go-logr/logr v1.4.2 // indirect
 	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/google/uuid v1.6.0 // indirect
-	github.com/grpc-ecosystem/grpc-gateway/v2 v2.26.3 // indirect
 	github.com/mattn/go-colorable v0.1.14 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
@@ -50,8 +55,5 @@ require (
 	go.opentelemetry.io/proto/otlp v1.5.0 // indirect
 	golang.org/x/net v0.38.0 // indirect
 	golang.org/x/text v0.23.0 // indirect
-	google.golang.org/genproto/googleapis/api v0.0.0-20250324211829-b45e905df463 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250324211829-b45e905df463 // indirect
-	google.golang.org/grpc v1.71.0 // indirect
-	google.golang.org/protobuf v1.36.6 // indirect
 )

go.sum

@@ -24,6 +24,8 @@ github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
 github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
+github.com/go-resty/resty/v2 v2.16.5 h1:hBKqmWrr7uRc3euHVqmh1HTHcKn99Smr7o5spptdhTM=
+github.com/go-resty/resty/v2 v2.16.5/go.mod h1:hkJtXbA2iKHzJheXYvQ8snQES5ZLGKMwQ07xAwp/fiA=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
 github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
@@ -139,3 +141,5 @@ gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntN
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+k8s.io/utils v0.0.0-20250321185631-1f6e0b77f77e h1:KqK5c/ghOm8xkHYhlodbp6i6+r+ChV2vuAuVRdFbLro=
+k8s.io/utils v0.0.0-20250321185631-1f6e0b77f77e/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=

main.go

@@ -20,9 +20,11 @@ import (
 	"golang.org/x/sys/unix"
 
 	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/app"
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
 	optshttp "gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/http/opts"
 
 	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/config"
+	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/demogrpc"
 	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/demohttp"
 )
 
@@ -47,10 +49,15 @@ func main() {
 
 	// Prepare servers
 	demoHTTP := demohttp.NewDemoHTTPServer(ctx, demoApp)
+	demoGRPC := demogrpc.NewDemoGRPCServer(ctx, demoApp)
 
 	// Prepare app
 	app := &app.App{
 		AppContext: ctx,
+		GRPC: &opts.AppGRPC{
+			Services:     demoGRPC.GetServices(),
+			GRPCDialOpts: demoGRPC.GetDialOpts(),
+		},
 		HTTP: &optshttp.AppHTTP{
 			Ctx:          ctx,
 			HealthChecks: demoHTTP.GetHealthCheckFuncs(),

pkg/config/custom.go

@@ -8,8 +8,8 @@ import (
 )
 
 type DemoConfig struct {
-	DemoField int       `yaml:"demoField" json:"demoField,omitempty"`
+	Timezone string    `yaml:"timezone" json:"timezone,omitempty" default:"UTC"`
-	DemoType  *DemoOpts `yaml:"demoType" json:"demoType,omitempty"`
+	Opts     *DemoOpts `yaml:"opts" json:"opts,omitempty"`
 
 	// Embeds go-app config, used by go-app to
 	// merge custom config into go-app config, and to produce
@@ -18,6 +18,13 @@ type DemoConfig struct {
 }
 
 type DemoOpts struct {
-	OptField int    `yaml:"optField" json:"optField,omitempty"`
+	FactLang string   `yaml:"factLang" json:"factLang,omitempty" default:"en"`
-	OptName  string `yaml:"optName" json:"optName,omitempty"`
+	FactType FactType `yaml:"factType" json:"factType,omitempty" default:"random" enum:"today,random"`
 }
+
+type FactType string
+
+const (
+	TypeToday  FactType = "today"
+	TypeRandom FactType = "random"
+)

pkg/demogrpc/demo.go

@@ -0,0 +1,86 @@
+package demogrpc
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/go-resty/resty/v2"
+	"github.com/rs/zerolog"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+
+	grpccodes "google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/otel"
+
+	pb "gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/api/demo/app/v1alpha1"
+	"gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/pkg/config"
+)
+
+const (
+	defaultFactType = config.TypeRandom
+	factsBaseURI    = "https://uselessfacts.jsph.pl/api/v2/facts"
+)
+
+type DemoGRPCServer struct {
+	tracer trace.Tracer
+	ctx    context.Context
+	cfg    *config.DemoConfig
+	client *resty.Client
+	pb.UnimplementedDemoAppServiceServer
+}
+
+func NewDemoGRPCServer(ctx context.Context, cfg *config.DemoConfig) *DemoGRPCServer {
+	if cfg.Opts == nil {
+		cfg.Opts = &config.DemoOpts{}
+	}
+
+	if cfg.Opts.FactType == "" {
+		cfg.Opts.FactType = config.TypeRandom
+	}
+
+	return &DemoGRPCServer{
+		ctx:    ctx,
+		cfg:    cfg,
+		tracer: otel.GetTracer(ctx, "demoGRPCServer"),
+		client: resty.New().SetBaseURL(factsBaseURI),
+	}
+}
+
+func (d *DemoGRPCServer) GetDemo(ctx context.Context, req *pb.GetDemoRequest) (
+	*pb.GetDemoResponse, error,
+) {
+	ctx, span := d.tracer.Start(ctx, "getDemo", trace.WithAttributes(
+		attribute.String("language", req.GetLanguage()),
+	))
+	defer span.End()
+
+	r := d.client.R().SetContext(ctx)
+
+	if req.GetLanguage() != "" {
+		r = r.SetQueryParam("language", req.GetLanguage())
+	}
+
+	fact := new(RandomFact)
+	r.SetResult(fact)
+
+	resp, err := r.Get(fmt.Sprintf("/%s", d.cfg.Opts.FactType))
+	if err != nil {
+		span.SetStatus(codes.Error, err.Error())
+		span.RecordError(err)
+
+		zerolog.Ctx(d.ctx).Err(err).Send()
+
+		return nil, status.Errorf(grpccodes.Unknown, "%s: %s",
+			err.Error(), string(resp.Body()))
+	}
+
+	span.SetAttributes(attribute.String("fact", fact.Text))
+	span.SetStatus(codes.Ok, "")
+
+	zerolog.Ctx(d.ctx).Debug().Str("fact", fact.Text).Msg("retrieved fact")
+
+	return fact.FactToProto(), nil
+}

pkg/demogrpc/fact.go

@@ -0,0 +1,25 @@
+package demogrpc
+
+import (
+	"google.golang.org/protobuf/types/known/timestamppb"
+
+	pb "gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/api/demo/app/v1alpha1"
+)
+
+type RandomFact struct {
+	ID        string `json:"id,omitempty"`
+	Text      string `json:"text,omitempty"`
+	Source    string `json:"source,omitempty"`
+	SourceURL string `json:"source_url,omitempty"`
+	Language  string `json:"language,omitempty"`
+	Permalink string `json:"permalink,omitempty"`
+}
+
+func (f *RandomFact) FactToProto() *pb.GetDemoResponse {
+	return &pb.GetDemoResponse{
+		Timestamp: timestamppb.Now(),
+		Fact:      f.Text,
+		Source:    f.SourceURL,
+		Language:  f.Language,
+	}
+}

pkg/demogrpc/server.go

@@ -0,0 +1,30 @@
+package demogrpc
+
+import (
+	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv/grpc/opts"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+
+	demoAppPb "gitea.libretechconsulting.com/rmcguire/go-http-server-with-otel/api/demo/app/v1alpha1"
+)
+
+func (ds *DemoGRPCServer) GetDialOpts() []grpc.DialOption {
+	return []grpc.DialOption{
+		// NOTE: Necessary for grpc-gateway to connect to grpc server
+		// Update if grpc service has credentials, tls, etc..
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+	}
+}
+
+func (ds *DemoGRPCServer) GetServices() []*opts.GRPCService {
+	return []*opts.GRPCService{
+		{
+			Name:    "Demo App",
+			Type:    &demoAppPb.DemoAppService_ServiceDesc,
+			Service: ds,
+			GwRegistrationFuncs: []opts.GwRegistrationFunc{
+				demoAppPb.RegisterDemoAppServiceHandler,
+			},
+		},
+	}
+}